What difference does squat stance width make?
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Why is squat stance width important?
Lifters make use of different squat stance widths for various reasons. Some believe that wider stance squats are more effective for powerlifting and allow them to move a greater weight. Others subscribe to the view that a narrower stance squat will target the quadriceps more effectively, while a wider stance squat targets the hip musculature. But what is really going on when we squat wider? In this article, Chris Beardsley (@SandCResearch) reviews a study that does not provide all of the answers but certainly gives some strong hints.
The study: A three-dimensional biomechanical analysis of the squat during varying stance widths, by Escamilla, Fleisig, Lowry, Barrentine and Andrews, in Medicine and Science in Sports and Exercise, 2001
(Too much detail? Skip to the practical implications)
What is the background?
Escamilla et al. begin by reviewing studies that have previously investigated the barbell squat from a biomechanical perspective. They reported that, at the time of their review, ten studies have quantified joint moments but none had studied how stance width affects joint moments. In addition, they note that four studies have reviewed joint and segment angles but none had studied how stance width affects joint and segment angles. In other words, if you want to see how stance width affects lower body kinetics and kinematics in the squat, this is the study you were looking for.
Escamilla et al. also explain that these previous studies were limited in that they employed a two-dimensional (2D) analysis and only recorded a sagittal view of the lifter. They noted that while spinal flexion and hip flexion and extension do occur in the sagittal plane, flexion and extension at the knee and ankle only occur in the sagittal plane if the feet are pointing straight ahead. While this is an acceptable assumption where narrow stances are used, it could easily lead to error with wider stances, because the feet are often turned out considerably.
What did the researchers do?
The researchers wanted to investigate and compare joint and segment angles and ankle, knee, and hip moments and moment arms in the barbell squat with varying stance widths. So they recruited 39 male powerlifters and recorded their movements during 1RM squatting with various stance widths using several cameras in order to create a 3D kinematic model.
To compare stance widths relative to the sizes of the powerlifters, the stance widths were expressed as a proportion of each subject’s shoulder width. The researchers then ranked the 39 normalized stances from lowest to highest (87–196% shoulder width) and then divided them into thirds by number, as follows:
- Narrow (87–118% shoulder width)
- Medium (121–153% shoulder width)
- Wide (158–196% shoulder width)
The researchers did not find any significant differences in work done between the three groups. However, there was a slight trend in that the wider the squat stance, the greater the work done, as shown in the chart below.
There was also a trend for increasing time spent in the acceleration phase in wider stance squats, which is an indicator that wider stance squats could provide a greater training effect. As we have discussed before in a previous review, greater time spent in the acceleration phase is one of the main arguments for using ballistic training. The trend across stance widths is shown in the chart below.
The researchers found that in general joint angles increased as stance width increased. They found that thigh angles with respect to the horizontal increased most with increasing stance width. On the other hand, they found that trunk and shank angles increased least with increasing stance width. Interestingly, the change in trunk angle with increasing stance width was non-significant, although many coaches feel that wider stance squats necessarily lead to greater forward trunk angles. The joint angles at 90 degrees of knee flexion for narrow, medium and wide stance squats are shown in the chart below:
The researchers found that the most significant differences occurred between the narrow and wide stance groups. At 90 degrees of knee flexion, the hips of the wide stance group flexed approximately 7 degrees more than in the narrow stance group, while the shanks were approximately 5 degrees more vertical, the thighs were approximately 12 degrees more horizontal, but the trunk was only 4 degrees more inclined.
Joint moments: ankle
The researchers found that all the joint moments were different between the different stance groups, although the most significant differences in moments involved the ankle. They observed that significant differences in knee and hip moments only occurred at 45 degrees of knee flexion. The following chart shows the ankle moments in bottom position and the ascent phase for narrow, medium and wide stance squats:
As can be seen from the negative results for the medium and wide stance squats in the chart above, the researchers saw that only the narrow stance generated ankle plantar flexor muscle moments, while the wide and medium stances generated ankle dorsiflexor muscle moments. The researchers noted that these changes occurred in part because the narrow stance squatters had approximately 4-6 cm greater forward knee movement in the direction of the toes compared with the medium and wide stance squats. The researchers also noted that peak ankle moments occurred at maximum knee flexion during the narrow stance squat while they occurred at 45 degrees of knee flexion during medium and wide stance squats.
