Ankle sensorimotor control and eversion strength after acute ankle inversion injuries

Assessment of chronic ankle instability: are functional scores relevant enough?

INTRODUCTION

A poorly treated acute ankle sprain can rapidly progress to chronic instability, with varying degrees of disability secondary to weakness of the ankle stabilizers. The aim of our study was to evaluate functional scores and physical tests in the assessment of eversion and proprioception deficits after non-surgical treatment of chronic ankle instability. Our hypothesis was that these functional scores and physical tests are suitable and sufficient for assessing the functional aspect of an unstable ankle.

MATERIAL AND METHOD

This was a prospective, single-center study of patients managed for chronic ankle instability between November 2020 and November 2021. An ankle assessment was performed using two functional scores, the Foot Ankle Ability Measurement (FAAM) and the Ankle Ligament Reconstruction - Return to Sport after Injury (ALR-RSI), as well as two validated physical tests (Y-Balance Test and Side Hope Test). An objective (quantified) assessment of stabilizer muscle strength and proprioception was carried out using a connected device (Myolux™ Medik e-volution).

RESULTS

At last recoil, twenty-eight unstable ankles were included. Only the ALR-RSI score correlated strongly with Myolux™ assessment of eversion strength (Rho ()ρ = 0.7; p < 0.001), and proprioception (Rho ()ρ = 0.8; p < 0.001). FAAM and physical tests were not or only very moderately correlated with Myolux™ assessments.

DISCUSSION

In the absence of the Myolux™ test, the ALR-RSI score seemed the most suitable functional assessment of an unstable ankle in contrast to the FAAM score and the physical examinations Y-Balance Test and Side Hope Test.

LEVEL OF EVIDENCE

IV; prospective study.

The effect of joint mobilization of Maitland on chronic ankle instability: A randomized trial

BACKGROUND

The aim of study was to observe the therapeutic effect of joint mobilization of Maitland on subjects with chronic ankle instability (CAI).

METHODS

76 subjects with CAI were recruited for this randomized, single-blinded trial and randomized divided into experimental group (EG) and control group (CG). The CG was received conventional rehabilitation, and the EG added 8-weeks treatment of Maitland technology based on the CG. The visual analogue scale, ankle range of motion, Y-balance test, and Foot and Ankle Ability Measure scores (the daily living part of Foot and Ankle Ability Measure scores and the sport part of Foot and Ankle Ability Measure scores) were measured before and 8 weeks after the intervention respectively.

RESULTS

There was no significant difference on outcomes between the 2 groups before treatment (P > .05). After 8 weeks of intervention, the visual analogue scale, ankle range of motion (dorsiflexion, plantar flexion, and varus), the value of Y-balance test (forward extension distance, inner extension distance, and posterior extension distance), the daily living part of Foot and Ankle Ability Measure scores, and the sport part of Foot and Ankle Ability Measure scores of the 2 groups were significantly improved (P < .01), and the improvement of the EG showed remarkable than CG (P < .01).

CONCLUSION

Maitland therapy is effective in the treatment of CAI. Conventional rehabilitation assisted by Maitland therapy were beneficial to improve pain and functional state in patients with CAI than only routine rehabilitation.

Acute Effects of Selective Strength Exercise on the Peroneus Longus and Brevis

The peroneus muscles are muscles that mainly act in ankle eversion and can be divided into PL and PB, which have different but important roles in foot and ankle functions. Therefore, PL and PB dysfunction can lead to foot and ankle issues, making. selective strength exercise necessary. This study aimed to identify the effect of two different exercise techniques on PL and PB morphologies. Two interventions were performed on separate days: the PL intervention, in which a Thera-Band® was placed on the ball of the foot and pushed out from the contact point, and the PB intervention, in which the Thera-Band® was pulled from the base of the fifth metatarsal. Cross-sectional area (CSA) and thickness of the peroneus muscles at 25% (showing the PL morphology) and 75% (showing the PB morphology) proximal to the line connecting the fibular head and lateral malleolus, as well as ankle strength was measured before and immediately after the interventions and at 10, 20, and 30 min later. A repeated-measures two-way analysis of variance was conducted to identify differences in the effects of the interventions on the PL and PB. Main and interaction effects on CSA, thickness, and ankle strength, with a significant increase in CSA and thickness in the proximal 25% in the PL intervention and the distal 75% in the PB intervention immediately after implementation, were observed (p < 0.05). The transient increase in muscle volume due to edema immediately after exercise indicates the acute effect of exercise. The CSA and thickness of the proximal 25% in the PL intervention and the distal 75% in the PB intervention increased immediately after the intervention, indicating that these interventions can be used to selectively exercise the PL and PB.

Misencoding of ankle joint angle control system via cutaneous afferents reflex pathway in chronic ankle instability

This study aimed to investigate how the cutaneous reflexes in the peroneus longus (PL) muscle are affected by changing the ankle joint position in patients with chronic ankle instability (CAI). We also investigated the correlation between the degree of reflex modulation and angle position sense of the ankle joint. The participants were 19 patients with CAI and 20 age-matched controls. Cutaneous reflexes were elicited by applying non-noxious electrical stimulation to the sural nerve at the ankle joint in the neutral standing and eversion/inversion standing positions. The suppressive middle latency cutaneous reflex (MLR; ~ 70-120 ms) and angle position sense of the ankle joint were assessed. During neutral standing, the gain of the suppressive MLR was more prominent in the CAI patients than in controls, although no significant difference was seen during 30° inversion standing. In addition, the ratios of the suppressive MLR and background electromyography in a neutral position were significantly larger than those at the 15°, 25°, and 30° inversion positions in CAI patients. No such difference was seen in control individuals. Furthermore, the correlations between reflex modulation degree and position sense error were quite different in CAI patients compared to controls. These findings suggest that the sensory-motor system was deteriorated in CAI patients due to changes in the PL cutaneous reflex pathway excitability and position sense of the ankle joint.

Morphological and Functional Characteristics of the Peroneus Muscles in Patients with Lateral Ankle Sprain: An Ultrasound-Based Study

Background and Objectives: The effectiveness of multiple ultrasound evaluations of the peroneus muscles morphology, including muscle cross-sectional area (CSA) and connective tissue, after lateral ankle sprain (LAS) is unknown. This study aimed to measure the peroneus muscles after LAS at three points, adding distal 75% to the conventional measurement points, in order to obtain a detailed understanding of the post-injury morphology and to propose a new evaluation index of the peroneus muscles for multiple LAS. Materials and Methods: Participants with and without LAS (LAS and control groups, 16 each) were recruited. The muscle cross-sectional area (CSA) and muscle echogenicity were measured using a B-mode ultrasound system at 25%, 50%, and 75% proximal to the line connecting the fibular head to the lateral malleolus. The ankle evertor strength was measured using a handheld dynamometer. Simultaneously, the peroneus longus (PL) and peroneus brevis (PB) muscle activities were measured using surface electromyography. Measurements for the LAS side, non-LAS side, and control leg were performed separately. Results: The CSA was significantly higher at 75% on the LAS side than on the non-LAS side and in the control leg. Muscle echogenicity of the LAS side at 75% was significantly lower than that of the non-LAS side and the control leg. Muscle activity of the PL was significantly lower and the PB was higher on the LAS side than on the non-LAS side and in the control leg. Conclusions: The PL was less active than the PB, while the PB was found to be overactive, suggesting that PB hypertrophy occurs due to an increase in the percentage of muscle fibers and a decrease in the connective tissue. Therefore, it is necessary to evaluate the condition of the PL and PB separately after LAS.

