Does a drop landing represent a whole skill landing and is this moderated by fatigue?

This study aimed to determine whether the landing phase of a drop landing (DL) differed with respect to a complete jumping and landing task, a spike jump (SJ), and whether fatigue altered the landing of these movements. Fourteen male volleyball players performed five DL and SJ in a counterbalanced order under two experimental conditions: non‐fatigued and fatigued. Fatigue, induced by repetitive jumping sets, was confirmed by decrements in vertical jump height >25% and increased blood lactate >6 mmol/L. Each landing task was characterized by the resultant ground reaction forces (GRF), sagittal plane kinematics and muscle recruitment patterns of six lower extremity muscles. Two‐way repeated analysis of variance results indicated a main effect of movement on many of the GRF, kinematic and electromyographic variables characterizing landing, indicating that the two tasks required substantially different lower limb biomechanics during landing. Although fatigue did not alter the GRF in either task, there were significant movement × fatigue condition interactions. The significant between‐task differences in the biomechanical variables characterizing landing and the differential effects of fatigue on each landing task, question the validity of using a DL as an experimental task to investigate lower limb landing mechanics of whole jumping and landing movements.     

Altered movement strategies during jump landing/cutting in patients with chronic ankle instability

Centrally mediated changes in sensorimotor function have been reported in patients with chronic ankle instability (CAI). However, little is known regarding supraspinal/spinal adaptations during lower‐extremity dynamic movement during a multiplanar, single‐leg landing/cutting task. The purpose of this study was to investigate the effect of CAI on landing/cutting neuromechanics, including lower‐extremity kinematic, electromyography (EMG) activation, and ground reaction force (GRF) characteristics. One hundred CAI patients and 100 matched healthy controls performed five trials of a jump landing/cutting task. Sagittal‐ and frontal‐plane ankle, knee and hip kinematics, EMG activation in eight lower‐extremity muscles, and 3D GRF were collected during jump landing/cutting. Functional analyses of variance (FANOVA) were used to evaluate between‐group differences for dependent variables throughout the entire ground contact of the task. Relative to the control group, the CAI group revealed (a) reduced dorsiflexion, increased knee and hip flexion angles, (b) increased inversion and hip adduction angles, (c) increased EMG activation of medial gastrocnemius, peroneus longus, adductor longus, vastus lateralis, gluteus medius, and gluteus maximus, and (d) increased posterior and vertical GRF during initial landing, and reduced medial, posterior, and vertical GRF during mid‐landing and mid‐cutting. CAI patients demonstrated alterations in landing/cutting movement strategies as demonstrated by a higher susceptibility of foot placement for lateral ankle sprains, and more flexed positions of the knee and hip with higher EMG activation of knee and hip extensors to modulate GRF to compensate for the unstable ankle. This apparent compensation may be due to mechanical (limited dorsiflexion angle) and/or sensorimotor deficits in the ankle.     

Altered leg muscle activity in volleyball players with functional ankle instability during a sideward lateral cutting movement

Objectives

To study the activation patterns of tibialis anterior, peroneus longus and gastrocnemius lateralis muscles during a lateral shuffle maneuver in volleyball players with functional instability of the ankle joint.

Design

Observational case-control study.

Setting

Research laboratory.

Participants

Sixteen players with functional instability and 18 matched controls.

Main outcome measures

RMS values of tibialis anterior, peroneus longus and gastrocnemius lateralis muscles for the 50 ms before initial ground contact, timing of onset of muscle activity and linear envelopes for the period of ground contact were calculated.

Results

Onset values showed similar patterns of activation for both groups. In healthy subjects, gastrocnemius lateralis activated earlier, followed by peroneus longus and tibialis anterior. In the unstable subjects, gastrocnemius lateralis and peroneus longus activated at the same time, followed by tibialis anterior. Unstable subjects also presented lower peroneus longus activity during the 50 ms before initial ground impact, a lower peroneus longus peak magnitude and a higher gastrocnemius lateralis peak magnitude.

Conclusions

Volleyball players with ankle functional instability showed decreased peroneus longus activity before ground impact that may predispose them to repetitive sprains and explain their “giving way” sensation, since peroneus longus is the main ankle evertor and an important stabilizer against sudden and excessive inversion.     

