The Effect Of Fatigue On Human Lower Extremity Biomechnics

Running offer a lot of benefits such as enhancing heart and lung function ability, boosting metabolism, im Poving the circulation of human body and increasing boy fitness. However, running result in the development of injuries as well, especially caused by overuse fatigue. Therefore, this study is to measure the effect of fatigue on human lower extremity biomechanics, and explore the internal relationship between fatigue and the biomechanical features of human lower extremity, in order to Povide the kinematic adjustments before and after fatigue for recreational runners, and discuss the correlation between fatigue and injuries for decreasing the risk of occurrence of injuries.In the Pesent study, all 8 male participants are from America Georgia Southern University with average weight 80.6±8.63 kg, height 177.6±0.02 cm, and age 22.5±1.6yr.All participants are recreational runners with 59.5±4.51 km running distance per week.We used Vicon Motion System for capturing kinematic movement, meanwhile, we employ AMTI three dimensional force treadmill for collecting kinetic data. All data was Pocessed by C-motion Visual3 D software and the results as follows:(1) After fatigue participants suggested stride length decreased and stride rate increased, and stance phase extended.(2) After fatigue participants tended to use forefoot strike landing for reducing the impact force in order to Pevent injuries.(3) After fatigue participants tried to keep knee flexion for decreasing the impact force; after fatigue participants displayed more knee flexion at the toe-off time, and dominant leg were more flexed than nondominant leg influenced by fatigue.(4) After fatigue the strength of ankle plantar flexion reduced resulted in reduction of muscle work ability.(5) After fatigue the strength of knee extension muscle of dominant leg was bigger than nondominant leg at the toe off time.