Until relatively recently, the conventional back squat was the tool of choice for lower body strength development. However, the split squat is now gaining ground and is used by many strength and conditioning coaches.

But what do we actually know about the split squat and how does it compare to the conventional back squat?  Well, there aren’t actually that many studies out there, so this post is a quick round-up of all of them I could track down.

(Too much detail? Skip to the practical implications)

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What’s the background?

The split squat can be performed with the back foot planted on the ground, or with the back foot elevated onto a bench or box. The split squat includes variations known as the Bulgarian (split) squat, the rear foot elevated split squat, and pitcher squat or modified unilateral squat. It is often used by strength and conditioning coaches as a replacement for the conventional back squat.

However, while the conventional back squat has been extensively researched (for references see Schoenfeld, 2010), the split squat has not been subject to the same degree of scrutiny.

The split squat is performed with the legs straddling the body’s center of mass in the sagittal plane. It can be performed with a barbell in the back squat position on the upper trapezius (e.g. McCurdy, 2010),with dumbbells held at arms’ length at the sides or with resistance bands looped under the front foot and over the shoulder (e.g. as lunges performed in Jakobsen, 2012).

As previously mentioned, while it is commonly performed with the rear foot elevated upon a box or bar (e.g. McCurdy, 2010), it can also be performed with the rear foot placed on the ground. With the rear foot placed on a box, McCurdy (2010) found that around 85% of the load was supported by the front foot.

A small number of studies have investigated acute biomechanical variables during split squats, while one study has investigated the chronic effects of a training program involving split squats.

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What have acute studies found?

Reliability of exercise performance

Reliability is an important feature of resistance training exercises if they are to be used to measure progress in any key strength measure. McCurdy (2004) tested the reliability of split squats with elevated rear foot and conventional back squats using the same relative loading (1RM and 3RM loads) in untrained male and female subjects. They found that the average 1RM and 3RM split squat loads were (first attempt/second attempt) 114.6 ± 17.9/121.6 ± 17.7kg and 98.6 ± 21.5/103.0 ± 21.5kg for males respectively and 44.0 ± 9.9/45.76 ± 10.7kg and 35.9 ± 10.4/39.77 ± 10.4kg respectively. The results are shown in the chart below:

The researchers reported that the test-retest measures were highly reliable and the split squat can therefore be used with confidence to assess unilateral lower body strength.

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Differences in split squat strength between dominant and non-dominant legs

A common assumption about unilateral exercise is that the dominant limb will prove stronger than the non-dominant limb. Indeed, some studies have reported differences between dominant and non-dominant limbs in lower body tasks (e.g. Hunter, 2000).

However, McCurdy (2005) investigated the difference in 1RM split squat strength on the dominant and non-dominant legs in untrained males and females. They did not find any significant difference in split squat strength between legs although the dominant leg was non-significantly stronger by a very small margin for both males and females. Male split squat strength was (dominant/non-dominant) 107.0 ± 5.2 and 106.0 ± 5.2kg while female split squat strength was 45.3 ± 2.5/45.0 ± 2.5kg. The results are shown in the chart below:

The chart shows that there was great similarity between the strength of the dominant and non-dominant legs in untrained subjects. Whether this implies that the net joint torques in the active leg are similar when performed by either the dominant or non-dominant legs is uncertain however, as Flanagan (2007) found that net joint torques are not equal on the right and left sides during the conventional back squat exercise.

Further research is therefore required both to confirm the finding of similar strength in the dominant and non-dominant limbs of the split squat in trained subjects and also to ascertain whether the net joint torques are different between sides despite similar loading. However, it is important to note that just because strength is equal between sides, it doesn’t mean that the exact same form is used or that the exact percentage of quadriceps and posterior chain contribution is used.

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Correlations between split squat performance and balance

Some researchers have proposed that lower body strength and balance are closely linked. Fukagawa (1995) reported an independent effect of strength on performance in a balance test performed by nursing home residents. However, performance in the split squat does not appear to correlate with specific balance tasks.

McCurdy (2006) investigated the relationship between 1RM split squat strength and balance ability on the stork stand and computerized wobble board in untrained males and females. They did not find any significant correlations between balance on the computerized wobble board and 1RM split squat strength nor between balance scores on the stork stand and 1RM split squat strength for either the males or females.

Therefore, where balance improvements are required, improving split squat strength may not be beneficial.

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Joint moments

The joint moments of split squats appear to differ from those of conventional back squats. Meyer (2005, unpublished masters thesis) investigated the joint moments in split squats with an elevated rear foot and compared them with the joint moments in conventional back squats in male athletes.

The athletes performed conventional squats with light, moderate and heavy loads (60, 70, and 80% of 1RM) and split squats with light, moderate and heavy loads (20, 25, and 30% of conventional back squat 1RM). Meyer reported that the split squat displayed greater hip extension moments than the conventional back squat with similar relative loading (323 ± 89Nm vs. 288 ± 97Nm).

Additionally, they found that the split squat displayed smaller knee extension moments than the conventional back squat with similar relative loading (118 ± 26Nm vs. 186 ± 30Nm). The results are shown in the chart below:

From these numbers, we can calculate that the hip-to-knee extension moment ratio was higher in split squats than in conventional back squats (1.57 ± 0.53 vs. 2.80 ± 0.71). The split squat is therefore 1.8 times as hip-dominant as the conventional back squat. While the study was unpublished and therefore not peer reviewed, we can gain some comfort regarding the data, as the ratios for the conventional back squat are very similar to those reported by Bryanton (2012), which ranged from 1.2 – 1.5 with similar relative loads.

Consequently, the split squat may be useful to substitute for the conventional back squat where a program requires a greater emphasis on hip-dominant exercises.

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Joint angles

The torso angle during split squats appears to be less than that during conventional back squats. McCurdy (2010) investigated the joint angle movements in female athletes performing a split squat with elevated rear foot and a conventional back squat using the same relative loading (85% of 3RM). They found that peak torso angle during split squats was less than that during conventional back squats (33.68 ± 7.6 degrees vs. 40.65 ± 7.0 degrees).

Meyer (2005, unpublished masters thesis) also investigated joint angles during split squats with an elevated rear foot and conventional back squats and observed that the forward lean of the trunk in the split squat was less than that in the conventional back squat (25 ± 12 degrees vs. 35 ± 6 degrees). The results are shown in the chart below:

Meyer suggested that this difference in torso angle might imply a reduced level of spinal loading. Whether this is the case is uncertain, although when Swinton (2012) investigated the differences between conventional, powerlifting and box squats, they found that the box squat displayed a significantly lower torso angle than the conventional squat (26.9 ± 3.8 degrees vs. 33.5 ± 4.6 degrees) and a concurrently significantly lower L5/S1 moment.

So reduced torso angle may indeed imply reduced lumbar spinal loading. Therefore, the split squat may be useful to substitute for the conventional back squat where reduced lumbar spinal loading is necessary or desirable.

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Force, power and rate of force development

Certain force-related variables are different between jump squats using split squat and conventional back squat techniques. Sleivert (2004) tested jump squat power output in male athletes with both conventional back squat and split-squat techniques. The optimal load for power output between 30 – 70% of 1RM was compared in each case. They found that peak power output and average power output were not significantly different between the conventional back squat and split squat techniques.

However, they did report that peak force was significantly greater during the split squat (19.10 ± 3.25N/kg vs. 14.88 ± 2.22N/kg), peak rate of force development was significantly greater during the split squat (41.10 ± 12.59N/s/kg vs. 33.04 ± 8.74N/s/kg) but peak velocity was significantly lower during the split squat (1.64 ± 0.17m/s vs. 1.97 ± 0.13m/s). They noted that the larger force but smaller velocity during the split squat resulted in similar power outputs for both squat techniques at the optimal load for power (albeit measurements were only taken between 30 – 70% of 1RM).

Whether such differences exist similarly between the split squat and conventional back squat as well as between jump squats performed with split squat and conventional back squat techniques is unclear, however.

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EMG activity

The research is conflicting whether there are any significant differences in respect of EMG activity during split squats and conventional back squats. McCurdy (2010) investigated the EMG activity of gluteus medius, hamstrings, and quadriceps in female athletes performing a split squat with elevated rear foot and a conventional back squat using the same relative loading (85% of 3RM). They found that gluteus medius and hamstring EMG activity were significantly higher during the split squat than during the conventional back squat while quadriceps EMG activity was significantly higher during the conventional back squat than during the split squat.

However, Jones (2012) measured the EMG activity of the biceps femoris, erector spinae, gluteus medius and vastus lateralis in male resistance-trained athletes performing a split squat with elevated rear foot and a conventional back squat using the same relative loading (10RM). They did not discern any differences in EMG activity between the two exercises.

McCurdy (2010b) also investigated the EMG activity of the external obliques in female athletes performing a split squat with elevated rear foot and a conventional back squat using the same relative loading (85% of 3RM). They found that the EMG activity of the external obliques was non-significantly higher for the split squat.

These findings suggest that the split squat can likely be substituted for the conventional back squat for developing lower body strength similarly across the various leg muscles with the proviso that the hamstrings may be stressed more effectively and the quadriceps less effectively during split squats. However, future research is required to confirm this finding.

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Hormonal response to exercise

Resistance training can alter the levels of endocrine hormones post-exercise, especially after workouts designed for hypertrophy. This observation led to what has become known as the hormone hypothesis. The hormone hypothesis proposes that acute post-exercise hormonal secretions assist in the process of muscular hypertrophy. However, while this hypothesis received strong support for a number of years, it was recently been called into question (see further Schoenfeld, 2013).

Migiano (2010) found that neither unilateral nor bilateral upper body resistance training was able to produce a post-exercise increase in anabolic hormones, while it was known from Linnamo (2005) that incorporating lower body bilateral exercise into a workout produced a post-exercise increase in anabolic hormones. Therefore, it has been suggested that unilateral lower body resistance training might fail to produce a post-exercise rise in hormones in the same way as upper body exercise.

However, Jones (2012) measured testosterone concentrations in male resistance-trained athletes after workouts in which they performed either split squats with elevated rear foot or conventional back squats using the same relative loading and set/rep scheme (4 sets of 10RM with 90 seconds rest between sets). They found that testosterone concentrations rose post-exercise similarly following both split squat and conventional back squat workouts.

To the extent that the hormone hypothesis is supported, split squats and conventional back squats are therefore likely to have similar beneficial effects on post-exercise hormonal milieu.

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What do chronic studies tell us?

