Delayed Latency of Peroneal Reflex to Sudden Inversion with Ankle Taping or Bracing

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.

Statistical ankle-shape and pressure analysis for design of elastic tubular bandage

Ankles can benefit from the elastic tube bandage (ETB) by providing the ankle joint with compression, but partial high- or low-pressure leads to body discomfort. The aim of this paper is to propose a method for analyzing the ankle shape with the fabric compression which is basis on the comfortable pressure on human body. First, a standard model of ankle is established from the scanned data of 306 samples, and the mapping of the fabric shape curves on ankle were constructed by the U-direction convex curves of the model. The positions or areas of maximum and minimum pressure are then marked by extracting the curvatures of the fabric shape curves. According to the Laplace's Law, the sizes of ETBs can be calculated given that the value of comfortable pressure on human body is the maximum one. The data of calculation is approximate to the relevant previous studies which has the same parameters of ETBs. Nine groups of the ankle shapes from the database are discussed, each group has a proportional coefficient to the standard model, and the result shows that six sizes of ETBs with comfort pressure match for the nine groups. These can be applied to the comfort design, and the method proposed can boost size customization of ETBs, as well as will inspire the research on other elastic compression garments.

Factors Contributing to Chronic Ankle Instability: A Systematic Review and Meta-Analysis of Systematic Reviews

BACKGROUND

Many factors are thought to contribute to chronic ankle instability (CAI). Multiple systematic reviews have synthesised the available evidence to identify the primary contributing factors. However, readers are now faced with several systematic reviews that present conflicting findings.

OBJECTIVE

The aim of this systematic review and meta-analysis was to establish the statistical significance and effect size of primary factors contributing to CAI and to identify likely reasons for inconsistencies in the literature.

METHODS

Relevant health databases were searched: CINAHL, MEDLINE, PubMed, Scopus and SPORTDiscus. Systematic reviews were included if they answered a focused research question, clearly defined the search strategy criteria and study selection/inclusion and completed a comprehensive search of the literature. Included reviews needed to be published in a peer-reviewed journal and needed to review observational studies of factors and/or characteristics of persons with CAI, with or without meta-analysis. There was no language restriction. Studies using a non-systematic review methodology (e.g. primary studies and narrative reviews) were excluded. Methodological quality of systematic reviews was assessed using the modified R-AMSTAR tool. Meta-analysis on included primary studies was performed.

RESULTS

Only 17% of primary studies measured a clearly defined CAI population. There is strong evidence to support the contribution of dynamic balance, peroneal reaction time and eversion strength deficits and moderate evidence for proprioception and static balance deficits to non-specific ankle instability.

CONCLUSIONS

Evidence from previous systematic reviews does not accurately reflect the CAI population. For treatment of non-specific ankle instability, clinicians should focus on dynamic balance, reaction time and strength deficits; however, these findings may not be translated to the CAI population. Research should be updated with an adequately controlled CAI population.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO 2016, CRD42016032592.

Review of ankle inversion sprain simulators in the biomechanics laboratory

Ankle inversion ligamentous sprain is one of the most common sports injuries. The most direct way is to investigate real injury incidents, but it is unethical and impossible to replicate on test participants. Simulators including tilt platforms, trapdoors, and fulcrum devices were designed to mimic ankle inversion movements in laboratories. Inversion angle was the only element considered in early designs; however, an ankle sprain is composed of inversion and plantarflexion in clinical observations. Inversion velocity is another parameter that increased the reality of simulation. This review summarised the simulators, and aimed to compare and contrast their features and settings.

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.

Effect of lace-up ankle braces on electromyography measures during walking in adults with chronic ankle instability

BACKGROUND

Lace-up ankle braces reduce the incidence of ankle sprains and have been hypothesized to do so through both mechanical and neuromuscular mechanisms.

OBJECTIVE

To determine the effect of lace-up ankle braces on surface electromyography (sEMG) measures during walking in adults with chronic ankle instability (CAI).

DESIGN

Randomized crossover.

SETTING

Laboratory.

PARTICIPANTS

Fifteen adults with CAI.

MAIN OUTCOME MEASURES

Surface EMG activity was recorded from the anterior tibialis, peroneus longus, lateral gastrocnemius, rectus femoris, biceps femoris and gluteus medius during treadmill walking with and without lace-up ankle braces. The dependent variables were sEMG amplitude 100 ms pre- and 200 ms post-initial contact, time of activation relative to initial contact, and percent of activation across the stride cycle.

