Occupational kneeling is associated with an increased risk for the development of knee osteoarthritis. Previous work studying occupational kneeling has neglected to account for the fact that in many industrial settings, workers are required to wear steeltoe work boots. Thus, the purpose of this study was to evaluate the effect of work boot wear on the center of pressure location of the ground reaction force, knee joint angle, and magnitude of the ground reaction force in a kneeling posture. Fifteen healthy males were fit with 3D motion capture markers and knelt statically over a force plate embedded in the floor. Using the tibial tuberosity as the point of reference, the center of pressure in shod condition was shifted significantly medially (on average 0.009 m [P = .005]) compared with the barefoot condition. The knee was significantly less internally rotated (shod: –12.5° vs. barefoot: –17.4° [P = .009]) and the anterior/posterior shear force was significantly greater in the shod condition (shod: 6.0% body weight vs. barefoot: 1.5% body weight [P = .002]). Therefore, wearing work boots alters the kneeling posture compared with barefoot kneeling, potentially loading different surfaces of the knee, as well as altering knee joint moments.
Liana Tennant, David Kingston, Helen Chong, and Stacey Acker are with the Faculty of Applied Health Sciences, Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada.