Effects of Hip Strengthening on Neuromuscular Control, Hip Strength, and Self-Reported Functional Deficits in Individuals With Chronic Ankle Instability

The Effect of Additional Neuromuscular Training on Peri-Ankle Muscle Morphology and Function in Chronic Ankle Instability Subjects: A Randomized Controlled Trial

BACKGROUND

Lateral ankle sprain is one of the most common musculoskeletal issues during sports and activities of daily living. This study investigated the effect of combined neuromuscular training and conventional training (including strengthening, range of motion, and balance exercises) on muscle morphology, dynamic balance, perceived ankle instability, and functional capacity in persons with chronic ankle instability (CAI).

HYPOTHESIS

The combination of neuromuscular and conventional training programs might result in additional benefits on the morphology of muscle, dynamic balance, and functional capacity in subjects with CAI.

STUDY DESIGN

A single-blind parallel-arm randomized controlled trial.

LEVEL OF EVIDENCE

Level 2.

METHODS

A total of 34 participants with CAI were divided randomly into experimental (EG) and control groups (CG). The EG received conventional and neuromuscular training, while the CG underwent conventional training. Cross-sectional areas of the peroneus longus and tibialis anterior muscles were measured using ultrasonography. Measurements included reaching direction distance, ankle instability, and the foot and ankle outcome score, all evaluated before and immediately after 12 intervention sessions and 4 weeks later in the follow-up phase.

RESULTS

Repeated-measures analysis of variance (ANOVA) revealed significant improvement in the EG, particularly in the cross-sectional area of the tibialis anterior muscle on the injured side and the posteromedial reaching direction displacement of the Y balance test. Moreover, the EG's foot and ankle outcome scores increased significantly compared with the CG (P < 0.05). However, the group effect size ranged from minor to moderate (Hedges g, 0.40-0.73).

CONCLUSION

Combining neuromuscular and conventional training programs yields greater benefits than conventional training alone regarding tibialis anterior muscle morphology, posteromedial dynamic balance, and functional capacity in persons with CAI.

CLINICAL RELEVANCE

The combination of neuromuscular and conventional training programs could enhance muscle morphology, dynamic balance, perceived ankle instability, and functional capacity in persons with CAI.

Effectiveness of exercise therapy on chronic ankle instability: a meta-analysis

Lateral ankle sprains are one of the most common musculoskeletal injuries. Up to 70% of individuals who sustain lateral ankle sprains develop chronic ankle instability (CAI). Exercise therapy is considered an effective treatment for patients with CAI. This meta-analysis investigated the efficacy of exercise therapy in CAI patients by reviewing 15 randomized controlled trials (RCTs) involving 586 participants. Databases including PubMed, EMBASE, Cochrane Library, and Web of Science were searched from inception to September 13, 2024. The Cochrane Risk of Bias Tool was used to assess study quality. Meta-analysis, sensitivity analysis, and publication bias analysis were conducted using RevMan 5.3.0 and Stata 18.0 software. The Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) approach was applied to evaluate the quality of evidence. Main outcomes were assessed using the Foot and Ankle Ability Measure (FAAM) and the Star Excursion Balance Test (SEBT). The results demonstrated that exercise therapy significantly improved FAAM-S (MD = 7.98, CI: 4.11 to 11.86, p < 0.0001, I² = 30%). Long-term exercise therapy (over 4 weeks) significantly enhanced FAAM-A (MD = 10.95, CI: 6.60 to 15.29, p < 0.00001, I² = 0%) and dynamic balance ability of ankle joint (SBET-A: MD = 4.83, CI: 1.04 to 8.63, p = 0.01, I² = 62%; SEBT-PM: MD = 6.93, CI: 2.37 to 11.48, p = 0.003, I² = 69%; and SEBT-PL: MD = 8.98, CI: 2.66 to 15.29, p = 0.005, I² = 86%). After categorizing by exercise type, the results indicated that strength training was more effective in improving SEBT-PL (MD = 8.15, CI: 6.09 to 10.21, p < 0.00001, I² = 0%), joint mobilization was more effective in improving SEBT-A (MD = 7.65, CI: 4.93 to 10.37, p < 0.00001, I² = 0%), and proprioceptive training was more effective in improving SEBT-PM (MD = 10.46, CI: 5.27 to 15.65, p < 0.0001, I² = 33%). In conclusion, long-term, multifaceted exercise therapy demonstrates superior rehabilitation efficacy for patients with CAI. Personalized treatment plans, informed by SEBT assessment results, should prioritize targeted interventions such as joint mobilization, strength training, or proprioceptive training. This approach holds significant theoretical and practical value for optimizing CAI treatment strategies and enhancing patient outcomes.

Isometric and isokinetic hip strength in males with chronic ankle instability and its relationship with dynamic balance and self-reported instability

OBJECTIVES

To investigate isometric and isokinetic hip strength as well as dynamic balance in males with chronic ankle instability (CAI) and explore potential associations between hip strength, dynamic balance, and self-reported instability.

DESIGN

Cross-sectional study.

SETTING

University laboratory.

PARTICIPANTS

Fifty male participants (25 with CAI and 25 healthy controls).

MAIN OUTCOME MEASURES

Hip isometric and isokinetic torque normalized to body weight, Lower Quarter Y-balance Test (YBT-LQ), the Polish version of The Cumberland Ankle Instability Tool (CAIT-PL).

RESULTS

Significant differences were observed only in the hip isometric abductors/adductors strength ratio (p = 0.034, ES = 0.65), which was lower in the CAI group. CAI participants showed reduced dynamic balance in posterolateral reach (p = 0.006, ES = 0.92) and composite score of YBT-LQ (p = 0.012, ES = 0.91). There was a moderate positive correlation between dynamic balance and hip abductors strength during posteromedial (r = 0.40, p = 0.049) and posterolateral (r = 0.40, p = 0.048) YBT-LQ reaches, and isometric hip abductors strength moderately positively correlated with self-reported instability (r = 0.46, p = 0.021) in the CAI group.

CONCLUSION

Males with CAI exhibit deficits in frontal plane hip isometric strength, specifically in the hip abductor/adductor ratio, while no deficits were observed in isokinetic strength. The relationships between hip abductors strength, dynamic balance, and self-reported ankle instability may suggest the importance of hip abductors isometric strength for functional outcomes in CAI-patients.

A Critical Review of Trunk and Hip Exercise Prescription: Applying Evidence for a Modern Approach

Exercise targeting the trunk and hip (core) musculature is common practice in rehabilitation and performance training. Historical underpinnings of core exercise focus on providing stability to the spine, thus improving the function of the spine and extremities, while instability has been postulated to result in pathology and impaired performance. Mechanistic studies on the topic are often conflicting and indeterminate, suggesting the theoretical underpinnings of targeted core exercise may be over assumed in common practice. The best modes of intervention also remain undefined, with combined methods having potential to optimize outcomes. This includes moving beyond isolated exercise camps and being inclusive of both targeted exercise and progressive multi-joint movements. The purpose of this clinical commentary is to describe the historical mechanisms of the stability-instability continuum and the role of exercise intervention. A spectrum of ideologies related to core exercise are examined, while appreciating positive outcomes of exercise interventions across healthy and pathological populations. Finally, exercise summaries were compiled to improve critical reasoning within current practice and inspire future investigations.

