Study Of The Effect Of Blood Flow Restriction Combined With Low-load Resistance Training On The Function Of Patients With Functional Ankle Instability

Patients with functional ankle instability(FAI)have symptoms such as decreased muscle strength and balance.However,it is not suitable for FAI patients with obvious pain symptoms,and there may be limitations such as delayed muscle soreness after the training.In recent years,the BFR technique has been gradually applied to the rehabilitation field,and it is often used for muscle strength restoration training in rehabilitation groups with skeletal muscle injuries or postoperative functional recovery of the lower extremities,while low-load blood flow restriction(LL-BFR)can induce greater neuromuscular adaptations with a smaller exercise load,and the improvement of muscle strength It can achieve similar effects to HLT,but its current application is mainly focused on the hip and knee,while little has been reported in the ankle.Therefore,it is unclear whether FAI patients can obtain better rehabilitation effects with less energy expenditure through LL-BFR training,effectively improve their ankle function,and provide a new rehabilitation idea for FAI patients with obvious pain symptoms that cannot tolerate HLT.Objective: To investigate whether LL-BFR is effective in improving ankle muscle strength and balance in patients with FAI,and whether it is more effective in improving muscle strength and balance around the ankle joint in patients with FAI compared with HLT training.Methods: Forty-six patients with FAI participated in this study.Experimental group(LL-BFR): LL-BFR training with elastic bands,exercise intensity of 20%-40%one-repetition maximum(1RM)and cuff restriction pressure of 80% arterial occlusion pressure;control group(HLT): HLT training with elastic bands,exercise intensity of70%-85% 1RM,with the cuff restriction pressure acting as a placebo only.The resistance movements in both groups were performed in the order of varus,valgus,dorsiflexion and plantar flexion,and each movement was performed in four sets,with30 reps in the first set and 15 reps in the remaining three sets,with an interval of 30 s between each set and a time control of 5-10 min.The cuff would be deflated during the rest period after the last set of each movement was completed,and the cuff would be pressurized again before the next functional movement training,twice a week for a total of six weeks.Patients’ internal rotation,external rotation,dorsiflexion,plantarflexion and dynamic balance were assessed at baseline,at the end of the third week of training and at the end of the sixth week of training;tibialis anterior(TA),triceps calf(TS)and peroneus longus(PL)thickness were assessed at baseline and at the end of the sixth week of training.Results:1.Repeated measures ANOVA showed significant differences between the LL-BFR group and the HLT group for plantar flexion(F(2,88)=3.936,P<0.027,η2=0.155),dorsiflexion(F(2,88)=4.839,P<0.05,η2=0.184),inversion(F(2,88)=4.199,P<0.05,η2=0.163),and eversion muscle strength(F(2,88)=8.326,P<0.01,η2=0.279)there was a significant difference between the group and test moment interaction main effects.Simple effects analysis was performed and found that plantarflexion,dorsiflexion,internal rotation,and valgus muscle strength were significantly stronger in both groups at the end of the third week of intervention and at the end of the sixth week of intervention than in the baseline period(p<0.001);plantarflexion,dorsiflexion,and internal rotation muscle strength in the LL-BFR and HLT groups were not significantly different between groups at the end of the third week of intervention and at the end of the sixth week of intervention,but valgus muscle strength in the LL-BFR group was The LL-BFR group had significantly higher external rotation strength than the HLT group at the end of the third week of intervention(p<0.05)and achieved the same intervention effect at the end of the sixth week of intervention.2.In the muscle thickness outcome index,significant differences were found in the thickness of TA,TS,and PL in the LL-BFR and HLT groups,respectively,at the end of the sixth week of intervention compared with the baseline period(p<0.05);when comparing between groups,no significant differences were found in the thickness of TA,TS,and PL in the LL-BFR group compared with the HLT group at 6 weeks of intervention(p>0.05).3.Repeated measures ANOVA revealed a significant difference in the group-to-test moment interaction main effect(F(2,88)=15.925,p<0.001,η2=0.426)for Y balance test scores between the LL-BFR and HLT groups.A simple effects analysis revealed that both groups had higher Y-balance test scores at the end of the third week of the intervention and at the end of the sixth week of the intervention than at the baseline period(p<0.001);when comparing between groups,there was no significant difference between the two groups at the baseline period and at the end of the sixth week of the intervention,but the LL-BFR group had significantly higher Y-balance test scores at the end of the third week of the intervention than the HLT group(p<0.05).Conclusion: 1.LL-BFR training was effective in improving ankle muscle strength and balance in patients with FAI and in increasing muscle thickness of related muscle groups;2.Six weeks of LL-BFR training allows FAI patients to achieve the same results as HLT in terms of improvement in ankle muscle strength,muscle thickness and balance with less energy expenditure,and can improve ankle muscle strength and balance better than HLT in the first three weeks of the intervention,and therefore can be an alternative to HLT,providing FAI patients with an efficient and reliable intervention to avoid the potential risk of muscle soreness and tears during HLT,and provide a new rehabilitation idea for FAI patients with significant pain symptoms that cannot tolerate HLT.