Modulation of prelanding lower-limb muscle responses in athletes with multiple ankle sprains

PURPOSE: The objective of this study was to investigate modulation in prelanding muscle responses and its associated impact force on landing from unexpected and self-initiated drops in male basketball players with a history of bilateral multiple ankle sprains (BMAS). METHODS: Prelanding EMG responses were recorded in four lower-limb muscles, together with the impact force on landing, while 20 healthy and 19 basketball players with BMAS performed unexpected, self-initiated drops from a height of 30 cm. RESULTS: Group differences were detected after self-initiated but not unexpected drops. Two main changes in prelanding EMG responses were observed in the injured basketball players during the self-initiated drops. First, tibialis anterior (TA) was activated significantly earlier in the injured group, whereas left tensor fascia latae appeared closer to the moment of landing (P < 0.025) than in the healthy players. Second, cocontraction indexes between left TA and peroneus longus, and left TA and medial gastrocnemius, were significantly greater in the injured than in the healthy players (P < 0.025). On landing, higher magnitude-of-impact forces were observed in the injured players on the right leg (by 23%, P = 0.012). CONCLUSION: In basketball players with BMAS, modulation of prelanding muscle response latencies occurred in injured (ankle) and uninjured (hip) joints during self-initiated but not unexpected drops. Greater cocontraction index between the left ankle muscle pairs in preparation for landing from self-initiated drops, and a significantly higher magnitude of impact force in the right leg on landing, were observed in the injured players.     

The role of footwear-independent variations in rearfoot movement on impact attenuation in heel-toe running

Impact forces and rearfoot eversion have been linked to overuse injuries in running. Modeling approaches suggest that both factors interact in that reduced foot eversion relates to increased impact maxima and vice versa. The aim of this study was to alter rearfoot eversion by applying three different combinations of ankle taping and bracing. Ten subjects were tested while running at 4 m/s on an instrumented treadmill. Sagittal plane kinematics, rearfoot eversion, tibial acceleration, pressure under the heel, and vertical ground reaction force (GRF) were collected simultaneously over 12 to 14 steps. All interventions reduced the maximum eversion significantly compared with unrestricted running. The largest effect was shown for combined bracing and taping, reducing rearfoot movement by 6.1 degrees while impact force varied only marginally. Overall, relationships between parameters contradict predictions by existing models of foot-ground interaction. Changes in muscular activation remain as a candidate in the regulation of impact mechanics in running.     

Foot posture is associated with morphometry of the peroneus longus muscle,tibialis anterior tendon,and Achilles tendon

The aim of this study was to investigate the association between foot type and the morphometry of selected muscles and tendons of the lower limb. Sixty‐one healthy participants (31 male, 30 female; aged 27.1 ± 8.8 years) underwent gray‐scale musculoskeletal ultrasound examination to determine the anterior‐posterior (AP) thickness of tibialis anterior, tibialis posterior, and peroneus longus muscles and tendons as well as the Achilles tendon. Foot type was classified based on arch height and footprint measurements. Potentially confounding variables (height, weight, hip and waist circumference, rearfoot and ankle joint range of motion, and levels of physical activity) were also measured. Multiple linear regression models were used to determine the association between foot type with muscle and tendon morphometry accounting for potentially confounding variables. Foot type was significantly and independently associated with AP thickness of the tibialis anterior tendon, peroneus longus muscle, and Achilles tendon, accounting for approximately 7% to 16% of the variation. Flat‐arched feet were associated with a thicker tibialis anterior tendon, a thicker peroneus longus muscle, and a thinner Achilles tendon. Foot type is associated with morphometry of tendons that control sagittal plane motion of the rearfoot; and the peroneus longus muscle that controls frontal plane motion of the rearfoot. These findings may be related to differences in tendon loading during gait.     

Delayed latency of peroneal reflex to sudden inversion with ankle taping or bracing

The purpose of the present study was to examine the effects of ankle taping and bracing based on the peroneal reflex in the hypermobile and normal ankle joints with and without history of ankle injury. Thirty-six ankle joints of 18 collegiate American football athletes with and without previous history of injury were studied. The angle of talar tilt (TT) was measured by stress radiograph for classifying normal (TT5 degrees ) ankles. They were tested with taping, bracing, and without any supports as a control. The latency of peroneus longus muscle was measured by a sudden inversion of 25 degrees using surface EMG signals. The results of the present study show no significant three-way Group (hypermobile or normal ankles) by History (previously injured or uninjured ankles) by Condition (control, taping, or bracing) interaction, while Condition main effect was significant (p<0.05). There were significant differences between control (80.8 ms) and taping (83.8 ms, p<0.01), between control and bracing (83.0 ms, p<0.05), but not between taping and bracing (p>0.05). In conclusion, ankle taping and bracing delayed the peroneal reflex latency not only for hypermobile ankles and/or injured ankle joints but also for intact ankle joints.     

