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The effectiveness of proprioceptive training in preventing ankle sprains in sporting populations: A systematic review and meta-analysis

      Abstract

      Objectives

      To systematically summarise the evidence on the effectiveness of proprioceptive training in reducing the incidence and recurrence rates of ankle sprains in the sporting population.

      Design

      A systematic review and meta-analysis of randomised controlled trials.

      Methods

      A computer-based literature search of MEDLINE, EMBASE, CINAHL, SPORTDiscus and PEDro (to October 2013) was conducted. Methodological quality of individual studies was assessed using the PEDro scale. Meta-analysis was performed on eligible studies to produce a pooled estimate of the effectiveness of the intervention.

      Results

      Seven moderate-to-high quality randomised controlled trials involving 3726 participants were included. Results of the meta-analysis combining all participants, irrespective of ankle injury history status, revealed a significant reduction of ankle sprain incidence when proprioceptive training was performed compared to a range of control interventions (relative risk = 0.65, 95% CI 0.55–0.77). Results favouring the intervention remained significant for participants with a history of ankle sprain (relative risk = 0.64, 95% CI 0.51–0.81). Results looking exclusively at primary prevention in those without a history were also statistically significant (relative risk = 0.57, 95% CI 0.34 to 0.97), although the pooled effect was obtained from two non-significant trials.

      Conclusions

      Proprioceptive training programmes are effective at reducing the rate of ankle sprains in sporting participants, particularly those with a history of ankle sprain. Current evidence remains inconclusive on the benefits for primary prevention of ankle sprains.

