Title: The Effects of Isokinetic Fatigue on Recovery of Maximal Isokinetic Concentric and Eccentric Strength in Women
Abstract: This investigation examined the effects of different types of isokinetic eccentric and concentric exercise on subsequent isokinetic maximal concentric and eccentric muscle strength performances at 30° · s–1 and 120° · s–1 during the acute 10-min recovery period. Tests were administered at 2.5, 5, and 10 minutes into recovery. Sixteen physically active women were randomly assigned to either a control group (n = 6) or an experimental group (n = 10). Each subject in the control group was asked to attend two testing sessions consisting of randomly assigned concentric and eccentric modes of testing without any fatigue tasks. A LIDO™ Active Isokinetic System was used for the fatigue tasks and for measuring concentric and eccentric peak torque values at 30° · s–1 and 120° · s–1 velocities of movement during the preexercise and following the fatigue task. Fatigue tasks (Concentric fatigue, Eccentric fatigue, and Concentric/Eccentric fatigue) consisted of each subject performing three sets of 30 repetitions at 120° · s–1 with maximal effort. During the recovery period following the last set of repetitions, each subject was tested for concentric and eccentric strength at 30° · s–1 and 120° · s–1. Only with the concentric/eccentric fatigue task was there a significant decrease in concentric strength (30° · s–1) observed 5 min postexercise. No other differences were observed during recovery following any of the fatigue tasks. The major finding is that concentric and eccentric muscle activity recovers quickly from an isokinetic fatigue task. From a practical perspective, exercise protocols can utilize shorter rest periods between sets without fear of compromising the force production and concentric and eccentric isokinetic testing protocols, or can utilize a rest period of 2.5 minutes and be assured that recovery has been completed.