Characteristics of walking techniques with different pelvic height and pelvic rotation: effect on muscle activation and energy consumption.

Purpose: Previous studies have proven that modifications in the natural walking technique alter muscle activation and energy consumption. This research aimed to determine the differences in muscle activation, energy consumption, kinematic characteristics, perceived muscular exertion and perceived cardio-respiratory fatigue between natural and modified walking techniques with altered pelvic height and rotation. Methods: Nine physically active, non-injured males walked on a treadmill. Modified walking techniques assumed maintenance of constant pelvic height and application of maximal pelvic rotation. Walking speed was subtransit - 0.4 km/h less than the transit. Sampled variables were: average normalized maximal activation during contact and swing phase relativized to maximal voluntary activation, average submaximal oxygen consumption relativized to body mass and subtransit speed, average step length and frequency, rating of perceived muscular exertion and perceived cardio-respiratory fatigue. Muscle activation, energy consumption and kinematic characteristics were assessed throughout each walking session. Perceived muscular exertion and perceived cardio-respiratory fatigue were evaluated post-session. Electromyographic activity was assessed for rectus femoris, gluteus maximus, vastus medialis, biceps femoris, tibialis anterior and gastrocnemius lateralis. Results: The most significant changes in muscle activation were observed during the contact phase. A decrease in pelvic height increased muscle activation of rectus femoris, vastus medialis and gastrocnemius lateralis. An increase in pelvic rotation increased muscle activation of all monitored muscles except for gluteus maximus. Both modifications increased energy consumption, perceived muscular exertion and perceived cardio-respiratory fatigue, and altered kinematic characteristics. Conclusions: Modifications in pelvic height and rotation at the same walking speed alter muscle activation, energy consumption, kinematic characteristics, perceived exertion and fatigue.