      Keywords

      1. Introduction

      Ankle sprains are the most common sports-related injury.
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      A systematic review on ankle injury and ankle sprain in sports.
      They are especially prevalent in sports requiring frequent jumping, directional changes and pivoting such as basketball, football, soccer, handball, netball, and volleyball.
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      • Hong Y.
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      A systematic review on ankle injury and ankle sprain in sports.
      Ankle sprains often result in pain, disability, dysfunction, time lost from activity, the requirement for treatment, and economic burden.
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      Ankle injuries in basketball: injury rate and risk factors.
      • Hiller C.E.
      • Nightingale E.J.
      • Raymond J.
      • et al.
      Prevalence and impact of chronic musculoskeletal ankle disorders in the community.
      Furthermore, athletes who sprain their ankle are prone to reinjure the same ankle,
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      • Payne W.R.
      • et al.
      Ankle injuries in basketball: injury rate and risk factors.
      • Verhagen E.A.
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      Optimising ankle sprain prevention: a critical review and practical appraisal of the literature.
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      • Bouter L.M.
      • et al.
      A one season prospective cohort study of volleyball injuries.
      with recurrent ankle sprains commonly leading to ongoing impairment and chronic instability.
      • Hiller C.E.
      • Nightingale E.J.
      • Raymond J.
      • et al.
      Prevalence and impact of chronic musculoskeletal ankle disorders in the community.
      • Verhagen E.A.
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      Optimising ankle sprain prevention: a critical review and practical appraisal of the literature.
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      • Bernsen R.M.
      • et al.
      What is the clinical course of acute ankle sprains? A systematic literature review.
      Popular interventions for preventing ankle sprains include tape, ankle braces, evertor muscle strengthening and proprioceptive training.
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      Optimising ankle sprain prevention: a critical review and practical appraisal of the literature.
      • McKeon P.O.
      • Mattacola C.G.
      Interventions for the prevention of first time and recurrent ankle sprains.
      Braces and tape have been shown to be effective preventive methods against ankle sprains,
      • Verhagen E.A.
      • Bay K.
      Optimising ankle sprain prevention: a critical review and practical appraisal of the literature.
      • McKeon P.O.
      • Mattacola C.G.
      Interventions for the prevention of first time and recurrent ankle sprains.
      • Dizon J.M.R.
      • Reyes J.J.B.
      A systematic review on the effectiveness of external ankle supports in the prevention of inversion ankle sprains among elite and recreational players.
      however, they do have disadvantages. For example, there is some evidence that braces may hinder elements of athletic performance,
      • Dizon J.M.R.
      • Reyes J.J.B.
      A systematic review on the effectiveness of external ankle supports in the prevention of inversion ankle sprains among elite and recreational players.
      • Cordova M.L.
      • Scott B.D.
      • Ingersoll C.D.
      • et al.
      Effects of ankle support on lower-extremity functional performance: a meta-analysis.
      while taping needs to be skilfully applied, loosens with activity, and can irritate the skin.
      • Dizon J.M.R.
      • Reyes J.J.B.
      A systematic review on the effectiveness of external ankle supports in the prevention of inversion ankle sprains among elite and recreational players.
      • Verhagen E.
      • Twisk J.
      • Bouter L.
      • et al.
      The effect of a proprioceptive balance board training program for the prevention of ankle sprains: a prospective controlled trial.
      Exercise programmes may avoid those disadvantages, although compliance is a potential barrier.
      • Verhagen E.A.
      • Bay K.
      Optimising ankle sprain prevention: a critical review and practical appraisal of the literature.
      • Hübscher M.
      • Zech A.
      • Pfeifer K.
      • et al.
      Neuromuscular training for sports injury prevention: a systematic review.
      Athletes may also choose to utilise several preventative measures in conjunction, such as taping and an exercise programme.
      • Verhagen E.A.
      • Bay K.
      Optimising ankle sprain prevention: a critical review and practical appraisal of the literature.
      Proprioception is a complex neuromuscular process concerned with the internal kinaesthetic awareness of body position and movement.
      • Lephart S.M.
      • Pincivero D.M.
      • Giraldo J.L.
      • et al.
      The role of proprioception in the management and rehabilitation of athletic injuries.
      • Raymond J.
      • Nicholson L.L.
      • Hiller C.E.
      • et al.
      The effect of ankle taping or bracing on proprioception in functional ankle instability: a systematic review and meta-analysis.
      It is reliant on appropriate afferent and efferent signalling and plays an important role in joint stability and injury prevention.
      • Lephart S.M.
      • Pincivero D.M.
      • Giraldo J.L.
      • et al.
      The role of proprioception in the management and rehabilitation of athletic injuries.
      • Postle K.
      • Pak D.
      • Smith T.O.
      Effectiveness of proprioceptive exercises for ankle ligament injury in adults: a systematic literature and meta-analysis.
      Proprioceptive training involves exercises that challenge the ability of the targeted joint to detect and react to afferent input regarding joint position.
      • Lephart S.M.
      • Pincivero D.M.
      • Giraldo J.L.
      • et al.
      The role of proprioception in the management and rehabilitation of athletic injuries.
      • Postle K.
      • Pak D.
      • Smith T.O.
      Effectiveness of proprioceptive exercises for ankle ligament injury in adults: a systematic literature and meta-analysis.
      • Sheth P.
      • Yu B.
      • Laskowski E.R.
      • et al.
      Ankle disk training influences reaction times of selected muscles in a simulated ankle sprain.
      Examples of proprioceptive exercises include balancing on a wobble board or ankle disc, throwing and catching or dribbling a ball whilst in single leg stance, or balancing with eyes closed.
      • Verhagen E.
      • Twisk J.
      • Bouter L.
      • et al.
      The effect of a proprioceptive balance board training program for the prevention of ankle sprains: a prospective controlled trial.
      • Hughes T.
      • Rochester P.
      The effects of proprioceptive exercise and taping on proprioception in subjects with functional ankle instability: a review of the literature.
      • McGuine T.A.
      • Keene J.S.
      The effect of a balance training program on the risk of ankle sprains in high school athletes.
      There is evidence showing that one's risk of suffering an ankle sprain is doubled in the year following initial injury.
      • Verhagen E.A.
      • Van der Beek A.J.
      • Bouter L.M.
      • et al.
      A one season prospective cohort study of volleyball injuries.
      • Bahr R.
      • Bahr I.A.
      Incidence of acute volleyball injuries: a prospective cohort study of injury mechanisms and risk factors.
      It is theorised that impaired proprioception in the injured joint pre-disposes it to re-injury.
      • Gross M.T.
      Effects of recurrent lateral ankle sprains on active and passive judgements of joint position.
      • Refshauge K.M.
      • Kilbreath S.L.
      • Raymond J.
      The effect of recurrent ankle inversion sprain and taping on proprioception at the ankle.
      Proprioceptive training aims to improve the capabilities of this system in order to prevent primary and secondary ankle injuries.
      Several systematic reviews have explored the effectiveness of exercise programmes for the prevention and management of ankle sprains.
      • Verhagen E.A.
      • Bay K.
      Optimising ankle sprain prevention: a critical review and practical appraisal of the literature.
      • Hübscher M.
      • Zech A.
      • Pfeifer K.
      • et al.
      Neuromuscular training for sports injury prevention: a systematic review.
      • Postle K.
      • Pak D.
      • Smith T.O.
      Effectiveness of proprioceptive exercises for ankle ligament injury in adults: a systematic literature and meta-analysis.
      • de Vries J.S.
      • Krips R.
      • Sierevelt I.N.
      • et al.
      Interventions for treating chronic ankle instability.
      • Loudon J.K.
      • Santos M.J.
      • Franks L.
      • et al.
      The effectiveness of active exercise as an intervention for functional ankle instability: a systematic review.
      • McKeon P.O.
      • Hertel J.
      Systematic review of postural control and lateral ankle instability, part II: is balance training clinically effective?.
      • Webster K.A.
      • Gribble P.A.
      Functional rehabilitation interventions for chronic ankle instability: a systematic review.
      • Zech A.
      • Hubscher M.
      • Vogt L.
      • et al.
      Neuromuscular training for rehabilitation of sports injuries: a systematic review.
      Components of these exercise programmes have included proprioceptive training, strengthening, agility, plyometrics, sport-specific exercises or a combination of several components (with the later often called neuromuscular training).
      • Verhagen E.A.
      • Bay K.
      Optimising ankle sprain prevention: a critical review and practical appraisal of the literature.
      • Zech A.
      • Hubscher M.
      • Vogt L.
      • et al.
      Neuromuscular training for rehabilitation of sports injuries: a systematic review.
      While most existing reviews have concluded that exercise programmes reduce ankle sprain injuries,
      • Verhagen E.A.
      • Bay K.
      Optimising ankle sprain prevention: a critical review and practical appraisal of the literature.
      • Hübscher M.
      • Zech A.
      • Pfeifer K.
      • et al.
      Neuromuscular training for sports injury prevention: a systematic review.
      • Loudon J.K.
      • Santos M.J.
      • Franks L.
      • et al.
      The effectiveness of active exercise as an intervention for functional ankle instability: a systematic review.
      • McKeon P.O.
      • Hertel J.
      Systematic review of postural control and lateral ankle instability, part II: is balance training clinically effective?.
      • Zech A.
      • Hubscher M.
      • Vogt L.
      • et al.
      Neuromuscular training for rehabilitation of sports injuries: a systematic review.
      no reviews have focussed exclusively on the effects of proprioceptive training alone without the addition of co-interventions such as strengthening, plyometrics or agility training. It has been hypothesised that proprioceptive exercises may be the most important component of ankle rehabilitation programmes,
      • Verhagen E.A.
      • Bay K.
      Optimising ankle sprain prevention: a critical review and practical appraisal of the literature.
      but to date the isolated effect of proprioceptive training has not been evaluated in a systematic review.
      The purpose of this systematic review was to determine whether proprioceptive training as a sole intervention is effective for reducing the incidence or recurrence rate of ankle sprains among sporting populations.

