ObjectiveTo investigate the lower limb muscle synergy patterns during jumping in patients after anterior cruciate ligament reconstruction (ACLR). MethodsFrom March to November, 2022, 23 patients after ACLR were enrolled as observation group, and 24 healthy ones matched in height, body mass and exercise level were recruited as control group at Wuhan Sports University. Surface electromyography (sEMG) data of lower limb muscles were collected during a single-leg vertical jump task. Non-negative matrix factorization was applied for synergy analysis. The number of synergies, variance accounted for, synergy structure (muscle weight) and activation coefficient were extracted. ResultsThree types of muscle synergy patterns were identified on the affected side and contralateral side of the observation group, and the control group. For Synergy 1, the weight of biceps femoris was higher on both the affected and contralateral sides than in the control group (P < 0.01); the weight of semitendinosus was higher on the affected side than on the contralateral side (P < 0.05). For Synergy 2, the weight of lateral gastrocnemius and soleus were higher on both sides of the observation group than in the control group (P < 0.05). For Synergy 3, the weight of gluteus maximus was lower on the affected side than on the contralateral side and in the control group (P < 0.05); the weight of tibialis anterior was higher on the affected side than on the contralateral side and in the control group (P < 0.001); the weight of vastus lateralis was lower on the contralateral side than on the affected side and in the control group (P < 0.001). In the observation group, the peak activation time and stop time of Synergy 3 were delayed bilaterally (P < 0.05). ConclusionPatients after ACLR exhibit altered structural and temporal characteristics of lower limb muscle synergy during jump task. The hamstrings show increased participation during the pre-activation phase, and calf muscles undertake more stabilizing functions during the landing phase.

OBJECTIVE:Exercise intervention is considered the cornerstone of rehabilitation after anterior cruciate ligament reconstruction.However,no clear conclusion has been reached regarding which exercise therapy is more effective in improving knee muscle strength and function in patients after anterior cruciate ligament reconstruction.To this end,this study used a network meta-analysis method to compare the efficacy of exercise therapy after anterior cruciate ligament reconstruction,providing evidence-based medical basis for selecting the best exercise therapy. METHODS:A computer search was conducted in PubMed,Web of Science,Embase,The Cochrane Library,and EBSCO to collect randomized controlled trials addressing exercise therapy following anterior cruciate ligament reconstruction.The search time limit was from the establishment of the database to 2023-11-20.Outcome indicators included three continuous variables:quadriceps muscle strength,hamstring muscle strength,and knee joint function score.EndNote X9.1 was used for literature screening.The Cochrane risk of bias assessment tool was used to evaluate the quality of the included literature.The GRADE score was used to rate the strength of evidence for the results of the article.Network meta-analysis was performed using Stata 16.0. RESULTS:A total of 36 randomized controlled trials were included,involving 1 179 patients undergoing anterior cruciate ligament reconstruction.The overall quality of the included literature was moderate.Nine types of exercise therapies were involved:isokinetic training,cross training,eccentric training,aquatic rehabilitation,blood flow restriction training,motor control training,plyometric training,whole-body vibration training,and multimodal training;the control measure was conventional rehabilitation training.The results of the network meta-analysis showed that compared with conventional rehabilitation training,eccentric training[standardized mean difference(SMD)=2.08,95%confidence interval(CI):0.56 to 3.60,P=0.007)had the best improvement effect on quadriceps muscle strength in patients undergoing anterior cruciate ligament reconstruction,followed by multimodal training(SMD=1.69,95%CI:0.11 to 3.27,P=0.249)and whole body vibration training(SMD=0.81,95%CI:0.11 to 1.51,P=0.042).In terms of improving patients'hamstring muscle strength,multimodal training(SMD=2.08,95%CI:0.30 to 3.86,P=0.022)had the best effect,followed by plyometric training(SMD=1.51,95%CI:0.18 to 2.84,P=0.026)and isokinetic training(SMD=1.37,95%CI:0.06 to 2.67,P=0.039).Multimodal training(SMD=4.60,95%CI:2.40 to 6.80,P<0.001)was the most effective in improving knee joint function scores,followed by eccentric training(SMD=1.75,95%CI:0.24 to 3.25,P=0.023)and aquatic rehabilitation(SMD=1.65,95%CI:0.07 to 3.24,P=0.041). CONCLUSION:Evidence of low to moderate strength suggests that multimodal training may be the most effective exercise therapy in improving knee muscle strength and function in patients after anterior cruciate ligament reconstruction,followed by eccentric training,plyometric training,isokinetic training,whole body vibration training,and aquatic rehabilitation.More high-quality clinical randomized controlled trials are still needed in the future to verify the reliability of the conclusions.

