Effect Of Hip Strength Training On Balance Ability In Individuals With Chronic Ankle Instability

Background and Objective:Ankle sprain is one of the most common sports injuries.40% of ankle sprains developed into chronic ankle instability(CAI),which manifested as repeated sprains,"giving way",pain,etc.70-80% of CAI individuals will develop osteoarthritis of ankle joint after trauma,which will lead to a serious decline in the quality of life of the patients.For a long time,the rehabilitation treatment of CAI individuals mainly focuses on ankle joint.In recent years,it has been proposed that the hip function of CAI individuals has also declined,and hip strength training is helpful to the recovery of CAI individuals.However,the effect of traditional balance training,hip strength training,balance training combined with hip strength training is not discussed.Therefore,the purpose of this study is to reveal the balance characteristics of CAI individuals under different hip movements through horizontal comparison,to reveal the specific relationship between hip strength and balance function,as well as the effect of balance training combined with hip strength training through vertical intervention,so as to provide theoretical and practical basis for the effective treatment of CAI individuals.This study is divided into two parts:Study 1 Horizontal comparison: Characteristics of center of pressure in CAI individuals and healthy people during "T-band" kicksMethods:Fifteen participants with CAI and 15 healthy controls were enrolled to perform "T-band" kicks on the force platform.The center of pressure(COP)data were recorded during "T-band" kicks in four directions(hip abduction,adduction,flexion,and extension),including the total length of COP trajectory,the anteroposterior(A-P)and mediolateral(M-L)COP trajectory,the A-P and M-L excursion range,and the COP area.Results: The M-L excursion range of the unaffected side of the CAI group during hip flexion was significantly greater than the dominant side of the control group(P < 0.05).Compared with the healthy controls,the total length of COP trajectory,the A-P and M-L COP trajectory,the A-P and M-L excursion range,and the COP area significantly increased in the CAI group during hip flexion(P<0.05).Additionally,all COP parameters of the affected side during hip abduction significantly increased in the CAI group(P<0.05).Conclusions: During "T-band" kicks,the stability of the hip joint in individuals with CAI was inferior to that of healthy controls during flexion and abduction.The rehabilitation treatment regimen could be more effective and time efficient in a clinical setting if CAI individuals only perform hip flexion and hip abduction.Study 2 Intervention study: The effect of balance training and hip strength training on the balance function of CAI individualsMethods: Sixty individuals with CAI were randomly divided into three groups,and 47 of them completed the training,including 15 in traditional balance training group,14 in hip muscle strength training group and 18 in combined training group.Using the Balance Error Scoring System(BESS),Star Excursion Balance Test(SEBT),surface electromyography(s EMG),hand-held dynamometer and figure-8 hop tests,the individuals were evaluated for static balance,dynamic balance,hip muscle strength,muscle activation and functional performance.The individuals were asked to use VAS score for self-evaluation of ankle stability.The investigator monitored the training of individuals in different groups on time at clinic,three times a week,and conducted the same assessment again one month later.Finally,the data were analyzed statistically.Results: Hip muscle strength was significantly correlated with dynamic balance,muscle activation,functional performance and self-stability score(P<0.05).After one month of training,there was no statistical significance in all the measurement indexes of the three groups of CAI individuals.The indexes before and after training were statistically significant.In the traditional balance training group,the dynamic balance in SEBT-PM direction was improved(P=0.003),the functional performance was improved(P=0.022),and the self-stability score was increased(P=0.000),the activation of gluteus medius(P=0.012),fibula longus(P=0.006)and fibula longus(P=0.015)in SEBT-PM were significantly reduced;in the hip muscle strength training group,the dynamic balance in SEBT-PM(P=0.038)and SEBT-PL(P=0.037)were significantly reduced,hip abductor strength(P=0.009),hip extension strength(P = 0.007),functional performance(P=0.001),self-stability score(P = 0.001),and gluteus maximus activation in SEBT-PM were significantly reduced(P=0.011).In the combined training group,the static balance(P=0.014),the dynamic balance in the direction of SEBT-PM(P=0.010),SEBT-PL(P=0.004)was improved,and the hip abductor strength(P=0.012),hip extensor strength(P=0.006)were improved,functional performance(P=0.002),self-stability score(P=0.000)and activation of fibula longus(P=0.031)in SEBT-ANT were significantly increased.Conclusions: There is a significant correlation between hip strength and balance.All three training methods can significantly improve the function and self-stability of individuals with CAI.In clinic,we should pay attention to hip strength,and choose the most appropriate way to train according to the actual situation and preference of patients,so as to improve patients’ participation and accelerate recovery.