Level of Evidence

5.

Comparing the Effects of Progressive Balance and Hip Strengthening Rehabilitation in Individuals With Chronic Ankle Instability

CONTEXT

Chronic ankle instability (CAI) is associated with motor-behavioral and sensory-perceptual impairments, including reduced balance performance, hip strength, and ankle function, and increased disablement, and injury-related fear. Progressive balance training (BAL) and hip strengthening (HIP) can both improve balance and function, but their comparative effects are unknown. Our objective was to compare the effects of progressive BAL and HIP on balance, hip strength, and patient-reported outcomes in those with CAI.

METHODS

Forty-five individuals with CAI volunteered for this randomized control study. Participants were randomly allocated to BAL, HIP, and control (CON) groups (n = 15 per group). BAL and HIP each participated in 8-week interventions while CON did not. Participants' involved limbs underwent testing of patient-reported outcomes (Foot and Ankle Ability Measure [FAAM-ADL, FAAM-S], modified Disablement in the Physically Active Scale [mDPA], Tampa Scale of Kinesiophobia-11 [TSK-11], Fear-Avoidance Beliefs Questionnaire [FABQ], and Self-Efficacy of Balance Scale [SEBS]), Star Excursion Balance Test (SEBT), and isometric hip strength (extension [EXT], abduction [ABD], and external rotation [ER]) before and after the intervention. Multiple imputation was used for missing data. Multivariate repeated-measures analyses of variance analyzed effects of the interventions.

RESULTS

A significant group × time interaction existed for psychosocial outcomes (P = .008), but not for balance (P = .159), strength (P = .492), or ankle function and disability (P = .128). Time main effects existed for balance (P = .003), strength (P < .001), function and disability (P < .001), and psychosocial outcomes (P = .006). BAL significantly improved in SEBT, EXT, ABD, and all patient-reported outcomes. HIP significantly improved in EXT, ABD, ER, FAAM-S, mDPA, FABQ, and SEBS.

CONCLUSIONS

Balance training and hip strengthening can both improve motor-behavioral and sensory-perceptual impairments in individuals with CAI; however, balance training remains the most effective option for clinicians.

Is chronic ankle instability associated with contractile thickness of gluteus medius and gluteus maximus during functional movement and exercise? A systematic review and meta-analysis

INTRODUCTION

The gluteus medius (GMED) and gluteus maximus (GMAX) play a crucial role in postural control, and postural control is impaired in individuals with chronic ankle instability (CAI). However, the association between CAI and the recruitment of these muscles remains unclear. The purpose of this study was to explore the contractile thickness of GMED and GMAX during functional movements in individuals with CAI compared to healthy controls.

EVIDENCE ACQUISITION

A systematic search was conducted in six databases (PubMed, Embase, Cochrane Library, Web of Science, EBSCO, and PEDro). Included studies involved the contractile thickness of GMED and/or GMAX comparing CAI with non-CAI. The extracted data were subjected to meta-analysis for observing the differences between the two. The correlation and difference in contraction between GMED and GMAX were analyzed using the Pearson Correlation Coefficient (PCC) and t-test, respectively.

EVIDENCE SYNTHESIS

Six studies with 176 participants were found. Contractile thickness measured by ultrasound showed GMED thickness change to be lower in CAI than in controls during functional movements and exercise (WMD: -0.08; 95% CI: -0.11, -0.04; P<0.00001). There was no significant difference between the two groups with respect to contraction of GMAX (WMD: 0.02; 95% CI: -0.01, 0.05; P=0.25). The PCC and P value (t-test) between the ratio of contractile thickness of GMED and GMAX in CAI were 0.397 and 0.029 respectively, indicating activity differences.

CONCLUSIONS

CAI may be associated with weaker GMED recruitment during functional movements and exercise, but the activation of GMAX in CAI may be unaffected.

What Will Deliver the Best Bang-For-Your-Treatment-Buck? Treatment Effects of Physical Therapy Approaches to Managing Chronic Ankle Instability: A Network Meta-Analysis of Randomized Controlled Trials

OBJECTIVE: To evaluate the relative efficacy of various physical therapy interventions for chronic ankle instability (CAI). DESIGN: A network meta-analysis of randomized controlled trials. LITERATURE SEARCH: PubMed, Cochrane Library, Embase, Scopus, and CINAHL bibliographic databases were searched up to December 2023. STUDY SELECTION CRITERIA: Randomized controlled trials examining nonsurgical treatments for CAI. DATA SYNTHESIS: We used frequentist network meta-analysis to assess 8 outcomes across 44 trials, including the Foot and Ankle Ability Measure (FAAM) Activities of Daily Living (ADL) scale or Sport scale, Cumberland Ankle Instability Tool (CAIT), Star Excursion Balance Test (SEBT) in 3 directions (anterior [A], posteromedial [PM], and posterolateral [PL]), dorsiflexion range of motion, and pain. Surface under the cumulative ranking curve (SUCRA) values identified the most effective interventions. RESULTS: Based on SUCRA rankings, a regimen combining balance and strengthening exercises, augmented with either manual therapy or dry needling, was identified as the most effective in enhancing function (SUCRA: FAAM ADL = 95.2% [manual]/83.9% [dry needling]; FAAM Sport = 87.9% [manual]/80.1% [dry needling]), improving dynamic balance (SUCRA [manual]: SEBT-A = 92.1%; SEBT-PM = 98.0%; SEBT-PL = 90.8%), and significantly relieving pain (SUCRA: 99.9%). A multimodal exercise approach combined with manual therapy showed superior efficacy in increasing dorsiflexion (SUCRA: 61.6%). Tai chi emerged as the most promising intervention for improving stability (SUCRA: 99.9%). CONCLUSION: Interventions that emphasized strengthening and balance exercises were the most effective strategy for achieving best function and pain relief for patients with CAI. Multimodal exercises and tai chi might improve ankle range of motion and instability, respectively. J Orthop Sports Phys Ther 2025;55(1):26-44. Epub 20 December 2024. doi:10.2519/jospt.2024.12601.

Do individuals with ankle instability show altered lower extremity kinematics and kinetics during walking? A systematic review and meta-analysis

OBJECTIVE

To determine if individuals with chronic ankle instability (CAI) demonstrate altered lower extremity kinematics and kinetics during walking.

DATA SOURCES

Relevant studies were sourced from PubMed, Embase, Cochrane Library, Web of Science, EBSCO and PEDro.

STUDY SELECTION

Kinematic and kinetic studies involving joint angle and/or joint moment measured in individuals with CAI were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

The Risk of Bias in Non-randomised Studies - of Interventions (ROBINS-I) tool was used to assess literature quality. Weighted mean differences (WMDs) in joint angles and moments between CAI and controls were analyzed as continuous variables.

RESULTS

1261 articles were screened, with a final selection of 13 studies involving 729 participants. Compared to non-CAI controls, CAI participants showed significantly greater ankle inversion angle (degree) (WMD: 3.71, 95% CI: 3.15 to 4.27, p < 0.001), hip adduction angle (degree) (WMD: 1.60, 95% CI: 0.09 to 3.11, p = 0.04), and knee valgus moment (N m/kg) (WMD: 0.07, 95% CI: 0.01 to 0.13, p = 0.02) during walking. Additionally, there were no consistent findings or specific altered patterns in other lower extremity joint angles, or moment changes, regardless of the motion plane (sagittal, coronal, horizontal), for CAI compared with controls.

