Effects of Different Gait Cadences on Lower Extremity Joint Loading during Stair Descent in Obese Children

IThe purpose of this study was to examine the effects of different gait cadences on lower extremity joint loading during stair descent in obese children. Twelve obese children (age = 12.0 ± 0.2 years, BMI = 30.07 ± 2.10 kg/m^2) and 12 non-obese children (age = 12.0 ± 0.2 years, BMI = 17.38 ± 1.32 kg/m^2) were recruited as the participants in this study. All participants were performed a stair descent task under four different conditions of gait cadences (self-paced, 60, 90 and 120 steps/min). A mega high-speed camera synchronized with an ATMI force plate was used to collect data during the landing phase of stair descent. The Kwon 3D and DASYLab 6.0 software were applied to analyze the kinematic data, ground reaction force and center of pressure. The joint moment, joint work and joint power of lower limb were calculated by the inverse dynamics method. Results indicated an interaction between group and gait cadences in negative work of the ankle joint. The obese group demonstrated a greater negative work of the ankle joint at 60 and 90 steps/min conditions than 120 steps/min and self-paced conditions. While walking at the speed of 60 and 90 steps/min, the obese group showed a larger negative work of the ankle joint compared to the non-obese group. Furthermore, the obese group demonstrated a smaller positive work of the hip joint than the non-obese group. These findings indicate that children’s body mass influences their gait cadences during stair descent. Obese children increase the risk for lower-extremity joint injury during the stair descent at lower cadences due to a weaker capacity of gait compensation that is resulting from more negative work at the ankle joint and less positive work at the hip joint.