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.

Chronic ankle instability is associated with proprioception deficits: A systematic review and meta-analysis

BACKGROUND

Acute ankle injury causes damage to joint mechanoreceptors and deafferentation and contributes to proprioception deficits in patients with chronic ankle instability (CAI). We aimed to explore whether deficits of proprioception, including kinesthesia and joint position sense (JPS), exist in patients with CAI when compared with the uninjured contralateral side and healthy people. We hypothesized that proprioception deficits did exist in patients with CAI and that the deficits varied by test methodologies.

METHODS

The study was a systematic review and meta-analysis. We identified studies that compared kinesthesia or JPS in patients with CAI with the uninjured contralateral side or with healthy controls. Meta-analyses were conducted for the studies with similar test procedures, and narrative syntheses were undertaken for the rest.

RESULTS

A total of 7731 studies were identified, of which 30 were included for review. A total of 21 studies were eligible for meta-analysis. Compared with the contralateral side, patients with CAI had ankle kinesthesia deficits in inversion and plantarflexion, with a standardized mean difference (SMD) of 0.41 and 0.92, respectively, and active and passive JPS deficits in inversion (SMD = 0.92 and 0.72, respectively). Compared with healthy people, patients with CAI had ankle kinesthesia deficits in inversion and eversion (SMD = 0.64 and 0.76, respectively), and active JPS deficits in inversion and eversion (SMD = 1.00 and 4.82, respectively). Proprioception deficits in the knee and shoulder of patients with CAI were not statistically significant.

CONCLUSION

Proprioception, including both kinesthesia and JPS, of the injured ankle of patients with CAI was impaired, compared with the uninjured contralateral limbs and healthy people. Proprioception varied depending on different movement directions and test methodologies. The use of more detailed measurements of proprioception and interventions for restoring the deficits are recommended in the clinical management of CAI.

Peroneal reaction time delayed but dynamic single-legged stability retained in collegiate footballers during a simulated prolonged football protocol

Delayed peroneal reaction time and impaired single-legged dynamic stability were risk factors of lateral ankle sprain (LAS), yet no study explored the change of them during a football match. The aim is to explore the change of peroneal reaction time and single-legged dynamic stability during a football simulation protocol. Twelve collegiate football players voluntarily completed a 105-min football match simulation protocol in which peroneal reaction time, root-mean-square of mediolateral ground reaction force in first 0.4 s (RMS ML 0.4), and the mean mediolateral ground reaction force in the late stage (late dynamic MLGRF), were measured for both legs at 15-min intervals during the protocol. Peroneal reaction time was tested using an electromyography (EMG) system. The ground reaction force variables were measured from GRF data after a single-legged drop-jump landing. Repeated measures one-way MANOVA was conducted to evaluate variables over time and leg dominance. Statistical significance was set at p < 0.05 level. Peroneal reaction time significantly increased for both legs at 45 minutes and after 60 minutes. RMS ML 0.4 of both legs and late dynamic MLGRF for dominant leg remained unchanged throughout the protocol and late dynamic MLGRF for non-dominant leg significantly reduced at the 90th minute.

Rehabilitation of the Dancer

Rehabilitation of dance injury should be a team-based approach lead by a medical practitioner with experience in both musculoskeletal medicine and dance specific demands. The rehabilitation protocol begins with a dance specific initial assessment, followed by injury management, progression of the rehabilitation program including dance specific movement, advancing to full independence.

Effects of lateral ankle sprain on range of motion, strength and postural balance in competitive basketball players: a cross-sectional study

BACKGROUND

Lateral ankle sprain is the most common injury in basketball, and many of these sprains resulted in residual functional deficits. This study aimed to compare ankle strength and range of motion, and postural balance between competitive basketball players with and without lateral ankle sprain.

METHODS

This was a cross-sectional study involving 42 male competitive basketball players. Subjects were divided into the injured and uninjured groups based on self-reported questionnaires. Ankle range of motion (ROM) was measured using a goniometer, ankle isokinetic strength testing performed using Biodex System 4 PRO, and single-leg stability tests performed using Biodex Balance System SD.

RESULTS

Between the injured and uninjured ankles, there was a decrease in plantarflexion ROM (44.89±6.85 vs. 50.75±9.31, P<0.05) and an increase in eversion ROM (14.50±5.63 vs. 11.74±4.53, P<0.05). There was a reduction in inversion and plantarflexion strength at 30°/s peak torque and 120 °/s peak torque (P<0.05). However, no significant difference observed in the postural stability indexes between the two groups.

CONCLUSIONS

This study proves that there are residual ROM and strength deficits after an ankle sprain, however, these deficits do not affect their balance ability.

Plausible mechanisms of and techniques to assess ankle joint degeneration following lateral ankle sprains: a narrative review

Lateral ankle sprain (LAS) is the most common lower extremity musculoskeletal injury sustained during daily life and sport. The cascade of events that starts with ligamentous trauma leads to clinical manifestations such as recurrent sprains and giving way episodes, hallmark characteristics of chronic ankle instability (CAI). The sequelae of lateral ankle sprains and CAI appear to contribute to aberrant biomechanics. Combined, joint trauma and aberrant biomechanics appear to directly and/or indirectly play a role in talar cartilage degeneration. Up to 80% of all cases of ankle osteoarthritis (OA) are post-traumatic in nature and common etiologies for ankle post-traumatic osteoarthritis (PTOA) are histories of a single and recurrent ankle sprains. Despite known links between LAS, CAI, and PTOA and evidence demonstrating the burden of LAS and its sequelae, early pathoetiological changes of ankle PTOA and how they can be assessed are poorly understood. Therefore, the purpose of this paper is to review the plausible mechanistic links among LAS and its sequelae of CAI and PTOA as well as review non-surgical techniques that can quantify talar cartilage health. Understanding the pathway from ligamentous ankle injury to ankle PTOA is vital to developing theoretically sound therapeutic interventions aimed at slowing ankle PTOA progression. Further, directly assessing talar cartilage health non-surgically provides opportunities to quantify if current and novel intervention strategies are able to slow the progression of ankle PTOA.

Performance Function Tests in Assessing Ankle Fitness

Introduction:

A challenge for any physician caring for athletes is determining readiness for return to competition after an injury. A wide variety of performance function tests (PFTs) have been described, but no norms or minimum performance levels exist for any of them. In this study, healthy athletes were given a series of PFTs to complete. We propose that there will be a minimum performance level for each of the PFTs that all athletes can complete. We also propose, for tests that assess the right and left legs independently, that performance of the right leg will consistently be within 10% of the left. Finally, we propose that performance on one of the functional tests will be predictive of function on all the tests.

