THE RELATIONSHIP BETWEEN MAXIMUM HEART RATE DURING AN EXHAUSTIVE FATIGUE PROTOCOL AND CO-CONTRACTION OF ANKLE JOINT MUSCLES IN OVERWEIGHT INDIVIDUALS COMPARED TO NORMAL INDIVIDUALS

Background & Aims: Co-contraction can be defined as the simultaneous activation of agonist and antagonist muscles around a joint.Co-contraction plays a fundamental role in movement control during physiological motor learning-related activities.The aim of the present study was to investigate the relationship between maximum heart rate (MHR) during an exhaustive fatigue protocol and cocontraction of the ankle joint muscles in overweight individuals compared to normal-weight individuals.Materials & Methods:The sample consisted of two groups of 12 individuals (n=24), divided into overweight and normal-weight groups.The activity of the ankle joint muscles, including the tibialis anterior and gastrocnemius, was recorded during running using electromyography (EMG).MHR was also recorded using a Polar device.Pearson's correlation coefficient was used to determine the correlation between variables at a significance level of 0.05. Results:The results indicate that changes in general and directed co-contraction of the ankle joint muscles in both phases of running did not change significantly before and after the induction of the fatigue protocol.Furthermore, no significant correlation was seen between MHR during the exhaustive fatigue protocol and changes in general and directed co-contraction in phase one and two of running (P > 0.05).Conclusion:This study revealed that MHR during exhaustive exercise does not significantly affect ankle muscle co-contraction.The lack of correlation between these two variables suggests that the neuromuscular response to fatigue may be independent of cardiovascular stress and body weight status.