RESULTS

When compared to no brace, ankle bracing resulted in lower pre-contact amplitude of the peroneus longus (p = 0.02). The anterior tibialis, peroneus longus, rectus femoris, and gluteus medius were activated later relative to initial contact (p < 0.03). The peroneus longus and rectus femoris were activated for a shorter percentage of the stride cycle (p < 0.05).

CONCLUSION

Braces cause a change in neuromuscular activity during walking. Clinicians should be aware of these changes when prescribing braces, as it may relate to the mechanism in which braces decrease sprains.

Foot structure and muscle reaction time to a simulated ankle sprain

CONTEXT

Foot structure has been shown to affect aspects of neuromuscular control, including postural stability and proprioception. However, despite an association between pronated and supinated foot structures and the incidence of lateral ankle sprains, no one to our knowledge has measured muscle reaction time to a simulated ankle-sprain mechanism in participants with different foot structures.

OBJECTIVE

To determine whether pronated or supinated foot structures contribute to neuromuscular deficits as measured by muscle reaction time to a simulated ankle-sprain mechanism.

DESIGN

Cross-sectional study.

SETTING

University biomechanics laboratory.

PATIENTS OR OTHER PARTICIPANTS

Thirty volunteers were categorized into 3 groups according to navicular-drop-height measures. Ten participants (4 men, 6 women) had neutral feet (navicular-drop height = 5-9 mm), 10 participants (4 men, 6 women) had pronated feet (navicular-drop height ≥ 10 mm), and 10 participants (4 men, 6 women) had supinated feet (navicular-drop height ≤ 4 mm).

INTERVENTION(S)

Three perturbations on a standing tilt platform simulating the mechanics of an inversion and plantar-flexion ankle sprain.

MAIN OUTCOME MEASURE(S)

Muscle reaction time in milliseconds of the peroneus longus, tibialis anterior, and gluteus medius to the tilt-platform perturbation.

RESULTS

Participants with pronated or supinated foot structures had slower peroneus longus reaction times than participants with neutral feet (P = .01 and P = .04, respectively). We found no differences for the tibialis anterior or gluteus medius.

CONCLUSIONS

Foot structure influenced peroneus longus reaction time. Further research is required to establish the consequences of slower peroneal reaction times in pronated and supinated foot structures. Researchers investigating lower limb muscle reaction time should control for foot structure because it may influence results.

Effects of previous lateral ankle sprain and taping on the latency of the peroneus longus

The latency of the peroneus longus may be a key factor in the prevention of lateral ankle sprains (LASs). In addition, ankle taping is often applied to help prevent LASs. The purpose of this study was to determine the effects of a previous LAS and ankle taping on the latency of the peroneus longus after an inversion perturbation. Twenty-six participants, including 13 participants with no previous history of a LAS and 13 participants with a history of a single LAS completed the testing. Ankle taping was applied in a closed basket weave technique on one of the two testing days. The latency of the peroneus longus was determined by the onset of muscle activity exceeding 10 SD from baseline activity, after initiation of the 25 degrees inversion perturbation. A significant main effect (p < 0.05) was present for the ankle support condition, with ankle taping causing a significant reduction in latency of the peroneus longus (65.04 +/- 10.81 to 57.70 +/- 9.39 ms). There was no difference (p > 0.05) in latency between the injury groups. Ankle taping, immediately after application, reduces the latency of the peroneus longus among participants with and without a history of a LAS.

Effects of Inversion Perturbation After Step-Down on the Latency of the Peroneus Longus and Peroneus Brevis

The purpose of this investigation was to determine the effect of different types of ankle sprains on the response latency of the peroneus longus and peroneus brevis to an inversion perturbation, as well as the time to complete the perturbation (time to maximum inversion). To create a forced inversion moment of the ankle, an outer sole with fulcrum was used to cause 25 degrees of inversion at the ankle upon landing from a 27 cm step-down task. Forty participants completed the study: 15 participants had no history of any ankle sprain, 15 participants had a history of a lateral ankle sprain, and 10 participants had a history of a high ankle sprain. There was not a significant difference between the injury groups for the latency measurements or the time to maximum inversion. These findings indicate that a previous lateral ankle sprain or high ankle sprain does not affect the latency of the peroneal muscles or the time to complete the inversion range of motion.

Dynamic ankle control in athletes with ankle instability during sports maneuvers

BACKGROUND

Ankle sprain is a common sports injury. While the effects of static constraints in stabilizing the ankle joint are relatively well understood, those of dynamic constraints are less clear and require further investigation.

PURPOSE

This study was undertaken to evaluate the dynamic stability of the ankle joint during the landing phase of running and stop-jump maneuvers in athletes with and without chronic ankle instability (CAI).

