Interrelationships between electromyographic, mechanical, muscle structure and reflex time measurements in man

Abstract

Reaction time (TRT) with its premotor (PMT) and motor time (MT) components, patellar reflex time (TRfT) with its latency (LAT) and motor time (RfMT) were studied with isometric force production and relaxation time variables in 1 leg isometric knee extension. These variables were intercorrelated together with muscle biopsy variables taken from m. [musculus] vastus lateralis. From these computations MT proved to demonstrate significant correlations to rate of isometric force development (RFD) (P < 0.01), maximum force (P0) (P < 0.001) and percent distribution of ST fibers (P < 0.001). These relationships apparently are determined by the pattern of the motor unit recruitment and by different characteristics of the slow and fast twitch muscle fibers to trigger the excitation-contraction coupling.