Biomechanical differences between unilateral and bilateral landings from a jump: gender differences.

OBJECTIVE: To determine the effect of landing type (unilateral vs. bilateral) and gender on the biomechanics of drop landings in recreational athletes. DESIGN: This study used a repeated measures design to compare bilateral and unilateral landings in male and female athletes. A repeated measures multivariate analysis of variance (type of landing*gender) was performed on select variables. SETTING: Biomechanics laboratory. PARTICIPANTS: Sixteen female and 16 male recreational athletes. MAIN OUTCOME MEASURES: Kinetic, kinematic, and electromyographic (EMG) data were collected on participants while performing bilateral and unilateral landings from a 40-cm platform. RESULTS: Compared to bilateral landings, subjects performed unilateral landings with increased knee valgus, decreased knee flexion at initial contact, decreased peak knee flexion, decreased relative hip adduction, and increased normalized EMG of the rectus femoris, medial hamstrings, lateral hamstrings, and medial gastrocnemius (P < 0.005). During both types of landing, females landed with increased knee valgus and normalized vertical ground reaction force (VGRF) compared to males (P < 0.009), however, the interaction of landing type*gender was not significant (P = 0.29). CONCLUSIONS: Compared to bilateral landings, male and female recreational athletes performed unilateral landings with significant differences in knee kinematic and EMG variables. Female athletes landed with increased knee valgus and VGRF compared to males during both types of landing.     

Changing sagittal plane body position during single-leg landings influences the risk of non-contact anterior cruciate ligament injury

Purpose

To examine the effects of different sagittal plane body positions during single-leg landings on biomechanics and muscle activation parameters associated with risk for anterior cruciate ligament (ACL) injury.

Methods

Twenty participants performed single-leg drop landings onto a force plate using the following landing styles: self-selected, leaning forward (LFL) and upright (URL). Lower extremity and trunk 3D biomechanics and lower extremity muscle activities were recorded using motion analysis and surface electromyography, respectively. Differences in landing styles were examined using 2-way Repeated-measures ANOVAs (sex × landing conditions) followed by Bonferroni pairwise comparisons.

Results

Participants demonstrated greater peak vertical ground reaction force, greater peak knee extensor moment, lesser plantar flexion, lesser or no hip extensor moments, and lesser medial and lateral gastrocnemius and lateral quadriceps muscle activations during URL than during LFL. These modifications of lower extremity biomechanics across landing conditions were similar between men and women.

Conclusions

Leaning forward while landing appears to protect the ACL by increasing the shock absorption capacity and knee flexion angles and decreasing anterior shear force due to the knee joint compression force and quadriceps muscle activation. Conversely, landing upright appears to be ACL harmful by increasing the post-impact force of landing and quadriceps muscle activity while decreasing knee flexion angles, all of which lead to a greater tibial anterior shear force and ACL loading. ACL injury prevention programmes should include exercise regimens to improve sagittal plane body position control during landing motions.     

The effect of ankle bracing on landing biomechanics in female netballers

ObjectivesInvestigate the impact of lace-up ankle braces on landing biomechanics.DesignWithin-subject repeated measures. Participants completed a drop jump, drop land, and netball-specific task in braced and unbraced conditions.SettingBiomechanical research laboratory.ParticipantsTwenty female high school netballers.Main outcome measuresLeg, knee, and ankle stiffness, knee/ankle stiffness ratio, knee and ankle sagittal excursion, peak vertical ground reaction force, time-to-peak vertical ground reaction force, and loading rate.ResultsIn the brace condition leg stiffness increased bilaterally during the drop land (ES = 0.21, 0.22), ankle stiffness increased bilaterally during the drop jump (ES = 0.37, 0.29) and drop land (ES = 0.40, 0.60), and knee/ankle stiffness ratio decreased in all three tasks (ES = −0.22 to −0.45). Ankle sagittal excursion decreased bilaterally during the drop jump (ES = −0.35, −0.53) and drop land (ES = −0.23, −0.46), and decreased in the lead limb during the netball jump (ES = −0.36). Knee excursion decreased bilaterally during the drop jump (ES = −0.36, −0.40) and in the lead limb during netball task (ES = −0.59). Lead limb TTP was greater during the netball jump (ES = 0.41).ConclusionsLace-up ankle braces may increase leg and joint stiffness and reduce joint excursion during landing but do not appear to affect landing forces. The observed effect on landing biomechanics may predispose young netballers to injury.     