STUDY DESIGN

Controlled laboratory study.

METHODS

Fifteen athletes with CAI and 15 age-matched athletes without CAI performed running and stop-jump landing tasks. The dynamic ankle joint stiffness, tibialis anterior (TA)/peroneus longus (PL) and TA/gastrocnemius lateralis (GL) co-contraction indices, ankle joint angle, and root-mean-square (RMS) of the TA, PL, and GL electromyographic signals were measured during each task.

RESULTS

During running, the CAI group exhibited a greater ankle inversion angle than the control group in the pre-landing phase (P = .012-.042) and a lower dynamic ankle joint stiffness in the post-landing phase (CAI: 0.109 ± 0.039 N·m/deg; control: 0.150 ± 0.068 N·m/deg; P = .048). In the stop-jump landing task, athletes with CAI had a significantly lower TA/PL co-contraction index during the pre-landing phase (CAI: 49.1 ± 19; control: 64.8 ± 16; P = .009). In addition, the CAI group exhibited a greater ankle inversion (P = .049), a lower peak eversion (P = .04), and a smaller RMS of the PL electromyographic signal in the post-landing phase (CAI: 0.73 ± 0.32; control: 0.51 ± 0.22; P = .04).

CONCLUSION

Athletes with CAI had a relatively inverted ankle, reduced muscle co-contraction, and a lower dynamic stiffness in the ankle joint during the landing phase of sports maneuvers and this may jeopardize the stability of the ankle.

CLINICAL RELEVANCE

Sports training or rehabilitation programs should differentiate between the pre-landing and post-landing phases of sports maneuvers, and should educate athletes to land with an appropriate ankle position and muscle recruitment.

Effects of kinesio tape compared with nonelastic sports tape and the untaped ankle during a sudden inversion perturbation in male athletes

STUDY DESIGN

Controlled laboratory study.

OBJECTIVES

To examine the effect of 2 adhesive tape conditions compared to a no-tape condition on muscle activity of the fibularis longus during a sudden inversion perturbation in male athletes (soccer, team handball, basketball).

BACKGROUND

Ankle sprains are common in sports, and the fibularis muscles play a role in providing functional stability of the ankle. Prophylactic ankle taping with nonelastic sports tape has been used to restrict ankle inversion. Kinesio Tape, an elastic sports tape, has not been studied for that purpose.

METHODS

Fifty-one male premier-league athletes were tested for functional stability of both ankles with the Star Excursion Balance Test. Based on the results, those with the 15 highest and those with the 15 lowest stability scores were selected for further testing. Muscle activity of the fibularis longus was recorded with surface electromyography during a sudden inversion perturbation. Each participant was tested under 3 conditions: ankle taped with nonelastic white sports tape, ankle taped with Kinesio Tape, and no ankle taping. Differences in mean muscle activity were evaluated with a 3-way mixed-model analysis of variance (ANOVA) for the 3 conditions, across four 500-millisecond time frames, and between the 2 groups of stable versus unstable participants. Differences in peak muscle activity and in the time to peak muscle activity were evaluated with a 2-way mixed-model ANOVA.

RESULTS

Significantly greater mean muscle activity was found when ankles were taped with nonelastic tape compared to no tape, while Kinesio Tape had no significant effect on mean or maximum muscle activity compared to the no-tape condition. Neither stability level nor taping condition had a significant effect on the amount of time from perturbation to maximum activity of the fibularis longus muscle.

CONCLUSION

Nonelastic sports tape may enhance dynamic muscle support of the ankle. The efficacy of Kinesio Tape in preventing ankle sprains via the same mechanism is unlikely, as it had no effect on muscle activation of the fibularis longus.

Análise da influência da bandagem funcional de tornozelo no tempo de reação do fibular longo em sujeitos saudáveis