McCurdy (2005) compared two 8-week resistance training programs in which untrained subjects performed either bilateral or unilateral squat training 2 days per week. The bilateral group performed conventional back squats and front squats and the unilateral group performed split squats with rear foot elevated, lunges and step-ups.

Both groups performed similar loading and volume protocols. There was no significant difference in either the improvement in the conventional back squat or the improvement in the split squat between groups, suggesting that both exercises are suitable for improving both bilateral and unilateral lower body strength.

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What are the practical implications?

For strength and conditioning coaches:

Since the test-retest measures of the split squat have been reported to be highly reliable, the split squat can be used with confidence to assess lower body strength.

For everyone resistance training:

Since the results of EMG studies indicate that there is little difference between the split squat and conventional back squat, the split squat can be substituted for the conventional back squat for developing lower body strength.

The split squat may involve a greater ratio of hip-to-knee moments, greater hamstring EMG activity and less quadriceps EMG activity. It may therefore be useful to substitute for the conventional back squat where a program requires a greater emphasis on hip-dominant exercises.

The split squat involves a lower torso angle. Lower torso angles during squats are associated with reduced lumbar spinal moments. Therefore, the split squat may be useful to substitute for the conventional back squat where reduced lumbar spinal loading is desirable.

Since testosterone concentrations rise post-exercise similarly following both split squat and conventional back squat workouts, both types of squats are therefore likely to have similar beneficial effects on post-exercise hormonal milieu and consequent hypertrophy.

For powerlifters:

For powerlifters, it is critical to note that the back squat is both a training tool and the event itself. Specificity and event practice are therefore important here. So while split squats may be useful as assistance work for some powerlifters, it is highly unlikely that the split squat would be able to replace conventional back squats in a powerlifting program.

Many EMG studies have shown how the hamstrings are not particularly active during back squats (e.g. Ebben, 2009, Wright, 1999, McCaw, 1998 and Paoli, 2009). Since EMG activity is regarded as being a good indicator of how hard a muscle is working, this suggests that the back squat is not the best choice of exercise for hamstring development.

However, does stance width affect how hard the hamstrings work during squats?  This study attempted to find out.

The study: Stance width and bar load effects on leg muscle activity during the parallel squat, by McCaw and Melrose, Medicine & Science in Sports & Exercise, 1998

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What is the background?

At the time the researchers were performing their study, the predominant question regarding stance width had been posed by bodybuilders. The main question was not whether there was a difference in hamstring activity but whether there was a difference in the activity levels of the individual quadriceps muscles.

In fact, claims were being made in various bodybuilding magazines that stance width could be manipulated to develop different parts of the quadriceps musculature to varying extents.

Specifically, it was believed that a wider stance would activate the adductors and vastus medialis to a greater extent, while a narrower stance would activate the vastus lateralis more. However, at the time these claims were being made, no studies had been previously performed to assess whether this was in fact the case.

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What did the researchers do?

The researchers wanted to investigate the EMG activity of the rectus femoris, vastus medialis, vastus lateralis, adductor longus, biceps femoris and gluteus maximus during squats of different stances widths. They therefore recruited 9 trained males who had 7 ± 2 years of resistance training experience. Their 1RM squat ranged from 118 – 250kg.

The researchers used surface electrodes to measure the EMG activity in these muscles while the subjects performed squats with 60% and 75% of their 1RM. The subjects performed squats for each load with three different stance widths: narrow (75% of shoulder width), moderate (shoulder width) and wide (140% of shoulder width). The subjects were allowed to choose their own foot position (i.e. degree of hip rotation) according to what was most comfortable.

The researchers did not normalize the EMG of each muscle during the squats to a maximum voluntary isometric contraction (MVIC). Normalizing muscle activity to an MVIC allows researchers to see how hard a muscle is working relative to its maximum capacity. Rather, they simply recorded the value in millivolts (mV). This has a specific disadvantage.

Some muscle groups are covered more by fat than others and this can lead to greater impedance when testing those muscles, which leads to lower EMG values. Hence, looking at the voltage (mV) alone doesn’t really give us sufficient information to draw strong conclusions about the relative EMG activity of the various muscles. However, the EMG activity of the same muscles in different conditions (stance widths) can be compared.

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What happened?

With 60% of 1RM load

The researchers found that there was no significant difference between the EMG activity of during wide, medium and narrow stance squats of any of the muscles, as the following chart shows:

Additionally, the chart shows that at 60% of 1RM, there is not even any kind of trend to indicate that there might have been a significant effect if more subjects had been tested. Moreover, although the EMG activity levels were not normalized, it is instructive to note how much larger the EMG activity levels of the quadriceps muscles are in comparison with the hamstrings and gluteus maximus.

With 75% of 1RM load

The researchers found that there was no significant difference between the EMG activity of during wide, medium and narrow stance squats of any of the muscles except the gluteus maximus, as the following chart shows:

Specifically, the researchers found that, at 75% of 1RM, the activity of the gluteus maximus was significantly greater in the wide stance condition than in the narrow stance condition. However, there was no significant difference between the wide and moderate stance conditions nor between the moderate and narrow stance conditions.

This difference in EMG activity with stance width is likely because the gluteus maximus appears to be more active when at a shorter length than when at a longer length, as a number of studies have shown. A wider stance moves the hip into greater degree of abduction, which shortens the gluteus maximus. It also typically externally rotates the hip somewhat, which also causes the muscle to shorten.

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Exploring the findings of other studies

The findings of this study are supported by a similar study performed by Paoli (2009), in which the researchers tested the EMG activity of the vastus medialis, vastus lateralis, rectus femoris, semitendinosus, biceps femoris, gluteus maximus, gluteus medius and adductor magnus in a group of 6 trained male subjects with 3 years of resistance training experience.

The researchers tested three stance widths (100, 150, and 200% of great trochanter distance) and three loads (0, 30 and 70% of 1RM). At 70% of 1RM, the researchers found that only the gluteus maximus displayed a significantly different degree of EMG activity between the stance widths, in that the wider stance again showed a greater degree of EMG activity than the narrower stance. The following chart shows the results:

Again, although the EMG activity levels were not normalized, it is instructive to note how much larger the EMG activity levels of the quadriceps muscles are in comparison with the hamstrings and gluteus maximus.

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What did the researchers conclude?

The researchers concluded that stance width does not affect the degree of muscular recruitment of the quadriceps or hamstrings during the back squat. However, they noted that a greater stance width does lead to increased gluteus maximus activity.

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What are the limitations?

As noted above, the study was limited in that it did not normalize the EMG of each muscle during the squats to a maximum voluntary isometric contraction (MVIC). Rather, they simply recorded the value in millivolts (mV). This has a specific disadvantage. Some muscle groups are covered more by fat than others and this can lead to greater impedance when testing those muscles, which leads to lower EMG values. Hence, looking at the voltage (mV) alone doesn’t really give us sufficient information to draw strong conclusions about the relative EMG activity of the various muscles.

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What are the practical implications?

For bodybuilders and physique athletes

Using different stance widths during squats is unlikely to develop different parts of the quadriceps preferentially. Stressing individual quadriceps muscles may therefore require other exercises.

Using a wider stance may help to increase gluteus maximus activity during squats. This may make the squat more useful as a way of strengthening the gluteus maximus.

For powerlifters

Using a wider stance may prove useful for powerlifters to make better use of the gluteus maximus during squats.

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The May 2013 edition of the monthly Strength and Conditioning Research review service came out last week. If you want to pick up a copy, you can buy it here. There are some very interesting studies on foam rolling that we cover in detail.

In this round-up, I’ve covered two of them. And as an added bonus, I’ve also added a third study from an older edition of the review that covers some similar ground. So if you were looking to read up on foam rolling, this is the place to be.

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What effect does foam rolling have on arterial function?

The study: Acute Effects of Self-Myofascial Release Using a Foam Roller on Arterial Function, by Okamoto, Masuhara and Ikuta, in Journal of Strength and Conditioning Research Publish Ahead of Print

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What’s the background?

Having stiffer arteries is a risk factor for a cardiovascular event, possibly because they result in an increase in systolic blood pressure. The stiffness of arteries is affected by vascular endothelial function. Vascular endothelial cells regulate vascular activity through the release of vasoactive substances including the well-known nitric oxide (NO).

Although self-myofascial release with a foam roller is a popular treatment for muscle soreness and fascial tightness, its effect on arterial stiffness and vascular endothelial function is unclear. The stiffness of arteries can be determined using pulse wave velocity.

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What did the researchers do?

The researchers wanted to explore the acute effect of self-myofascial release with a foam roller on arterial stiffness and vascular endothelial function, as measured using pulse wave velocity. They therefore recruited 10 healthy but sedentary subjects (7 males and 3 females).

There were two conditions: self-myofascial release with a foam roller and a control condition. In the self-myofascial release condition, the subjects rolled the adductors, hamstrings, quadriceps, iliotibial band and upper back including the trapezius.

All subjects performed both conditions on separate days in a randomized, cross-over design. The two conditions were performed at least 3 days apart. The researchers measured brachial-ankle pulse wave velocity and plasma NO concentrations both before and 30 minutes after both conditions. The measurements were taken following 30 minutes in which the subject rested supine.

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What happened?

Effect on pulse wave velocity

The researchers found that brachial-ankle pulse wave velocity significantly decreased after the self-myofascial release with a foam roller condition (from 1202 ± 105 to 1073 ± 106 cm/s). However, they noted that brachial-ankle pulse wave velocity did not change following the control condition (from 1198 ± 118 to 1184 ± 105 cm/s). The researchers noted that the difference between these two conditions was significant. The following chart shows these results:

Effect on plasma NO concentration

The researchers found that plasma NO concentrations significantly increased after the self-myofascial release with a foam roller condition (from 20.4 ± 6.9 to 34.4 ± 17.2 μmol/L). However, they noted that the plasma NO concentrations did not change significantly after the control condition (from 19.1 ± 4.3 to 17.5 ± 4.7 μmol/L). The following chart shows these results:

What did the researchers conclude?

The researchers concluded that after self-myofascial release with a foam roller, arterial stiffness (as measured by pulse wave velocity) decreased acutely and the plasma NO concentrations significantly increased. They therefore propose that self-myofascial release with a foam roller is able to reduce arterial stiffness, improve arterial function and improve vascular endothelial function in sedentary subjects. They suggest it may therefore be a useful tool for improving cardiovascular health in the general population.

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What were the limitations?

The study was limited in that it only reviewed an acute effect of self-myofascial release with a foam roller and only compared it to no treatment. Further acute trials in which the treatment was compared with stretching or low-level exercise would be useful, as these may not display the same differences.

