Medial Gastrocnemius Muscle Activity during Single-Leg Hopping to Exhaustion

Abstract

This study described changes in leg muscle activation characteristics during exhaustive single-leg hopping. Twenty-seven healthy men performed trials (132 hops/min) to exhaustion, without a target height, to a target height with visual feedback and target height with tactile feedback. Mean muscle activation amplitude of the medial gastrocnemius (MG) decreased during the anticipatory period while duration of MG activity was maintained when hopping to a target height and contrasted the changes during hopping without a target height. Changes to MG activity were specific to whether the hopping height had been maintained or not. Changes during the anticipatory period of MG activity, indicative of adaptation in descending motor pathways, implicate utility of a motor learning strategy to allow completion of an exhaustive task.

Keywords:

• Augmented feedback
• fatigue
• feed forward
• motor control

Acknowledgments

The authors acknowledge the assistance of Dr. Chris Wang from the School of Science and Health at Western Sydney University for developing custom MATLAB software for data processing.