OBJETIVOS: O objetivo deste estudo foi analisar a influência da bandagem funcional de tornozelo no tempo de reação do fibular longo de indivíduos sadios. MÉTODOS: A amostra foi composta por oito indivíduos do gênero masculino, fisicamente ativos, sem histórias prévias de lesões de tornozelo e, com os resultados negativos aos testes de instabilidade articular de tornozelo. Foram usados como instrumentos da pesquisa, a bandagem funcional de tornozelo tipo bota fechada, para realizar o teste uma plataforma capaz de inclinar 30o no plano frontal simulando a entorse lateral do tornozelo e um eletromiógrafo de oito canais (Bortec Electronics Incorporation, Canadá) para aquisições dos sinais eletromiográficos. Os sinais EMG foram coletados juntamente com o sinal da plataforma (sincronismo). A coleta dos dados foi realizada em dois momentos, primeiramente sem a bandagem e logo após com a bandagem. RESULTADOS: Os indivíduos tinham idade média de 23,3 anos (± 2,8), massa corpórea de 74,4kg (± 9,4), estatura de 1,7m (± 0,4) e IMC de 23,7kg/m2 (± 2,4). O estudo encontrou diferença estatisticamente significativa p = 0,018 na situação da bandagem funcional de tornozelo com diminuição do tempo de reação do fibular longo. CONCLUSÃO: Acreditamos que esta melhora se deva ao íntimo contato da bandagem com os receptores cutâneos do tornozelo, aumentando a ativação do reflexo fibular, com consequente ganho proprioceptivo e, assim, aumentando a habilidade dos sujeitos em responder a situações súbitas de entorses. O estudo demonstrou diminuição no tempo de reação do fibular longo de indivíduos sadios com o uso da bandagem funcional de tornozelo quando submetidos à inclinação lateral súbita do tornozelo.

Neuromuscular control and ankle instability

Lateral ankle sprains (LAS) are common injuries in athletics and daily activity. Although most are resolved with conservative treatment, others develop chronic ankle instability (AI)-a condition associated with persistent pain, weakness, and instability-both mechanical (such as ligamentous laxity) and functional (neuromuscular impairment with or without mechanical laxity). The predominant theory in AI is one of articular deafferentation from the injury, affecting closed-loop (feedback/reflexive) neuromuscular control, but recent research has called that theory into question. A considerable amount of attention has been directed toward understanding the underlying causes of this pathology; however, little is known concerning the neuromuscular mechanisms behind the development of AI. The purpose of this review is to summarize the available literature on neuromuscular control in uninjured individuals and individuals with AI. Based on available research and reasonable speculation, it seems that open-loop (feedforward/anticipatory) neuromuscular control may be more important for the maintenance of dynamic joint stability than closed-loop control systems that rely primarily on proprioception. Therefore, incorporating perturbation activities into patient rehabilitation schemes may be of some benefit in enhancing these open-loop control mechanisms. Despite the amount of research conducted in this area, analysis of individuals with AI during dynamic conditions is limited. Future work should aim to evaluate dynamic perturbations in individuals with AI, as well as subjects who have a history of at least one LAS and never experienced recurrent symptoms. These potential findings may help elucidate some compensatory mechanisms, or more appropriate neuromuscular control strategies after an LAS event, thus laying the groundwork for future intervention studies that can attempt to reduce the incidence and severity of acute and chronic lateral ankle injury.

Evidence of sensorimotor deficits in functional ankle instability: a systematic review with meta-analysis

Functional ankle instability (FAI) has been associated with impaired sensorimotor function; however individual studies have produced conflicting results. In an attempt to reduce this ambiguity, a systematic review with meta-analysis was undertaken to determine which sensorimotor deficits exist with FAI. Fifty-three studies assessing sensorimotor factors in subjects with FAI were included from 465 identified articles. Studies were rated for methodological quality and data were pooled for peroneal reaction time, joint position sense, and postural sway during single-leg stance and time to stabilisation from a single-leg jump. Data on joint movement sense were unable to be pooled. When subjects with unstable ankles were compared to healthy controls, sensorimotor impairments were demonstrated for passive joint position sense (mean difference (MD)=0.7 degrees , 95% confidence interval (CI): 0.2-1.2 degrees , p=0.004), active joint position sense (MD=0.6 degrees , 95% CI: 0.2-1.0 degrees , p=0.002), postural sway in single-leg stance (standardised MD (SMD)=0.6, 95% CI: 0.2-1.0, p=0.002), the star excursion balance test (SMD=0.4, 95% CI: 0.1-0.7, p=0.009), and time to stabilisation from a single-leg jump in a medio-lateral (MD=0.6 ms, 95% CI: 0.4-0.8, p<0.0001) and an antero-posterior direction (MD=0.7 ms, 95% CI: 0.4-1.0, p<0.0001). Peroneal reaction time was not affected. Sensorimotor deficits occur for joint position sense and postural control in subjects with FAI. Deficits in peroneal muscle reaction time following perturbation are not evident.

Tape that increases medial longitudinal arch height also reduces leg muscle activity: a preliminary study

PURPOSE

: To evaluate the initial effects of antipronation taping (APT) on foot posture and electromyographic (EMG) activity of tibialis anterior (TA), tibialis posterior (TP), and peroneus longus (PL) muscles during walking.