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What are the practical implications?

For the general population

Foam rolling may have health implications in respect of arterial stiffness and vascular endothelial function. While much further research is needed to demonstrate the chronic effects, there could be a place for foam rolling in fitness programs for the general population simply for health reasons.

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What effect does foam rolling have on performance?

The study: The Effects of Myofascial Release with Foam Rolling on Performance, by Healey, Hatfield, Blanpied, Dorfman and Riebe, in Journal of Strength and Conditioning Research Publish Ahead of Print

What’s the background?

Many athletes now make use of self-myofascial release techniques, such as foam rolling, prior to practice or training sessions. Moreover, foam rollers are now commonly found in commercial gyms as well as in high school and collegiate strength and conditioning facilities. However, whether the use of foam rolling is beneficial for increasing the volume or intensity of work that can be performed in a consequent training or practice session is unclear.

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What did the researchers do?

The researchers wanted to investigate whether self-myofascial release using a foam roller was able to enhance athletic performance acutely in comparison with a control condition. The researchers therefore recruited 26 recreationally active, college-aged subjects (13 males and 13 females) for the trial, which involved two conditions: foam rolling and a control. All subjects completed both conditions on separate days in a randomized, crossover design. The two testing days were separated by 5 days to avoid any interactions between trials.

The foam rolling was performed over the lower extremities and back, including the quadriceps, hamstrings, iliotibial band, calves, latissimus dorsi and rhomboids for 30 seconds on each muscle. Rather than use no activity as a control, the researchers decided to replicate the foam rolling position closely but without the self-myofascial release effect. They therefore chose to use planking for 30 seconds as the control, in that it involves holding a similar position isometrically.

Before and after each trial, the researchers also took measurements of muscle soreness, fatigue and perceived exertion. Additionally, they measured performance after each trial in 3 different tests: isometric quarter squat force in a Smith machine squat bar using a force plate, counter-movement jump height and power using a force plate, and agility using the 5-10-5 yard shuttle run.

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What happened?

Athletic tests

The researchers reported that there were no significant differences between the foam rolling and planking conditions for all of the athletic tests.

Measurements of fatigue, soreness, and exertion

The researchers reported that there were significant differences in respect of fatigue either side of each exercise trial. They noted that fatigue was significantly greater after the planking than after the foam rolling.

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What did the researchers conclude?

The researchers concluded that foam rolling on the lower-limbs and back had no effect on performance in comparison with planking. The researchers also concluded that the planking produced more fatigue than the foam rolling. The researchers therefore propose that this indicates that the use of a foam roller prior to exercise does not improve athletic performance.

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What were the limitations?

The study was limited in that foam rolling may be beneficial for other purposes other than acute performance enhancement and therefore it is unclear from this study whether foam rolling is still a useful tool for athletes or for the general population. Additionally, while the subjects used in this study were recreationally active, they were not trained and different results might be observed in trained subjects.

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What are the practical implications?

For athletes

Foam rolling prior to a workout should not be performed in the belief that this will lead to greater volumes or intensities of work. However, foam rolling can still be performed for other reasons, such as to increase range of motion acutely for a specific purpose, such as a key barbell exercise.

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Does foam rolling increase joint range of motion?

The study: An Acute Bout of Self Myofascial Release Increases Range of Motion Without a Subsequent Decrease in Muscle Activation or Force, by MacDonald, Penney, Mullaley, Cuconato, Drake, Behm and Button, in Journal of Strength and Conditioning Research, 2012

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What is the background?

At the time this study was published, very little research had been done on self-myofascial release. The only study performed prior to this one in relation to changes in ROM found that a foam-rolling program was not effective.

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What did the researchers do?

The researchers wanted to establish whether self-myofascial release using a foam roller would affect knee joint ROM, voluntary and involuntary muscular force, rate of force development and EMG activity. The reason for assessing muscular force is that stretching interventions prior to exercise have been found to lead to acute reductions in force production. Therefore, if self-myofascial release is able to increase ROM without the same reductions in force, this could be an interesting development.

For the study, the researchers recruited 11 male subjects from a university and had them perform each experimental condition over 4 sessions, with 24 – 48 hours rest between sessions.  The first two conditions were controls and the second two conditions used the foam roller. During the foam roller conditions, the subjects performed self-myofascial release on the right quadriceps for two bouts lasting 1-minute with 1 minute of rest between each bout.

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What happened?

Quadriceps strength

The researchers found no significant differences in muscle force, rate of force development or muscular activation between the control and foam roller conditions.

Knee joint ROM

The researchers found that there was a significant difference in knee joint ROM between the control and foam roller conditions. They found that using the foam roller led to an increase of around 10 degrees more ROM than the control. The following chart shows the difference in knee joint ROM:

What did the researchers conclude?

The researchers concluded that two 1-minute bouts of foam rolling significantly increased joint ROM but did not impede the production of muscular force or rate of force development.

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What are the limitations?

This study was limited in that there is very little literature with which to compare it.  Consequently, while the protocol used of two sets of 1-minute (for example) was effective at increasing joint ROM, this does not imply that this is the most effective protocol, simply that it is effective. Moreover, while it is assumed that static stretching would lead to a reduction in force production when used in the same manner to produce a similar improvement in knee joint ROM, the researchers did not test this and therefore it is not certain.

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What are the practical implications?

For athletes

Foam rolling significantly increases joint ROM acutely and does not impede the production of muscular force or rate of force development.

In many ways, the increasing popularity of powerlifting methods for improving strength has led to a much more technical approach to strength and conditioning. Most obviously, prominent powerlifting groups have popularized extremely detailed linear and undulating periodization models as well as accommodating resistance for improving rate of force development. Such developments are obviously very welcome and have clearly improved strength- and power-related athletic ability in a number of team sports.

However, not everything that is associated with the use of powerlifting methods necessarily stands up to investigation. One popular belief in some powerlifting groups is that the hamstrings are very active during the conventional back squat. Unfortunately, the research suggests that this is not the case. Let’s take a quick look at two studies that show just how active the hamstrings are in comparison with other leg muscles in the squat.

The study: Hamstring Activation During Lower Body Resistance Training Exercises, By Ebben, in International Journal of Sports Physiology and Performance, 2009

(Too much detail? Skip to the practical implications)

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What’s the background?

One of the main reasons that sports scientists are so interested in the hamstrings is that they are one of the most frequently injured muscle groups, representing up to around 25% of all athletic injuries depending on the type of sport.

Some researchers have proposed that such injuries might arise because of hamstring weakness and indeed some studies have found that weaker hamstrings or lower hamstring-to-quadriceps strength ratios might predispose athletes to hamstring strain injury.

Anterior cruciate ligament (ACL) injuries are also very common, particularly among female athletes. Again, researchers have suggested that athletes might be predisposed to ACL injury where they have a low hamstring-to-quadriceps strength ratio.

For these reasons, researchers have explored which resistance training exercises might lead to the greatest levels of hamstring activation, as it is generally believed that exercises involving higher levels of muscular activity lead to greater hypertrophy.

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What did the researchers do?

The researchers wanted to identify the exercises that maximally activate the hamstrings.  They also wanted to determine the activation ratios between the quadriceps and hamstrings muscles during those exercises. For subjects, they recruited 34 athletes (21 men and 13 women) who were in the NCAA Division-I or Division-III.

First of all, the subjects performed a maximum voluntary isometric contraction (MVIC) at 60 degrees of knee flexion for both the hamstrings and the quadriceps.  Next, the subjects tested their 6RM on the squat, seated leg curl, stiff leg dead lift, single leg stiff leg dead lift, good morning, and Russian curl. The Russian curl is a natural glute-ham raise with added weight where possible.

After carrying out these tests, the subjects rested for c. 72 hours, before returning to perform two full range-of-motion (ROM) repetitions using their 6RM loads with 5 minutes rest between exercises.  While the subjects performed the exercises, the researchers recorded EMG activity using surface electrodes.

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What happened?

Hamstring activation

The researchers found significant differences in hamstring activation between exercises.  The following chart shows the different activity produced by each exercise.

The researchers found that the Russian curl was the most effective exercise for activating the hamstrings, while the squat was the least effective.

Hamstring to quadriceps ratio

The researchers found that the various exercises produced very different ratios of hamstring-to-quadriceps activity, as the following chart shows:

What is slightly misleading about the above chart is that you might assume that there is therefore a 1:1 ratio of hamstring-to-quadriceps muscle activity during the squat. This is not the case. In fact the ratio was 0.37:1.0, so the conventional back squat actually produced 2.7 times more quadriceps activity than hamstring activity. In other words, the conventional back squat is most definitely a quadriceps exercise.

***

Exploring the findings of other, similar studies

Without going into too much detail regarding the methods of other studies, it is probably worth just noting that a number of other researchers have made very similar findings. For example, McCaw (1999) found that the activity of each of the quadriceps muscles was very much higher than that of the hamstrings and gluteal muscles during the conventional back squat, as is shown in the chart below:

Similarly, Paoli (2009) also found that the normal stance width back squat did not significantly recruit the hamstrings in comparison with the quadriceps.  The conventional parallel squat seems to be a knee-dominant exercise that is limited by the strength of the quadriceps and not by the strength of the hamstrings.

The above two studies are not ideal on their own as a picture of the relative activity of the hamstrings and quadriceps muscles, as they did not normalize the EMG activity data to MVIC. Some muscle groups are covered more by fat than others and this can lead to greater impedance when testing those muscles, which leads to lower EMG values. Hence, looking at the voltage (mV) alone doesn’t really give us sufficient information to draw strong conclusions about the relative EMG activity of the various muscles. So we must see these studies as supportive rather than conclusive.

On the other hand, Wright (1999) compared the medial (semitendinosus) and lateral (biceps femoris) activity during leg curls, stiff-leg deadlifts and squats and normalized the data to MVIC. The following chart shows the details:

These researchers found that the squat produced markedly less medial and lateral hamstrings activity than either of the other two exercises. Unfortunately, they did not also measure quadriceps EMG activity.

 ***

What did the researchers conclude?

The researchers concluded that the Russian curl and seated leg curl are the most effective hamstring exercises and that the conventional back squat is not an effective hamstrings exercise.

***

What are the limitations?

Obviously, the key limitations are that technique and equipment are going to play some role in affecting the degree of hamstrings muscular activity during the squat.

It is reasonable to expect that athletes who sit back more into a squat and use a more hip-dominant squatting pattern might generate more hamstrings activity than those who squat more upright. However, whether this actually occurs is uncertain. I will look at a couple of studies next week that investigate this area a bit more closely.

