Effects of Lower-Extremity and Trunk Muscle Fatigue on Balance

Abstract

Objective: To examine the impact of lower-extremity and trunk muscle fatigue on static and dynamic balance tests. Methods: An isokinetic dynamometer at constant angular velocities of 60°/s, 90°/s, 120°/s, and 180°/s was used to test the isokinetic strength of knee and trunk muscles in 30 healthy sedentary volunteers (14 men and 16 women). Lower- extremity fatigue was produced with the StairMaster, and trunk muscle fatigue was produced with an isokinetic dyna- mometer. Static and dynamic balance measurements were assessed with a balance assessment system before and after muscle fatigue in each subject. Results: There was a significant difference between the prefatigue - postfatigue trunk and lower extremity muscles and the static balance scores. But the dynamic right, left and front balance test scores were not significantly different before and after fatigue of the trunk and lower-extremity muscles. Conclusion: Balance is affected by a generalized fatigue of trunk muscles and lower-extremity muscles. However, it ap- pears that static balance control is affected by the fatigue of trunk and lower-extremity muscles while dynamic balance is affected partly by trunk and lower-extremity muscular fatigue.