Biomechanical Analysis Of Lower Limbs On The Effect Of Fatigue On Hockey Stop

Purpose: The study shows that exercise fatigue is one of the important reasons for increasing the risk of injury and decreasing performance of ice hockey players.This study intends to compare the biomechanical characteristics and myoelectric indexes of the lower limbs when hockey players complete the emergency stop before and after fatigue Changes,analysis of biomechanical factors affecting injury and athletic performance.The research data obtained can help coaches and athletes develop targeted training programs,improve their ability to maintain athletic performance,and reduce the possibility of injuries.Methods: The study used three SONY high-speed cameras to shoot four emergency stop actions on the ice before and after fatigue intervention of 10 special college students of hockey(single foot inner blade emergency stop,single foot outer blade emergency stop,double foot inner blade emergency stop,inner and outer blade Emergency stop)to obtain the ice kinematics data of the dominant side action.Use the DELSYS surface EMG tester to synchronously collect the EMG signals of the subjects to complete the action,and use the FIRSTBEAT team heart rate bag to monitor the heart rate of the subjects during the test in real time.Two pairs of SMART SPEED velocimeters were used to measure the exercise speed of the subjects in the fatigue intervention,and the best exercise performance was combined with heart rate and RPE index to determine the athlete’s fatigue standard.Statistical analysis of the results was performed using repeated measures two-factor analysis of variance.When the main effect was significant,paired t test was used as a follow-up test for pairwise comparison.Results: Fatigue will reduce the horizontal speed of the center of gravity in the hockey emergency stop action and increase the time required to complete the action(P<0.01).The specific performance is to reduce the horizontal speed of the center of gravity during the buffer phase(P<0.05),reduce the horizontal speed of the center of gravity during the starting phase(P<0.01),and increase the operating time of the starting phase(P < 0.01);fatigue will significantly increase the athlete’s buffering during the emergency stop process.The left hip angle(P<0.01),left knee angle(P<0.01),and right ankle angle(P < 0.05)during the stage;fatigue will significantly increase the athlete’s right knee angle(P < 0.01)during the start phase of the emergency stop process.)And left ankle angle(P<0.01);during the emergency stop buffer phase,the root mean square amplitude of the tibialis anterior muscle after fatigue is significantly reduced compared with that before fatigue(left P<0.05,right P<0.01),which decreases Root mean square amplitude value of the medial head of the right quadriceps(P <0.01),both sides of the rectus femoris muscles exhibited lower root mean square amplitude values after fatigue(P<0.01),left and right biceps femoris Both showed that the root-mean-square amplitude value after fatigue was smaller than the result before fatigue(P<0.05 on the left side and P<0.01 on the right side),and the root-mean-square amplitude value of the left and right hemitendon muscles showed that the fatigue root value was smaller than that before fatigue(Left P<0.05,right P<0.01),before and after fatigue Left and right side muscles muscle showed results(P < 0.01)after fatigue is greater than the amplitude value before fatigue.The root mean square amplitude of the tibialis anterior muscle after fatigue during the start of the emergency stop is significantly reduced(P <0.01),the root mean square amplitude of the right gastrocnemius muscle is reduced(P<0.05),The square root amplitude decreases(P<0.01),the left root quadriceps lateral root mean square root amplitude decreases(P < 0.01),in the rectus femoris,biceps femoris,hemitendonis In the comparison of the two gluteal muscles,the result is that fatigue will reduce the root mean square amplitude of the muscles(P<0.05).Conclusions: 1.Fatigue will affect the performance of athletes during the emergency stop,reduce the speed when completing the emergency stop,and increase the time to complete the action.2.Fatigue will increase the hip,knee,and ankle angles of the athletes during the emergency stop buffer phase and the moment of emergency stop.Among them,the knee angle increases most significantly after fatigue in the one-leg outer blade movement.3.Fatigue will significantly increase the knee flexion angle during the start phase of the emergency stop action.4.After fatigue,athletes complete the emergency stop action at a speed lower than before fatigue,reducing the intensity of the action,reducing the muscle load,resulting in a decrease in muscle activation,and the most significant impact on the thigh muscle group.5.The four emergency stop modes are affected to different degrees by fatigue.