Also, it is reasonable to assume that using powerlifting gear might also lead to greater hamstrings activity during a squat because of the restrictions that it places on the freedom of movement and the greater ability that it allows for lifters to sit back. This is certainly an area that needs more research and I am not aware of any studies that have actually explored this issue as yet.

***

What are the practical implications?

For athletes

The squat is not a suitable exercise for developing the hamstrings. Therefore, where hamstring development is required for sports performance or for injury prevention, other exercises should be introduced into a program, such as the Nordic curl or Romanian deadlift.

Where the squat is programed extensively for building strength and size, care should be taken that the hamstrings are not neglected as a result. Many programs that are built around the squat program the deadlift in much lower volumes and frequencies out of necessity. However, this could lead to muscular imbalances and a predisposition to either hamstring strains or ACL injury.

For powerlifters

It is likely that training the squat alone will not increase performance in the deadlift, as the deadlift involves a very marked contribution from the hamstrings. Therefore, powerlifters who are unable to deadlift often should include alternative hamstring exercises in their routines, such as good mornings.

For bodybuilders

While the squat is probably still the king of leg exercises additional hamstring exercises are certainly needed to maximize all-over thigh hypertrophy.

***

Want more about hamstring training?

For the most up-to-date, scientific training methods for the posterior chain, including the gluteus maximus and hamstrings, get hold of Chris and Bret’s latest full-color e-book – Hip Extensor Training.

For a limited time only, we’re going to offer Hip Extensor Training for $39.95. After next month, we’ll put it up to $49.95.

Follow the link to read more or just buy your copy by clicking on the button below:

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When I first started lifting weights, I followed a basic routine built around regular, moderate-volume squatting and weekly, low-volume deadlifting.

I ate well, did my squats and left plenty of sweat on the gym floor. As my squat grew, the bathroom scale revealed the progress. I put on weight, went up a couple of T-shirt sizes and started having trouble finding suits that fit.

For some reason, though, my deadlift didn’t move at the same rate as my squat. At the time, I couldn’t figure out what the problem was. Later, as I got into sports science, I realised that I’d made the classic mistake that many lifters make.

I’d assumed that because I was squatting regularly, I was training my whole lower body equally. After all, the squat is the king of exercises, right?

Right, but the problem is that while the squat is great for the quadriceps, it’s not so good for the hamstrings. The ratio of hamstrings to quadriceps EMG activation is around 0.37, so the quadriceps get activated around 2.7 times as much as the hamstrings.

Since EMG activity is a fairly good predictor of muscle force and also of how effective an exercise is for causing muscular hypertrophy, this means that the squat isn’t great for hamstrings hypertrophy. And since the deadlift relies much more on hamstrings strength than quadriceps strength, this explains why my squat wasn’t building my deadlift that effectively.

Of course, once I put some glute-ham raises, RDLs and good mornings into my routine, my deadlift started moving again.

It’s fair to say that I only moved forwards once I stopped paying attention to the way my legs felt and started paying attention to what the sports science said about EMG activity. And when I spent a little more time looking at the anatomy of the hamstrings and realized that they don’t really change length during a squat, that made it even more obvious what I was missing.

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Why am I telling you this?

I am telling you this because it underlines the importance of knowing what the EMG studies say when it comes to designing strength training programs.

It’s also the reason why Bret and I have spent the last 3 months working on Hip Extensor Training.

Hip Extensor Training is not a sports science manual. It’s a practical guide to training the posterior chain muscles for maximum hypertrophy. We’ve reviewed hundreds of articles, including all the EMG studies on the hamstrings and gluteals, and summarized the important findings for you.

If you want bigger and stronger hamstrings and gluteals, this the book to read. It’s perfect for powerlifters who need to bring their deadlift up and it’s perfect for bodybuilders searching for that elusive all-round thigh development. And, of course, it’s essential for figure athletes, as you might expect…

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How user-friendly is Hip Extensor Training?

Hip Extensor Training is our most user-friendly and practical product ever. It starts with a basic introduction to the muscles and their anatomy and then quickly takes you through the key EMG findings before making easy-to-implement, practical recommendations for training.

To make Hip Extensor Training as easy as possible to use, we divided the book into three sections, one for each muscle. So you can just turn to the relevant section whenever you want. Need bigger hamstrings? Start at the beginning. Need to work on glute development? No problem, just flick to the last section.

In every section, we cover which exercises produce the greatest EMG activity. Where possible, we tell you whether different exercise variants (such as squat stance width or hip rotation during leg curls) affect EMG activity. This allows you to see exactly which exercises and variants are ideal for maximizing hip extensor hypertrophy.

And at the end of each chapter, we pull it all together into a single page of key recommendations that refers back to all the EMG study results and anatomy. Just like this one, for the hamstrings:

So if you want to get into all of the detail, it’s all there. But if you need to get going right away and apply the sports science of posterior chain training to your own routine or to the routines of your clients, you can flick through to the chapter summaries and apply things immediately.

***

Is that all?

Not at all! As an added bonus that you will not find from anyone else, Bret has spent many days performing his own EMG experiments on a range of subjects. Hip Extensor Training has all of this information, which covers a much wider range of exercises than anywhere you will find in the sports science literature.

While research studies tend to cover just a couple of exercises, Bret has performed trials on dozens, many of which have never before been researched. To give you an idea (you won’t be able to read this small in the image below), here’s a slide from just one of the hamstrings muscle Bret has researched:

This information really is an amazing addition to the book. Bret could just as easily have left these experiments out to make sure he was always ahead of the game when he was training his own clients. But to make sure that we provide the best possible picture of what we currently know about the EMG activity of the posterior chain muscles, we added them in. Read this and you will know everything we know about maximizing hamstring and gluteal hypertrophy.

***

How much is it?

For a limited time only, we’re going to offer Hip Extensor Training for $39.95. After next month, we’ll put it up to $49.95, which will be in line with our previous book, Hip Extension Torque.

We don’t normally do discounts but we want to make sure as many people as possible can make use of this very practical guide to hamstring and gluteal hypertrophy.

Click on the button below then follow the instructions to the checkout to download your copy today.

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Strength and conditioning coaches and rehabilitation professionals both often use different types of cues to help athletes or patients perform exercises better. Many experts advise only using external cues, as researchers have found that these enhance motor performance more than internal cues. I wrote about external cues last week.

However, other researchers have reported that internal cues can increase the recruitment of specific muscles during compound exercises. Moreover, bodybuilders have been using internal cues and internal focus with the “mind-muscle connection” for many years. So are internal cues useful for bodybuilders and physique athletes?

The study: Effect of verbal instruction on muscle activity during the bench press exercise, by Snyder and Fry, 2011

***

What’s the background?

Strength and conditioning coaches and rehabilitation professionals often use cues to help athletes or patients perform exercises better. Cues fall into two main categories, depending on how they direct the attentional focus of the athlete. Cues that direct the athlete’s attention towards the effect of the movement on the environment are said to have an external focus while instructions that direct the trainee’s attention to the movement itself are said to have an internal focus.

Many researchers have concluded that since external focus improves both performance and motor learning compared to internal focus or no attentional focus, it is therefore always better to use an external focus. However, other researchers have found that there may be benefits to using internal focus in certain situations. For example, internal focus seems to be capable of increasing the muscular activity of specific prime movers during compound movements.

• Palmerud (1995) – the researchers found that by providing feedback, they were able to assist the subjects to alter the muscular recruitment of various shoulder muscles (supraspinatus, infraspinatus, anterior and middle deltoids, and trapezius) without altering posture.
• Palmerud (1998) – the researchers found that by providing visual feedback, they were able to alter the recruitment of various parts of the middle-back musculature in 6 different arm positions. They found that the subjects were able voluntarily to increase recruitment of the rhomboid major and minor and the transverse part of the trapezius, increasing their activity on the average to over 200% of the levels performed without feedback. Such alterations in muscular activity were performed without changing posture.
• Karst (2004) – the researchers found that by providing internal cues to untrained subjects to focus on either rectus abdominis activity or oblique abdominis activity, the subjects were able to increase the relative activity in either set of muscles during a trunk curl exercise.
• Lewis and Sahrmann (2009) – the researchers reported that internal verbal cues to use the gluteals during a prone hip extension led to increased EMG activity of the glutes (with simultaneous decrease of hamstring EMG) compared to when no cues were given.
• Snyder (2009) – the researchers found that by providing internal verbal cues to novice trainees to use the latissimus dorsi muscle more during a lat pull-down led to increased latissimus dorsi activity compared with no cues.
• Marchant (2009) – the researchers found that an internal attentional focus led to greater biceps EMG activation during isokinetic elbow flexion movements compared to external attentional focus but that this simultaneously decreased force and torque measurements.

In summary, there is evidence that internal cues leading to internal attentional focus, or what bodybuilders might refer to as “the mind-muscle connection” can be used to increase muscular recruitment of a specific muscle during a multi-joint exercise.

***

What did the researchers do?

The researchers wanted to investigate the effects of internal cues on muscle recruitment during the bench press with 50% and 80% of 1RM. They therefore used surface electrodes to measure the EMG activity in the pectoralis major, triceps brachii, anterior deltoid, biceps brachii and posterior deltoid muscles, while the subjects performed 6 sets of 3 repetitions of the bench press, alternating between 50% and 80% of 1RM. The EMG data were normalized to those produced during maximum voluntary isometric contractions (MVCs).

The first two sets (i.e. pair of 50% and 80% of 1RM exercises) were performed with no cues. The second two sets were performed with an internal cue to focus on the chest muscles. The final two sets were performed with an internal cue to focus on the arm muscles.

The researchers recruited 11 male Division III football players with at least 6 months of resistance training experience on the bench press for the study.

***

What happened?

Chest cue with 50% of 1RM

The researchers found that the cue to focus on the chest muscles caused a significant increase in EMG activity of 22% in comparison with no cue. There was no significant effect of cueing on the activity of the anterior deltoid or triceps brachii or of the antagonist muscles.

Arms cue with 50% of 1RM

The researchers found that the cue to focus on the arms led to an increase in the activity of the triceps brachii of 26% but there was no change in the activity of the pectoralis major or anterior deltoid in comparison with the no cue condition. The following chart shows the effect of both chest and arms cues with 50% of 1RM:

Chest cue with 80% of 1RM

The researchers found that the cue to focus on the chest muscles caused a significant increase in EMG activity of 13% in comparison with no cue. There was no significant effect on the activity of the triceps brachii or of the antagonist muscles. However, the anterior deltoid activity also increased significantly by 17%.

