A Kinetic Based Analysis of the Lower Limb’ Joints with Increasing Running Speed

Purpose: Due to the paucity of the information regarding the lower limb biomechanics in slow speeds running as well as  concentration of the majority of previous studies in a single movement plane, aim of the present study was investigation on a kinetic based analysis of lower limb’ joints with increasing running speed. Methods: 28 runners asked to stay on the belt speed of treadmill that was incrementally increased to 2.5 m.s-1, 3.5 m.s-1 and 4.5 m.s-1 speeds. The three dimensional joint moment and sagittal mechanical muscle power of lower limbs during stance phase of running were calculated. Repeated measures analyses of Variance with Bonferroni post Hoc test were conducted to examine the variables during running at various speeds. Results:The results showed that, at the hip joint in frontal plane, an adduction moment developed in the middle of stance phase, and the greatest peak adduction moment is obvious at the highest speed condition (4.5 m/s). Also, the time elapsed to peak in the highest speed condition is less than the others. In transverse plane, although 3.5 speed condition experienced the most external rotation peak moment, but 4.5 condition speed reached sooner to internal status than two other speeds. In sagittal plane, the highest speed condition showed the highest extension and also flexion moments. Conclusions: Increasing Running speed in runners leads to more kinetic output and mechanical power gradient.