CONCLUSIONS

This review provides further evidence of altered lower limb kinematics and kinetics in the frontal plane in CAI participants during certain walking phases, which may partially explain the high level of recurrent ankle sprains observed in the CAI population, and support hip abduction and ankle eversion motor control exercises for CAI rehabilitation.

SYSTEMATIC REVIEW REGISTRATION NUMBER

Systematic Review Registration Number PROSPERO CRD42023420418. CONTRIBUTION OF THE PAPER.

External focus instruction using a soft paper balloon on muscle activation patterns in isometric hip abduction exercises: A comparative analysis with external resistance tools

BACKGROUND

This study investigates a novel isometric method utilizing an external focus instruction technique with a soft paper balloon. By emphasizing control to avoid crushing the balloon, this method promotes co-contraction of muscles without exerting pressure on the object. We aim to evaluate differences in muscle activation patterns during isometric hip abduction exercises between the paper balloon task and tasks using external resistance (hard plastic, non-elastic, and elastic bands), and further determine their influence on the contralateral side.

METHODS

Thirteen healthy adult males aged 20-28 years were recruited. Six trunk muscles (transversus abdominis [TrA], internal oblique [IO], external oblique, rectus abdominis, multifidus [MF], and lumbar erector spinae) and five lower-extremity muscles (gluteus maximus [GMax], gluteus medius [GMed], adductor longus, rectus femoris [RF], and biceps femoris [BF]) were measured using surface and fine-wire electrodes to compare the different isometric hip abduction exercises.

RESULTS

The muscle activity did not differ between the abduction sides except for GMax and GMed with the elastic band and RF and BF with the hard plastic (p > 0.05).

CONCLUSIONS

The trunk muscles (TrA, IO, and MF) were similarly activated with the paper balloon and external loading tasks; however, the paper balloon task activated trunk muscles without bearing weight, potentially avoiding pressure on the spine, knee, or hip joints. Moreover, all tasks showed muscle activation on the opposite side of the body.

Cross-education effects of balance training in individuals with chronic ankle instability

BACKGROUND

Individuals with chronic ankle instability (CAI) often experience deficits in balance, hip strength, and lumbopelvic stability. Unilateral balance training can lead to improved balance in the contralateral limb, but it is unknown if similar cross-education effects occur for hip strength and lumbopelvic stability. Our purpose was to determine if unilateral balance training improved balance, hip strength, and lumbopelvic stability of the contralateral limbs in individuals with CAI.

METHODS

Using a randomized-controlled trial, 30 individuals with CAI were separated into control (CON) and balance (BAL). Uninvolved limbs underwent testing at baseline and post-intervention. We tested balance with the star excursion balance test in anterior (SEBT-ANT), posterolateral (SEBT-PL), and posteromedial (SEBT-PM) directions. We tested hip strength with a handheld dynamometer in extension (EXT), abduction (ABD), and external rotation (ER). We tested lumbopelvic stability with a unilateral hip bridge. After baseline, BAL completed an 8-week balance training program on the involved limb. CON did not participate in the intervention. Two-way repeated measures ANOVAs analyzed effects of group and time on each outcome. Cohen's d effect sizes analyzed each group's changes from baseline to post-intervention.

RESULTS

Eleven participants discontinued the study (5 CON, 6 BAL) before completion. There were significant group-by-time interactions for SEBT-PL (P = 0.03) and hip bridge (P = 0.03). BAL had moderate to large effect sizes for SEBT-PM (d = 0.69 [-0.06,1.41]), SEBT-PL (d = 0.87 [0.10,1.60]), EXT (d = 0.73 [-0.02,1.45]), ABD (d = 0.79 [0.03,1.51]), and hip bridge (d = 0.83 [0.07,1.55]).

CONCLUSION

A balance training program for limbs with CAI led to contralateral improvements in balance, hip strength, and lumbopelvic stability.

The Influence of Hip-Strengthening Program on Patients with Chronic Ankle Instability

Background and Objectives: Repetitive ankle sprains lead to mechanical instability of the ankle. Patients with chronic ankle instability may experience decreased muscle strength and limited postural control. This study investigated the effects of a hip-strengthening exercise program on muscle strength, balance, and function in patients with chronic ankle instability. Materials and Methods: A total of 30 patients participated in the study and were randomly assigned to the two groups. Among the 30 participants, 14 were assigned to the hip joint-strengthening exercise group and 16 to the control group. The experimental group underwent a hip-strengthening exercise program and received training for 40 min per session twice a week for four weeks. The control group received the same frequency, duration, and number of sessions. Measurements were performed before and after the training period to assess changes in hip strength, balance, and function. Results: In the within-group and between-group comparisons, both groups showed significant differences in hip joint strength, static balance, dynamic balance, and function (FAAM; foot and ankle ability measures) (p < 0.05). Statistically significant differences were observed in the time × group interaction effects among the hip abductors and external rotation in hip joint strength, path length in static balance, posterolateral and posteromedial in dynamic balance, and FAAM-ADL and FAAM-SPORT functions (p < 0.05). Conclusions: Accordingly, this study confirmed that hip joint-strengthening exercises have a positive effect on the strength, balance, and function of patients with chronic ankle instability, and we believe that hip joint-strengthening exercises will be recommended as an effective intervention method for patients suffering from chronic ankle instability.

Ankle dorsiflexion range of motion and hip abductor strength can predict Lower Quarter Y-Balance Test performance in healthy males

OBJECTIVES

The aim of the study was to assess whether strength and range of motion (ROM) of the hip and ankle are the factors determining performance in the Lower Quarter Y-Balance test (YBT-LQ).

DESIGN

Cross-sectional study.

PARTICIPANTS

66 healthy males (age: 25.2±6.8 years) participated in this study.

MAIN OUTCOME MEASURES

Participants underwent assessments of ankle dorsiflexion (DF) ROM, hip internal rotation (IR) ROM, external rotation (ER) ROM and isometric strength of hip abductor (ABD), extensor (EXT) and external rotators (ERS) muscles together with YBT-LQ for both legs. A forward 2-steps multiple linear regression analysis was conducted to examine the relationship between the predictor variables and the criterion variable.

RESULTS

Ankle DF ROM predicted anterior (ANT) reach (R2 = 0.49; R2 = 0.33; p < 0.001). The model with hip ABD strength and ankle DF ROM explained posteromedial (PM) reach variance for stance leg (R2 = 0.35; p < 0.001), while only hip ABD strength was included for kicking leg (R2 = 0.19; p = 0.007). The model with ankle DF ROM and hip ABD strength explained posterolateral (PL) reach for stance leg (R2 = 0.41; p < 0.001). Hip ABD was the only predictor for kicking leg PL reach (R2 = 0.15; p < 0.001). YBT-LQ composite score was explained by ankle DF ROM and hip ABD strength for both legs (R2 = 0.44; p < 0.001) and (R2 = 0.25; p = 0.002).

