A multi-experiment investigation of the effects stance width on the biomechanics of the barbell squat.

Abstract

This two-experiment study aimed to explore habitual and manipulated stance widths on squat biomechanics. In experiment 1, 70 lifters completed back squats at 70% 1 repetition maximum (1RM) and were split (NARROW <1.06*greater trochanter width (GTW), MID 1.06-1.18*GTW and WIDE >1.37 *GTW) according to their self-selected stance width. In experiment 2, 20 lifters per-formed squats at 70% 1RM in 3 conditions (NARROW, MID and WIDE, 1.0, 1.25 and 1.5*GTW). Three-dimensional kinematics were measured using a motion capture system, ground reaction forces (GRF) using a force platform and muscle forces using musculoskeletal modelling. In experiment 2 peak power was significantly greater in the NARROW condition, whereas both experiments showed medial GRF impulse was significantly greater in the WIDE stance. Experiment 2 showed the NARROW condition significantly increased quadriceps forces, whereas both experiments showed that the WIDE stance width significantly enhanced posterior-chain muscle forces. The NARROW condition may improve high mechanical power movement performance and promote quadriceps muscle development. Greater stance widths may improve sprint and rapid change of direction performance and promote posterior-chain muscle hypertrophy. Whilst it appears that there is not an optimal stance width, these observations can be utilized by strength and conditioning practitioners seeking maximize training adaptations.