METHODS

: Five asymptomatic individuals who exhibited lower medial longitudinal arch height on a clinical assessment of gait walked on a treadmill for 10 min before and after the application of an APT technique-specifically, the augmented low-Dye. Arch height (AH) in standing as well as peak and average amplitude, duration, time of onset, and time of offset of recorded EMG activity during walking were analyzed for each condition.

RESULTS

: APT produced a mean (95% confidence interval (CI)) increase in AH of 12.9% (6.5-19.3; P = 0.005). Mean (95% CI) reductions in peak and average EMG activation of TA (peak: -23.9% (-34.0 to -13.9); average: -7.8% (-13.6 to -2.0)) and TP (peak: -45.5% (-77.3 to -13.7); average: -21.1% (-41.6 to -0.6)) were observed when walking with APT (P < 0.05). The APT also produced a small increase in duration of TA EMG activity of 3.7% (0.9-6.5) of the stride cycle duration, largely because of an earlier onset of EMG activity (4.4%; -8.1 to -0.8 of a stride cycle; P < 0.05).

CONCLUSION

: APT reduces activity of the TA and TP muscles during walking while increasing AH, which provides preliminary evidence of its role in reducing the load of these key extrinsic muscles of the ankle and the foot. Follow-up study is required to evaluate these findings.

Ankle bracing, plantar-flexion angle, and ankle muscle latencies during inversion stress in healthy participants

CONTEXT

Ankle braces may enhance ankle joint proprioception, which in turn may affect reflexive ankle muscle activity during a perturbation. Despite the common occurrence of plantar-flexion inversion ankle injuries, authors of previous studies of ankle muscle latencies have focused on inversion stresses only.

OBJECTIVE

To examine the latency of the peroneus longus (PL), peroneus brevis (PB), and tibialis anterior (TA) muscles in response to various degrees of combined plantar-flexion and inversion stresses in braced and unbraced asymptomatic ankles.

DESIGN

Repeated measures.

SETTING

University biomechanics laboratory.

PATIENTS OR OTHER PARTICIPANTS

Twenty-eight healthy females and 12 healthy males (n = 40: mean age = 23.63 years, range = 19 to 30 years; height = 172.75 +/- 7.96 cm; mass = 65.53 +/- 12.0 kg).

INTERVENTION(S)

Participants were tested under 2 conditions: wearing and not wearing an Active Ankle T1 brace while dropping from a custom-made platform into 10 degrees , 20 degrees , and 30 degrees of plantar flexion and 30 degrees of inversion.

MAIN OUTCOME MEASURE(S)

The time between platform drop and the onset of PL, PB, and TA electromyographic activity was measured to determine latencies. We calculated a series of 2-way analyses of variance to determine if latencies were different between the conditions (braced and unbraced) and among the plantar-flexion angles (alpha = .05).

RESULTS

No interaction was found between condition and plantar-flexion angle. No significant main effects were found for condition or plantar-flexion angle. Overall means for braced and unbraced conditions were not significantly different for each muscle tested. Overall means for angle for the PL, PB, and TA were not significantly different.

CONCLUSIONS

Reflexive activity of the PL, PB, or TA was unaffected by the amount of plantar flexion or by wearing an Active Ankle T1 brace during an unanticipated plantar-flexion inversion perturbation.

The effect of fatigue and habituation on the stretch reflex of the ankle musculature

Many ankle injuries are said to occur when athletes are in a fatigued state; therefore, studies investigating the role that fatigue plays in ankle injuries are warranted. Furthermore, the contributions of the stretch reflex in countering the injury mechanism are still unclear. We hypothesized that (1) fatigue would impair the reflex response, (2) there would be no differences between genders, (3) habituation would be present, and (4) fatigue would exacerbate the effect of habituation. Forty healthy subjects participated and were divided into treatment and control groups. Stretch reflex measurements were taken for the tibialis anterior (TA), peroneus longus (PL), and peroneus brevis (PB) muscles in response to a rapid inversion perturbation. A fatigue intervention was administered to the treatment group, while the control group sat quietly. Post-test measurements were recorded within 5min and reflex latency (RL) and amplitude (RA) were calculated. RA decreased significantly, however a significant improvement was noted in RL in the PL and PB muscles. The effect that peripheral fatigue has on RL should not be considered a cause of ankle injuries. However, the diminished RA may suggest reduced dynamic stability after fatigue. Habituation was present and was exacerbated by fatigue, indicating that reflex testing is affected by fatigue and habituation, which must be taken into consideration in future studies.