The Effects of Fatigue on Electromyography Activity of Lower Extremity Muscles in their Functional Testing

  The lower extremity is one of the important factors affecting performance, and lower limb muscles play a significant role in the performance of individuals. Lower limb muscles play an important role in maintaining postural control, especially in single movements. Ineffectiveness or weakness of these muscles during dynamic movements may increase incomplete dynamical control, and muscle tiredness affects muscle activity. The aim of this study was to compare the electromyography activity of lower extremity muscles before and immediately after fatigue 20 men students in the field of physical education participated in this study. Surface electromyography activity of rectus femoris, lateral hamstring, tibialis anterior, and medial gastrocnemius muscles before and after using the device were evaluated. Lower extremity muscle fatigue protocol to exhaustion by Biodex machine was used. The paired t test was used for statistical analysis with a significance level of P < 0.050. There was significant difference between before and after fatigue in the level of activity of rectus (P = 0.020), hamstrings (P < 0.001), tibialis anterior (P < 0.001), and medial gastrocnemius (P < 0.001) muscles. Lower extremity muscle fatigue has negative effect on the activity of the muscles around the knee joint. Muscle fatigue may cause changes in lower limb muscles, which may increase joints vulnerability. These results can be addressed in the design of athletes’ rehabilitation and training programs to prevent biomechanical parameters changes which lead to loss or damage.