Objective The differences in biomechanical characteristics of the lower limbs between individuals with chronic ankle instability(CAI)and healthy individuals during unanticipated and anticipated jumping were compared,in order to provide practical references and ideas for the prevention and treatment of recurrent ankle sprains.Methods Thirty subjects were recruited,including 15 patients with CAI and 15 healthy volunteers.All subjects completed unanticipated and anticipated jumping tests in a random order,with a 1-week interval between the two tests.Kinematic and kinetic data of lower limbs were collected synchronously using Vicon infrared high-speed motion capture system and Kistler three-dimensional force platform.Results At the moment of touchdown,knee flexion angle was significantly greater during unanticipated jumping than that during anticipated jumping(P=0.009),while ankle eversion angle was notably lower(P=0.043).During the early landing phase,unanticipated jumping showed significantly greater peak hip flexion and abduction angles,as well as knee flexion(P=0.038,P=0.036,P=0.04),while peak ankle dorsiflexion and eversion angles were significantly lower(P=0.001,P=0.01)compared to anticipated jumping.Additionally,peak hip abduction moment during unanticipated jumping was significantly higher in patients with CAI than that during anticipated jumping(P=0.028).Conclusions Unanticipated jumping reduced ankle dorsiflexion and eversion angles in individuals with CAI,putting the ankle in an open,sprain-prone position.Individuals with CAI compensated proximally by increasing hip flexion,abduction,knee flexion angles,and hip extension moment to stabilize the ankle.

Objective The differences in biomechanical characteristics of the lower limbs between individuals with chronic ankle instability(CAI)and healthy individuals during unanticipated and anticipated jumping were compared,in order to provide practical references and ideas for the prevention and treatment of recurrent ankle sprains.Methods Thirty subjects were recruited,including 15 patients with CAI and 15 healthy volunteers.All subjects completed unanticipated and anticipated jumping tests in a random order,with a 1-week interval between the two tests.Kinematic and kinetic data of lower limbs were collected synchronously using Vicon infrared high-speed motion capture system and Kistler three-dimensional force platform.Results At the moment of touchdown,knee flexion angle was significantly greater during unanticipated jumping than that during anticipated jumping(P=0.009),while ankle eversion angle was notably lower(P=0.043).During the early landing phase,unanticipated jumping showed significantly greater peak hip flexion and abduction angles,as well as knee flexion(P=0.038,P=0.036,P=0.04),while peak ankle dorsiflexion and eversion angles were significantly lower(P=0.001,P=0.01)compared to anticipated jumping.Additionally,peak hip abduction moment during unanticipated jumping was significantly higher in patients with CAI than that during anticipated jumping(P=0.028).Conclusions Unanticipated jumping reduced ankle dorsiflexion and eversion angles in individuals with CAI,putting the ankle in an open,sprain-prone position.Individuals with CAI compensated proximally by increasing hip flexion,abduction,knee flexion angles,and hip extension moment to stabilize the ankle.

OBJECTIVE:Some studies have shown that kinesio taping has positive effects in elevating muscle strength,improving joint stability and reducing pain and oedema in patients after anterior cruciate ligament reconstruction.However,existing studies have divergent results on the clinical efficacy of kinesio taping.In this study,a meta-analysis was conducted to systematically evaluate the effect of kinesio taping in postoperative rehabilitation period following anterior cruciate ligament reconstruction. METHODS:Randomized controlled trials about the effects of kinesio taping on anterior cruciate ligament reconstruction were electronically searched in PubMed,Web of Science,Embase,The Cochrane Library,EBSCO,CNKI,WanFang,and VIP databases,from database inception to December 06,2022.The outcome measures included six continuous variables:quadriceps strength,hamstring strength,knee swelling,knee range of motion,Lysholm knee function score,and Visual Analogue Scale score.EndNote X9.1 was used to screen the literature.The Cochrane Risk Bias Assessment Tool and Jadad Scale were used to evaluate the quality of the included literature.RevMan 5.3 software was used for Meta-analysis. RESULTS:A total of 6 randomized controlled trials involving 252 patients undergoing anterior cruciate ligament reconstruction were finally included.There were 126 cases in control group and 126 in kinesio taping group.The results of Meta-analysis showed that compared with the control group,kinesio taping significantly improved hamstring strength[standardized mean difference(SMD)=0.68,95%confidence interval(CI):0.12 to 1.23,P=0.02)and reduced Visual Analogue Scale score[mean difference(MD)=-0.56,95%CI:-1.04 to-0.08,P=0.02).However,for quadriceps strength,knee swelling,knee range of motion,and Lysholm knee function score,kinesio taping did not show significant difference from the control group(P＞0.05). CONCLUSION:Kinesio taping may help to improve hamstring strength and reduce pain in patients after anterior cruciate ligament reconstruction.However,it cannot significantly improve quadriceps strength,knee swelling,knee range of motion,and functional scores.

