Dynamics of the ankle joint analyzed through moment-angle loops during human walking: gender and age effects.

Aim of this study was to provide a non-invasive assessment of the dynamic properties of the ankle joint during human locomotion, with specific focus on the effects of gender and age. Accordingly, flexion-extension angles and moments, obtained through gait analysis, were used to generate moment-angle loops at the ankle joint in 120 healthy subjects walking at a same normalized speed. Four reproducible types of loops were identified: Typical Loops, Narrow, Large and Yielding loops. No significant changes in the slopes of the main loop phases were observed as a function of gender and age, with the exception of a relative increase in the slope of the descending phase in elderly males compared to adult females. As for the ergometric parameters, the peak ankle moment, work produced and net work along the cycle were slightly, but significantly affected, with progressively decrease in the following order: Adult Males, Adult Females, Elderly Males and Elderly Females. The evidence that only few of the quantitative aspects of moment-angle loops were affected suggests that the control strategy which regulates the biomechanical properties of the ankle joint during walking is rather robust and qualitatively consistent across genders and age.