Methods:

Athletes were put through a testing protocol, beginning with range of motion and progressing through a series of functional ankle tests of increasing difficulty. Right and left leg data were recorded separately for the first five tests. For each test, mean values, ranges, and SDs were calculated.

Results:

Eighty-one athletes completed the protocol. A wide variation existed in performance ability between athletes; the SD for any of the tests was too high to determine a minimum performance threshold. However, when comparing right to left leg in any one athlete, the difference in performance testing was always less than 10%. Furthermore, performance on the side hop test was predictive of performance on the other tests.

Discussion:

A wide range of performance was noted in all the PFTs, so it is not possible to define a minimum threshold. However, performance of an injured leg to within 10% of the opposite (uninjured) leg suggests achievement of normal function. The side hop test might be a good test by itself to represent overall ankle readiness.

Health Belief Model Scale and Theory of Planned Behavior Scale to assess attitudes and perceptions of injury prevention program participation: An exploratory factor analysis

OBJECTIVES

To examine the psychometric properties of the Health Belief Model Scale (HBMS) and Theory of Planned Behavior Scale (TPBS), and determine construct validity by evaluating which subscales were most associated with intention to participate in an Exercise-related Injury Prevention Program (ERIPP) within physically active adults.

DESIGN

Cross-sectional.

METHODS

Two hundred and eighty-four physically active individuals volunteered to participate in this study and completed the HBMS and TPBS on one occasion. The HBMS consisted of 39 items and the TPBS consisted of 22 items. Both scales aimed to assess attitudes and perceptions of ERIPP participation. Exploratory factor analysis evaluated the loading factors of the HBMS and TPBS. Linear regression determined if the HBMS and TPBS subscales were predictors of intention to participate in an ERIPP.

RESULTS

Nine factors were identified within the HBMS and five factors were identified within the TPBS. The subscales of the HBMS and TPBS had acceptable internal consistencies. Perceived benefits, social norms, and social influence from the TPBS and perceived benefits, individual self-efficacy, and general health cues from the HBMS were positively and significantly associated with intention to participate while perceived barriers had a negative association.

CONCLUSIONS

The HBMS and TPBS demonstrated strong psychometric properties to assess behavioral determinants of ERIPP participation within physically active adults. The social influence, social norm, and individual self-efficacy subscales were the best predictors of intention to participate followed by benefits, general health cues, and barriers.

Peroneal muscle activity during different types of walking

BACKGROUND

As the most common form of movement, walking happens not only on flat but also on uneven surfaces, where constant loss and regaining of balance occur. The main balancing function of the ankle joint is performed by tibial muscles. When changing inclination in a frontal plane, an essential balancing function is performed by the peroneal muscles. One of the methods for improving the activity of peroneal muscles is walking with different foot placement. The objective of this study was to analyze the activity of the peroneal muscles when performing different types of walking.

METHODS

Sixteen healthy participants took part in this study, walking on a flat surface (NORM), on a medial incline ramp with the plantar surface of the foot fully placed on the surface (FULL), and on a medial incline ramp with elevated lateral part of the foot (LAT). We monitored the changes of EMG signals in peroneus longus (PL), peroneus brevis (PB), tibialis anterior (TA), soleus (SOL), gastrocnemius medialis (GM) and gastrocnemius lateralis (GL) muscles. We monitored kinematic parameters (gait speed, stride length, contact time, foot position). The parametric ANOVA test and a non-parametric Friedman test were used at an alpha level of 0.05.

RESULTS

This study shows that the EMG activities of peroneal muscles increases when walking on the medial incline ramp. Statistically significant EMG differences were observed in the peroneal muscles, TA and GL muscles. We observe a very high percentage of normalized EMG value of the PL muscle in LAT walking. Walking on a medial incline ramp impacts the foot position, contact time, and stride length but not the gait speed.

CONCLUSIONS

Walking on a medial incline ramp could be an effective exercise to improve the neuro-muscular function of the peroneal muscles and, therefore, might be a suitable exercise for people with weakened ankle evertors.

Effectiveness of Foot Biomechanical Orthoses to Relieve Patients' Knee Pain: Changes in Neural Strategy After 9 Weeks of Treatment

Knee pain is one of the most common lower leg complaints. It is often treated with plantar orthoses to provide cushioning and correct locomotion, imbalances of the foot, and postural deficits. However, the published scientific data are poor concerning the mechanisms involved in pain reduction after wearing foot orthoses, and, to the best of our knowledge, no trial has investigated the mid-term effectiveness. The aim of the present study was to evaluate the effectiveness of foot orthoses according to sound biomechanical principles in the treatment of knee pain. Attention was mainly focused on changes in the central control strategies. Fifteen subjects were included in the protocol. The patients with knee pain were compared with healthy participants (control group) exhibiting no knee pain. In the patients with knee pain, pain perception, dynamic analysis of the gait, stabilometry, the soleus Hoffmann reflex at rest and during voluntary contraction, and V-wave were measured before and 3, 6, and 9 weeks after wearing orthoses. In the control group (n = 5), the same parameters were recorded at 0, 3, 6, and 9 weeks, but the subjects had not worn orthoses. In the patient group (n = 10), the results indicated that pain had significantly decreased from the third week onward, although the parameters of gait and stabilometry remained unchanged. From the sixth week, the soleus Hoffmann reflex during voluntary contraction wave was significantly reduced, suggesting an increase in motoneuronal presynaptic inhibition by non-nociceptive afferents. The V-wave amplitude increased throughout the 9 weeks of the experiment, suggesting a progressive increase in corticospinal and/or extrapyramidal descending pathway inputs, probably due to pain reduction. In the control group, no change was observed throughout the experimental sessions. Our data indicated that foot orthoses relieved patients' knee pain and reduced the descending motor inhibition. Changes in spinal modulation could contribute to a better quality of life. However, this treatment failed to change the altered gait, despite changes in spinal and supraspinal modulation.

Electromyographic analysis of balance exercises in single-leg stance using different instability modalities of the forefoot and rearfoot

PURPOSE

To investigate the activity of lower extremity muscles in response to single-leg stance on a training device, destabilizing the forefoot while the rearfoot stands on a fixed plate and vice versa compared with a balance pad and the floor.

DESIGN

Cross-sectional study.

SETTING

University's laboratory.

PARTICIPANTS

Twenty-seven healthy adults.

METHODS

Surface electromyography and 2D video analysis were used to record the activity of lower extremity muscles and to control sagittal knee joint angle during single-leg stance trials under one stable control condition and five unstable conditions.

RESULTS

The majority of lower extremity muscles were significantly more active when the forefoot was destabilized while the rearfoot remained stable compared with the stable condition and the conditions where the forefoot was stable and the rearfoot unstable (p <0 .001). Mean change of knee joint angle was significantly increased under the conditions rearfoot stable/forefoot unstable (p = 0.001). The soleus muscle activation was significantly increased when balancing on the balance pad (p < 0.001).