Arms cue with 80% of 1RM

The researchers found that the cue to focus on the arms led to a significant increase in the activity of the anterior deltoid by 17% in comparison with the no cue condition. However, neither the activity of the pectoralis major nor the activity of the triceps brachii were affected. The following chart shows the effect of both chest and arms cues with 80% of 1RM:

***

What did the researchers conclude?

The researchers concluded that resistance-trained subjects are able to alter the muscular recruitment of the prime movers during a compound exercise in response to internal cues. They concluded that in response to chest cues the subjects were able to increase pectoralis activity and in response to arms cues they were able to increase triceps brachii activity.

However, the researchers also concluded that since there was no reduction in the activity of the triceps brachii during the chest cues condition and no reduction in the activity of the pectoralis major during the arms cues condition, this implies that “functional isolation” of the muscles did not occur.

The researchers concluded that “if increased activity of a specific muscle is the desired result, then an internal focus may be more appropriate than an external focus, whereas if motor task performance is of greater interest, an external attentional focus would be more desirable.”

So it seems that while an internal focus does not appear to benefit performance (i.e. lead to greater force or power production), it does lead to greater EMG activity. So future research needs to show whether such increased EMG activity as a result of internal focus indeed leads to greater hypertrophic adaptations.

***

What are the limitations?

The study was limited as follows:

• The order of the cue conditions was not randomized across the subjects and therefore there could have been confounding effects as a result of either fatigue or postactivation potentiation.
• The study was not able to explain the difference in relative recruitment between the prime movers in the 50% and 80% of 1RM conditions.

***

What are the practical implications?

For bodybuilders and physique athletes:

Using an internal focus can help to increase the activity of a specific prime mover muscle during a multi-joint exercise. For example, focusing on using the chest muscles during the bench press may help increase the activity of the pectorals during that exercise.

When giving cues, we can categorize the type of cue into those that have an external focus and those that have an internal focus. External cues are generally used when the goal is to produce a better objective performance (e.g. a longer jump or a greater power output). But how much difference does the type of cue actually make?

The study: Effects of varying attentional focus on health-related physical fitness performance, by Bredin, Dickson and Warburton, in Applied Physiology: Nutrition and Metabolism, 2013

***

What’s the background?

Coaching instructions can direct the focus of attention externally or internally. An external focus is one that directs the athlete’s attention away from their body and towards the effects of their movement on the environment. An internal focus directs the athlete’s attention to their own body movements.

Previous research has found that an external focus of attention is optimal for improving the objective performance of the movement (i.e. greater jumping distance or height, greater power output, etc.) while an internal focus leads to reductions in objective performance but may lead to better form, as measured by differences in joint angles.

• Marchant (2009) – the researchers found that an external attentional focus led to greater force and torque during isokinetic elbow flexion movements while simultaneously decreasing muscle activation as measured by EMG.
• Porter (2010) – the researchers found that directing attention toward jumping as far past the starting line as possible had a much greater effect at increasing broad jump distance compared to focusing attention on extending the knees as fast as possible.
• Wulf (2010) – the researchers found that an external focus led to increased jump height with simultaneously lower EMG activity compared to an internal focus of attention.
• Wu (2012) – the researchers found that an external attentional focus let to increased broad jump distances despite not affecting peak force production compared to an internal attentional focus.
• Makaruk (2012) – the researchers found that 9 weeks of plyometric training with an external focus led to greater standing long jump and countermovement jump (but not drop jump) performance compared to training with an internal focus.
• Porter (2012) – the researchers found that an external focus far away from the body led to greater results than an internal focus or an external focus near the body in terms of standing long jump performance.

So in general, the main factor that is associated with external focus is an increase in performance. Also, there may be a tendency for reduced EMG activity at the same time. This is interesting, as it may be a mirror image of what happens with internal focus.

***

What did the researchers do?

The researchers wanted to compare the effects of internal and external attentional focus on performance in a health-related physical fitness appraisal. Specifically, they wanted to see whether the difference in focus would alter performance in parts of the musculoskeletal and aerobic components of the Canadian Physical Activity, Fitness and Lifestyle Approach (CPAFLA) test. The CPAFLA test is administered on more than 1 million Canadians each year by trained and certified health and fitness professionals.

The researchers therefore recruited 16 young but untrained adults (8 females and 8 males). The subjects performed certain specific parts of the CPAFLA test 3 times in a randomized cross-over design, with one performance using external cues, another using internal cues and a third using no cues.

The aerobic part was the modified Canadian Aerobic Fitness Test and the musculoskeletal tests involved grip strength, push-ups, sit and reach, partial curl-ups, vertical jump, and a modified Biering–Sorenson (horizontal) back extension test.

***

What happened?

The researchers found that external cues resulted in significantly better performances for all 7 measures of health-related physical fitness in comparison with both internal cues with no cues. Also no cues resulted in significantly better performance for 3 measures (grip strength, push-ups, and vertical jump) in comparison with internal cues. The following chart shows the difference in vertical jump performance between the three types of cue for both males and females:

The researchers found that external cues improved vertical jump performance by around 10 – 17% in untrained males and females in comparison with no cues. Additionally, the researchers found that external cues improved vertical jump performance in untrained males and females by around 15 – 22% in comparison with internal cues.

While such large differences might not be expected in trained subjects or athletes, it is evident that external cues make a very marked difference on the objective performance of large, full-body, explosive movements such as vertical jumps.

***

What did the researchers conclude?

The researchers concluded that for sporting performance movements requiring the generation of force or power, performance can be enhanced significantly by externally-directed cues.

So it appears that when instructed to focus attention outside of the body and toward the interaction with the environment, the neuromuscular system is coordinated to a greater degree compared to an internal focus inside of the body. With external cueing, the precise motor units are activated to the optimal degree at the optimal onset times in order to maximize performance, whereas with internal cueing, an unnecessary amount of motor units may be activated and force production may be altered in a way that negatively impacts performance.

***

What were the limitations?

The study was limited in a number of key respects:

• No biomechanical data was recorded to show whether the subjects changed the way in which they performed any of the movements when the different cues were used.
• The subjects were untrained and different results might be expected with trained subjects who were more accustomed to performing the movements.
• No resistance training exercises were performed. Therefore, it is difficult to assess whether a similar magnitude of performance enhancement might be expected with, say, a standard back squat as with the vertical jump.

***

What are the practical implications?

For athletes and strength coaches:

Large, powerful, full-body movements such as plyometrics and probably also resistance exercises can be significantly enhanced by appropriate, externally-directed cues.

The bench press is a difficult lift to progress and can be uncomfortable for some lifters to train regularly. Consequently, many trainees make use of different exercises to train the same muscles, including bench press variations (incline, decline, dumbbell, etc.) and machines.

But how similar are these exercises in developing the pectorals, anterior deltoids and triceps brachii? This collection of study reviews covers a wide range of exercises and provides some of the answers.

(Too much detail? Skip to the practical implications)

***

The study: A Comparison of Muscle Activity Between a Free Weight and Machine Bench Press, by McCaw, and Friday, in Journal of Strength and Conditioning Research, 1994

What’s the background?

Although the barbell bench press is a popular exercise, many lifters make use of a machine bench press, such as the Smith machine. However, whether the Smith machine bench press is as effective as the barbell bench press is unclear.

What did the researchers do?

The researchers wanted to compare the EMG activity of the pectoralis major, anterior deltoids, middle deltoids, triceps brachii and biceps brachii during the barbell and machine bench presses. Therefore, they recruited 5 male subjects who had been involved in resistance training for at least 3 times per week for the previous year. They measured the activity of the muscles while the subjects performed 5 trials with 80% of 1RM and 5 trials with 60% of 1RM.

What happened?

The researchers reported that the only muscles that displayed significant differences in EMG activity levels between exercises were the anterior and middle deltoids. These muscles displayed greater activity during the barbell bench press in comparison with the machine bench press. The EMG activity of the triceps brachii and pectoralis major trended towards being greater in the barbell bench press but the differences were not significant.

What did the researchers conclude?

The researchers concluded that the barbell bench press was superior to the machine bench press for developing the shoulder muscles. However, it appears similar in respect of the pectoralis major and triceps brachii.

***

The study: Comparison among the EMG activity of the pectoralis major, anterior deltoidis and triceps brachii during the bench press and peck deck exercises, by de Araújo Rocha Júnior, Gentil, Oliveira and Carmo, in Revista Brasileira de Medicina do Esporte, 2007

What’s the background?

Welsch (2005) had compared the EMG activity of the pectoralis major and anterior deltoids when performing a 6RM barbell bench press, dumbbell bench press and dumbbell fly. Welsch et al. found no differences in respect of either muscle group for the 3 exercises. However, no previous researchers had reviewed the differences in EMG activity between the pec deck and barbell bench press.

What did the researchers do?

The researchers set out to compare the EMG activity of the pectoralis major, anterior deltoid and triceps brachii in the barbell bench press and machine pec deck. They therefore recruited 13 trained male subjects with an average of 7.8 ± 4.4 years resistance training experience. They established the 10RM for each lift for each subject. Then, in a separate testing session, they measured the EMG activity of each muscle, while the subjects performed a maximal effort with their 10RM for each lift.

What happened?

The researchers found that there was significantly more EMG activity in the triceps brachii during the bench press compared to the pec deck. There was no significant difference between exercises in respect of the EMG activity of either the pectoralis major and anterior deltoids.

During the bench press, there was greater EMG activity of the pectoralis major than the triceps brachii. However, there were no differences in EMG activity between the pectoralis major and the anterior deltoids.

During the pec deck, there was greater EMG activity of anterior deltoids and pectoralis major muscles in comparison with the triceps brachii. However, there was no difference in EMG activity between the pectoralis major and anterior deltoids.

What did the researchers conclude?

The researchers concluded that the anterior deltoids and pectoralis major muscles are similarly involved in the pec deck and bench press. They therefore suggest that it is not accurate to describe the pec deck and bench press as primarily exercises for the pectoralis major but that these exercises should be seen as challenging the anterior deltoids and pectoralis major equally.

***

The study: Effects of Variations of the Bench Press Exercise on the EMG Activity of Five Shoulder Muscles, by Barnett, Kippers and Turner, in Journal of Strength and Conditioning Research, 1995

What’s the background?

