Note: group –normal BMI group and obese group; PRF– Preferred speed walking; FF– Fast speed walking; OCMB-TL– Stance of trailing limb before Obstacle crossing medium height; OCHB-TL– Stance of trailing limb before Obstacle crossing high height; OCMA-LL – Stance of leading limb after Obstacle crossing medium height; OCHA-LL– Stance of leading limb after Obstacle crossing high height; Knee Peak – peak flexion angle during early stance; Knee Excursion – knee excursion from initial to peak (range of motion between heel-strike and midstance); Peak Moment – peak knee extensor moment during early stance; Moment Range – knee moment range from local minimum to peak; CI (Confidence interval); Conditional R2 – the variance explained by both fixed and random effects in the model; Marginal R2 – the variance explained by the fixed effects alone; * – Significance with p <0.05; ** – Significance with p <0.01; *** – Significance with p <0.001.