CONCLUSION

Hip ABD strength and ankle DF ROM can determine performance in the YBT-LQ. Strength of hip EXT, ERS as well as ROM of hip IR and ER did not predict YBT-LQ performance.

Preseason lower extremity range of motion, flexibility, and strength in relation to in-season injuries in NCAA division I gymnasts

OBJECTIVES

To determine if preseason lower extremity ROM, flexibility, and strength differ in collegiate gymnasts (NCAA Division 1) who do or do not sustain an injury during the competitive season.

METHODS

Over four seasons, a total of 15 female gymnasts (age = 20.5 ± 1.0 years) underwent preseason screening (30 gymnast-season). We tested joint ROM (hip: flexion, internal and external rotation; ankle: weightbearing dorsiflexion), muscle flexibility (passive straight leg raise, Thomas,' Ober's, Ely's tests) and strength (hip extensors, abductors, and flexors isometric strength via a handheld dynamometer; knee: quadriceps and hamstring isokinetic strength at 60°/sec). The team athletic trainer tracked overuse lower extremity injuries (restricted gymnasts from full participation, occurred as from participation in organized practice or competition, and required medical attention) during each season. For athletes that tested multiple seasons, each encounter was considered independent, and each preseason assessment was linked to overuse injuries sustained during the same competitive season. Gymnasts were dichotomized into injured and non-injured groups. An independent t-test was used to measure differences in preseason outcomes between injured and non-injured groups.

RESULTS

During four years, we recorded 23 overuse lower extremity injuries. Gymnasts that sustained an in-season overuse injury demonstrated significantly lower hip flexion ROM (mean difference: -10.6°; 95% confidence interval: -16.5, -4.6; p < 0.01) and lower hip abduction strength (mean difference: -4.7% of body weight; 95% confidence interval: -9.2, -0.3; p = 0.04).

CONCLUSION

Gymnasts who sustain an in-season overuse lower extremity injury have significant preseason deficit of hip flexion ROM and weakness in the hip abductors. These findings indicate potential impairments in the kinematic & kinetic chains responsible for skill performance and energy absorption during landing.

Strengthening the Intrinsic Muscles of the Foot and Its Action on Foot Posture and Self-Reported Function in Individuals With Lower Limb Injuries: Systematic Review and Meta-Analysis

OBJECTIVE

The aim of this study was to systematically review the influence of the intrinsic foot musculature on lower limb injuries, with regard to improving foot posture and self-reported function, and to point out the biomechanical effects of strengthening the intrinsic foot musculature.

METHODS

A comprehensive literature search using National Library of Medicine (Medline-PubMed), Scopus, Web of Science, Pedro, SportDiscus, and Cochrane was undertaken.

SELECTION CRITERIA

A literature search was peformed using: Clinical trials of patients with injuries in the lower limbs, and with alterations in the intrinsic musculature of the foot were included and published in the period up to and including April 2023.

DATA SYNTHESIS

Data analysis was measured as standardized mean difference and confidence interval was set at 95%. Random effects model was used.

RESULTS

A total of 1,051 studies were found, but, after evaluation, only 4 were included in the present study. The effect of intrinsic foot musculature strengthening improved medial longitudinal arch height in studies included in the meta-analysis (P < .00001).

CONCLUSION

Based on this systematic review, it is possible to conclude that increasing the strength of intrinsic foot muscles proved to be effective in promoting positive biomechanical changes in the longitudinal arch of the foot of these patients.

Influence of lower limb muscle isometric strength and cardiovascular parameters on locomotor capacity in children and adolescents

BACKGROUND

Although measures of exercise performance and physical activity are known to be related to 6-minute walk test (6mWT), the role of the strength of each muscle group of the lower limb in the locomotor capacity during the development period is unknown.

OBJECTIVE

To identify the role of the isometric strength of lower limb muscles and cardiovascular parameters on the locomotor capacity in children and adolescents, controlling for participants sex, age, and height.

METHODS

Participants (7 to 15 years old; female, n= 113; male, n= 128) were assessed for isometric strength (seven lower limb muscles), cardiovascular parameters (diastolic pressure, oxygen saturation, resting heart rate, respiratory rate), and 6mWT. Participants were split into nine age groups and separated by 1-year intervals.

RESULTS

Hip flexors-controlled for sex, age, and height-explained a meaningful percentage of the variance (R=2 0.45; p< 0.001) for 6mWT distance, and the resting heart rate explained a change in R2 of only 2% (p= 0.008).

CONCLUSIONS

Isometric strength of hip flexors explained ∼ 50% of the 6mWT distance, suggesting the importance of strength from an early age. Other factors, such as cardiovascular parameters, while relevant, may exert a secondary role on youth's capacity.

Effects of Conservative Interventions on Static and Dynamic Balance in Individuals With Chronic Ankle Instability: A Systematic Review and Meta-analysis

OBJECTIVE

To determine which conservative interventions are effective for static and dynamic balance in patients with chronic ankle instability (CAI).

DATA SOURCES

PubMed, Cochrane Library, Web of Sciences, and CINAHL databases were searched up to March 20, 2022.

STUDY SELECTION

Randomized controlled trials investigating the effects of conservative interventions on static and/or dynamic balance in patients with CAI compared with those of different conservative interventions or controls were included.

DATA EXTRACTION

Two independent reviewers extracted the data. Certainty of the evidence was assessed using the GRADE approach.

DATA SYNTHESIS

Forty-eight studies (1906 participants) were included. Whole-body vibration training (WBVT) was significantly more effective than controls for both static (standardized mean difference, 1.13; 95% confidence interval [CI], 0.58-1.68; moderate-certainty evidence) and dynamic balance (0.56; CI, 0.24-0.88; low-certainty evidence). Balance training (BT) and joint mobilization were significantly more effective than controls for dynamic balance (0.77; CI, 0.41-1.14; and 0.75; CI, 0.35-1.14, respectively), but not for static balance (very low to low-certainty evidence). Adding other interventions to BT had no significant effect on either type of balance compared with that of BT alone (moderate to low-certainty evidence). Strength training (ST) and taping had no significant effect on either type of balance (very low- to low-certainty evidence). Multimodal interventions were significantly effective in improving dynamic balance (0.76; CI, 0.32-1.20; low-certainty evidence). Adding transcranial direct current stimulation to ST was significantly more effective for dynamic balance than ST (0.81; CI, 0.08-1.53; moderate-certainty evidence). The effects on balance were not significantly different among BT, ST, and WBVT (very low- to low-certainty evidence).

CONCLUSIONS

The significantly effective interventions reviewed may be treatment options for balance impairments associated with CAI. However, interventions should be chosen carefully, as much of the certainty of evidence is very low to low.

Cross-Education Balance Effects After Unilateral Rehabilitation in Individuals With Chronic Ankle Instability: A Systematic Review

OBJECTIVE

To conduct a systematic review of existing literature on cross-education balance effects after unilateral training in the population with chronic ankle instability (CAI).

DATA SOURCES

PubMed, SPORTDiscus, CINAHL Plus.

STUDY SELECTION

To be included in the systematic review, studies were required to have been published in English, included participants with CAI, had participants undergo a unilateral therapeutic exercise for the lower extremity, and measured balance performance of the untrained lower extremity before and after the intervention.

