Changes in knee mechanics with systemic fatigue and soccer cleat stud shape appear to differ by sex

Anterior cruciate ligament (ACL) tears occur at a 3x higher rate in female soccer athletes than males (Wald en et al., 2010). This sex-based disparity is associated with differences in neuromuscular control, joint laxity, and anatomical alignment, altering kinetic and kinematic performance profiles (Decker et al., 2003). These differences widen with fatigue, furthering the risk of injury in females (Kernozek et al., 2007). Despite mechanical differences between sex, soccer footwear is designed for male users. With known sex differences in movement patterns and joint loading, it should not be assumed that females are able to withstand the same amount of traction as males. High traction footwear may exacerbate female susceptibility to torsional injury mechanisms, such as those of ACL injury, if rotational resistance exceeds ligament loading capacity (Butler et al., 2012). Cleat outsole properties, such as stud shape, are moderators of rotational resistance at the shoe-surface interface (Butler et al., 2012). However, the effect of stud shape on female mechanics remains unknown.