The Effect of Exercise Fatigue on Body Kinematics and Leg Electromyography during Running

Objective:The purpose of present study was to evaluate the effect of fatigue on kinematics and electromyography data during exhaustive running.Methods:8 healthy male volunteers participated in this study by running to fatigue on the treadmill at 12Km/h.Body Kinematics was recorded and analyzed along with surface electromyography of lower Extremities muscles.Results:During the process of running to fatigue,1)the stride length and frequency changed significantly(P<0.05);right-left step decreased(1.68m to 1.65m),left-right step increased(1.61m to 1.64m),on the contrary,the stride frequency increased(2.77steps/s,2.84 steps /s,2.87 steps/s) and decreased(2.88 steps/s,2.84 steps/s,2.78 steps/s).2)Torso tilt and rotation angle varied(P<0.05),joint angle of hip and knee differed at the end of running(P<0.05),no difference was found pre and after fatigue in ankle joint angle;3)IEMG of lower limb muscles trend to increase during running to fatigue,no consistency was found between MSF of bilateral muscles.Conclusion:During the process of running to fatigue 1) the step length of left to right foot increased and the step frequency decreased,meanwhile the step length of right to left foot shortened with step frequency raised.Exhaustive running intensified the whirl of the torso and led to a less torso tilt strategy.2) the muscles IEMG increased while the MSF tend to decreased except gastrocnemius,however the phase and amplitude of changes between two legs were not the same.