DATA EXTRACTION

The certainty of evidence in each included study was assessed via the Downs and Black checklist. A score of 24 to 28 indicated excellent or very low risk of bias; 19 to 23, good or low risk of bias; 14 to 18, fair or moderate risk of bias; and <14, poor or high risk of bias. We extracted information from each study regarding design, participant characteristics, inclusion criteria, independent and dependent variables, intervention, and results. Baseline and postintervention balance performance data for participants' untrained limbs were used to calculate the Hedges g effect sizes and 95% CIs.

DATA SYNTHESIS

Our search returned 6 studies that met the inclusion criteria. The articles' risk of bias ranged from high to low (11-19). In 4 of 5 studies that examined unilateral balance training, the authors reported a cross-education effect. In the lone study that examined resistance training at the ankle joint, a cross-education effect was also present. Several cross-education effects were associated with large effect sizes. This systematic review was limited by a small number of studies that varied in methods and quality.

CONCLUSIONS

Our results suggest that unilateral therapeutic exercise can improve balance performance of the untrained limb of individuals with CAI. More work is needed to determine which training protocols are most effective for generating a cross-education effect.

Comparison of effect of wobble board training with and without cognitive intervention on balance, ankle proprioception and jump landing kinetic parameters of men with chronic ankle instability: a randomized control trial

Background

The aim of the present study was to compare the effect of a wobble board training (WBT) course with and without cognitive intervention (CI) on balance, ankle proprioception and jump-landing kinetic parameters in active men with chronic ankle instability (CAI).

Methods

Twenty-one active men in the age range of 18–25 years with CAI were randomly divided into three groups of WBT for five weeks as follows: with CI (n = 7); without CI (n = 7); control (n = 7). In this study, balance was evaluated by Y-Balance Test and Balance Error Scoring System, proprioception was evaluated as active and passive replication of 15-degree inversion angle and Maximum inversion angle minus 5-degrees, and single-leg jump-landing test was used for measurement of kinetic variables as pre-test and post-test in similar conditions.

Results

Post-test of both groups of WBT with and without CI showed a significant improvement in all variables compared to pre-test (p ≤ 0.05); however, in post-test, there was no significant difference in any of the variables between WBT groups with and without CI (p ≥ 0.05).

Conclusions

A course of WBT with and without CI leads to a significant improvement in balance, proprioception and jump-landing kinetic parameters, including time to stabilization and center of pressure displacement in active men with CAI. Although the WBT group with CI showed a greater improvement in mean than WBT group without CI, but the difference was not significant in any of the variables.

Trial registration

Retrospectively Registered. irict.ir Identifier: IRCT20200617047818N1 on 05–02-2021.

Sex differences in the relationship of hip strength and functional performance to chronic ankle instability scores

Background

While decreased hip abductor strength, functional performance, and self-reported instability scores have all been shown in association with CAI, any sex difference in the relationship between these indicators is unclear. This study was to determine whether sex differences are present in the relationship between these indicators in individuals with CAI.

Methods

Thirty-two women and twenty-nine men with unilateral CAI took part. Hip abductor strength and functional performance were respectively assessed using a hand-held dynamometer and the figure-8-hop test. All 61 participants scored the Cumberland Ankle Instability Tool (CAIT) for self-reported ankle instability. Independent sample t-tests and correlation analysis were conducted.

Results

Normalized hip abductor strength and functional performance measures for females were lower than for males. The self-reported ankle instability CAIT score, where higher values represent less instability, was significantly and positively correlated with both normalized hip abductor strength (p = 0.003) and functional performance (p = 0.001) on the affected side in females, but not in males (p = 0.361 and p = 0.192 respectively).

Conclusions

Sex differences were observed in that there were significant relationships between normalized hip abductor strength, functional performance, and CAIT scores in female CAI participants, but not males, suggesting that CAI evaluation and rehabilitation strategies should be sex-specific.

Highlights

In females with CAI, hip abductor strength and functional performance showed significant relationships with self-reported instability scores.

Correspondingly, in clinical practice with individuals with CAI, evaluation criteria may be formulated according to these observed sex differences.

Sex differences should be factored into the evaluation and treatment of CAI individuals.

Hip strength assessment should be employed with CAI individuals.

Hip strengthening and functional hopping may be recommended for the rehabilitation of CAI, especially in female patients.

The effectiveness and sustainability of supervised balance training in chronic ankle instability with grade III ligament injury: a one-year prospective study

Background

To determine the effectiveness and sustainability of supervised balance training in people with chronic ankle instability (CAI) with grade III ligament injury.

Methods

Twenty young adults (12 males and 8 females) diagnosed with CAI with grade III ligament injury underwent 3 months of supervised balance training. The self-reported functional questionnaire, plantar pressure (walking and single leg standing), and isokinetic ankle strength were consecutively evaluated at pre-training, 3 months, 6 months and one year. Paired T tests were used to explore changes in muscle strength and plantar pressures following the supervised balance training. According to whether the patient had sprain recurrence, the patients were divided into sprain recurrence group and control group. The risk factors of sprain recurrence were explored with univariate analysis and multivariable logistic regression.

Results

The self-reported functional scores, the plantar pressure distribution and the muscle strength showed significant immediate improvements after 3 months of supervised balance training. At 6 months post-training, peak force under 2nd metatarsal, time to peak force under the medial hindfoot, time to boundary measurements and dorsiflexion, and eversion strength were partly declined to the pre-training level. 16 patients (80%) resumed the daily life and sports without sprain recurrence during the follow-up. Four patients (20%) reported ankle sprain during the follow-up, and the sprain recurrence group showed significantly higher Beighton scores (p = 0.012) and weaker initial inversion strength (p = 0.022) than the control group.

Conclusions

Three months’ of supervised balance training could effectively improve postural control and muscle strength of CAI cases with grade III ligament injury, although these improvements would partially deceased over time. Additional strength exercises for dorsiflexion and eversion should be supplemented from 6 months. Higher Beighton score and initial inversion muscle strength weakness might increase the risk of sprain recurrence.

Trial registration

ChiCTR, ChiCTR1900023999, Registered 21 June 2019, https://www.chictr.org.cn/edit.aspx?pid=39984&htm=4

Supplementary Information

The online version contains supplementary material available at 10.1186/s13047-022-00514-x.

Gluteal Activity During Gait in Patients With Chronic Ankle Instability Following Rehabilitation: A Randomized Controlled Trial

CONTEXT

Ankle positioning gait biofeedback (GBF) has improved ankle inversion for patients with chronic ankle instability. However, the effects on proximal deficits remain unknown. The purpose of this study was to determine the effects of impairment-based rehabilitation with GBF and without biofeedback on gluteal activity during walking in patients with chronic ankle instability.

DESIGN

Randomized controlled trial.

