Greater squat stance width alters three-dimensional hip moment demands

Barbell squat exercise may be performed with different stance widths, which will influence lower limb kinematics and joint reaction forces. Consequently, three-dimensional hip moments may vary with stance width, influencing muscle loading, and the muscles trained when performing squat exercise. To examine how squat stance width affects hip moments, males (n = 11) and females (n = 13) performed barbell squats at narrow, medium, and wide stance widths. Motion capture and force platform data were used to calculate three-dimensional hip net joint moments (NJM) as indicators of the muscular moments required. Hip extensor NJM was greater for wide than medium (P < 0.001) and narrow (P < 0.001) stance squats. Hip adductor NJM was not different between squat stance widths (P = 0.414). Hip lateral rotator NJM was greater in medium versus narrow squats (P < 0.001), and in wide versus medium (P < 0.001) and narrow (P < 0.001) squats. Taken together, the rotational demands at the hip increase as stance width increases, due to higher hip extensor and lateral rotator NJM. In contrast hip adductor NJM is invariant. These data provide insight into the three-dimensional requirements that muscles must meet at the hip when squat exercise is performed at different stance widths.