The relation between hip and knee extensor and flexor muscle strengths and jump action

Abstract

[Purpose] The objective of this research was to investigate the relationship between jump actions involving changes in direction and hip and knee muscle strength. [Subjects] The subjects were 32 healthy adults (average age, 21.05 years) with no medical history of orthopedic problems of the lower limbs. The subjects were given an explanation of the study protocol prior to the experiment and their consent to participation was obtained. [Method] Using the BIODEX isokinetic muscle strength measuring device, we measured hip and knee joint extension and flexion strengths 3 times. Three types of jump action were performed, 6 m hopping on one leg, figure of 8 jumping, and slalom jumping, and the times taken to reach the goal were recorded. Correlations between muscle strengths and jump times were investigated using Pearson's correlation coefficient. [Results] We found significant correlations between each of the muscles strengths and each of the jump actions. [Conclusion] Jump actions involving changes in direction were more strongly related to muscle strength than jump action in a straight line, and the relationship was especially strong for knee flexion strength. © 2013 by the Society of Physical Therapy Science.