METHODS

Eighteen patients with chronic ankle instability (14 women and 4 men; age 22 [4] y; height 171 [10] cm; mass 71.6 [13.8] kg) were recruited from a university setting, following International Ankle Consortium guidelines. Patients were randomly allocated to GBF or without biofeedback groups (N = 9 per group). Both groups performed 4 weeks of exercises and treadmill walking. The GBF group alone received feedback on frontal ankle positioning at initial contact during walking. Ultrasound videos of the gluteus maximus and medius were recorded during walking at baseline and follow-up by a blinded clinician. Gluteal activity ratios were obtained at each 10% of the gait cycle. Statistical parametric mapping repeated-measures analysis of variance were used to compare groups and time points.

RESULTS

Both groups demonstrated significantly increased gluteus medius activity across the gait cycle compared with baseline (P < .01, mean differences: 0.13-0.21, Hedge g: 0.97-1.89); however, there were no significant between-group differences. There were no statistically significant changes noted for the gluteus maximus. No adverse events were observed.

CONCLUSIONS

Impairment-based rehabilitation led to increased gluteus medius activity, but GBF did not provide any additional improvement to this parameter. Clinicians may consider implementing impairment-based strengthening interventions to improve gluteus medius function during gait for patients with CAI.

Effect of Functional Rehabilitation on Performance of the Star Excursion Balance Test Among Recreational Athletes With Chronic Ankle Instability: A Systematic Review

OBJECTIVE

To determine (1) the effectiveness of rehabilitation for chronic ankle instability as measured by the Star Excursion Balance Test (SEBT) and (2) the relative efficacy and the long-term effects of these rehabilitation interventions.

DATA SOURCES

Ten electronic databases were searched (2009-2019).

STUDY SELECTION

Included articles were randomized controlled trials in English investigating recreational athletes aged ≥18 years with chronic ankle instability. At least 1 functional rehabilitation intervention had to be included and the SEBT test (or the modified version) used as an outcome measure.

DATA EXTRACTION

Two researchers (L.A., O.N.) extracted data regarding participant demographics; intervention characteristics; trial size; and results at baseline, postintervention, and at follow-up, where appropriate.

DATA SYNTHESIS

A systematic review and narrative synthesis was conducted. Methodological quality of included studies was assessed using the Cochrane Risk of Bias Tool and the van Tulder scale. The review was registered with PROSPERO (ID: 164468). Ten studies (n=368), 2 high-quality, 1 moderate-quality, and 7 low-quality, were included in the review. Interventions included balance training, strength training, vibration training, and mixed training. Results suggest that rehabilitation of chronic ankle instability that includes wobble board exercises (average percentage change: 14.3%) and hip strengthening exercises (average percentage change: 12.8%) are most effective. Few studies compared different types of rehabilitation for chronic ankle instability. However, improvements on the SEBT suggest that a rehabilitation program focusing on wobble board training and hip strengthening performed 3 times weekly for 4-6 weeks is the optimal rehabilitation program to improve dynamic postural control in recreational athletes with chronic ankle instability.

CONCLUSIONS

Few studies directly compared different rehabilitation interventions, and there was limited long-term follow-up; therefore, the relative efficacy of different rehabilitation programs remains unclear. However, it seems that rehabilitation of chronic ankle instability should include proprioceptive and strengthening exercises of relatively short duration.

Assessments of Sensorimotor Deficits Used in Randomized Clinical Trials With Individuals With Ankle Sprains and Chronic Ankle Instability: A Scoping Review

The main purpose of this scoping review was to summarize the most common tasks and outcome measures in randomized control trials (RCTs) used to assess sensorimotor function following ankle sprain and chronic ankle instability (CAI). We also aimed to summarize the description of inclusion criteria used in articles. We searched for RCTs published between 2008 and 2018 using the following databases: MEDLINE, PubMed, SPORTDiscus, and Web of Science. Eligible studies included participants of either sex who had had at least one ankle sprain with/without subsequent CAI. All articles assessed sensorimotor function. The tasks, outcome measures, and inclusion criteria were categorized, and frequencies of use in each category were calculated. Of 272 publications, 31 met the eligibility criteria. The most common task was single-limb stance (58% of 31). The most common outcome measure was the posterior-medial reach distance of the Star Excursion Balance Test (SEBT) (13 of 16 articles, 81%). Different inclusion criteria for a history of ankle sprains or CAI were used. A wide range of sensorimotor assessments and inclusion criteria was used among studies involving individuals with a history of ankle sprain with or without CAI, which could make it difficult to compare and generalize study results. This scoping review provides a baseline for planning future studies exploring outcome measures to assess sensorimotor function of individuals with a history of ankle sprain with or without CAI.

Does Strength Training for Chronic Ankle Instability Improve Balance and Patient-Reported Outcomes and by Clinically Detectable Amounts? A Systematic Review and Meta-Analysis

OBJECTIVE

Strength training as a form of exercise therapy has long been used to maintain or promote strength, but its effectiveness as a treatment intervention in chronic ankle instability (CAI) is not fully understood. The purpose of this study was to evaluate the effects of strength training compared with no exercise and neuromuscular control training on balance and self-reported function in people with CAI.

METHODS

Eight databases (PubMed, Embase, Cochrane Library, Web of Science, EBSCO, PEDro, CNKI, and WanFang) were searched in June 2020. Randomized controlled trials (RCTs) involving strength training conducted on individuals with CAI were included. Data were extracted by 2 independent reviewers using a standardized form. Methodological quality and risk of bias were assessed by using the PEDro Scale. In addition, the GRADE evaluation system (Grading of Recommendations Assessment, Development and Evaluation) was used to determine the strength of evidence. A total of 554 studies were initially screened, resulting in a final selection of 11 RCTs involving 428 participants, and 8 RCTs were included in the final meta-analysis. Compared with no exercise, strength training demonstrated some benefits in the Star Excursion Balance Test (anterior: weighted mean difference [WMD] = 2.39, 95% CI = 0.60-4.18; posteromedial: WMD = 3.30, 95% CI = 0.24-6.35; posterolateral: WMD = 2.97, 95% CI = 0.37-5.57), but these intervention results did not reach the minimal detectable change values.

CONCLUSION

Available evidence showed that, compared with controls, strength training did not produce any minimal detectable changes on Star Excursion Balance Test or Foot and Ankle Ability Measure scores in individuals with CAI. Clinicians should use strength training cautiously for improving balance and symptoms in CAI.

IMPACT

The results of this study may have an impact on selecting effective physical therapy interventions for managing symptoms associated with CAI.

Short-Term Effects of Balance Training with Stroboscopic Vision for Patients with Chronic Ankle Instability: A Single-Blinded Randomized Controlled Trial

Chronic Ankle Instability (CAI) is one of the most common musculoskeletal dysfunctions. Stroboscopic vision (SV) training has been deemed to enhance somatosensorial pathways in this population group; nevertheless, until recently no studies have addressed the additional effects of this treatment option to the traditional therapeutic approach.

METHODS

To evaluate the effectiveness of a partial visual deprivation training protocol in patients with CAI, a randomized controlled trial was carried out. Patients with CAI (n = 73) were randomized into either a balance training, SV training, or a control (no training) group. For participants assigned into training groups, they received 18 training sessions over 6 weeks. The primary outcome was dynamic balance as measured by the Star Excursion Balance Test assessed at baseline and after 6 weeks of intervention. Secondary outcome measures included ankle dorsiflexion range of motion, self-reported instability feeling, and ankle functional status.