Joint moments: knee
The researchers found that the different stance widths only produced different knee extensor moments at 45 degrees of knee flexion, at which point the wide stance squat produced the greatest knee extension moment. The following chart shows the knee moments in the bottom position and then the ascent phase for narrow, medium and wide stance squats:
The researchers noted that peak knee moments occurred at maximum knee flexion. This corresponds with other studies that have shown that knee extension moments are greatest during deep squats and that the quadriceps are likely the most active during deep squats (see previous review of the effects of squat depth).
Joint moments: hip
The researchers found that the different stance widths only produced different hip extensor moments at 45 degrees of knee flexion, at which point the medium and wide stance squats produced much greater hip extension moments than the narrow stance squat. The following chart shows the hip moments in the descent then the ascent phase for narrow, medium and wide stance squats:
The researchers noted that peak hip moments occurred at minimum bar velocity. This suggests that the hip extensors may be most active at the sticking point, possibly as a result of the knee extensor moment being lower at this point than at maximum knee flexion.
What were the limitations?
The study was limited by the specific population used as subjects. Non-powerlifters may display slightly different biomechanics as a result of learning different form for the lift. Additionally, since c. 1RM loads were used, the kinetics and kinematics of the lifts may differ significantly from other studies in which much lower percentages of 1RM were used. Also, because the powerlifters did not all each perform the three different stance squats, it is not easy to assess accurately whether the different stances led to relatively different hip, knee and ankle moments, as the data may be affected by the strength of the lifters who selected each stance width.
What are the key points?
The key points were as follows:
- There was no significant difference in work done between the three stance widths although there was a trend for wider squats to involve greater work.
- While there was no significant difference in the time spent in the various phases between squats of differing stance widths, there was a trend for increasing time spent in the acceleration phase in wider stance squats, which is an indicator that wider stance squats could provide a greater training effect.
- Ankle moments were significantly different between stance widths at all measurement points, while significant differences in knee and hip moments were noted only at 45 degrees of knee flexion. However, there was a trend for both knee and hip moments to increase with increasing stance width.
- While it is difficult to compare the relative hip, knee and ankle moments of the three stance widths because of differences between subjects, there is no indication in this study that wider stance width squats involve lower knee extension moments than narrow stance width squats. In fact, the wider stance squats seemed to produce greater knee extension moments, suggesting they may be better for strengthening the quadriceps than narrow stance squats.
- Only narrow stance squats generate ankle plantar flexor resultant muscle moments, while wide and medium stance squats generate ankle dorsiflexor resultant muscle moments.
- The difference in ankle moments results from the difference in knee movement between the narrow and wider stance squats: the narrow stance squatters had forward knee movement of 4-6cm more than the wide stance squatters. This may imply that selecting a medium or wide stance squat may help reduce knee shear forces.
- Peak knee moments occur at maximum knee flexion, suggesting that the knee extensors are most active at the bottom position of the squat. This corresponds with other studies that have shown that the quadriceps are most active during deep squats.
- Peak hip moments occurred at minimum bar velocity. This suggests that the hip extensors may be most active at the sticking point, possibly as a result of the knee extensor moment being lower at this point than at maximum knee flexion.
What are the practical implications?
There was no significant difference in work done in the three different stance widths, so physique athletes looking to do as much work as possible in a set period of time are probably best advised to select the most comfortable stance.
Peak knee moments occur at maximum knee flexion, suggesting that the knee extensors are most active at the bottom position of the squat. Deeper squats may therefore be best for physique athletes wanting to develop the quadriceps.
Narrow stance squats do not produce greater knee extension moments than moderate or wide stance squats (in fact, wider stance squats produced greater moments). Therefore, narrow stance squats will probably not work the quadriceps to a greater extent than wide stance squats.
There was a trend for greater time spent in the acceleration phase in wider stance squats, which is an indicator that wider stance squats could provide a greater training effect. Strength and power athletes may therefore obtain greater benefits from wider stance squats.
There was a trend for both knee and hip moments to increase with increasing stance width. This provides another reason for strength and power athletes looking to develop leg strength and power to prefer wider stance squats.
The narrow stance squatters had forward knee movement of 4-6cm more than the wide stance squatters. This may imply that selecting a medium or wide stance squat may help reduce knee shear forces, which may be helpful for people who have had a knee injury previously.
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