Foot Turnout and Knee Alignment Affect the Transverse Plane Hip Moment in Barbell Squats.
Level 3 - non-randomized controlled study
Within-subject cross-sectional laboratory biomechanical study
PubMed 42479711 · doi:10.1519/JSC.0000000000005612
What was done
Twelve men and twelve women (n = 24) performed barbell squats in a motion capture laboratory under conditions of low versus high foot turnout combined with neutral versus medial knee alignment. Researchers measured the hip lateral rotator net joint moment (NJM) and the transverse plane moment arm for the ground reaction force (GRF).
What was found
Low foot turnout produced a larger hip lateral rotator NJM than high foot turnout with neutral knee alignment (p < 0.001). Medial knee alignment increased hip lateral rotator NJM, which reached its highest value during high foot turnout with medial knee alignment (p < 0.001). Transverse plane GRF moment arms differed significantly across conditions (p < 0.006), mirroring the NJM results. Exact numeric means, standard deviations, and effect sizes were not reported in the abstract.
Why it matters
This study provides a biomechanical explanation for transverse plane hip demands during barbell squats, showing that foot turnout and knee path directly modulate hip rotator joint moments via shifts in the ground reaction force moment arm.
Limits
The sample size is modest (n = 24), and participant training background, load intensity, and absolute kinetic values were not reported in the abstract. As an acute kinetic evaluation, it does not assess muscle activation (EMG), chronic adaptations, or injury risk.