Kinematics & kinetics analysis of the lower extremity of normal weight, overweight, and obese individuals during stair ascent & descent

The purpose of this study was to examine the effects of body mass and sex on the joint biomechanics of the lower extremity during stair ascent and descent. Nineteen normal weight (8M and11F; BMI: 22.1 ± 1.8 kg/m 2), 18 overweight (14M and 4F; BMI: 27.4 ± 1.3 kg/m 2) and 8 obese subjects (3M and 5F; BMI: 33.3 ± 2.5 kg/m2) were recruited. Joint mechanical loading presented by joint moment of force and peak joint angles at the hip, knee, and ankle during stair climbing were recorded and analyzed using a motion analysis system with 10 cameras and 4 force plates. The MANOVA and linear regression analysis found a significantly larger knee extensor moment (p=0.026) among the overweight compared to the normal weight participants during descent. Sex differences were found in the peak joint angles, as the females abducted their knees more than the males (p=0.002; r(51) = 0.51) during descent.