      2. Methods

      A systematic review was performed using the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)
      • Moher D.
      • Liberati A.
      • Tetzlaff J.
      • et al.
      Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement.
      and the Cochrane handbook.
      • Higgins J.
      • Green S.
      Cochrane handbook for systematic reviews of interventions version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011.
      Ethical approval was not required for this review.
      A computerised literature search was performed in October 2013 using MEDLINE, EMBASE, CINAHL, SPORTDiscus and the Physiotherapy Evidence Database (PEDro). Search terms were developed in order to identify proprioceptive training programmes for the ankle joint in sporting populations. Full search terms for MEDLINE are presented in Supplemental File 1. Filters were utilised to limit results to human participants and studies published in English. No limitations were imposed on the date of publication. Additionally, the reference lists of all the selected publications and relevant systematic reviews were screened to retrieve any additional studies. As terminology for balance, proprioceptive and neuromuscular training is often used interchangeably,
      • McKeon P.O.
      • Hertel J.
      Systematic review of postural control and lateral ankle instability, part II: is balance training clinically effective?.
      • Zech A.
      • Hubscher M.
      • Vogt L.
      • et al.
      Neuromuscular training for rehabilitation of sports injuries: a systematic review.
      we searched for all terms but only included studies that focussed solely on proprioceptive training (exercises to challenge the detection and maintenance of ankle joint position) without the addition of adjunct interventions such as muscle strengthening exercises.
      Studies were included if they met the following criteria: (1) the study design was a moderate-to-high quality randomised controlled trial with a PEDro score of at least 4/10,
      • Dodd K.J.
      • Shields N.
      A systematic review of the outcomes of cardiovascular exercise programs for people with Down syndrome.
      (2) participants were involved in recreational or professional sport, with or without a history of ankle sprain, (3) the intervention group received exclusively a proprioceptive training programme with no other adjunct interventions and was compared to a control group who did not receive proprioceptive training and (4) incidence or recurrence rate of ankle sprain was reported as an outcome measure.
      Search results were stored and organised using the EndNote X6 computer software (Thomson-Reuters). Duplicates were removed and two authors (GSS & AJH) independently reviewed the studies for eligibility based on title and abstract. Studies deemed potentially eligible by at least one reviewer were then assessed independently by both reviewers for eligibility based on the full text. Any disagreements were to be resolved by consensus with the third author (LAR), however, this was not required.
      The methodological quality of the included studies was assessed using the Physiotherapy Evidence Database (PEDro) scale. The scale is used to rate studies from 0–10 according to 10 methodological criteria (Supplemental File 2). This appraisal tool was chosen because it has been shown to provide sufficient reliability and validity for use in systematic reviews of physiotherapy related RCTs.
      • Macedo L.G.
      • Elkins M.R.
      • Maher C.G.
      • et al.
      There was evidence of convergent and construct validity of physiotherapy evidence database quality scale for physiotherapy trials.
      • Maher C.G.
      • Sherrington C.
      • Herbert R.D.
      • et al.
      Reliability of the PEDro scale for rating quality of randomized controlled trials.
      The scale was applied independently by two reviewers (GSS & AJH), with any differences in an article's assigned score being resolved by consensus.
      • Higgins J.
      • Green S.
      Cochrane handbook for systematic reviews of interventions version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011.
      For this review, it was considered unlikely that participants, therapists or assessors would be blinded to the intervention; therefore, a maximum score of 7 was predicted. With this in mind, studies scoring 6 or 7 were considered to be of ‘excellent’ quality, those scoring 5 were deemed ‘good’ quality and a score of 4 was felt to be of ‘moderate’ quality. Studies scoring less than 4 were considered to be of ‘poor’ quality and were excluded from the review.
      • Dodd K.J.
      • Shields N.
      A systematic review of the outcomes of cardiovascular exercise programs for people with Down syndrome.
      Two reviewers (GSS & LAR) independently extracted data from each included study. The data extracted included the number of participants, the nature, frequency and duration of the intervention received, details of the control group, follow-up periods and incidence rates of ankle sprain injuries. Relative risks (RR) and numbers needed to treat (NNT) were calculated using the PEDro confidence interval calculator (www.pedro.org.au). Data were assessed for statistical heterogeneity, which was considered likely if p-values of <0.1 were obtained on the X2 test, or if the I2 statistic was >25%.
      • Higgins J.P.T.
      • Thompson S.G.
      • Deeks J.J.
      • et al.
      Measuring inconsistency in meta-analyses.
      • Hahne A.J.
      • Ford J.J.
      • McMeeken J.M.
      Conservative management of lumbar disc herniation with associated radiculopathy: a systematic review.
      Trials that were deemed to be statistically homogenous were subjected to meta-analysis. Meta-analyses were undertaken with RevMan 5.2 using a random-effects model. It was planned to undertake a pre-specified subgroup analysis that divided effects into those relating to participants with a history of ankle sprain and those without a history. Additional data were sought from authors of eligible studies for this purpose if it was not available within the article.

      3. Results

      Electronic database searches yielded 345 studies after the removal of duplicates (Fig. 1). Eighteen articles underwent full-text review. Eleven of these studies were excluded for the following reasons: they were not completed randomised controlled trials,
      • de Bie R.
      Functional treatment superior to cast immobilisation for complete ruptures of the lateral ligaments of the ankle.
      • Garrick J.G.
      • Requa R.
      Structured exercises to prevent lower limb injuries in young handball players.
      • Janssen K.W.
      • Van Mechelen W.
      • Verhagen E.A.L.M.
      Ankles back in randomized controlled trial (ABrCt): braces versus neuromuscular exercises for the secondary prevention of ankle sprains. Design of a randomised controlled trial.
      • Nurse M.
      Proprioceptive training to prevent ankle injuries in basketball.
      • Ødegaard T.T.
      • Risberg M.A.
      Warm-up exercise prevents acute knee and ankle injuries in young handball players.
      the proprioceptive training administered consisted of adjunct interventions (e.g. evertor strengthening),
      • Emery C.A.
      • Cassidy J.D.
      • Klassen T.P.
      • et al.
      Effectiveness of a home-based balance-training program in reducing sports-related injuries among healthy adolescents: a cluster randomized controlled trial.
      • Emery C.A.
      • Meeuwisse W.H.
      The effectiveness of a neuromuscular prevention strategy to reduce injuries in youth soccer: a cluster-randomised controlled trial.
      the control group also received proprioceptive exercises,
      • Holme E.
      • Magnusson S.P.
      • Becher K.
      • et al.
      The effect of supervised rehabilitation on strength, postural sway, position sense and re-injury risk after acute ankle ligament sprain.
      or the study scored less than 4/10 on the PEDro scale.
      • Stasinopoulos D.
      Comparison of three preventive methods in order to reduce the incidence of ankle inversion sprains among female volleyball players.
      • Wedderkopp N.
      • Kaltoft M.
      • Holm R.
      • et al.
      Comparison of two intervention programmes in young female players in European handball – with and without ankle disc.
      • Wester J.U.
      • Jespersen S.M.
      • Nielsen K.D.
      • et al.
      Wobble board training after partial sprains of the lateral ligaments of the ankle: a prospective randomized study.
      This left seven total studies (involving 3726 participants) for inclusion in the final analysis.
      • Verhagen E.
      • Twisk J.
      • Bouter L.
      • et al.
      The effect of a proprioceptive balance board training program for the prevention of ankle sprains: a prospective controlled trial.
      • McGuine T.A.
      • Keene J.S.
      The effect of a balance training program on the risk of ankle sprains in high school athletes.
      • Eils E.
      • Schröter R.
      • Schröder M.
      • et al.
      Multistation proprioceptive exercise program prevents ankle injuries in basketball.
      • Emery C.A.
      • Rose M.S.
      • McAllister J.
      • et al.
      A prevention strategy to reduce the incidence of injury in high school basketball: a cluster randomized controlled trial.
      • Hupperets M.D.
      • Verhagen E.A.
      • van Mechelen W.
      Effect of unsupervised home based proprioceptive training on recurrences of ankle sprain: randomised controlled trial.
      • Mohammadi F.
      Comparison of 3 preventive methods to reduce the recurrence of ankle inversion sprains in male soccer players.
      • Söderman K.
      • Werner S.
      • Pietilä T.
      • et al.
      Balance board training: prevention of traumatic injuries of the lower extremities in female soccer players?.
      One author provided additional data for the purposes of the planned subgroup analysis.
      • Verhagen E.
      • Twisk J.
      • Bouter L.
      • et al.
      The effect of a proprioceptive balance board training program for the prevention of ankle sprains: a prospective controlled trial.
      Characteristics of the included studies are presented in Table 1.
      Table 1Characteristics of studies included for review.
      Study detailsParticipantsInterventionOutcome (ankle sprain rate)
      StudyQualityCharacteristicsnInterventionFrequency/dosageDurationControlFollow-up
      Hupperets et al.
      • Hupperets M.D.
      • Verhagen E.A.
      • van Mechelen W.
      Effect of unsupervised home based proprioceptive training on recurrences of ankle sprain: randomised controlled trial.
      Excellent PEDro = 7Female (48%) and male athletes aged 12–70 (mean age 28) who had sustained an ankle sprain in the preceding two months522Usual care immediately post injury plus home based unsupervised proprioceptive training programme3× 30 min sessions a week8 weeksUsual care immediately post injury onlyOne year
      Emery et al.
      • Emery C.A.
      • Rose M.S.
      • McAllister J.
      • et al.
      A prevention strategy to reduce the incidence of injury in high school basketball: a cluster randomized controlled trial.
      Excellent PEDro = 7Female (50%) and male high school (12–18 years, median age 16) basketball players without (85%) and with (15%) history of ankle sprain920Sport-specific balance training programme and a home-based balance training programme using wobble board5 min at each practice sessions (5× weekly) plus 20 min at home (unspecified frequency)18 weeksStandardised warm-up programme onlyBaseline, 18 weeks. Phone follow up until 12 months post study for sustained but unresolved injuries obtained during the study
      McGuine and Keene
      • McGuine T.A.
      • Keene J.S.
      The effect of a balance training program on the risk of ankle sprains in high school athletes.