CONCLUSIONS

Increased activity in the majority of lower extremity muscles and sagittal knee joint angles indicate that destabilizing the forefoot while the rearfoot remains stable is the most challenging balance task. Soleus muscle activation increased when performing ankle plantarflexion on the soft balance pad.

Acute lateral ankle sprain to chronic ankle instability: a pathway of dysfunction

Lateral ankle sprains (LAS) have been reported as one of the most common musculoskeletal injuries observed in sports and in individuals who are recreationally active. Approximately 40% of individuals who sustain a LAS develop a condition known as chronic ankle instability (CAI). Years of research has identified numerous impairments associated with CAI such as decreases in range of motion (ROM), strength, postural control, and altered movement patterns during functional activities when compared to individuals with no LAS history. As a result, an impairment-based rehabilitation model was developed to treat the common impairments associated with CAI. The impairment-based rehabilitation model has been shown to be an effective rehabilitation strategy at improving both clinical and patient-oriented outcomes in patients with CAI. To date, the efficacy of an impairment-based rehabilitation model has not been evaluated in patients with an acute LAS. Prior to implementing an impairment-based model for the treatment of an acute LAS, similarities between impairments associated with acute LAS and CAI across the spectrum of the healing process is warranted. Therefore, the purpose of this review paper is to compare and contrast impairments and treatment techniques in individuals with an acute LAS, sub-acute LAS, and CAI. A secondary purpose of this review is to provide clinical commentary on the management of acute LAS and speculate how the implementation of an impairment-based rehabilitation strategy for the treatment of acute LAS could minimize the development of CAI. The main findings of this review were that similar impairments (decreased ROM, strength, postural control, and functional activities) are observed in patients with acute LAS, sub-acute LAS, and CAI, suggesting that the impairments associated with CAI are a continuation from the original impairments developed during the initial LAS. Therefore, the use of an impairment-based model may be advantageous when treating patients with an acute LAS.

Anatomic stabilization techniques provide superior results in terms of functional outcome in patients suffering from chronic ankle instability compared to non-anatomic techniques

PURPOSE

To determine the best surgical treatment for chronic ankle instability (CAI) a systematic review was performed to compare the functional outcomes between various surgical stabilization methods.

METHODS

A systematic search was performed from 1950 up to April 2016 using PubMed, EMBASE, Medline and the Cochrane Library. Inclusion criteria were a minimum age of 18 years, persistent lateral ankle instability, treatment by some form of surgical stabilization, described functional outcome measures. Exclusion criteria were case reports, (systematic) reviews, articles not published in English, description of only acute instability or only conservative treatment, medial ankle instability and concomitant injuries, deformities or previous surgical treatment for ankle instability. After inclusion, studies were critically appraised using the Modified Coleman Methodology Score.

RESULTS

The search resulted in a total of 19 articles, including 882 patients, which were included in this review. The Modified Coleman Methodology Score ranged from 30 to 73 points on a scale from 0 to 90 points. The AOFAS and Karlsson Score were the most commonly used patient-reported outcome measures to assess functional outcome after surgery. Anatomic repair showed the highest post-operative scores [AOFAS 93.8 (SD ± 2.7; n = 119); Karlsson 95.1 (SD ± 3.6, n = 121)], compared to anatomic reconstruction [AOFAS 90.2 (SD ± 10.9, n = 128); Karlsson 90.1 (SD ± 7.8, n = 35)] and tenodesis [AOFAS 86.5 (SD ± 12.0, n = 10); Karlsson 85.3 (SD ± 2.5, n = 39)]. Anatomic reconstruction showed the highest score increase after surgery (AOFAS 37.0 (SD ± 6.8, n = 128); Karlsson 51.6 (SD ± 5.5, n = 35) compared to anatomic repair [AOFAS 31.8 (SD ± 5.3, n = 119); Karlsson 40.9 (SD ± 2.9, n = 121)] and tenodesis [AOFAS 19.5 (SD ± 13.7, n = 10); Karlsson 29.4 (SD ± 6.3, n = 39)] (p < 0.005).

CONCLUSION

Anatomic reconstruction and anatomic repair provide better functional outcome after surgical treatment of patients with CAI compared to tenodesis reconstruction. These results further discourage the use of tenodesis reconstruction and other non-anatomic surgical techniques. Future studies may be required to indicate potential value of tenodesis reconstruction when used as a salvage procedure. Not optimal, but the latter still provides an increase in functional outcome post-operatively. Anatomic reconstruction seems to give the best results, but may be more invasive than anatomic repair. This has to be kept in mind when choosing between reconstruction and repair in the treatment of CAI.

LEVEL OF EVIDENCE

IV.

Peroneus Longus activity according to various angles of a ramp during cross-ramp walking and one-legged standing

BACKGROUND

Ankle sprain are one of the most common injuries in sports and public health in general. Cross-slope may creat a risk for ankle sprain and are commonly found in both urban and rural environment.

OBJECTIVE

The purpose of study was to clarify the environmental risk factor that can be easily occurred ankle sprain during walking (stance phase) and one leg standing at various ramp environment.

METHODS

Participants was measured muscle activation on peroneus longus during both conditions (walk across the ramp and one leg stand in the transverse direction) of seven different angle (0∘, 2∘, 5∘, 10∘, 15∘, 20∘, 25∘). The measured data were analyzed using one-way ANOVA to investigate the effect of muscle activation on the each condition.

RESULTS

Ankle sprain can be easily occurred when cross walk and one-leg stand on a ramp from higher than 10∘, and highest risk was angle of 25∘ or more. As a people with peroneus longus weakness walks a ramp, the ramp angle has a cross relationship with the sprain on the ankle.

CONCLUSIONS

If people with peroneus longus weakness walk on the more than 10∘ of ramp angle, they will need a lot of attention for prevent ankle sprain.

Eversion Strength and Surface Electromyography Measures With and Without Chronic Ankle Instability Measured in 2 Positions

BACKGROUND

Individuals with chronic ankle instability (CAI) have demonstrated strength deficits compared to healthy controls; however, the influence of ankle position on force measures and surface electromyography (sEMG) activation of the peroneus longus and brevis has not been investigated. The purpose of this study was to compare sEMG amplitudes of the peroneus longus and brevis and eversion force measures in 2 testing positions, neutral and plantarflexion, in groups with and without CAI.

METHODS

Twenty-eight adults (19 females, 9 males) with CAI and 28 healthy controls (19 females, 9 males) participated. Hand-held dynamometer force measures were assessed during isometric eversion contractions in 2 testing positions (neutral, plantarflexion) while surface sEMG amplitudes of the peroneal muscles were recorded. Force measures were normalized to body mass, and sEMG amplitudes were normalized to a resting period.

