The purpose of this investigation was to assess the effects of stance width and foot rotation angle on three-dimensional knee joint moments during bodyweight squat performance. Twenty-eight participants performed 8 repetitions in 4 conditions differing in stance or foot rotation positions. Knee joint moment waveforms were subjected to principal component analysis. Results indicated that increasing stance width resulted in a larger knee flexion moment magnitude, as well as larger and phase-shifted adduction moment waveforms. The knee’s internal rotation moment magnitude was significantly reduced with external foot rotation only under the wide stance condition. Moreover, squat performance with a wide stance and externally rotated feet resulted in a flattening of the internal rotation moment waveform during the middle portion of the movement. However, i is speculated that the differences observed across conditions are not of clinical relevance for young, healthy participants.
Sivan Almosnino (Corresponding Author) is with the Biomechanics and Ergonomics Laboratory, School of Kinesiology and Health Studies, Queen’s University, Kingston, ON, Canada and with the Human Mobility Research Centre, Queen’s University & Kingston General Hospital, Kingston, ON, Canada. David Kingston and Ryan B. Graham are with the Biomechanics and Ergonomics Laboratory, School of Kinesiology and Health Studies, Queen’s University, Kingston, ON, Canada.