      Excellent PEDro = 6Female (68%) and male high school (12–18 years, mean age 16) basketball and soccer players without (76%) and with (24%) history of ankle sprain7655-phase balance training programme using single-leg stance exercises and wobble board5× 5 min of balance training per week for 4 weeks preseason. 3× 10 min of balance training per week throughout the season4 weeks pre-season and throughout season (unspecified duration)Standard conditioning exercises as part of usual trainingBaseline and conclusion of season (exact duration not specified)
      Mohammadi
      • Mohammadi F.
      Comparison of 3 preventive methods to reduce the recurrence of ankle inversion sprains in male soccer players.
      Good PEDro = 5Professional male soccer players aged 22–26 (mean age 25) years with a past history of ankle inversion sprain80Home-based proprioceptive training programme using ankle disc30 min daily120 sessionsAnkle evertor muscle strength training OR orthosis OR no interventionBaseline and conclusion of season (approx 120 sessions of play. 1 session is equal to a training session or match)
      Verhagen et al.
      • Verhagen E.
      • Twisk J.
      • Bouter L.
      • et al.
      The effect of a proprioceptive balance board training program for the prevention of ankle sprains: a prospective controlled trial.
      Good PEDro = 5Community-based female (57%) and male volleyball players (mean age of 24 years) without (33%) and with (67%) a past history of ankle sprain1127Balance board training programme performed as part of team warm-up4× weekly for 5 min36 weeksUsual training routine onlyBaseline and 36 weeks
      Soderman et al.
      • Söderman K.
      • Werner S.
      • Pietilä T.
      • et al.
      Balance board training: prevention of traumatic injuries of the lower extremities in female soccer players?.
      Moderate PEDro = 4Female soccer players without (and with a history of ankle sprain (unspecified percentages)140Specific training programme consisting of balance board training in addition to their standard soccer practice and games10–15 min, daily for first 30 days, and then 3× per week for rest of the season7 monthsStandard soccer practice and games only7 months (one season)
      Eils et al.
      • Eils E.
      • Schröter R.
      • Schröder M.
      • et al.
      Multistation proprioceptive exercise program prevents ankle injuries in basketball.
      Moderate (PEDro = 4)Professional basketball players (14–43 years) without (53%) and with (47%) a history of ankle sprain who had never previously worn ankle brace or performed proprioceptive training172Multistation proprioceptive exercise programmeOnce a week for 20 minOne season (unspecified duration)Standard workout routines onlyBaseline and conclusion of season (unspecified duration)
      The PEDro scores of the included studies ranged from 4 to 7, with an average score of 5.4/10 (see Supplemental File 2 for individual scores). Using our PEDro score grading system, three articles were considered to be of “excellent” quality (scoring 6 or 7),
      • McGuine T.A.
      • Keene J.S.
      The effect of a balance training program on the risk of ankle sprains in high school athletes.
      • Emery C.A.
      • Rose M.S.
      • McAllister J.
      • et al.
      A prevention strategy to reduce the incidence of injury in high school basketball: a cluster randomized controlled trial.
      • Hupperets M.D.
      • Verhagen E.A.
      • van Mechelen W.
      Effect of unsupervised home based proprioceptive training on recurrences of ankle sprain: randomised controlled trial.
      two were considered good quality (scoring 5),
      • Verhagen E.
      • Twisk J.
      • Bouter L.
      • et al.
      The effect of a proprioceptive balance board training program for the prevention of ankle sprains: a prospective controlled trial.
      • Mohammadi F.
      Comparison of 3 preventive methods to reduce the recurrence of ankle inversion sprains in male soccer players.
      and two were rated as moderate quality (scoring 4).
      • Eils E.
      • Schröter R.
      • Schröder M.
      • et al.
      Multistation proprioceptive exercise program prevents ankle injuries in basketball.
      • Söderman K.
      • Werner S.
      • Pietilä T.
      • et al.
      Balance board training: prevention of traumatic injuries of the lower extremities in female soccer players?.
      The seven trials were found to be statistically homogenous, allowing for meta-analysis to be undertaken. Results of the meta-analysis revealed a statistically significant reduction in ankle sprains favouring the proprioceptive training group (7 trials, RR = 0.65, 95% CI 0.55–0.77) (Fig. 2 – top). This represented a pooled number needed to treat (NNT) of 17 (95% CI 33–11), indicating that 17 athletes would need to undertake proprioceptive training in order for one ankle sprain to be prevented. Comparison interventions included usual care/warm-up routines, strength training and an orthosis. When results were sub-divided to look at the secondary preventative effects of proprioceptive training on those exclusively with a history of ankle sprain, results were similarly in favour of the intervention (4 trials, RR = 0.64, 95% CI 0.51–0.81; NNT = 13, 95% CI 100–7) (Fig. 2 – middle). When looking at proprioceptive training's effect as a form of primary prevention amongst sporting participants with no history of ankle injury, the pooled results were statistically significant (RR = 0.57, 95% CI 0.34 to 0.97; NNT = 33, 95% CI 1000 to 16), although only two non-significant trials were included in this comparison and the confidence interval was wide. (Fig. 2 – bottom).
      Figure thumbnail gr2
      Fig. 2Meta-analysis forest plots showing relative risk of ankle sprain (proprioceptive training versus control) in: (top) all participants regardless of injury history; (middle) participants with a history of ankle sprain, and; (bottom) participants without history of ankle sprain.

