Affiliations:
Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada
Correspondence:
[*]
Address for correspondence: Stacey M. Acker, PhD, Department of Kinesiology, Biomechanics of Human Mobility Laboratory, Faculty of Applied Health Sciences, University of Waterloo, 200 University Avenue West, Waterloo, ON, Canada, N2L 3G1. Tel.: +1 519 888 4567/Ext. 31338; E-mail: [email protected].
Abstract: BACKGROUND:Deep knee bending has been reported as an occupational hazard to workers who have to adopt such postures. High knee joint moments have been associated with knee osteoarthritis initiation and progression. OBJECTIVE:This study aimed to compare four high knee flexion postures (dorsiflexed and plantarflexed kneeling, and flat-foot and heels-up squatting) to determine which one results in lower knee joint flexion and ab/adduction moments. METHODS:Forty-three participants performed five trials of each posture. Peak (for descent/ascent) and mean (for the static hold) external knee flexion and ab/adduction moments were analyzed for each posture using 2-way ANOVAs and post-hoc pairwise comparisons. RESULTS:It was observed that the flat-foot squat resulted in significantly lower knee flexion moment compared to the other three postures (4.63±0.99 % BW·H during the static phase, and 5.83±1.24 % BW·H and 5.94±1.24 % BW·H during descent and ascent phases, respectively). During ascent phase, significant differences was indicated in peak adduction moments for the flat-foot squat in comparison to both styles of kneeling. CONCLUSIONS:When high knee flexion is required but posture is not dictated, flat-foot squat will reduce exposures to high knee moments.