RESULTS

The group with CAI demonstrated less force when compared to the control group ( P < .001) in both the neutral and plantarflexion positions: neutral position, CAI: 1.64 Nm/kg and control: 2.10 Nm/kg) and plantarflexion position, CAI: 1.40 Nm/kg and control: 1.73 Nm/kg). There were no differences in sEMG amplitudes between the groups or muscles ( P > .05). Force measures correlated with both muscles' sEMG amplitudes in the healthy group (neutral peroneus longus: r = 0.42, P = .03; plantarflexion peroneus longus: r = 0.56, P = .002; neutral peroneus brevis: r = 0.38, P = .05; plantarflexion peroneus longus: r = 0.40, P = .04), but not in the group with CAI ( P > .05).

CONCLUSIONS

The group with CAI generated less force when compared to the control group during both testing positions. There was no selective activation of the peroneal muscles with testing in both positions, and force output and sEMG activity was only related in the healthy group.

CLINICAL RELEVANCE

Clinicians should assess eversion strength and implement strength training exercises in different sagittal plane positions and evaluate for other pathologies that may contribute to reduced eversion strength in patients with CAI.

LEVEL OF EVIDENCE

Level III, cross-sectional.

Acute ankle sprain: conservative or surgical approach?

Ankle sprains fall into two main categories: acute ankle sprains and chronic ankle instability, which are among the most common recurrent injuries during occupational activities, athletic events, training and army service.

Acute ankle sprain is usually managed conservatively and functional rehabilitation failure by conservative treatment leads to development of chronic ankle instability, which most often requires surgical intervention.

Enhancing the in-depth knowledge of the ankle anatomy, biomechanics and pathology helps greatly in deciding the management options.

Cite this article: Al-Mohrej OA, Al-Kenani NS. Acute ankle sprain: conservative or surgical approach? EFORT Open Rev 2016;1:34-44. DOI: 10.1302/2058-5241.1.000010.

3D strength surfaces for ankle plantar- and dorsi-flexion in healthy adults: an isometric and isokinetic dynamometry study

BACKGROUND

The ankle is an important component of the human kinetic chain, and deficits in ankle strength can negatively impact functional tasks such as balance and gait. While peak torque is influenced by joint angle and movement velocity, ankle strength is typically reported for a single angle or movement speed. To better identify deficits and track recovery of ankle strength after injury or surgical intervention, ankle strength across a range of movement velocities and joint angles in healthy adults is needed. Thus, the primary goals of this study were to generate a database of strength values and 3-dimensional strength surface models for plantarflexion (PF) and dorsiflexion (DF) ankle strength in healthy men and women. Secondary goals were to develop a means to estimate ankle strength percentiles as well as examine predictors of maximal ankle strength in healthy adults.

METHODS

Using an isokinetic dynamometer, we tested PF and DF peak torques at five joint angles (-10° [DF], 0° [neutral], 10° [PF], 20° [PF] and 30° [PF]) and six velocities (0°/s, 30°/s, 60°/s, 90°/s, 120°/s and 180°/s) in 53 healthy adults. These data were used to generate 3D plots, or "strength surfaces", for males and females for each direction; surfaces were fit using a logistic equation. We also tested predictors of ankle strength, including height, weight, sex, and self-reported physical activity levels.

RESULTS

Torque-velocity and torque-angle relationships at the ankle interact, indicating that these relationships are interdependent and best modeled using 3D surfaces. Sex was the strongest predictor of ankle strength over height, weight, and self-reported physical activity levels. 79 to 97 % of the variance in mean peak torque was explained by joint angle and movement velocity using logistic equations, for men and women and PF and DF directions separately.

CONCLUSIONS

The 3D strength data and surface models provide a more comprehensive dataset of ankle strength in healthy adults than previously reported. These models may allow researchers and clinicians to quantify ankle strength deficits and track recovery in patient populations, using angle- and velocity-specific ankle strength values and/or strength percentiles from healthy adults.

Four Weeks of Balance Training does not Affect Ankle Joint Stiffness in Subjects with Unilateral Chronic Ankle Instability

Background

Balance training has been shown to be effective in preventing ankle sprain recurrences in subjects with chronic ankle instability (CAI) but the biomechanical pathways underlying the clinical outcomes are still unknown. This study was conducted to determine if a 4-week balance training intervention can alter the mechanical characteristics in ankles with CAI.

Methods

Twenty-two recreationally active subjects with unilateral CAI were randomized to either a control (n = 11, 35.1 ± 9.3 years) or intervention (n = 11, 33.5 ± 6.6 years) group. Subjects in the intervention group were trained on the affected limb with static and dynamic components using a Biodex balance stability system for 4-weeks. The ankle joint stiffness and neutral zone in inversion and eversion directions on the involved and uninvolved limbs was measured at baseline and post-intervention using a dynamometer.

Results

At baseline, the mean values of the inversion stiffness (0.69 ± 0.37 Nm/degree) in the involved ankle was significantly lower (p < 0.011, 95% CI [0.563, 0.544]) than that of uninvolved contralateral ankle (0.99 ± 0.41 Nm/degree). With the available sample size, the eversion stiffness, inversion neutral zone, and eversion neutral zone were not found to be significantly different between the involved and uninvolved contralateral ankles. The 4-week balance training intervention failed to show any significant effect on the passive ankle stiffness and neutral zones in inversion and eversion.

Conclusion

Decreased inversion stiffness in the involved chronic unstable ankle was found that of uninvolved contralateral ankle. The 4-week balance training program intervention was ineffective in altering the mechanical characteristics of ankles with CAI.

Level of evidence

Randomized controlled clinical trial; Level of evidence, 1.

Reliability of two-point discrimination thresholds using a 4-2-1 stepping algorithm

PURPOSE

A 4-2-1 stepping algorithm reliably captures light touch thresholds but has not been used to assess two-point discrimination (TPD) thresholds. Therefore, the purpose of this investigation was to determine the intra- and inter-rater reliability of a 4-2-1 stepping algorithm at determining TPD thresholds.

MATERIALS AND METHODS

Fifteen healthy, physically active young adults were assessed twice over a 1-week period using digital calipers and a 4-2-1 stepping algorithm. TPD thresholds were assessed by an expert and a novice examiner at each time point. Reliability was assessed on the plantar surface of the foot at the head of the first and base of the fifth metatarsal.

RESULTS

Three intra-rater intraclass correlation coefficient (ICC) values exceeded 0.75 and were interpreted as good. The inter-rater reliability was good with ICC values ranging from 0.76 to 0.93 at both sites during both test sessions.

CONCLUSIONS

The 4-2-1 stepping algorithm demonstrates good intra- and inter-tester reliability at determining TPD thresholds on the plantar surface of the foot at the head of the first and base of the fifth metatarsal in young healthy adults.

The effect of lifting and lowering an external load on repositioning error of trunk flexion-extension in subjects with and without low back pain

Objective: To determine whether the repositioning error of trunk flexion-extension in individuals with low back pain is different from that in those not experiencing low back pain when lifting and lowering external loads.

Design: A case-control study.

Setting: Physical therapy department of a medical centre.