Prior to this study being performed, few researchers had considered using EMG activity investigations to look into how different bench press variations might develop the upper body. Moreover, there was a lack of clarity regarding whether the sternocostal and clavicular heads of the pectoralis major could be preferentially activated by different exercises. Therefore, there was therefore a need to understand how both grip width and bench incline or decline affected the EMG activity of the key upper body pressing muscles.

What did the researchers do?

The researchers wanted to compare the EMG activity of the sternal and clavicular heads of the pectoralis major, the anterior deltoids, the triceps brachii and the latissimus dorsi between different bench press variations ranging in incline as follows: (unsupported but seated) vertical, 40-degrees incline, horizontal and 18-degrees decline; and ranging in grip width as follows: 100% of biacromial breadth and 200% of biacromial breadth. They therefore recruited 6 male subjects with at least 2 years of resistance training experience and tested their 1RM for each lift variation. The subjects then performed trials with 80% of 1RM while the researchers measured the EMG activity of the various muscles.

What happened?

The researchers observed that the amount of weight lifted decreased as trunk inclination increased from decline through to vertical. In respect of the EMG activity of the muscles tested, they made the following observations:

• Pectoralis major (sternocostal head) – EMG activity was highest in the order: horizontal > incline > decline > vertical.
• Pectoralis major (clavicular head) – EMG activity was highest in the order: incline > horizontal > decline > vertical.
• Anterior deltoids – EMG activity was highest in the order: vertical > incline > horizontal > decline.
• Triceps brachii – EMG activity was highest in the order: horizontal > decline > vertical > incline.
• Latissimus dorsi – EMG activity of the latissimus dorsi was very low in all conditions but was higher in the decline press than in the other presses.

The researchers observed the following statistically significant differences between the various bench press variations:

• Pectoralis major (sternocostal head) – EMG activity was significantly lower in the vertical bench press than in all other presses. EMG activity was significantly higher in the horizontal bench press than in all other presses (but only with a wide grip in respect of the decline bench press). Grip width had no effect except in respect of incline presses, where wide grip was superior to narrow grip.
• Pectoralis major (clavicular head) – EMG activity during the incline bench press was significantly higher than that in the decline bench press but only non-significantly greater than that in the horizontal bench press. Across all presses, a narrow grip produced greater EMG activity than a wide grip.
• Anterior deltoids – with wide hand spacing, EMG activity was significant greater during vertical and incline bench presses in comparison with horizontal and decline bench presses. Grip width had no effect.
• Triceps brachii – EMG activity was significantly lower in the incline and vertical bench presses in comparison with the horizontal bench press. Across all presses, a narrow grip produced greater EMG activity than a wide grip.

What did the researchers conclude?

The researchers concluded that the horizontal bench press is best for targeting the pectoralis major (sternocostal head). They concluded that the incline bench press is not superior for targeting the pectoralis major (clavicular head) than the horizontal bench press, although there was a non-significant trend for EMG activity to be greatest during this exercise. They concluded that the decline bench press is not superior for developing the either head of the pectoralis major.

The researchers concluded that a narrow grip during bench presses is best for developing the pectoralis major (sternocostal head) and triceps brachii. They concluded that the anterior deltoids are best developed using the vertical bench press.

***

The study: Electromyographical activity of the pectoralis muscle during incline and decline bench presses, by Glass and  Armstrong, in Journal of Strength and Conditioning Research, 1997

What’s the background?

This study was performed after the preceding study by Barnett (1995) and begins by referencing it, noting that the exact portion of the sternocostal head of the pectoralis major that Barnett et al. studied was actually the middle portion of the overall pectoral muscle, or the upper part of the sternocostal head. It was therefore apparent that a further study could be performed in order to assess the effects of the incline and decline bench press on the EMG activity of the lower portion of the pectoral muscle, i.e. the lower portion of the sternocostal head.

What did the researchers do?

The researchers recruited 15 college-aged males with an average of 5.08 ± 1.5 years of resistance training experience and who were all able to bench press at least bodyweight. The researchers tested the 1RM of the subjects in the incline (30 degrees) and decline (-15 degrees) bench presses. On a separate day, the researchers then recorded the EMG activity of the clavicular head of the pectoralis major and of the lower portion of the sternocostal head of the pectoralis major while the subjects performed 6 reps with 70% of their 1RM in each exercise.

What happened?

The researchers reported that the subjects were significantly stronger in the decline than in the incline press. They pressed an average of 1.25 times bodyweight for the decline press and 1.07 times bodyweight for the incline press.

The researchers found no significant difference in EMG activity of the clavicular head of the pectoralis major between the incline and decline bench press. This lack of significant finding was in direct contradiction to the findings of Barnett (1995) and may have been related to the smaller difference in inclines used (30 vs. 40 degrees for incline and 15 vs. 18 degrees for decline). The researchers also found that the decline bench press produced significantly higher EMG activity of the lower portion of the sternocostal head of the pectoralis major than the incline bench press.

What did the researchers conclude?

The researchers concluded that the decline bench press is best for developing the very lowest portion of the pectoral muscle, the lower sternocostal portion.

***

The study: The influence of grip width and forearm pronation/supination on upper-body myoelectric activity during the flat bench press, by Lehman, in Journal of Strength and Conditioning Research, 2005

What’s the background?

Only a small number of studies have looked at the effect of grip width on muscle activity during the bench press. As noted above, Barnett (1995) looked the effect of grip width as well as the degree of incline but they only reviewed two grip widths (100 and 200% of biacromial breadth). Clemons and Aaron (1997) investigated four grip widths between 100 – 190% of biacromial breadth. While Barnett et al. found that the grip width affected different muscles to varying extents, Clemons and Aaron found that the narrow grip produced lower activity in all muscles every time. However, this is likely because they used the same loads in each case.

What did the researcher do?

The researcher wanted to clarify the effect of grip width on muscle activity during the bench press. He also wanted to see how the reverse grip bench press differed from the standard grip. Therefore, he recruited 12 males with at least 6 months of resistance training experience. He recorded the EMG activity of the sternocostal head of the pectoralis major, clavicular head of the pectoralis major, triceps brachii and biceps brachii muscles during isometric bench press holds with 5 different hand positions. The weight was the same for each subject in each trial and was set as 12RM for the supinated grip at 100% of biacromial breadth.

The 5 different hand positions were: 100% of biacromial breadth (standard grip), 100% of biacromial breadth (reverse grip), 200% of biacromial breadth (standard grip), 200% of biacromial breadth (reverse grip), and 1-hand width grip between hands (standard grip).

What happened?

The researcher observed the following:

• Pectoralis major (clavicular head) – a reverse grip led to greater muscle activity compared to a standard grip.
• Pectoralis major (sternocostal head) – there was no difference between a standard and a reverse grip. A very narrow grip led to a significant reduction in muscle activity.
• Triceps brachii – the very narrow grip led to the highest muscle activity but there was no significant difference between standard or reverse grips.
• Biceps brachii – a wide grip produced greater biceps brachii activity for both standard and reverse grip widths. A reverse grip increases biceps brachii activity in comparison with a standard grip.

What did the researcher conclude?

The researcher concluded that a narrower grip width does lead to greater triceps brachii activity at the expense of the activity of the pectoralis major (sternocostal head). He also concluded that the use of the reverse grip leads to greater involvement of the biceps brachii without reducing activity to other muscle groups.

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The study: Electromyographic activity and 6-RM strength in bench press on stable and unstable surfaces, by Saeterbakken and Fimland, in in Journal of Strength and Conditioning Research, 2012

What’s the background?

Resistance training on unstable surfaces, such as Swiss balls, BOSU balls and balance discs is a common way of training. However, it is uncertain whether the use of such unstable surfaces helps increase muscle activity of the prime movers or reduces it.

What did the researchers do?

The researchers recruited 16 resistance-trained males with 4.6 ± 2.1 years of resistance training experience. The subject performed 6RM strength tests for the barbell bench press on a flat bench, on a balance cushion and on a Swiss ball. In a separate test, the subjects performed their 6RM for each exercise again while the researchers recorded the EMG activity of the pectoralis major, deltoid anterior, biceps brachii, triceps brachii, rectus abdominis, oblique external and erector spinae.

What happened?

The 6RM on the stable bench was 85.0 kg ± 15.6. The 6RM on the balance cushion was 79.0 kg ± 15.1 and on the Swiss ball was 78.5 kg ± 14.3. The 6RM on the stable bench was therefore significantly greater than either the 6RM on the balance cushion or on the Swiss ball. However, the balance cushion and Swiss ball produced similar 6RM loads.

The researchers reported that the EMG activity in pectoralis major relative to the stable bench was 81% using Swiss ball and 90% for the balance cushion. Also, EMG activity in the anterior deltoids was similar across all movements. Finally, EMG activity in the triceps brachii relative to stable bench was 79% using the balance cushion and 69% using the Swiss ball.

What did the researchers conclude?

The researchers concluded that on unstable surfaces (i.e. balance cushion and Swiss ball), the EMG activities in pectoralis major and triceps brachii were lower compared to the stable bench.

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What are the practical implications?

Based on the above studies, we can make the following practical recommendations for bodybuilders/physique athletes and for powerlifters/strength athletes:

In respect of machine training, for bodybuilders:

The barbell bench press is better than the (Smith) machine bench press for developing the anterior and middle deltoids but the two exercises are similar for developing the pectoralis major and triceps brachii. This suggests that the machine bench press is likely better suited to the chest day of a 5-day body part split routine while the barbell bench press would more properly fit into a 3-day upper body push-, upper body pull-, legs-style split.

The pec deck is similar to the barbell bench press for developing the anterior deltoids and pectoralis major but is not effective for the triceps brachii. This suggests that the pec deck would better allow the separation of chest and arms days within a body part split routine.

In respect of bench press variations, for bodybuilders:

The barbell bench press involves the anterior deltoids and pectoralis major to a similar extent. It should not therefore be considered as solely an exercise for the chest but as a combined chest and shoulders exercise.

The horizontal bench press can be used for specifically targeting the lower part of the pectoralis major (i.e. the sternocostal head). The lower part of the pectoralis major (i.e. the sternocostal head) can be further targeted by selecting a narrow rather than a wide grip.

The decline bench press can be used for specifically working the very lowest portion of the pectoralis major, the lower sternocostal portion, although it does not appear to be equally effective for the upper part of the sternocostal portion.

Using a wide grip during bench press variations can reduce the involvement of the triceps brachii, while using a narrow grip can increase their involvement. Therefore, in body part split routines, wide grips might be optimal where bench press variations are used, to reduce the involvement of the arms. In upper push splits, narrow grips might be superior, to involve a more even balance of muscles.