      4. Discussion

      Overall results of this systematic review and meta-analyses indicate that when considering all sporting participants, irrespective of their ankle injury history status, there was a preventative effect of proprioceptive training on ankle sprains (Fig. 2 – top). The pooled NNT values of 17 (95% CI 33–11) for all participants and 13 (95% CI 100–7) for those with a history of ankle sprain appear clinically relevant, as this equates to approximately one ankle sprain being prevented per sporting team by proprioceptive training. Subgroup analyses revealed that proprioceptive training programmes are effective as a form of secondary prevention for reducing the recurrence rate of ankle sprains in athletes with a history of injury (Fig. 2 – middle). The effectiveness of proprioceptive training as a form of primary prevention amongst athletes with no history of ankle sprain remains inconclusive, as the pooled point estimate was significant but should be interpreted with caution since it was derived from only two non-significant trials. (Fig. 2 – bottom).
      The effectiveness of proprioceptive training for athletes with a history of ankle injury suggests that a rehabilitative effect may be an underlying mechanism. It has been proposed that proprioceptive training may address underlying impairments that predispose athletes to recurrent ankle sprains following an initial injury, such as restoring disrupted afferent pathways and protective reflexes around the ankle joint.
      • Ergen E.
      • Ulkar B.
      Proprioception and ankle injuries in soccer.
      • Lephart S.M.
      • Pincivero D.M.
      • Rozzi S.L.
      Proprioception of the ankle and knee.
      Applying this to a clinical context, the importance of this intervention should therefore be emphasised amongst those sporting participants with a history of ankle sprain.
      Neither of the two trials with data relating to participants with no history of ankle sprain showed a primary preventative effect of proprioceptive training. However, there was a statistically significant pooled effect obtained via meta-analysis for this comparison in favour of proprioceptive training. (Fig. 2 – bottom). It is important to note that there were only two studies included in this pooled estimate investigating primary prevention.
      • Verhagen E.
      • Twisk J.
      • Bouter L.
      • et al.
      The effect of a proprioceptive balance board training program for the prevention of ankle sprains: a prospective controlled trial.
      • McGuine T.A.
      • Keene J.S.
      The effect of a balance training program on the risk of ankle sprains in high school athletes.
      Another study that did not differentiate between primary and secondary ankle injury in their results showed overall significant effects in favour of proprioceptive training despite 47% of their sample reporting no prior history of ankle injury (RR = 0.50, 95% CI 0.26–0.96).
      • Eils E.
      • Schröter R.
      • Schröder M.
      • et al.
      Multistation proprioceptive exercise program prevents ankle injuries in basketball.
      If future studies report outcomes relating specifically to participants with no history of ankle sprain then estimates of the primary preventative effects of proprioceptive training should become more accurate.
      A limitation of the studies included in this review is the substantial variability and lack of detail reported in training parameters of the included studies. For example, the training frequency of the programmes ranged from 20 min a week
      • Verhagen E.
      • Twisk J.
      • Bouter L.
      • et al.
      The effect of a proprioceptive balance board training program for the prevention of ankle sprains: a prospective controlled trial.
      • Eils E.
      • Schröter R.
      • Schröder M.
      • et al.
      Multistation proprioceptive exercise program prevents ankle injuries in basketball.
      to 30 min daily,
      • Mohammadi F.
      Comparison of 3 preventive methods to reduce the recurrence of ankle inversion sprains in male soccer players.
      while the duration of the programmes ranged from 8 weeks
      • Hupperets M.D.
      • Verhagen E.A.
      • van Mechelen W.
      Effect of unsupervised home based proprioceptive training on recurrences of ankle sprain: randomised controlled trial.
      to 36 weeks.
      • Verhagen E.
      • Twisk J.
      • Bouter L.
      • et al.
      The effect of a proprioceptive balance board training program for the prevention of ankle sprains: a prospective controlled trial.
      Furthermore, three of the studies failed to provide specific programme durations.
      • McGuine T.A.
      • Keene J.S.
      The effect of a balance training program on the risk of ankle sprains in high school athletes.
      • Eils E.
      • Schröter R.
      • Schröder M.
      • et al.
      Multistation proprioceptive exercise program prevents ankle injuries in basketball.
      • Mohammadi F.
      Comparison of 3 preventive methods to reduce the recurrence of ankle inversion sprains in male soccer players.
      Despite this variability in training parameters, an overall effect was still detected in this review.
      While the optimal dose-response ratio to achieve the prophylactic effects of proprioceptive training is not known, a cumulative effect may exist whereby longer programmes have a greater preventative effect.
      • Bahr R.
      • Lian O.
      • Bahr I.A.
      A twofold reduction in the incidence of acute ankle sprains in volleyball after the introduction of an injury prevention program: a prospective cohort study.
      Given the lack of detail in many of the included studies relating to intervention dosage and duration, it is difficult to determine whether the training programmes were implemented with sufficient training parameters to enable the intervention's prophylactic potential to truly take effect. Future studies should report training parameters fully to enable such considerations to be made.
      Compliance levels must be taken into account when considering the impact of the proprioceptive training programme, as this will alter the intervention's apparent effect.
      • Verhagen E.A.
      • Bay K.
      Optimising ankle sprain prevention: a critical review and practical appraisal of the literature.
      There was substantial variability in both the level of discussion of compliance in the studies, as well as in the levels of compliance reported in those studies that did monitor it. One study failed to mention compliance levels,
      • Eils E.
      • Schröter R.
      • Schröder M.
      • et al.
      Multistation proprioceptive exercise program prevents ankle injuries in basketball.
      three studies acknowledged the lack of monitoring of compliance as limitations in their study designs,