Subjects: Twenty subjects with subacute low back pain and 20 control subjects without low back pain.

Interventions: Tasks with and without lifting and lowering an external load.

Main outcome measures: The trunk repositioning errors were measured with Measurand Shape Tape.

Results: In subjects with low back pain, trunk repositioning errors were significantly reduced when lifting and lowering an external load in the direction of flexion (3.779 ±1.26 degrees in a loaded condition versus 4.82±2.97 degrees in an unloaded condition; P B< 0.05) and extension (3.17±2.15 degrees in a loaded condition versus 5.039±3.74 degrees in an unloaded condition; p < 0.05). In control subjects, trunk repositioning errors were not significantly changed when lifting and lowering an external load in the direction of flexion (2.80±1.39 degrees in a loaded condition versus 2.63±1.24 degrees in an unloaded condition; p < 0.05) and extension (2.87±1.40 degrees in a loaded condition versus 3.15±1.50 degrees in an unloaded condition; P>0.05). The direction of motion (trunk flexion or extension) was not shown to be significant in this study.

Conclusion: Performing the task whilst lifting or lowering a submaximal load showed a reduced trunk repositioning error in subjects with subacute low back pain. Lifting and lowering a submaximal load might be considered as one of the rehabilitative strategies to hasten a return to work.

Rehabilitation for Chronic Ankle Instability With or Without Destabilization Devices: A Randomized Controlled Trial

CONTEXT

Individuals with chronic ankle instability (CAI) have deficits in neuromuscular control and altered movement patterns. Ankle-destabilization devices have been shown to increase lower extremity muscle activity during functional tasks and may be useful tools for improving common deficits and self-reported function.

OBJECTIVE

To determine whether a 4-week rehabilitation program that includes destabilization devices has greater effects on self-reported function, range of motion (ROM), strength, and balance than rehabilitation without devices in patients with CAI.

DESIGN

Randomized controlled clinical trial.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 26 patients with CAI (7 men, 19 women; age = 21.34 ± 3.06 years, height = 168.96 ± 8.77 cm, mass = 70.73 ± 13.86 kg).

INTERVENTION(S)

Patients completed baseline measures and were randomized into no-device and device groups. Both groups completed 4 weeks of supervised, impairment-based progressive rehabilitation with or without devices and then repeated baseline measures.

MAIN OUTCOME MEASURE(S)

We assessed self-reported function using the Foot and Ankle Ability Measure. Ankle ROM was measured with an inclinometer. Ankle strength was assessed using a handheld dynamometer during maximal voluntary isometric contractions. Balance was measured using a composite score of 3 reach directions from the Star Excursion Balance Test and a force plate to calculate center of pressure during eyes-open and eyes-closed single-limb balance. We compared each dependent variable using a 2 × 2 (group × time) analysis of variance and post hoc tests as appropriate and set an a priori α level at .05. The Hedges g effect sizes and associated 95% confidence intervals were calculated.

RESULTS

We observed no differences between the no-device and device groups for any measure. However, both groups had large improvements in self-reported function and ankle strength.

CONCLUSIONS

Incorporating destabilization devices into rehabilitation did not improve ankle function more effectively than traditional rehabilitation tools because both interventions resulted in similar improvements. Impairment-based progressive rehabilitation improved clinical outcomes associated with CAI.

Rehabilitation for Chronic Ankle Instability With or Without Destabilization Devices: A Randomized Controlled Trial

CONTEXT

Individuals with chronic ankle instability (CAI) have deficits in neuromuscular control and altered movement patterns. Ankle-destabilization devices have been shown to increase lower extremity muscle activity during functional tasks and may be useful tools for improving common deficits and self-reported function.

OBJECTIVE

To determine whether a 4-week rehabilitation program that includes destabilization devices has greater effects on self-reported function, range of motion (ROM), strength, and balance than rehabilitation without devices in patients with CAI.

DESIGN

Randomized controlled clinical trial.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 26 patients with CAI (7 men, 19 women; age = 21.34 ± 3.06 years, height = 168.96 ± 8.77 cm, mass = 70.73 ± 13.86 kg).

INTERVENTION(S)

Patients completed baseline measures and were randomized into no-device and device groups. Both groups completed 4 weeks of supervised, impairment-based progressive rehabilitation with or without devices and then repeated baseline measures.

MAIN OUTCOME MEASURE(S)

We assessed self-reported function using the Foot and Ankle Ability Measure. Ankle ROM was measured with an inclinometer. Ankle strength was assessed using a handheld dynamometer during maximal voluntary isometric contractions. Balance was measured using a composite score of 3 reach directions from the Star Excursion Balance Test and a force plate to calculate center of pressure during eyes-open and eyes-closed single-limb balance. We compared each dependent variable using a 2 × 2 (group × time) analysis of variance and post hoc tests as appropriate and set an a priori α level at .05. The Hedges g effect sizes and associated 95% confidence intervals were calculated.

RESULTS

We observed no differences between the no-device and device groups for any measure. However, both groups had large improvements in self-reported function and ankle strength.

CONCLUSIONS

Incorporating destabilization devices into rehabilitation did not improve ankle function more effectively than traditional rehabilitation tools because both interventions resulted in similar improvements. Impairment-based progressive rehabilitation improved clinical outcomes associated with CAI.

History-dependent changes in the recovery process of the middle latency cutaneous reflex gain after ankle sprain injury

PURPOSE

We previously reported that suppressive middle latency cutaneous reflexes (MLRs) in the peroneus longus (PL) are exaggerated in subjects with chronic ankle instability, and the changes are related to functional instability. However, the time-varying history of these neurophysiological changes after an ankle sprain is yet to be elucidated. Therefore, in the present study, we investigated the time course of the changes in the PL MLR after an ankle sprain in relation to the number of sprain recurrences.

METHODS

Twenty-three subjects with ankle sprain were classified into 3 groups according to their history of ankle sprain: first ankle sprain, 2-3 ankle sprains, and ≥4 ankle sprains. Twenty-three age-matched control subjects also participated. The PL MLRs were elicited by stimulating the sural nerve while the subjects performed different levels of isometric ankle eversion. Gain of MLR was estimated using linear regression analysis (slope value) of the amplitude modulation of MLRs obtained from graded isometric contractions.

RESULT

The gain of MLRs first increased 4 weeks after the injury. In subjects with their first ankle sprain, the MLRs returned to almost baseline levels after 3 months. In contrast, the increase in MLR gain persisted even after 3 months in subjects with recurrent ankle sprains. In addition, the MLR gains were closely related to functional recovery of the ankle joint.

CONCLUSIONS

Our findings suggest that the recovery process of MLR gains were strongly affected by the history of ankle sprains as well as the functional recovery of the ankle joint.

Peroneal reaction time after ankle sprain: a systematic review and meta-analysis

BACKGROUND

Many studies have examined the temporal response of the peroneal muscles to sudden inversion perturbation in patients with a previous ankle sprain. The purpose of this systematic review with meta-analysis was to synthesize the evidence and determine whether peroneal reaction time (PRT) impairments are present after ankle sprain.