RESULTS

Better scores in stroboscopic training and balance training groups in all outcome measures were observed in comparison with the control group with moderate to large effect sizes. Stroboscopic training was more effective than neuromuscular training in self-reported instability feeling (cohen's d = 0.71; p = 0.042) and anterior reach distance of the star excursion balance test (cohen's d = 1.23; p = 0.001).

CONCLUSIONS

Preliminary findings from the effects of SV Stroboscopic training in patients with CAI, suggest that SV may be beneficial in CAI rehabilitation.

Hip and knee muscle torque and its relationship with dynamic balance in chronic ankle instability, copers and controls

OBJECTIVES

We compared hip and knee isometric muscle torque between individuals with chronic ankle instability (CAI), those who have sustained one ankle sprain with no ongoing problems (copers) and healthy controls. Our secondary objective was to compare balance between groups and investigate the relationship between muscle torque and balance.

DESIGN

Cross-sectional study.

METHODS

22 CAI, 20 copers and 22 uninjured participants were tested. Isometric torque (normalised to body mass (Nm/kg)) was measured using a rigidly-fixated hand-held dynamometer. Balance was assessed with the Y-balance test.

RESULTS

Knee and hip flexor and extensor, and hip adductor and abductor muscle torque was less in individuals with CAI compared to controls (standardised mean difference (SMD) >1.2). Hip and knee flexor and extensor muscle torque was less in CAI participants than copers (SMD: 0.69-1.1). Hip external and internal rotator torque did not differ between groups. There was no difference in hip or knee muscle torque between controls and copers (SMD: 0.01-0. 54). Balance was impaired in CAI participants compared to copers and controls in all directions. There was a strong positive correlation between posterolateral Y-balance test performance and torque of the hip adductors (r=0.53), flexors (r=0.52) and extensors (r=0.50).

CONCLUSIONS

Individuals with CAI have weak knee and hip muscles compared to copers and controls. Hip strength was shown to be related to posterolateral balance performance. Future studies may investigate the effect of hip and knee strengthening exercise on ongoing ankle problems, such as episodic giving way in individuals with CAI.

Effects of Resistance Exercise on Balance Ability: Systematic Review and Meta-Analysis of Randomized Controlled Trials

With this systematic review, we explored whether resistance exercise (RE) could be used to improve balance in addition to muscular strength and power. Scientific databases were searched for randomized controlled trials that investigated the effects of RE on the performance of various balance tests. Studies were considered if they involved healthy participants of any age group. Thirteen studies were included in the meta-analysis. The results showed moderate to large improvements in balance ability following RE in older adults, as reflected in functional reach test (mean difference (MD): +4.22 cm, p < 0.001), single-leg standing test (MD: +1.9-37.6 s, p < 0.001) and timed-up-and-go test (MD: -0.55 s; p = 0.002). Moderate to large improvements following RE were seen in adults in star excursion balance test (MD: +4.09-5.17 cm; p = 0.001-0.020), but not for Y-balance test score (MD: +4.94%, p = 0.14). The results implicate that RE interventions may significantly improve balance ability in adults and older adults. Therefore, RE could be used to improve balance in these populations, while further studies are needed to investigate children populations. Performing RE alone could be a time-efficient compromise for individuals who are unwilling or unable to perform large volumes of exercise or different exercise modalities.

Effect of an injury prevention program on the lower limb stability in young volleyball players

BACKGROUND

Volleyball players have a high risk of injury in the lower limbs as a consequence of the specific characteristics of the sport, such as repetitive jumps and falls. The objective of the present study was to evaluate the effects of a multidisciplinary injury prevention program on lower limb stability in young volleyball players.

METHODS

The experimental design was a non-randomized controlled trial. All the measurements were performed in a standardized room in a sports center. Twenty-six young male volleyball players (mean age: 15.39±1.16 years), divided into experimental (N.=15) and control groups (N.=11) participated in this study. The experimental group performed an 8-week prevention program including lower limb strength and plyometric training, and joint and core stability. The Y-Balance and force platform landing tests were carried out as the pre- and post-tests.

RESULTS

The main outcome measures were the injuries history, distance and difference reached in anterior, post-lateral and post-medial axis of the Y-Balance test, and the force produced on the z, x, and y axis after landing. Differences were found between groups and measurements in all the variables of the Y-Balance test, except in the frontal axis for the dominant leg and for the differences between legs (P=0.039-0.001); and in the ground reaction forces (z axis) (P=0.040), the x axis (P=0.014) and the dynamic postural stability index (P=0.025) of the lateral jump with the non-dominant leg.

CONCLUSIONS

An 8-week prevention program seems to improve the lower limb stability in young volleyball players.

THE RELATIONSHIP BETWEEN SINGLE LEG BALANCE AND ISOMETRIC ANKLE AND HIP STRENGTH IN A HEALTHY POPULATION

Background

Impaired balance and strength commonly affect athletes with conditions like chronic ankle instability (CAI). Yet, clinical research surrounding the relationship between balance, strength, and CAI is still growing. Deeper investigation of these relationships is warranted to better inform clinical practice patterns when managing athletes with balance deficits.

Purpose

To investigate the relationship between single leg balance, ankle strength, and hip strength in healthy, active adults.

Study Design

Observational study.

Methods

Forty healthy participants (age 23.7 ± 4.9 years) were assessed for static balance, using a modified version of the Balance Error Scoring System (mBESS), as well as isometric strength of ankle and hip musculature via handheld dynamometry. Pearson's correlations were used to analyze relationships between balance and strength measures. Paired t-tests were utilized to compare dominant and non-dominant limb performance.

Results

Negligible to low, negative correlations were found between balance scores and hip extension strength (r = -0.24 to -0.38, p<0.05). High, positive correlations were found between ankle and hip strength measures (r = 0.75 to 0.84, p<0.05). When comparing dominant to non-dominant limbs, only minimal differences were noted in ankle eversion strength (mean difference = 6.0%, p<0.01) and hip extension strength (mean difference = 5.5%, p<0.01).

Conclusions

Minimal relationships were identified between static balance and isometric ankle and hip strength. Comparison of dominant and non-dominant limbs suggests that clinicians should expect relative symmetry in balance and strength in healthy adults. Thus, asymmetries found during clinical examination should raise suspicion of specific impairments that may lead to dysfunction.

Level of Evidence

2c.

Is chronic ankle instability associated with impaired muscle strength? Ankle, knee and hip muscle strength in individuals with chronic ankle instability: a systematic review with meta-analysis

OBJECTIVE

Determine whether impairments in lower limb muscle strength exist in individuals with chronic ankle instability (CAI) compared with uninjured controls.

DESIGN

Systematic review with meta-analysis.

DATA SOURCE

A comprehensive search of PubMed, Cochrane, CINAHL, Web of Science and EMBASE electronic databases from inception to 10 February 2019.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Cross-sectional and case-control studies were included if they objectively measured lower limb muscle strength in individuals with CAI compared with controls. Risk of bias and quality of included studies were assessed. Data of included studies were extracted, and meta-analysis was conducted where appropriate.