      • Verhagen E.
      • Twisk J.
      • Bouter L.
      • et al.
      The effect of a proprioceptive balance board training program for the prevention of ankle sprains: a prospective controlled trial.
      • Mohammadi F.
      Comparison of 3 preventive methods to reduce the recurrence of ankle inversion sprains in male soccer players.
      • Söderman K.
      • Werner S.
      • Pietilä T.
      • et al.
      Balance board training: prevention of traumatic injuries of the lower extremities in female soccer players?.
      while the three studies of excellent methodological quality reported non-compliance levels of 10%
      • McGuine T.A.
      • Keene J.S.
      The effect of a balance training program on the risk of ankle sprains in high school athletes.
      , 35%
      • Hupperets M.D.
      • Verhagen E.A.
      • van Mechelen W.
      Effect of unsupervised home based proprioceptive training on recurrences of ankle sprain: randomised controlled trial.
      and 40%
      • Emery C.A.
      • Rose M.S.
      • McAllister J.
      • et al.
      A prevention strategy to reduce the incidence of injury in high school basketball: a cluster randomized controlled trial.
      respectively. It is therefore possible, that had there been greater levels of compliance, the preventive effects of the proprioceptive training programme would have been larger.
      • Verhagen E.A.
      • Bay K.
      Optimising ankle sprain prevention: a critical review and practical appraisal of the literature.
      • Hübscher M.
      • Zech A.
      • Pfeifer K.
      • et al.
      Neuromuscular training for sports injury prevention: a systematic review.
      However, compliance issues are a reality of the clinical setting with any exercise intervention, so the studies in this review reflect this clinical reality.
      There are inherent study limitations relating to this area of research that influence methodological quality.
      • McGuine T.A.
      • Keene J.S.
      The effect of a balance training program on the risk of ankle sprains in high school athletes.
      Owing to the nature of the intervention, subject, therapist and assessor blinding were not possible in any of the included studies. This lack of blinding may introduce an element of performance and detection bias which could potentially lead to an overestimation of the effect of intervention.
      • Herbert R.
      • Jamtvedt G.
      • Birger Hagen K.
      • et al.
      Practical evidence-based physiotherapy.
      However, as active or usual routine controls were used in all of the included studies, the impact of this on results is likely to be minimal.
      • Herbert R.
      • Jamtvedt G.
      • Birger Hagen K.
      • et al.
      Practical evidence-based physiotherapy.
      A common strength of the included studies was the minimisation of attrition bias.
      • McGuine T.A.
      • Keene J.S.
      The effect of a balance training program on the risk of ankle sprains in high school athletes.
      • Eils E.
      • Schröter R.
      • Schröder M.
      • et al.
      Multistation proprioceptive exercise program prevents ankle injuries in basketball.
      • Emery C.A.
      • Rose M.S.
      • McAllister J.
      • et al.
      A prevention strategy to reduce the incidence of injury in high school basketball: a cluster randomized controlled trial.
      • Hupperets M.D.
      • Verhagen E.A.
      • van Mechelen W.
      Effect of unsupervised home based proprioceptive training on recurrences of ankle sprain: randomised controlled trial.
      • Mohammadi F.
      Comparison of 3 preventive methods to reduce the recurrence of ankle inversion sprains in male soccer players.
      This was due to the minimal drop-out rates and/or intention-to-treat analysis being used, thereby preserving group randomisation and maintaining validity of the results.
      • Herbert R.
      • Jamtvedt G.
      • Birger Hagen K.
      • et al.
      Practical evidence-based physiotherapy.
      Due to a number of similarities between the clinical context and that of the included studies, the results in this study can be applied clinically. Subjects included in the studies are representative of the population likely to be treated in practice, as they cover a wide range of age groups (12–70 years), include a relatively even representation of both genders, and range from community-based to professional athletes participating in high-risk ankle injury sports. The intervention and outcome measure are highly applicable as they are already widely used,
      • Mohammadi F.
      Comparison of 3 preventive methods to reduce the recurrence of ankle inversion sprains in male soccer players.
      are inexpensive,
      • Hupperets M.D.
      • Verhagen E.A.
      • Heymans M.W.
      • et al.
      Potential savings of a program to prevent ankle sprain recurrence: economic evaluation of a randomized controlled trial.
      • McGuine T.A.
      • Keene J.S.
      The effect of a balance training program on the risk of ankle sprains in high school athletes.
      safe,
      • Verhagen E.
      • Twisk J.
      • Bouter L.
      • et al.
      The effect of a proprioceptive balance board training program for the prevention of ankle sprains: a prospective controlled trial.
      • McGuine T.A.
      • Keene J.S.
      The effect of a balance training program on the risk of ankle sprains in high school athletes.
      • Emery C.A.
      • Cassidy J.D.
      • Klassen T.P.
      • et al.
      Effectiveness of a home-based balance-training program in reducing sports-related injuries among healthy adolescents: a cluster randomized controlled trial.
      • Eils E.
      • Schröter R.
      • Schröder M.
      • et al.
      Multistation proprioceptive exercise program prevents ankle injuries in basketball.
      • Hupperets M.D.
      • Verhagen E.A.
      • van Mechelen W.
      Effect of unsupervised home based proprioceptive training on recurrences of ankle sprain: randomised controlled trial.
      • Mohammadi F.
      Comparison of 3 preventive methods to reduce the recurrence of ankle inversion sprains in male soccer players.
      • Söderman K.
      • Werner S.
      • Pietilä T.
      • et al.
      Balance board training: prevention of traumatic injuries of the lower extremities in female soccer players?.
      and can be independently self-administered once initially taught.
      • McGuine T.A.
      • Keene J.S.
      The effect of a balance training program on the risk of ankle sprains in high school athletes.
      This review has several strengths that differentiate it from previous reviews relating to the topic. Firstly, our review focuses very specifically on the effectiveness of proprioceptive training programmes as a sole intervention. Unlike other reviews in this field,
      • Verhagen E.A.
      • Bay K.
