The purpose of our study was to examine the association between obesity and gait mechanics in older adults with knee osteoarthritis (OA). Subjects were 101 older adults (25 males and 76 females) with knee OA. High-speed video analysis and a force platform were used to record sagittal view lower extremity kinematic data and ground reaction forces. Increased body mass index (BMI) was significantly related to both decreases in walking velocity and knee maximum extension. There were no significant relationships between BMI and any of the hip or ankle kinematic variables. BMI was directly related to vertical force minimum and maximum values, vertical impulse, and loading rate. Increases in braking and propulsive forces were significantly correlated with increased BMI. Maximum medially and laterally directed ground reaction forces were positively correlated with BMI. Our results suggests that, in subjects with knee OA, obesity is associated with an alteration in gait.
S.P. Messier andT.E. Doyle are with the J.B. Snow Biomechanics Laboratory, Department of Health and Sport Science, Wake Forest University, Winston-Salem, NC 27109. W.H. Ettinger, Jr., is with the Department of Internal Medicine/Gerontology, and T. Morgan and M.K. James are with the Department of Public Health Sciences, Bowman Gray School of Medicine, Wake Forest University. M.L. O'Toole is with the Department of Orthopedic Surgery, and R. Burns is with the Department of Preventive Medicine, The University of Tennessee-Memphis Medical Center, Memphis, TN 38163.