Lower Extremities Biomechanics Patterns of Obese and Normal Body Mass Adults during Stairs Ascent and Descent

Obesity has been found to be associated with functional and structural limitations, which included differences in normal gait, and in ascending and descending stairs. The purpose of this study was to investigate the differences between ascending and descending stairs in an obese population compared to a normal body mass (normal mass) population. Eleven obese (BMI 34.5 ± 0.92 kg/m2) and 13 normal mass (BMI 23.39 ± 0.36 kg/m2) adults participated in this study. Lower extremity kinematic and kinetic data were collected while ascending and descending the stairs at self-selected walking speeds. A repeated measures ANOVA identified significant differences between the obese and normal mass groups. Normal mass group had a significant higher range of motion (ROM) at hip and knee flexion/extension ROM (p < 0.05), and at ankle inversion/eversion ROM (p < 0.001) during stair descending, and higher knee flexion/extension ROM (p < 0.05) during stair ascending.The normal mass group had a higher peak hip adduction and peak knee abduction moments (p < 0.05) during stair descending. On the other hand, the obese group had a higher peak hip adduction moment and peak knee anterior shear force (p < 0.05) during stair ascending. No further differences where observed between the groups. The findings indicate that obese individuals adopt a different kinematic and kinetic stair ascending and descending strategies. The strategies adopted by the obese group may be an attempt to better dissipate the larger ground reaction forces due to their increased weight.