An Experimental Study on "Speed Endurance"

Abstract

A consept of "speed endurance" proposed by Ikai (1963) was experimentally investigated on the human elbow flexor muscles. Using an apparatus, previously described by Kaneko (1970), the subject made a series of repetitive contractions at a rate of 40 times per minute. The load was provided by the fractions (%) of the maximum strength (Fo) of individual. The results were as follows : 1) The mean diminuation rates in speed (-Δv/contraction) were ranged from 6.1×10^<-3> to 36.6×10^<-3> m/sec, and the rates increased with the greater loads. 2) The total power summed up to n-th contraction suggested the most effective load (% Fo) under a certain limit of work condition as indicated by parenthesis; 40% Fo (less than 14 contractions), 30% Fo (15-43 contractions) and 20% Fo (more than 43 contractions). 3) Force-velocity relationships have shifted from the hyperbola type to the linear type relation along with repetitive contractions. 4) Substantial change of muscle have been discussed based on the dynamic constants in Hill's characteristic equation.