The effects of bar positioning, stance width, repetition, and load on muscle activity during the barbell back squat
File(s)
Accepted version
Author(s)
Lee, Chloe XY
Crossman, Antony J
Kedgley, Angela
Type
Journal Article
Abstract
The barbell back squat is used widely across multiple sporting disciplines as part of strength and
conditioning training. There are multiple training variations within performing a BBS. The hypothesis
of this study was that bar positioning (high bar versus low bar), stance width (wide stance versus
narrow stance), weight, and the number of repetitions completed (light weight – ten repetitions at 50%
of maximum; heavy weight – three repetitions at 80% of maximum) can be manipulated for targeted
training effects. The aim of the study was to quantify the effect squatting technique has on the
activation of the rectus femoris, vastus medialis, vastus lateralis, gastrocnemius, biceps femoris,
semitendinosus, gastrocnemius and gluteus maximus. Surface electromyography and kinematic data
were recorded from eighteen healthy participants (twelve male, six female). Mean total area under the
activation curve was compared for each muscle. Adopting a wide stance width showed increases in
both peak and cumulative activation of the vastus medialis (p < 0.015). Squatting with increased
weight showed increased cumulative activation of the vastus lateralis and semitendinosus (p < 0.041).
An increased peak activation of the biceps femoris was observed when a high bar and wide stance
technique was performed with a heavy weight compared to a light weight (p = 0.047). A narrow
stance squat showed a 3.7° increase in peak knee flexion (p = 0.010) and a decrease of 8.2° of hip
abduction (p < 0.001). A low bar position revealed increased hip flexion of 3.4° (p = 0.012).
Overall, consistent muscle activations did not favour any combination of squat parameters. Athletes
wishing to increase strength may choose one of several combinations of squat stance, bar positioning,
and weight-to-repetition ratios, guided by what is most comfortable for the athlete.
conditioning training. There are multiple training variations within performing a BBS. The hypothesis
of this study was that bar positioning (high bar versus low bar), stance width (wide stance versus
narrow stance), weight, and the number of repetitions completed (light weight – ten repetitions at 50%
of maximum; heavy weight – three repetitions at 80% of maximum) can be manipulated for targeted
training effects. The aim of the study was to quantify the effect squatting technique has on the
activation of the rectus femoris, vastus medialis, vastus lateralis, gastrocnemius, biceps femoris,
semitendinosus, gastrocnemius and gluteus maximus. Surface electromyography and kinematic data
were recorded from eighteen healthy participants (twelve male, six female). Mean total area under the
activation curve was compared for each muscle. Adopting a wide stance width showed increases in
both peak and cumulative activation of the vastus medialis (p < 0.015). Squatting with increased
weight showed increased cumulative activation of the vastus lateralis and semitendinosus (p < 0.041).
An increased peak activation of the biceps femoris was observed when a high bar and wide stance
technique was performed with a heavy weight compared to a light weight (p = 0.047). A narrow
stance squat showed a 3.7° increase in peak knee flexion (p = 0.010) and a decrease of 8.2° of hip
abduction (p < 0.001). A low bar position revealed increased hip flexion of 3.4° (p = 0.012).
Overall, consistent muscle activations did not favour any combination of squat parameters. Athletes
wishing to increase strength may choose one of several combinations of squat stance, bar positioning,
and weight-to-repetition ratios, guided by what is most comfortable for the athlete.
Date Acceptance
2026-07-27
Citation
PLoS ONE
ISSN
1932-6203
Publisher
Public Library of Science (PLoS)
Journal / Book Title
PLoS ONE
Copyright Statement
Copyright This paper is embargoed until publication. Once published the Version of Record (VoR) will be available on immediate open access.
License URL
Publication Status
Accepted