The use of unstable surfaces for bench press variations, such as balance cushions or Swiss balls, is not recommended, as it leads to reduced potential for developing the pectoralis major and triceps brachii although not for the anterior deltoids.

In respect of bench press variations, for powerlifters:

The reverse grip bench press involves the biceps brachii to a significant effect but does not decrease the activity of the prime movers. Therefore, so long as the biceps brachii are not a weak link for a lifter, the reverse grip bench press could be used to train for the bench press effectively.

Using a narrow grip during bench press variations can increase the involvement of the triceps brachii. Where a lifter needs to emphasize the development of these muscles to strengthen the bench press at lockout, a narrower grip can be utilized

March was another great month for us to take stock of the research that has been coming out. We found some amazing studies that have really useful, practical implications.  The research review itself covers nearly 50 of the best studies but here are 3 great studies about sleep that we couldn’t resist sharing in advance.

Find out below whether exercise makes you need more sleep and whether losing sleep or having your sleep disturbed can make you fat…

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The study: The effects of moderate to vigorous aerobic exercise on the sleep need of sedentary young adults, by Wong, Halaki and Chow, in Journal of Sports Sciences, 2013

What’s the background?

Sleep need is very roughly defined as the daily amount of sleep that enables an individual to be fully awake and to engage in optimal daytime performance. Where sleep needs are not met, this is said to lead to sleep debt, which is associated with reductions in daytime performance, in both functional and physiological respects. Researchers have found that sleep need varies significantly between individuals and also varies with both age and gender. However, the extent to which sleep varies according to daytime activity is unclear.

What did the researchers do?

The researchers wanted to see how sleep was affected by aerobic exercise at several different intensities in a group of 12 (9 female and 3 male) young, sedentary individuals with no sleep complaints. They took care to exclude subjects who were shift workers or who had travelled between different time zones in the last 2 weeks.

What happened?

The researchers reported that the sleep duration did not differ significantly between exercise conditions. However, when sleep was analyzed between light and heavy sleep periods, the researchers found that the subjects spent more of their total sleep time in light sleep after exercise at 65% and 75% than after no-exercise, as shown in the chart below:

The researchers also noted that there was a non-significant trend for a reduced proportion of time spent in Rapid Eye Movement (REM) sleep with increasing exercise intensity.

What are the key points?

Treadmill exercise for 40 minutes at or above 65% of VO2-max, 6-hours before bedtime, leads to an increase in light sleep at the expense of heavy sleep, as well as a non-significant trend for a reduction in REM sleep.

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The study: Effects of sleep fragmentation on appetite and related hormone concentrations over 24 h in healthy men, by Gonnissen, Hursel, Rutters, Martens and Westerterp-Plantenga, in British Journal of Nutrition, 2013

What’s the background?

Perhaps the most pressing healthcare issue of our time is the rapidly increasing rise in obesity. Many researchers have tried to find the exact cause for this rise by looking at the correlations with other lifestyle factors that have changed in recent years. One factor that is not frequently explored is the tendency for reduced sleep duration. However, it is apparent that sleep duration has in fact reduced in parallel with the increase in obesity. Whether there is a causal link between these two trends, however, is unclear.

What did the researchers do?

The researchers wanted to investigate whether disturbed sleep would lead to decreased appetite control in the same way as reduced sleep duration. They therefore tested the subjects in two conditions: disturbed and non-disturbed. In the non-disturbed condition, the subjects were allowed to sleep through the night but in the disturbed (fragmented) condition, they were woken several times in the night.

What happened?

Sleep duration

The researchers reported that there were no significant differences in sleep duration or time awake between the non-disturbed and disturbed nights. The subjects were awoken an average of 5 times in the disturbed night. The researchers reported that REM sleep was significantly shorter during the disturbed night compared with the non-disturbed night.

Glucose and insulin concentrations

The researchers reported that the postprandial rise in insulin was significantly lower after breakfast in the disturbed condition (but higher after dinner) than in the non-disturbed condition, which was lower after dinner.

Cortisol concentrations

The researchers found that cortisol concentrations were significantly higher in the disturbed sleep condition, in the evening, compared with the undisturbed sleep condition.

What are the key points?

Disturbed sleep does not alter the total sleep time or time awake but does lead to reductions in REM sleep. Since REM sleep is believed to be important for health and restoration, this suggests that sleep disturbance could have adverse health implications.

Additionally, a night of disturbed sleep is accompanied by a change in the pattern of postprandial insulin secretion over the day without changes in glucose secretions. Disturbed sleep leads to decreased insulin secretion in the morning and increased insulin secretion in the afternoon, which could lead to increased food intake and snacking in the evenings. This is therefore a mechanism by which reduced sleep quality could lead to body fat gain.

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The study: Effects of three weeks of mild sleep restriction implemented in the home environment on multiple metabolic and endocrine markers in healthy young men, by Robertson, Russell-Jones, Umpleby and Dijk, in Metabolism Clinical and Experimental, 2013

What’s the background?

There is growing evidence that sleep duration and the disruption of circadian rhythms are factors that affect the onset of metabolic syndrome, obesity and type II diabetes, particularly via their association with increased bodyweight, glucose intolerance and high blood pressure.

What did the researchers do?

The researchers wanted to investigate the effects of a moderate amount of sleep loss (1.5 hours) on healthy individuals of normal weight over a 3-week period. Specifically, the researchers wanted to see whether this amount of sleep deprivation would reduce insulin sensitivity and alter circulating levels of leptin.

What happened?

Sleep duration

The researchers reported that there was a significant effect on normal sleep duration as a result of the intervention, with the sleep-deprivation group experiencing 1 hour 31 minutes less time in bed, as was intended, by setting their alarm clocks for 1 hour 30 minutes earlier than was normal for them.

Effect on insulin sensitivity

In the sleep restriction group, the researchers reported that insulin sensitivity initially decreased and then recovered to baseline levels but did not change in the control group.

Effect on leptin levels

The researchers reported that in the sleep deprivation group, leptin concentrations stayed near baseline in the first 2 weeks then fell significantly in the third week and remained significantly lower than baseline. There were no such changes in the control group. Since leptin is known to suppress appetite, reduced leptin levels would be expected to increase appetite.

Effect on bodyweight

In the sleep-deprived group, bodyweight fell initially below baseline in weeks 1 and 2 but then significantly increased in week 3. There were no significant changes in the control group.

What are the key points?

Moderate levels of sleep-deprivation lead to initial reductions and then significant increases in bodyweight concomitantly with significant reductions in circulating leptin concentrations. Since leptin is known to suppress appetite, reduced leptin levels would be expected to increase appetite. This is therefore a mechanism by which reduced sleep quantity could lead to body fat gain.

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The bench press is perhaps one of the most beloved lifts in gyms all around the world. It is also probably the one that brings the most recreational lifters the greatest frustration with their lack of progress.

These days, it is not widely studied, as sports scientists concentrate on exploring the squat and the deadlift, as well as the mechanics of sprinting, so that they can better help strength and conditioning coaches prepare their athletes for sports performance.

However, if we dig back into the archives, there are some great studies on the biomechanics of the bench press that really get under the skin of this fascinating exercise.

The study: A biomechanical analysis of the sticking region in the bench press, by Elliott, Wilson and Kerr, in Medicine and science in sports and exercise, 1989

(Too much detail? Skip to the practical implications)

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What’s the background?

Lifters often remark upon the existence of a “sticking point” in the bench press, where bar speed slows and the movement becomes much more difficult. Early research into the biomechanics of the bench press also noted this sticking region (e.g. Lander, 1985 and Madsen, 1984). However, what causes it remains unclear.

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What did the researchers do?

The researchers set out to identify the reasons for the sticking region in the bench press. They recruited 10 elite powerlifters who were able to bench press between 150 – 245kg and who ranged in bodyweight from 75kg – 120kg+. The elite status of the powerlifters was such that they were all at least state champions and three of them were Australian national record holders.

The subjects attended a single testing session in which they performed up to five lifts while the researchers videoed them. The video allowed the researchers to measure the length of time spent in the different phases of the lift (both absolute and relative). It also enabled the researchers to measure the external moment arms of the barbell at the shoulder and at the elbow.

The lifts were based on the lifters’ own estimates of their one-repetition maximum (1RM) for the day in question and comprised proposed lifts of an estimated 80%, 95%, 100%, 103% and 105% of 1RM. The final two lifts were only included if the preceding lift was successful.

For each lift, the researchers enforced competition standards that the powerlifters were familiar with. Lifts that did not comply with the rules were repeated. Since the lifters were in training for the 1987 Australian State Powerlifting Championships, it is assumed that the rules applicable to that event were used.

As well as the video, the researchers took surface EMG measurements of the triceps brachii, sternal head of the pectoralis major, anterior deltoid and biceps brachii.

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What are the various phases of the bench press?

The researchers note that there are generally four clear phases to the bench press: the acceleration phase, the sticking region, the maximum strength phase and the deceleration phase.

1. Acceleration phase – the acceleration phase lasts from the start of the concentric phase of the lift with the bar on the chest until the bar stops accelerating, which is the same point as the point of peak velocity (called MAX-V in the charts below). In the middle of the acceleration phase is the point of maximum force (called MAX-F in the charts below).
2. Sticking region – the sticking region starts at the point of peak velocity and ends at the point of minimum velocity (called MIN-V in the charts below). In the middle of the sticking region is the point of minimum force (called MIN-F in the charts below).
3. Maximum strength phase – the maximum strength phase starts at the point of minimum velocity and ends slightly arbitrarily when the bar speed reaches the same velocity again. In the middle of the maximum strength phase is another point of maximum force (also called MAX-F in the charts below).
4. Deceleration phase – the deceleration phase starts at the second point of minimum velocity and ends with the completion of the lift.

The important thing to remember is that the points of maximum and minimum force are not identical to the points of maximum and minimum velocity. Although the points of maximum and minimum velocity are used to mark the starts and ends of phases, they in fact lag behind the points of maximum and minimum force, which are the true turning points within the lift where things start to get either easier or harder.

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What happened?

Distance at which each phase of the lift occurred

The researchers were pleased to discover that the distance of the bar from the chest at which each sticking point occurred was very similar to that seen in previous studies. The following chart shows the results of this study and compares it to the results of Lander, 1985.

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Time spent in each phase of the lift

The following chart shows the average time spent by the elite powerlifters in each phase relative to the overall lift for two heavy loads.

