The Effects Of Compression Garment On Lower Extremity Kinematics And Muscle Activity Before And After Running Fatigue

Purpose:Prolonged muscle activity during running will induce muscle fatigue,and result in running performance decreased and injuries.To improve performance,a number of interventions were taken to delay fatigue or accelerate recovery,including compression garment（CG）.Studies have found that CG can enhance venous hemodynamics and tissue oxygenation,and then reduce muscle fatigue.Furthermore,the use of CG can reduce soft-tissue vibration in lower extremities during running,and reduce energy cost.However,there is still ambiguity concerning the benefit of CG on muscle activity,performance,and fatigue resistance during running.Thus,the present study aims to investigate the effects of CG on lower extremity kinematics and muscle activity before and after running fatigue.Methods:12 male subjects were recruited to complete two sessions.Subjects were required to choose garments randomly（compression garment,CG and control condition,CC）and wear unified shoes before the pre-test of first session.Subjects ran at 12km/h for at least 30s.K4b2 gas analyzer,Vicon motion capture system,Noraxon wireless EMG system and Bertec instrumented treadmill were used to synchronously collect the oxygen uptake(V_O2),EMG of 9 muscles（gluteus maximus,GM,biceps femoris,BF,rectus femoris,RF,vastus medialis,VM,vastus lateralis,VL,tibialis anterior,TA,medial gastrocnemius,MG,lateral gastrocnemius,LG,soleus,SOL）and kinematics data in lower extremity in stance and swing phases for 15s.To induce fatigue,with 1min rest between groups,the subjects ran for 4mins at 8,10,12 and14km/h,respectively,and continuing to run at 14 km/h until fatigue.The intervention was terminated when both following criteria were met:1)subjects were unable to continue running,and 2)the heart rate（HR）of the subjects reached（220-age-10）bpm.The post-test started immediately after a successful fatigue intervention,with the same protocol of pre-test.With minimal 48-hour interval from the first session,the subjects chose different garment condition and started second session.Two-way repeated-measures ANOVA was used to compare the kinematics and muscle activity of lower extremity between 2 garment conditions before and after fatigue,paired sample t test was used to compare the V_O2,duration of fatigue intervention and maximum HR between 2 garment conditions,and Wilcoxon signed-rank test was used to compare the RPE between 2 garment conditions.Results:1)the duration of fatigue intervention was significantly longer with CG;2)In stance phase,the hip maximum flexion and adduction angle increased significantly with CG,and the hip maximum flexion angle reduced significantly with CC after fatigue.The hip ROM at flexion and extension,knee maximum flexion angle（CG:39.33±3.76°vs.37.64±3.68°,CC:42.19±3.82°vs.39.06±4.22°）and angle at initial contact（CG:-14.25±5.28°vs.-11.95±6.65°,CC:-18.32±8.32°vs.-14.22±5.28°）were significantly increased in both garment condition after fatigue.Besides,compared with CC,the maximum flexion angle of hip（pre-test:35.32±4.66°vs.41.21±9.24°,post-test:37.65±5.44°vs.39.05±13.19°）and knee（pre-test:37.64±3.68°vs.39.06±4.22°,post-test:39.33±3.76°vs.42.19±3.82°）and the knee angle at initial contact（pre-test:-11.95±6.65°vs.-14.22±5.28°,post-test:-14.25±5.28°vs.-18.32±8.32°）after fatigue were significantly smaller with CG.In swing phase,the hip maximum flexion angle,angular velocity and the ROM at abduction and adduction were significantly increased in both garment condition after fatigue.Compared with CC,the maximum flexion angle of hip and knee was significantly smaller with CG;3)In stance phase,the median frequency（MF）of TA with CG was significantly decreased after fatigue,the MF of MG and SOL were significantly increased in both garment condition,and the RMS of TA was significantly decreased with CC and lower than that with CG.In swing phase,the MF of GM increased significantly,and the RMS of TA and GM decreased significantly in both garment condition.Conclusions:Based on the successful running fatigue intervention,the duration of fatigue intervention was significantly longer,and the maximum flexion angle of hip and knee significantly decreased with compression garment.The present study indicated that compression garment has a significant effect on fatigue delay,and kinematic adaption appeared in lower extremity of subjects.Compression garment can be used as assistant to help runners to delay fatigue.However,muscle activity changes in time and frequency domain may be affected by compensatory and motor control strategies.Future studies can combine multiple methods to explore the relationship between sports performance and muscle activity when wearing compression garment.