OBJECTIVE:To systematically review the clinical effect of blood flow restriction training on rehabilitation after anterior cruciate ligament reconstruction to provide a reference for clinical practice. METHODS:Databases including CNKI,WanFang,PubMed,Web of Science and EBSCO were searched to collect randomized controlled trials of blood flow restriction training in the intervention of anterior cruciate ligament reconstruction from inception to August 10,2022.Outcomes included knee muscle strength,knee muscle mass,and knee function evaluation,all of which were continuous variables.Two reviewers independently screened the literature and extracted data.Cochrane bias risk assessment tool and Physiotherapy Evidence Database Scale were used to evaluate the bias risk of the included articles.Meta-analysis was then performed using RevMan 5.4 software. RESULTS:A total of 9 publications were included,including 226 subjects,114 in the trial group and 112 in the control group.Meta-analysis results showed that compared with conventional resistance training,the blood flow restriction training group could significantly improve knee muscle strength[SMD=0.54,95%CI(0.29,0.79),P＜0.01],muscle mass[SMD=0.26,95%CI(0.06,0.46),P=0.01]and knee joint function[SMD=1.17,95%CI(0.53,1.80),P＜0.01].Subgroup analysis showed that only when the intervention time was more than 4 weeks,there were significant improvements in knee joint muscle strength[SMD=0.68,95%CI(0.38,0.97),P＜0.01]and muscle mass[SMD=0.38,95%CI(0.09,0.68),P=0.01]. CONCLUSION:Current evidence shows that blood flow restriction training can improve muscle strength and knee function in patients with anterior cruciate ligament reconstruction and reduce muscle atrophy.It is recommended that the postoperative intervention time should be more than 4 weeks to achieve better muscle strength and muscle mass improvement.

Objective To explore whether the single leg vertical jump height limb symmetry index(LSI)＞90%can represent the normal lower limb biomechanics in athletes after anterior cruciate liga-ment reconstruction(ACLR)during jumping.Methods Forty-six athletes after ACLR were divided into a low symmetry group(jump height LSI＜90%,n=23)and a high symmetry group(jump height LSI＞90%,n=23)according to the symmetry of single leg vertical jump height,while 24 healthy counter-part athletes were chosen into the control group.The kinematic and kinetic characteristics were com-pared among the three groups.Results(1)At the take-off stage,compared with the control group,both sides of the low-symmetry group had higher peak hip flexion angle(P＜0.05),but only the operat-ed side showed lower knee flexion moment(P=0.002),knee power(P=0.01),ankle power(P=0.045)and peak vertical ground reaction force(P=0.008).(2)At the take-off stage,there were no significant differences between the operated side of the high symmetry group and the control group in all measure-ments.However,compared with the healthy side,the operated side demonstrated lower knee flexion moment(P=0.001),knee power(P=0.002),total power of lower limb(P=0.001)and peak vertical ground reaction force(P=0.046).(3)During landing,compared with the control group,bilateral sides of the low symmetry group showed a higher peak hip flexion angle(P＜0.05)and a lower peak flexion knee angle(P＜0.05),but its operated side demonstrated lower peak ankle dorsiflexion angle(P=0.018),knee flexion moment(P=0.005),knee power(P=0.037),ankle power(P=0.002),total power of lower limb(P=0.042),and peak vertical ground reaction force(P=0.022).(4)During landing,there were no significant differences in all variables between the operated side of the high symmetry group and the control group.However,compared with its healthy side,the affected side of the high symmetry group demonstrated lower knee flexion moment(P=0.002),ankle dorsiflexion moment(P=0.003),knee power(P＜0.001),total power of lower limbs(P=0.001),and peak vertical ground reaction force(P=0.023).Conclusion Despite achieving the single leg vertical jump height LSI＞90%,athletes after ACLR still showed abnormal lower limb biomechanical characteristics during propulsion and landing.In addition,such abnormality is more obvious in athletes after ACLR with jump height LSI＜90%.Therefore,sym-metry in jump height does not represent normal lower extremity biomechanics in athletes after ACLR.