We can see from the chart that the heavier lift spent relatively more time in the acceleration phase and sticking region and relatively less time in the maximum strength and deceleration phases. This makes good sense, as the heavier weight would have taken more time to accelerate initially, thereby increasing the time spent in that phase. Similarly, the time spent in the sticking region would be expected to be proportionately longer for the heavier weight.

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External moment arms during the bench press

If you have read Hip Extension Torque, you will understand fully how external and internal moment arms affect a lift. If not, here’s a brief reminder:

It’s important to recall that although muscles themselves produce force by contracting, it is torque or the turning force about the joint that causes the barbell to move. Very simply, torque is force multiplied by moment arm length. Moment arm lengths are the perpendicular distances between the pivots and the lines of action of the force. So larger forces and larger moment arms both produce greater torque.

Instinctively, we know this, because when we need to turn a wrench we grasp it lower down the handle to make the job easier for ourselves. In this case, the wrench handle is the moment arm.

In a barbell lift, we have two categories of torque acting: the external torque (i.e. the barbell and bodyweight loads acting on the joints) and the internal torque (i.e. the torque produced by the muscular actions on the joints in order to counteract the barbell and bodyweight loads).

So while it might sound like a long moment arm is always a good thing, there are two sides to every coin. With external moment arms, which are the perpendicular distances between the joint centers and the direction of force of the external weight (i.e. vertically downwards, in most cases where free weights are concerned), longer moment arms make the lift harder. This is why the deadlift and squat are really hard at the bottom and easier at the top. The external moment arms for the hip joint are much longer in the bottom position.

On the other hand, with internal moment arms, which are the perpendicular distance from the muscle’s line of action to the joint’s center of rotation, longer moment arms make the lift easier to perform. So in a biceps curl, at 90 degrees of elbow angle, where the internal moment arm length is quite long, the torque that you can exert is greatest. Whether that means you will find the lift easiest at this point is another matter, because that will depend upon the relative difference between the internal and external moment arms…

Again, if you read Hip Extension Torque, all of this will become clear…

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Shoulder external moment arms

Anyway, back to the bench press. In this study, researchers used their video to calculate the external moment arms of the bench press about the shoulder joint at varying points during the lift. The chart shows the results:

The chart shows that the two loads were very similar in terms of the external moment arm about the shoulder that they produced. However, more importantly, the researchers found that the external shoulder moment arms decreased throughout the lift and were largest when the bar is on the chest. This would require the shoulder muscle to produce the most force at the start of the concentric phase, in order to generate a similar torque. It also implies that the lift might become steadily easier for the shoulder muscles from the beginning to the end.

In terms of understanding the sticking region, however, it would suggest that the sticking region is not caused by an adverse change in the external moment arm at the shoulder. In other words, the bench press does not become suddenly more difficult for the shoulder muscles in the sticking region as a result of changing leverages.

It is worth noting that how easy the shoulder would find it to produce a greater force at that joint angle would also depend upon the length-tension relationship of the shoulder muscles, as well as the way in which neural drive alters with joint angle for those muscles. These variables are not always predictable and could lead to significant differences in the ability of the shoulder to generate force at different joint angles.

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Elbow external moment arms

The researchers also used their video to calculate the external moment arms of the bench press about the elbow joint at varying points during the lift. The chart shows the results:

From the chart we can see that there is a slight trend for decreasing external moment arm lengths about the elbow from the start of the lift through to the point of minimum velocity, which marks the start of the maximum strength phase. At this point, the bar begins accelerating again. This tells us that the triceps find that the lift gets steadily easier the further the bar goes from the chest, at least up to the start of the maximum strength phase.

So again, in terms of understanding the sticking region, it would suggest that the sticking region is not caused by an adverse change in the external moment arm at the elbow. In other words, the bench press does not become suddenly more difficult for the triceps brachii muscles in the sticking region as a result of changing leverages.

Interestingly, there is a big spike in the external moment arm about the elbow around lockout, which suggests that the triceps suddenly find themselves mechanically disadvantaged. This may reflect the tendency of some lifters to struggle to lockout the last few inches of a lift, despite breaking through the sticking region.

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EMG activity

The researchers noted that the three prime movers (triceps brachii, sternal head of the pectoralis major and anterior deltoid) all mostly displayed significant levels of EMG activity during the lift and did not differ markedly in the level of activity at any joint angle during the lift. They noted that the triceps brachii occasionally displayed a slight delay in activity in some lifters but this was not a strong trend across the whole group.

However, Krol (2010) and Van Den Tillaar (2009) proposed that the co-ordination of the various prime movers was key to the creation of the sticking region. Krol noted that the activity of the triceps is delayed with increasing weight and Van Den Tillaar noted that failure does not always occur in the sticking region.

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Angle of bar path

The researchers used the video recording to measure the exact angle of the bar path. They found that the bar did not travel completely vertically. The following chart shows the relative angle of the bar with respect to the horizontal at various points during the lift. The larger the angle, the steeper the bar path. A vertical bar path would be 90 degrees and a horizontal bar path would be 0 degrees.

The chart shows three different kinds of lift. The 81% lift occurred without any sticking region or maximum strength region and just had acceleration and deceleration phases. The angle of bar path became more horizontal as the lift progressed. However, in the 100% lift, the bar path stayed around the same angle the whole way through. Finally, in the 104% lift, which was a failed attempt, the bar suddenly starting moving almost entirely horizontally (towards the head) at the point of failure.

The researchers suggested that the bar path became more horizontal because the lifter was trying to reduce the external moment arm about the shoulder by moving the bar to be positioned directly over the shoulder joint. This would theoretically increase the leverage of the shoulder at this point in the lift. However, it does not explain why the sticking point occurs where it does.

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Further investigation into the sticking region

Another factor that might affect the sticking region that was not addressed by the researchers is the internal moment arm of each of the pectorals, triceps and shoulder muscles. Before we think about these moment arms, it’s probably helpful just to cover the joint angle terminology, as it is quite easy to get confused between degrees of joint angle and degrees of flexion and extension.

• Shoulder: at the start of the bench press, the shoulder joint is at least in full extension in the sagittal plane and probably slightly hyperextended, which amounts to a shoulder angle of less than 0 degrees. At lockout, the shoulder joint is in around 90 degrees of shoulder angle in the sagittal plane. (I’m going to ignore the frontal and transverse planes because that this post is getting out of hand).
• Elbow: in contrast, the elbow joint is probably at around 110 degrees of elbow angle the start of the bench press and finishes in 0 degrees, fully extended.

So, with those angle ranges in mind (shoulder: from 0 – 90 degrees; elbow: from 110 – 0 degrees), let’s take a look at how the internal moment arm changes during the bench press movement:

• Shoulder: Ackland (2008) reported that the superior pectoralis major internal moment arm in the sagittal plane is maximal at 71 degrees (being 53.7mm) and minimal at 2.5 degrees (being 9.6mm). The researchers only tested between 2.5 – 120 degrees, so it is probable that 0 degrees of shoulder angle is in fact the smallest internal moment arm for the superior pectoralis major in the sagittal plane. So the internal moment arm for the superior pectoralis major is around 495% greater in 71 degrees of flexion than in 2.5 degrees flexion.  They found that the anterior deltoid internal moment arm in the sagittal plane is maximal at 120 degrees (being 40.0mm) and minimal at 2.5 degrees (being 11.6mm). So the internal moment arm for the anterior deltoid is around 245% greater in 120 degrees of flexion than in 2.5 degrees flexion.
• Elbow: Sugisaki (2010) reported that the triceps internal moment arm in the sagittal plane increased as the elbow angle decreased, from 17.4mm at 110 degrees to 23.9mm at 30 degrees. This means that the internal moment arm for the triceps is at least 37.3% greater when it is 30 degrees from full extension than when the elbow is fully flexed in a similar position to the start of the bench press.

So these internal moment arm differences suggest that the ratio of muscular force to torque produced by the prime movers (in the sagittal plane only) is greatest towards the end of the lift and least at the beginning of the lift. This is diametrically opposite to the external moment arms, suggesting that the bench press should always be hardest off the chest. The existence of the sticking region mid-way through the lift therefore remains problematic.

For completeness, it’s important to note that the moment arms in these studies were calculated in purely the sagittal plane. When actually performing the bench press in which there is also a degree of humeral movement in the transverse and frontal planes. So the moment arms during the bench press may be different from those in more controlled joint angle studies.

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What did the researchers conclude?

The researchers concluded that the sticking region in the bench press is not caused by adverse changes in the external moment arms at either the shoulder or the elbow. They also concluded that the sticking region is not caused by changes in neural drive to the prime movers.

In consequence, the researchers speculated that the sticking region is therefore caused by the gradual reduction in stored elastic energy as a result of the eccentric phase prior to the lift. They proposed that the sticking region is the phase between the release of the stored elastic energy and the onset of a more mechanically advantageous position for the movement. Whether this is the case, however, requires further investigation.

It is possible that titin may provide very large amounts of passive elastic force contribution at the bottom of the lift. Because of the age of this study, this research wasn’t mentioned by the researchers. It could be that the sticking region starts at the point where titin contribution reduces significantly.

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What are the limitations?

The study was limited as follows:

• The study included only elite powerlifters and they may have used very specific techniques in order to achieve their maximum lifts. Different results might be observed in athletes who are not bench press specialists.
• The study only covered the EMG activity of four muscles and did not record the activity of the trunk, back or leg muscles. While these muscles may not be prime movers, their importance is known to powerlifters and the elite status of these athletes indicates that any and all muscles may have been involved in the lift so far as was possible.
• The researchers did not normalize the EMG activity and did not formally calculate onset times for the muscles during the lifts. This may have led to them missing features of muscular activity.
• The study presented a number of factors that do not appear to be the cause of the sticking region in the bench press but they did not present a factor that could be taken as the cause. Their proposal of elastic energy being the cause was made on the basis of not finding any other reason, which is not quite the same thing as showing that it is the cause. To demonstrate the effect of elastic energy in the bench press on the sticking region, the researchers would have to compare a concentric-only bench press with an eccentric-concentric bench press and show that the concentric-only bench press failed at the chest rather than in the sticking region. Personally, I don’t think this would happen but I would be curious to hear other peoples’ views.

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What are the practical implications?

For powerlifters and strength athletes:

The performance of the eccentric phase may be critical during the bench press. Care should therefore be taken to maximize the benefit of the elastic energy storage during this phase. Maintaining tightness in the bottom position to ensure maximum recoil may lead to improved performance.

The bottom position of the bench press is likely the most difficult, as it is the least mechanically advantageous for the shoulders and triceps. Lifts that increase the strength of these muscles in this position may be useful as assistance work.