METHODS

An electronic search was conducted using PubMed Central and EBSCOhost (1965-January 2013). Articles were included if they 1) examined the PRT to sudden inversion perturbation in patients with a history of ankle sprain using a mechanical tilt platform, 2) made comparisons with a control group or contralateral limb with no history of ankle sprain, and 3) provided data for the calculation of effect sizes (ES). In addition to examining the overall effect of sustaining an ankle sprain on PRT, the effects of study design and subject characteristics on PRT were evaluated. Bias-corrected Hedges g ES and 95% confidence intervals (CI) were calculated to make comparisons across studies.

RESULTS

A total of 23 studies met the inclusion criteria. The overall ES was 0.67 (95% CI = 0.37-0.95, P < 0.001), indicating that a previous ankle sprain, regardless of study design or subject characteristics, resulted in moderate-to-strong PRT deficits. Further analyses determined studies with patients classified as having chronic ankle instability demonstrated large magnitude PRT deficits in between groups (ES = 0.72, 95% CI = 0.29-1.14, P = 0.001) and side-to-side (ES = 1.24, 95% CI = 0.70-1.79, P < 0.001) comparisons, whereas patients with all other ankle sprain histories demonstrated weak PRT alterations in between groups (ES = -0.21, 95% CI = -1.01 to 0.59, P = 0.61) and side-to-side (ES = 0.21, 95% CI = -0.19 to 0.60, P = 0.31) comparisons.

CONCLUSIONS

Overall, this meta-analysis determined that individuals with a previous ankle sprain exhibit delayed PRT. Further analyses determined that these deficits are more evident in patients with chronic ankle instability when compared with the contralateral uninvolved limb or a healthy control group.

Lateral Ankle Sprain and Chronic Ankle Instability: A Critical Review

Many studies investigated the contributing factors of chronic ankle instability, but a consensus has not yet been obtained. The objective of this critical review is to provide recent scientific evidence on chronic ankle instability, including the epidemiology and pathology of lateral ankle sprain as well as the causative factors of chronic ankle instability. We searched MEDLINE from 1964 to December 2013 using the terms ankle, sprain, ligament, injury, chronic, functional, mechanical, and instability. Lateral ankle sprain shows a very high recurrence rate and causes considerable economic loss due to medical care, prevention, and secondary disability. During the acute phase, patients with ankle sprain demonstrate symptoms such as pain, range of motion deficit, postural control deficit, and muscle weakness, and these symptoms may persist, leading to chronic ankle instability. Although some agreement regarding the effects of chronic ankle instability with deficits in postural control and/or concentric eversion strength exists, the cause of chronic ankle instability remains controversial.

LEVELS OF EVIDENCE

Therapeutic Level IV: Review of Level IV studies.

Intra-Tester Reliability of Hand-Held Dynamometry and Strap-Mounted Dynamometry for Assessment of Ankle Strength

Context:

Measurement of ankle evertor and invertor strength is important for assessment of ankle sprain risk and assessment of restoration of normal function after an ankle sprain.

Objective:

To compare the intra-tester reliability of ankle evertor and invertor strength measurements derived from hand-held dynamometry (HHD) and strap-mounted dynamometry (SMD) for both make-test and break-test techniques.

Participants:

25 healthy individuals.

Main Outcome Measure:

Repeated measurements of isometric evertor and invertor strength derived from both HHD and SMD devices using both make-test and break-test techniques.

Results:

High make-test reliability values were found for both inversion and eversion force measured by both the HHD and SMD devices (ICC = 0.80 to ICC = 0.88). The correlation coeffcients between HHD and SMD measurements for the inversion make-test, the inversion break-test, and the eversion make-test ranged from r = 0.74 to r = 0.87, but the correlation between HHD and SMD measurements for the eversion break-test was poor.

Conclusion:

The fndings suggest that testers with limited experience can obtain reliable measurements of ankle evertor and invertor strength using either HHD or SMD.

Ankle kinematics and muscle activity in functional ankle instability

OBJECTIVE

Following an ankle injury, many patients have functional ankle instability (FAI) with an increased predisposition to reinjury. The purpose of this study was to assess the effects of FAI on ankle kinematics and muscle activity during a lateral hop movement.

DESIGN

Cross-sectional and observational study; all data collection for each subject was performed on 1 day.

SETTING

Clinical biomechanics laboratory.

PATIENTS

Two groups were studied: (1) Control group-no ankle injury (n = 12), and (2) FAI group (n = 12).

INTERVENTIONS

The lateral hop movement consisted of multiple lateral and medial 1-legged hops over an obstacle (width, 72.5 cm; depth, 25.5 cm; height, 14.3 cm) onto adjacent force platforms. Each subject was instructed to perform as many lateral hops as possible during the 6-second trial. Means, SDs, 95% confidence intervals of the differences, and P-values were calculated.

MAIN OUTCOME MEASURES

Ankle kinematics and muscle activity throughout the lateral hop movement.

RESULTS

Significant differences existed between groups for mean (SD) dorsiflexion ankle positions--FAI 82.4 degrees (6.4) versus normal 75.2 degrees (10.1) and tibialis anterior normalized muscle activity--FAI 0.27 (0.21) versus normal 0.16 (0.13) at ground contact.

CONCLUSIONS

The FAI group revealed greater tibialis anterior muscle activity and dorsiflexion ankle position at contact moving in the lateral direction. These differences between groups may have been related to an inherent predisposition to ankle injuries, a preexisting difference in task performance, a consequence of injuries, or a compensatory adaptation to previous injuries.

The role of arthroscopy in the treatment of functional instability of the ankle

BACKGROUND

Ankle sprains are common, the majority resolving with functional rehabilitation. Some patients are left with symptoms of functional instability (FI). Ankle arthroscopy in those with symptoms of FI is not well covered in the literature. Our aim was to assess its role in FI of the ankle.

METHODS

Retrospective case note analysis of patients with FI following an ankle sprain from 2005 to 2007. All underwent arthroscopy, provided mechanical instability was excluded (EUA and stress X-rays), and there were no signs of soft tissue impingement. These patients had exhausted all options of conservative therapy.

RESULTS

Seventy-seven patients with a mean age of 38.1: five had true mechanical instability and were excluded. 72 underwent arthroscopy: 67 (93.1%) had significant amounts of scar tissue needing debridement, most commonly in the antero-lateral corner (58.3%). 52 patients improved (72.2%) at a minimum of 6 months follow-up.

CONCLUSION

Our study supports the role of ankle arthroscopy in the treatment of FI following trauma. It should be considered when conservative measures have failed.