The effect of different running shoes on treadmill running mechanics and muscle activity assessed using statistical parametric mapping (SPM)

BackgroundDifferences in joint mechanics between running shoes are commonly assessed using discrete parameters, yet statistically significant differences in these parameters between shoes are often scarce with small effect sizes. Statistical parametric mapping (SPM) has been suggested as suitable method for analyzing one-dimensional data such as kinematic, kinetic or muscle intensity time series.Research questionThe purpose of this study was to determine differences in treadmill running mechanics between novel running shoes using SPM.MethodsJoint kinematics, muscle activity and ground reaction force were assessed in 19 rearfoot runners in their own shoes and in two test shoes during treadmill running (test shoe 1: 13 distinct rubber elements in the outer sole, springboard within EVA midsole with posterior elements shifted anteriorly by approximately 1.5 cm; test shoe 2: 17 distinct EVA elements with conventional heel geometry). Joint kinematics were measured using an inertial sensor system, and ground reaction force was measured using an instrumented treadmill.ResultsSPM analysis with repeated measures ANOVA revealed significant reductions in the ankle angle and in tibialis anterior, peroneus longus, vastus medialis and lateralis muscle activity during weight acceptance and in peroneus longus muscle activity during early and late swing and in semitendinosus muscle activity during late swing for the test shoes. Significant differences in muscle activity were observed in the interval of the main activity of the respective muscle. SPM on individual data revealed statistically significant and relevant within-subject differences between conditions in kinematic, muscle activity and ground reaction force patterns.SignificanceInertial sensor systems and SPM may provide an efficient way of detecting changes in joint mechanics between running shoes within runners. Detecting within-subject differences in running mechanics between conditions not only requires statistical criteria but also criteria on the relevance of the magnitude of differences.     

Unilateral jump landing neuromechanics of individuals with chronic ankle instability

ObjectivesTo assess the neuromechanical (kinematic, kinetic and electromyographic (EMG)) differences between individuals with and without chronic ankle instability (CAI) during unilateral jump landing.DesignCase-control study.MethodsKinematic, kinetic and EMG data of 32 participants with CAI and 31 control participants were collected during unilateral side jump landing (SIDE) and unilateral drop landing on three surfaces (even (DROP), unstable (FOAM) and laterally inclined (WEDGE)). Each participant had to complete five trials of each task in a randomised sequence. To compare the neuromechanical differences between groups, a one-dimensional statistical non-parametric mapping analysis was performed.ResultsCompared to the control group, the CAI group exhibited increased biceps femoris muscle activity during the preactivation and landing phases, decreased gluteus medius and peroneus longus muscles activity during the preactivation phase and increased knee extension moment during the landing phase of the WEDGE task. The CAI group also exhibited increased ankle dorsiflexion during the landing phase of the FOAM task and decreased vastus lateralis muscle activity during the preactivation phase of the DROP task. Finally, the CAI group exhibited decreased biceps femoris muscle activity during the preactivation and landing phases and decreased gluteus medius muscle activity during the preactivation phase of the SIDE task compared to the control group.ConclusionsIndividuals with CAI present neuromechanical differences during unilateral jump landing compared to healthy individuals. The results of this study will improve our understanding of underlying deficits associated with CAI and will help researchers and clinicians to better target them during rehabilitation.     

Failed jump landing trials: deficits in neuromuscular control

The purpose of this investigation was to compare neuromuscular control variables during successful and failed jump landings in multiple directions (sagittal, diagonal, and lateral). All data were collected during a single leg hop stabilization maneuver, which required subjects to stand 70 cm from the center of a force plate, jump off both legs, touch a designated marker placed at a height equivalent to 50% of their maximum vertical jump, and land on a single leg for all directions. Twenty-six subjects [10 males (22+/-3.9 years of age, 70.9+/-7.6 kg, and 176.8+/-0.5 cm) and 16 females (20.6+/-0.5 years of age, 65.6+/-9.1 kg, and 166.4+/-5.9 cm)] volunteered to participate in this investigation. Muscle activation times, average preparatory, and reactive electromyographic (EMG) amplitudes were calculated for the vastus medialis, semi-membranosis, lateral gastrocnemius, and tibialis anterior. EMG data revealed that successful jump landing trials had earlier activation times and higher preparatory and reactive EMG amplitudes. There was no difference for EMG activation times or amplitudes among directions. The results indicate neuromuscular control differences between successful and failed trials because of earlier muscle onset and greater amplitude. The results also suggest that in a healthy population, the direction of the jump protocol will not affect lower extremity EMG characteristics.     