RESULTS

12 397 unique studies were identified, of which 20 were included and 16 were eligible for meta-analysis. Reviewed studies clearly described the aim/hypothesis and main outcome measure, but most lacked sample size calculation and assessor blinding. Meta-analyses showed individuals with CAI had lower eccentric and concentric evertor strength (30 and 120°/s; Nm; standardised mean difference (SMD) between -0.73 and -0.95), eccentric invertor strength (60 and 120°/s; both Nm and Nm/kg; SMD between -0.61 and -1.37), concentric invertor strength (60 and 120°/s; Nm; SMD=-0.7) and concentric knee extensor strength (SMD=-0.64) compared with control participants. Ankle eccentric dorsiflexor strength was not different between groups. Although pooling was not possible, data from three separate studies indicated that hip flexor, abductor and external rotator strength, but not hip adductor and extensor strength, was lower in individuals with CAI than in control participants.

CONCLUSION

Individuals with CAI have ankle inversion and eversion strength deficits. Our data also point to differences between individuals with CAI and controls in hip and knee strength. These elements of the kinetic chain should be evaluated by clinicians who rehabilitate individuals with CAI.

PROSPERO REGISTRATION NUMBER

CRD42016037759.

Ankle-Joint Self-Mobilization and CrossFit Training in Patients With Chronic Ankle Instability: A Randomized Controlled Trial

CONTEXT

Ankle-joint mobilization and neuromuscular and strength training have been deemed beneficial in the management of patients with chronic ankle instability (CAI). CrossFit training is a sport modality that involves these techniques.

OBJECTIVE

To determine and compare the influence of adding self-mobilization of the ankle joint to CrossFit training versus CrossFit alone or no intervention in patients with CAI.

DESIGN

Randomized controlled clinical trial.

SETTING

Research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Seventy recreational athletes with CAI were randomly allocated to either self-mobilization plus CrossFit training, CrossFit training alone, or a control group.

INTERVENTION(S)

Participants in the self-mobilization plus CrossFit group and the CrossFit training-alone group pursued a CrossFit training program twice a week for 12 weeks. The self-mobilization plus CrossFit group performed an ankle self-mobilization protocol before their CrossFit training, and the control group received no intervention.

MAIN OUTCOME MEASURE(S)

Ankle-dorsiflexion range of motion (DFROM), subjective feeling of instability, and dynamic postural control were assessed via the weight-bearing lunge test, Cumberland Ankle Instability Tool, and Star Excursion Balance Test (SEBT), respectively.

RESULTS

After 12 weeks of the intervention, both the self-mobilization plus CrossFit and CrossFit training-alone groups improved compared with the control group (P < .001). The self-mobilization plus CrossFit intervention was superior to the CrossFit training-alone intervention regarding ankle DFROM as well as the posterolateral- and posteromedial-reach distances of the SEBT but not for the anterior-reach distance of the SEBT or the Cumberland Ankle Instability Tool.

CONCLUSIONS

Ankle-joint self-mobilization and CrossFit training were effective in improving ankle DFROM, dynamic postural control and self-reported instability in patients with CAI.

Landing Kinematics and Isometric Hip Strength of Individuals With Chronic Ankle Instability

BACKGROUND

Chronic ankle instability (CAI) is associated with hip strength deficits and altered movement in the lower extremity. However, it remains unclear how hip strength deficits contribute to lateral ankle sprain (LAS) mechanisms. We aimed to compare lower extremity landing kinematics and isometric hip strength between individuals with and without CAI and examine associations between hip kinematics and strength.

METHODS

Seventy-six individuals completed 5 single-leg landings, during which we collected three-dimensional ankle, knee, and hip kinematics from 200 milliseconds pre-initial contact to 50 milliseconds post-initial contact. We calculated average peak torque (Nm/kg) from 3 trials of isometric hip extension, abduction, and external rotation strength testing. One-way analyses of variance assessed group differences (CAI, LAS coper, and control) in hip strength and kinematics. Pearson product moment correlations assessed associations between hip kinematics and strength. We adjusted the kinematic group comparisons and correlation analyses for multiple comparisons using the Benjamini-Hochberg method.

RESULTS

The CAI group exhibited less hip abduction during landing than LAS copers and controls. The CAI group had lower hip external rotation strength than LAS copers (P = .04, d = 0.62 [0.05, 1.17]) and controls (P < .01, d = 0.87 [0.28, 1.43]). Effect sizes suggest that the CAI group had deficits in EXT compared with controls (d = 0.63 [0.06, 1.19]). Hip strength was not associated with hip landing kinematics for any group.

CONCLUSION

Altered landing mechanics displayed by the CAI group may promote mechanisms of LAS, but they are not associated with isometric hip strength. However, hip strength deficits may negatively impact other functional tasks, and they should still be considered during rehabilitation.

LEVEL OF EVIDENCE

Level III, case-control study.

Isometric Hip Strength and Dynamic Stability of Individuals With Chronic Ankle Instability

CONTEXT

  Compared with individuals who have a history of lateral ankle sprain (LAS) without markers of chronic ankle instability (CAI; LAS copers) and healthy people, those with CAI often exhibit neuromuscular impairments and dynamic-stability deficits at the hip. However, the influence of hip-strength deficits on dynamic stability remains unknown.

OBJECTIVE

  To compare isometric hip strength and dynamic stability in individuals with or without CAI and examine the degree of dynamic-stability variance explained by isometric hip strength.

DESIGN

  Case-control study.

SETTING

  Research laboratory.

PATIENTS OR OTHER PARTICIPANTS

  Sixty individuals (47 women, 13 men; age = 23.7 ± 4.6 years, height = 166.6 ± 7.7 cm, mass = 70.8 ± 15.7 kg) separated into CAI, LAS coper, and control groups based on previously established criteria.

MAIN OUTCOME MEASURE(S)

  Group differences in resultant vector time to stabilization (RVTTS) and isometric hip-extension, -abduction, and external-rotation strength were determined using 1-way analyses of covariance that controlled for sex and limb (dominant or nondominant) tested and Cohen d effect sizes (95% confidence intervals). Backward linear regressions and Cohen f² effect sizes (95% confidence intervals) determined the amount of RVTTS variance explained by isometric hip strength. Significance was set a priori at P < .05.

RESULTS

  The CAI group had less isometric hip-extension strength than LAS copers ( P = .02, d = 0.72 [0.06, 1.34]) and controls ( P = .01, d = 1.19 [0.50, 1.84]) and less external-rotation strength than LAS copers ( P = .03, d = 0.78 [0.13, 1.41]) and controls ( P = .01, d = 1.02 [0.34, 1.65]). No group differences existed for RVTTS ( F_2,57 = 1.16, P = .32) or abduction strength ( F_2,57 = 2.84, P = .07). Resultant vector time to stabilization was explained by isometric hip strength for LAS copers ( R² = 0.21, f² = 0.27 [0.22, 0.32], P = .04) but not for the CAI ( R² = 0.12, f² = 0.14 [0.06, 0.22], P = .22) or control ( R² = 0.10, f² = 0.11 [0.03, 0.19], P = .18) groups.

CONCLUSIONS

  Participants with CAI had decreased isometric hip strength, but that did not equate to dynamic-stability deficits. Clinicians should include hip-muscle strengthening in rehabilitation protocols for patients with CAI, yet these gains may not enhance dynamic stability when landing from a jump.