Electromyographic and kinematic analysis of therapeutic knee exercises under water

Objective. This study aimed to evaluate muscle function and kinematics duri ng commonly used knee rehabilitation exercises performed in water. Design. Maximal effort single extension and flexion trials in still water a nd repeated extension-flexion trials in flowing water in barefoot condition were analysed from 18 healthy participants (8 men, 10 women). Background. Despite the fact that water exercises are widely used, there ar e only few studies involving biomechanical and hydrodynamical analysis of a quatic exercises in rehabilitation. Methods. Electromyography of the quadriceps (vastus medialis, vastus latera lis) and hamstring muscles (biceps femoris, semitendinosus) and angular vel ocities of the movements were recorded under water. Results. In the repeated extension-flexion exercises the early reduction of agonist activity occurred concurrently with a high level of activity of th e antagonists. In the single trial exercises the level of antagonistic acti vity was low throughout the range of motion, whereas the level of agonist a ctivity was higher during the final phase of the range of motion as compare d with the repeated exercises. Angular velocity patterns and values were si milar between the two types of exercises. Conclusions. The present data demonstrated that the flowing properties of w ater modified the neuromuscular function of the quadriceps and hamstring mu scles acting as agonists and antagonists in the knee flexion-extension exer cises.