      Optimising ankle sprain prevention: a critical review and practical appraisal of the literature.
      • Hübscher M.
      • Zech A.
      • Pfeifer K.
      • et al.
      Neuromuscular training for sports injury prevention: a systematic review.
      • Postle K.
      • Pak D.
      • Smith T.O.
      Effectiveness of proprioceptive exercises for ankle ligament injury in adults: a systematic literature and meta-analysis.
      • de Vries J.S.
      • Krips R.
      • Sierevelt I.N.
      • et al.
      Interventions for treating chronic ankle instability.
      • Loudon J.K.
      • Santos M.J.
      • Franks L.
      • et al.
      The effectiveness of active exercise as an intervention for functional ankle instability: a systematic review.
      • McKeon P.O.
      • Hertel J.
      Systematic review of postural control and lateral ankle instability, part II: is balance training clinically effective?.
      • Webster K.A.
      • Gribble P.A.
      Functional rehabilitation interventions for chronic ankle instability: a systematic review.
      • Zech A.
      • Hubscher M.
      • Vogt L.
      • et al.
      Neuromuscular training for rehabilitation of sports injuries: a systematic review.
      our review excluded studies allowing co-interventions (such as strengthening, agility training or plyometrics) that may confound the effects of the proprioceptive training element of the intervention. Results of other reviews may also be confounded by the inclusion of lower quality studies,
      • Verhagen E.A.
      • Bay K.
      Optimising ankle sprain prevention: a critical review and practical appraisal of the literature.
      • Postle K.
      • Pak D.
      • Smith T.O.
      Effectiveness of proprioceptive exercises for ankle ligament injury in adults: a systematic literature and meta-analysis.
      • de Vries J.S.
      • Krips R.
      • Sierevelt I.N.
      • et al.
      Interventions for treating chronic ankle instability.
      • Loudon J.K.
      • Santos M.J.
      • Franks L.
      • et al.
      The effectiveness of active exercise as an intervention for functional ankle instability: a systematic review.
      • Webster K.A.
      • Gribble P.A.
      Functional rehabilitation interventions for chronic ankle instability: a systematic review.
      • Zech A.
      • Hubscher M.
      • Vogt L.
      • et al.
      Neuromuscular training for rehabilitation of sports injuries: a systematic review.
      wheras our review focussed exclusively on moderate-to-high quality studies thereby increasing validity of the results and conclusions drawn. Another strength of our review is that it differentiates between the effectiveness of the intervention for those with and without history of ankle sprain. This enables more specific conclusions relating to functional outcomes in different populations. A further strength of our review that differentiates it from most others is that we used meta-analysis in order to establish pooled estimates of the effect of the intervention. Two previous reviews have utilised meta-analysis
      • Hübscher M.
      • Zech A.
      • Pfeifer K.
      • et al.
      Neuromuscular training for sports injury prevention: a systematic review.
      • Postle K.
      • Pak D.
      • Smith T.O.
      Effectiveness of proprioceptive exercises for ankle ligament injury in adults: a systematic literature and meta-analysis.
      , but they included only three
      • Hübscher M.
      • Zech A.
      • Pfeifer K.
      • et al.
      Neuromuscular training for sports injury prevention: a systematic review.
      and two
      • Postle K.
      • Pak D.
      • Smith T.O.
      Effectiveness of proprioceptive exercises for ankle ligament injury in adults: a systematic literature and meta-analysis.
      studies respectfully (with one study from each not qualifying for our review), whereas ours included seven.
      Limitations of our review include the potential for publication bias as we did not search for unpublished trials. Furthermore, studies published in languages other than English were excluded. However, there is some evidence to suggest that excluding non-English articles does not typically have a large impact on systematic review results.
      • Moher D.
      • Pham B.
      • Lawson M.L.
      • et al.
      The inclusion of reports of randomised trials published in languages other than English in systematic reviews.
      Further research is likely to make additional contributions to knowledge in this field. In particular, there is a need for more high quality trials relating to the preventative effects of proprioceptive training for those without a history of injury, given that only two such studies were included in our review. Even in participants with a history of ankle sprain, proprioceptive training has not been compared to a wide range of comparisons, providing scope for future trials to add to existing knowledge. For example, a new RCT that was published after the completion of our review reported that a proprioceptive programme was less effective than bracing, however, compliance with exercises and bracing was poor and the confidence intervals were wide
      • Janssen K.W.
      • van Mechelen W.
      • Verhagen E.A.
      Bracing superior to neuromuscular training for the prevention of self-reported recurrent ankle sprains: a three-arm randomised controlled trial.
      . Further evaluation of the relative effects of proprioceptive training programmes in comparison to commonly used alternatives (such as bracing and taping) appear warranted, as does the evaluation of methods for increasing compliance to interventions.

      5. Conclusion

      This review found that proprioceptive training reduces the risk of sustaining an ankle sprain among sporting populations. Preventive effects have been established in mixed populations and in those with a history of ankle injury. The effectiveness of this intervention for participants without a history of ankle sprain was found to be inconclusive.

      Practical implications

      • Proprioceptive training is effective at reducing the rate of ankle sprains in sporting participants.
      • Approximately 17 sporting participants, or 13 participants with a history of ankle sprain, need to undergo proprioceptive training in order to prevent one future ankle sprain.
      • The preventative benefits of proprioceptive training have been well established in sporting participants with a history of ankle sprain (prevention of recurrence), but there is still insufficient evidence to be sure that it prevents initial injuries in those without a history of ankle sprain.

      Funding

      No funding was received for this research.

      Conflict of interests

      None.

      Appendix A. Supplementary data

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