The Effects of Lower Extremity Static Muscle Fatigue on Balance Components

Abstract

Background: The body exhibits dynamic and static movements in response to the changes in the center of gravity in some positions. Balance plays a key role in all sports branches and daily life because it can control the lowest energy consumption and muscle activation. Objectives: This study investigated the effects of lower extremity static muscle fatigue on static and dynamic balance components. Design/Methods: The sample consisted of 40 healthy volunteers aged 18-24 years. Participants took part in an isometric fatigue protocol for lower extremity muscles. A squat position was used for static fatigue for lower extremity muscles. Measurements were performed in a squat press for 25 seconds, with the knee at a 90-degree angle and a load of about 30% of the participant's weight isometrically. The protocol was repeated five times. The participant was allowed to rest for two minutes between each repetition. The muscles and their antagonists that contracted most actively during the squat press exercise were vastus lateralis obliquus, rectus femoris, tibialis anterior, biceps femoris, semi tendineus, and lateral gastrocnemius. Electromyography (EMG) measurements were conducted on these muscles bilaterally and motion analysis system was used to standardize the 90-degree angle of the knee joint. Results: There was a significant difference between pre-test and post-test Eyes Open (EO) static balance scores, pre- and post-exercise posttest dynamic balance scores between non-athletes and athletes, pre- and post-exercise posttest dominant leg EO, and pretest non-dominant leg between non-athletes and athletes (p<.05). There was a significant difference in the MF (Hz) values of the dominant leg agonist rectus femoris (p<.05) and the antagonist muscle semi tendineus (p<.05) scores during isometric squat press between athletes and non-athletes. There were statistically significant differences in the co-fatigue (coordinated fatigue) scores of the dominant leg agonist and antagonist muscle groups between non-athletes and athletes during isometric squat press (p<.05). Conclusions: we need different applications to understand the mechanisms underlying balance and discover athletes' potential. Lower extremity proprioception exercises have positive effects on static body balance parameters, and a co-fatigue index can help us investigate co-fatigue, especially during isometric effort at different knee joint angles and different joints.