A mechanical and electromyographical analysis of the effects of various joint counterforce braces on the tennis player

Biomechanical data on most bracing and protective equipment systems is lacking. To better understand the clinical success of counterforce bracing, a biomechanical analysis of braced and unbraced tennis players (serve and backhand strokes) was undertaken. Three-dimensional cinematography and electromyographic techniques were used. Three commonly used counterforce braces (lateral elbow, medial elbow, and radial-ulnar wrist) were compared with the unbraced condition. The overall results basically reveal positive biomechanical alterations in forearm muscle activity and angular joint acceleration dependent upon the brace and joint area analyzed.     

Factors influencing rearfoot kinematics during a rapid lateral braking movement.

Understanding the morphological, movement, and biomechanical characteristics that influence rearfoot motion during lateral movements is necessary for footwear design and for the determination of injury mechanisms. The purpose of this study was to identify factors related to rearfoot kinematics during a lateral braking movement. Seven highly skilled male tennis players performed 24 trials of side shuffle movements at various speeds. A rear view of the right leg performing a braking step onto a force platform was filmed. The neutral-O landing style was most commonly demonstrated. Average movement velocity, foot velocity at touchdown, and body mass were variables demonstrating weak or nonsignificant correlations with the rearfoot parameters. Although structural inversion was correlated significantly with the maximum rearfoot angle and velocity (r = -0.52 and -0.69), the results were affected by movement speed and sample size. The biomechanical characteristics displayed the greatest influence on the various rearfoot kinematic parameters. The magnitude of the significant (P less than 0.0001) correlations generally decreased in the following order: maximum horizontal and vertical force gradients, corresponding times to the maximum gradient values, maximum horizontal and vertical forces, and the corresponding times to maximum forces. In conclusion, the gradient-associated parameters were the most useful biomechanical parameters for predicting changes in rearfoot kinematics.     

Jump landing strategies in male and female college athletes and the implications of such strategies for anterior cruciate ligament injury

BACKGROUND: Female athletes are more likely than male athletes to injure the anterior cruciate ligament. Causes of this increased injury incidence in female athletes remain unclear, despite numerous investigations. HYPOTHESIS: Female athletes will exhibit lower hamstring muscle activation and smaller knee flexion angles than male athletes during jump landings, especially when the knee muscles are fatigued. STUDY DESIGN: Controlled laboratory study. METHODS: Eight female and six male varsity college basketball athletes with no history of knee ligament injury performed jump landings on the dominant leg from a maximum height jump and from 25.4 cm and 50.8 cm high platforms under nonfatigued and fatigued conditions. Knee joint angle and surface electromyographic signals from the quadriceps, hamstring, and gastrocnemius muscles were recorded. RESULTS: Women landed with greater knee flexion angles and greater knee flexion accelerations than men. Knee muscle activation patterns were generally similar in men and women. CONCLUSION: As compared with male college basketball players, female college basketball players did not exhibit altered knee muscle coordination characteristics that would predispose them to anterior cruciate ligament injury when landing from jumps. This conclusion is made within the parameters of this study and based on the observation that hamstring muscle activation was similar for both groups. The greater knee flexion we observed in the female subjects would be expected to decrease their risk of injury. CLINICAL RELEVANCE: Factors other than those evaluated in this study need to be considered when attempting to determine the reasons underlying the increased incidence of anterior cruciate ligament injuries consistently observed in elite female athletes.     

The effect of ankle bracing on knee kinetics and kinematics during volleyball‐specific tasks

The purpose of this study was to examine the effects of ankle bracing on knee kinetics and kinematics during volleyball tasks. Fifteen healthy, elite, female volleyball players performed a series of straight‐line and lateral volleyball tasks with no brace and when wearing an ankle brace. A 14‐camera Vicon motion analysis system and AMTI force plate were used to capture the kinetic and kinematic data. Knee range of motion, peak knee anterior–posterior and medial–lateral shear forces, and peak ground reaction forces that occurred between initial contact with the force plate and toe off were compared using paired sample t‐tests between the braced and non‐braced conditions (P < 0.05). The results revealed no significant effect of bracing on knee kinematics or ground reaction forces during any task or on knee kinetics during the straight‐line movement volleyball tasks. However, ankle bracing was demonstrated to reduce knee lateral shear forces during all of the lateral movement volleyball tasks. Wearing the Active Ankle T2 brace will not impact knee joint range of motion and may in fact reduce shear loading to the knee joint in volleyball players.     

