Abstract

In order to determine whether a prestretch potentiation of human leg extensor muscle is affected during explosive type of strength training, the squatting jump, counter movement jump, and rebound jump were performed by 24 subjects which were divided according to their athletic specificity, i.e., swimmers, jumpers, and weight trainers. We regarded swimmers as untrained subjects, jumpers as trained subjects being familiar with ballistic jump movement, and weight trainers as specially trained subjects regarding the strenght of leg muscles. Four parameters, height of jump, knee angular velocity, positive force integral which would show the use of prestretch potentiation, and coupling-time which would affect the former three parameters, were obtained from the measurement of force-time curve and goniogram. The results indicated that prestretch potentiation was utilized more effectively in trained subjects compared with untrained subjects. The use of prestretch potentiation may increase the first half of knee extension speed, and the strength training for the muscle contractile component may increase the latter half of knee extension speed during jumping action. The training effect on prestretch potentiation of skeletal muscle plays an important role during explosive type of jumping action. The present findings thus further support the concept of specificity of the muscle strength training. Elastic component of the muscle is also discussed. Verf.-Referat