Plantarflexor electromechanical delay: influence of contraction type and muscle-tendon unit length

Abstract

Electromechanical delay (EMD) is an important determinant of explosive neuromuscular performance. Factors such as muscle contraction type and initial muscle-tendon unit (MTU) length influence this delay period. The aim of this study is to compare differences in EMD from plantar flexors across different contraction modes and MTU lengths. EMD of physically-active individuals (n = 14) was assessed during a series of twitch and explosive isometric plantarflexions across different MTU lengths. For involuntary and voluntary explosive conditions, EMD tended to decrease while the MTU length increased from plantarflexion to neutral/dorsiflexion. No significant differences in EMD were observed between neutral and dorsiflexion MTU lengths. These results have implications for sporting performance where the ability to rapidly produce muscular force is crucial.