Upper-limb motion and drop jump: effect of expertise

AIM: In this study, the role of arm motion in a drop jump was investigated in skilled and unskilled subjects. METHODS: Nine skilled volleyball players and 8 novice individuals performed a series of jumps from two different heights: 30 cm and 60 cm. Free and restricted arm motion were used to determine the effect of arm motion on the vertical jump. Participants were instructed to land on a force plate and jump as high as possible. The ground reaction force was measured with an AMTI force plate (500 Hz). The kinematics of the jumps was recorded with two digital cameras (50 Hz). RESULTS: The motion of the arms during the jumps was found to increase the jump height by 15% for the volleyball players and 12% for unskilled jumpers. Volleyball players performed better in the 60 cm than in 30 cm drop height (+8.5%). In the volleyball players, the peak vertical ground reaction force during take-off increased by 7%, the peak power increased by 10.6% while the peak impact force decreased by 6.3%. CONCLUSIONS: Skilled jumpers were found to have a better use of arm motion than novices in (i) increasing the vertical jump performance, (ii) controlling the balance of the body at take-off (iii) leaving the ground with an optimal body orientation.     

The effect of ankle supports on lower limb biomechanics during functional tasks: A systematic review with meta-analysis

ObjectivesTo systematically review the literature on the effects of ankle supports on lower extremity biomechanics during functional tasks.DesignSystematic review with meta-analysis.MethodsEight electronic databases were searched from inception to July 2019. Studies of biomechanical outcomes during functional tasks that used a within-participant (repeated measures) design were included. Two independent reviewers screened studies, extracted data, assessed the methodological quality of the included studies and rated the quality of evidence. Meta-analysis was performed and reported as standardised mean differences and 95% confidence intervals.ResultsA total of 8350 studies were identified in the electronic search and 42 studies involving a total of 761 participants were included in the review (21 studies included for qualitative reporting and 21 studies in the meta-analysis). Most individual studies and the meta-analyses demonstrated no effect of ankle supports on ground reaction force or ankle inversion angle. However, there was high quality evidence that ankle taping decreased plantarflexion angle at initial contact during landing from a height (P = 0.0009, standerdised mean differences = 0.72, 95% confidence intervals = 1.15, 0.03, I ² = 3%). The effect of ankle supports on transverse plane ankle biomechanics has not been adequately investigated.ConclusionsAnkle taping only decreased plantarflexion angle at initial contact during landing from a jump. Ankle supports did not affect inversion angle or forces in linear and multiplanar tasks. There was insufficient evidence on the effect of ankle supports on ankle transverse plane biomechanics.     

The effects of external ankle support on dynamic restraint characteristics of the ankle in volleyball players.

OBJECTIVE: To examine any changes in electromechanical delay and reaction time as a result of the use of external ankle supports over an entire season (3-5 months) in college volleyball players. DESIGN: A 2 x 3 pre-post factorial design. SETTING: Biomechanics laboratory, Human Performance Research Center. PARTICIPANTS: Thirty healthy, active male and female intercollegiate volleyball players were recruited for this study (age, 20.4 +/- 2.3 years; height, 183.1 +/- 8.6 cm; weight, 74.0 +/- 9.5 kg). INTERVENTIONS: External supports consisted of the subjects wearing either tape or braces for practices and games for the duration of the volleyball season. Subjects in the control group wore nothing on their ankles for practices and games for the duration of the volleyball season. MAIN OUTCOME MEASURES: The electromechanical delay (EMD) of the peroneus longus was determined by the onset of force contribution after artificial activation, as measured by electromyographic (EMG) and forceplate data. Reaction time was measured after an inversion perturbation during walking. RESULTS: No significant (F2,27 = 0.141, P = 0.869) interaction was observed for reaction time between the groups over time. No significant (F2,27 = 0.236, P = 0.791) interaction was observed for EMD between groups over time. CONCLUSION: Use of an external ankle support over an entire season does not induce neuromuscular changes in the onset timing of the peroneus longus.