Human capacity for explosive force production: neural and contractile determinants

This study assessed the integrative neural and contractile determinants of human knee extension explosive force production. Forty untrained participants performed voluntary and involuntary (supramaximally evoked twitches and octets - eight pulses at 300 Hz that elicit the maximum possible rate of force development) explosive isometric contractions of the knee extensors. Explosive force (F0-150 ms) and sequential rate of force development (RFD, 50-ms epochs) were measured. Surface electromyography (EMG) amplitude was recorded (superficial quadriceps and hamstrings, 50-ms epochs) and normalized (quadriceps to Mmax, hamstrings to EMGmax). Maximum voluntary force (MVF) was also assessed. Multiple linear regressions assessed the significant neural and contractile determinants of absolute and relative (%MVF) explosive force and sequential RFD. Explosive force production exhibited substantial interindividual variability, particularly during the early phase of contraction [F50, 13-fold (absolute); 7.5-fold (relative)]. Multiple regression explained 59-93% (absolute) and 35-60% (relative) of the variance in explosive force production. The primary determinants of explosive force changed during the contraction (F0-50, quadriceps EMG and Twitch F; RFD50-100, Octet RFD0-50; F100-150, MVF). In conclusion, explosive force production was largely explained by predictor neural and contractile variables, but the specific determinants changed during the phase of contraction.

National Athletic Trainers' Association position statement: conservative management and prevention of ankle sprains in athletes

OBJECTIVE

To present recommendations for athletic trainers and other allied health care professionals in the conservative management and prevention of ankle sprains in athletes.

BACKGROUND

Because ankle sprains are a common and often disabling injury in athletes, athletic trainers and other sports health care professionals must be able to implement the most current and evidence-supported treatment strategies to ensure safe and rapid return to play. Equally important is initiating preventive measures to mitigate both first-time sprains and the chance of reinjury. Therefore, considerations for appropriate preventive measures (including taping and bracing), initial assessment, both short- and long-term management strategies, return-to-play guidelines, and recommendations for syndesmotic ankle sprains and chronic ankle instability are presented.

RECOMMENDATIONS

The recommendations included in this position statement are intended to provide athletic trainers and other sports health care professionals with guidelines and criteria to deliver the best health care possible for the prevention and management of ankle sprains. An endorsement as to best practice is made whenever evidence supporting the recommendation is available.

[Neuromuscular deficits in chronic ankle instability. Frequency and significance - multicenter study]

The peroneal reaction time (PRT) is used in the assessment of neuromuscular deficits in chronic functional ankle instability. Powered by the Editorial Manager and Preprint Manager from Aries Systems Corporation the present study was conducted to determine the PRT in a large collective of patients with chronic ankle instability because it is unclear if this parameter of neuromuscular deficit is prolonged. In this study 186 patients underwent a diagnostic algorithm consisting of anamnesis, clinical examination, X-ray and determination of the PRT on a tilting platform. A prolonged PRT as a manifestation of a neuromuscular deficit could be detected in the majority of the patients (n = 143, 77%). Comparing the affected and healthy legs 77 patients (41%) showed a significant difference in talar shift (p = 0.002) and talar tilt (p = 0.04) in the radiological stress views. Of these 77 patients only 15 (8%) showed radiological evidence of a mechanical problem. As a consequence of recurring ankle sprains a post-traumatic deficit in proprioception has to be expected in most cases. In general a conservative therapy approach should be followed including specific training to improve neuromuscular and proprioceptive deficits.

A new paradigm for rehabilitation of patients with chronic ankle instability

Lateral ankle sprains have been shown to be one of the most common musculoskeletal injuries in both athletes and the recreationally active population. Moreover, it is estimated that approximately 30% of people who incur a lateral ankle sprain will sustain recurrent ankle sprains and experience symptoms of pain and instability that last > 1 year. Chronic ankle instability (CAI) is the term used to describe cases involving repetitive ankle sprains, multiple episodes of the ankle "giving way," persistent symptoms, and diminished self-reported function for > 1 year after the initial ankle sprain. The optimal conservative treatment for CAI is yet to be determined; however, comparison between patients with CAI and individuals showing no history of ankle sprain has revealed several characteristic features of CAI. These include diminished range of motion, decreased strength, impaired neuromuscular control, and altered functional movement patterns. We propose a new treatment paradigm for conservative management of CAI with the aim of assessing and treating specific deficits exhibited by individual patients with CAI.

Gait termination strategies differ between those with and without ankle instability

BACKGROUND

Chronic ankle instability is a common occurrence after an ankle sprain. Yet, some people (copers) possess a mechanism that limits recurrent injury and disability. During gait termination, those with chronic ankle instability exhibit altered feed-forward and feedback control but little is known about alterations in copers. Therefore, the purpose of this investigation was to determine the biomechanical control alterations present in controls, copers, and those with chronic ankle instability during planned and unplanned gait termination.

METHODS

Twenty subjects with chronic ankle instability, 20 copers, and 20 uninjured controls completed planned and unplanned gait termination tasks. Unplanned gait termination required subjects to stop, when cued, during randomly selected trials. Planned gait termination required intended stopping. A total of 10 trials were recorded for each condition. Normalized propulsive and braking force magnitudes and dynamic postural stability indices were calculated and compared among the groups.

FINDINGS

Normalized maximum braking forces were significantly higher in the chronic ankle instability group (Mean: 2.82 SD: 0.93N/kg), relative to copers (Mean: 2.59 SD: 0.84N/kg) and controls (Mean: 2.51 SD: 0.78N/kg). Similarly, the antero-posterior postural stability index revealed higher scores in the chronic ankle instability group (Mean: 0.15 SD: 0.03) compared to the coper (Mean: 0.14 SD: 0.02) and control group (Mean: 0.14 SD: 0.02). Copers did not differ from controls.

INTERPRETATION

The findings suggest that the ability of copers to terminate gait in a manner similar to uninjured controls may represent part of the underlying mechanism that limits recurrent injury and disability in copers.

Changes in biomechanics and muscle activation in injured ballet dancers during a jump-land task with turnout (Sissonne Fermée)

Large impact loading with abnormal muscle activity and motion patterns may contribute to lower extremity injuries in ballet dancers. Yet, few studies investigated the influence of injury on the ballet movement. The purpose of this study was to find the neuromuscular and biomechanical characteristics in dancers with and without ankle injury during a jump-landing Sissonne Fermée task. Twenty-two ballet dancers were recruited and divided into the injured group (n = 11) and the uninjured group (n = 11). They performed a ballet movement called "Sissonne Fermée" with reflective markers and electrodes attached to their lower extremities. Ground reaction force, joint kinematics, and muscle activity were measured. The injured dancers had greater peak ankle eversion but smaller hindfoot-to-tibial eversion angles. Also, the injured dancers had greater activity of the hamstring of the dominant leg and tibialis anterior of the non-dominant leg during the pre-landing phase. The injured dancers had greater tibialis anterior activity of the dominant leg but less muscle activity in the medial gastrocnemius of the non-dominant leg during the post-landing phase. The injured dancers had a greater co-contraction index in the non-dominant ankle and a lower loading rate. The higher co-contraction indices showed that the injured dancers required more muscle effort to control ankle stability. Furthermore, the injured dancers used a "load avoidance strategy" to protect themselves from re-injury. Neuromuscular control training of the ankle joint for ballet dancers to prevent injury is necessary.