Effects of Blood Flow Restriction on Balance Performance During Dynamic Balance Exercises in Individuals With Chronic Ankle Instability.

CONTEXT: Blood flow restriction (BFR) is a rehabilitation tool which may introduce a constraint, similar to muscle fatigue, that challenge patients' sensorimotor system during balance exercises. The purpose of our study was to examine whether adding BFR to dynamic balance exercises produced a decrease in balance performance and an increase in ratings of perceived exertion and instability in individuals with chronic ankle instability (CAI) compared with dynamic balance exercises without BFR. DESIGNS: Crossover design. METHODS: Our sample included N = 25 young adults with a history of CAI. Participants completed 2 laboratory visits. At each visit, participants completed 4 sets (30×-15×-15×-15×) of dynamic balance exercises, performed similar to the modified star excursion balance test (SEBT), once with BFR and once with control (no BFR) conditions. We measured composite SEBT scores at baseline and during the final repetitions of each set of balance exercise (sets 1-4). We also measured ratings of perceived exertion and instability following each balance exercise set. RESULTS: We observed no difference in composite SEBT scores between conditions at baseline; however, composite SEBT scores were significantly lower during all balance exercises sets 1 to 4 with the BFR condition compared with control. During the BFR condition, composite SEBT scores were significantly lower during all balance exercise sets compared with baseline. During the control condition, composite SEBT scores did not significantly change between baseline and each balance exercise set. Ratings of perceived exertion and instability scores were significantly greater in the BFR group compared with the control group during all balance exercise sets. CONCLUSIONS: Individuals with CAI demonstrated lower composite SEBT scores and greater perceived instability and exertion during dynamic balance exercise with BFR compared to without BFR. BFR introduced a novel muscle fatigue constraint during dynamic balance exercises in individuals with CAI. Additional research is needed to determine if adding BFR to balance training could improve clinical outcomes in CAI patients.

Within-session and between-session effects of auditory biofeedback training on center of pressure location during gait in patients with chronic ankle instability.

OBJECTIVES: To establish preliminary gait training dosage parameters for patients with chronic ankle instability (CAI) by determining the within-session and between-session effects of auditory biofeedback training on center of pressure (COP) location during gait. DESIGN: Observational Longitudinal. SETTING: Laboratory. PARTICIPANTS: 19 participants with CAI, 8 participants who did not receive auditory biofeedback (NoFeedback group) and 11 participants who did receive auditory biofeedback (AuditoryFeedback group) over an 8-session 2-week intervention. MAIN OUTCOME MEASURES: COP location was measured at the start and at each 5-min interval during treadmill walking across all eight 30-min training sessions. RESULTS: The AuditoryFeedback group had significant within-session lateral-to-medial shifts in COP location during only session-1 at the 15-min (45% of stance; peak mean difference = 4.6 mm), 20-min (35% and 45%; 4.2 mm), and 30-min time intervals (35% and 45%; 4.1 mm). Furthermore, the AuditoryFeedback group had significant between-session lateral-to-medial shifts in COP location at session-5 (35-55% of stance; 4.2 mm), session-7 (35%-95%; 6.7 mm), and session-8 (35%-95%; 7.7 mm). The NoFeedback group had no significant changes in COP location within-sessions or between-sessions. CONCLUSIONS: Participants with CAI who received auditory biofeedback during gait needed an average of 15-min during session-1 to meaningfully shift their COP location medially and 4-sessions before retaining the adapted gait pattern.

Exercise-Induced Changes in Femoral Cartilage Thickness in Patients With Patellofemoral Pain.

CONTEXT: Rehabilitative exercises alleviate pain in patients with patellofemoral pain (PFP); however, no researchers have analyzed the cartilage response after a bout of those athletic activities in patients with PFP. OBJECTIVE: To determine if a single session of rehabilitative exercises alters femoral cartilage morphology. DESIGN: Crossover study. SETTING: Research laboratory. PATIENTS OR OTHER PARTICIPANTS: Twelve participants with PFP (age = 21.0 ± 2.0 years, height = 1.72 ± 0.1 m, mass = 68.7 ± 12.6 kg) and 12 matched healthy participants (age = 21.3 ± 2.8 years, height = 1.71 ± 0.1 m, mass = 65.9 ± 12.2 kg) were enrolled. INTERVENTION(S): Participants completed treadmill running, lower extremity strengthening exercises, and plyometric exercises for 30 minutes each. MAIN OUTCOME MEASURE(S): Patient-reported outcomes on the visual analog scale, Anterior Knee Pain Scale (AKPS), Knee injury and Osteoarthritis Outcome Score (KOOS), and Knee Injury and Osteoarthritis Outcome Score for Patellofemoral Pain and Osteoarthritis were collected. Femoral cartilage ultrasonographic images were obtained at 140° of knee flexion. Ultrasound images were segmented into medial and lateral images using the intercondylar notch. Medial and lateral cartilage cross-sectional area (mm2) and echo intensity (EI), defined as the average grayscale from 0 to 255, were analyzed by ImageJ software. The difference between loading conditions was calculated using repeated-measures analysis of variance. The Spearman correlation was calculated to find the association between the cartilage percentage change (Δ%) and patient-reported outcomes. RESULTS: Pain increased in the PFP group after all loading conditions (P values < .007). No differences were found in cartilage cross-sectional area or EI alteration between or within groups (P values > .06). The KOOS was negatively associated with the Δ% of the lateral femoral cartilage EI after plyometric loading (ρ = -0.87, P = .001), and the AKPS score was positively correlated with the Δ% of lateral femoral cartilage EI (ρ = 0.57, P = .05). CONCLUSIONS: Ultrasound imaging did not identify cartilaginous deformation after all loading conditions. However, because lateral cartilaginous EI changes were associated with the AKPS and KOOS score, those questionnaires may be useful for monitoring changes in femoral cartilage health.

Plantar pressure profile during walking is associated with talar cartilage characteristics in individuals with chronic ankle instability.

BACKGROUND: Individuals with chronic ankle instability typically present with abnormal gait patterns favoring the lateral foot. This gait pattern may alter cartilage stress potentially increasing the risk of osteoarthritis development, thus exploring this relationship may provide insights for early interventions. The purpose of this study was to examine the relationship gait biomechanics and talar articular cartilage characteristics. METHODS: Talar articular cartilage was assessed with ultrasound at rest and after walking for 30-min in twenty-five adults (14 females, 22.6 ± 3.12 years, 168.12 ± 9.83 cm, 76.00 ± 15.47 kg) with chronic ankle instability. Cartilage was segmented into Total, Medial, and Lateral regions. During the 30-min walking period, plantar pressure of the entire foot was recorded every 5-min and condensed to create a biomechanical loading pattern and center of pressure gait line. Relationships between resting cartilage thickness and echo intensity, changes in thickness and echo intensity, and plantar pressure profiles were assessed with correlation coefficients. FINDINGS: There was a significant relationship between plantar pressure in the lateral forefoot and medial talar cartilage deformation (r = 0.408, p < .05). Early stance center of pressure was correlated with deformation in the total (r = 0.439-0.524) and lateral (r = 0.443-0.550) regions (p < .05). There were no significant correlations between echo intensity and biomechanics. INTERPRETATION: This study contributes to the growing evidence that talar cartilage strain patterns are associated with biomechanics during walking. Further validation is needed to determine a causal relationship between biomechanics and ultrasound cartilage characteristics after ankle sprains. In addition, research should continue determining the utility of ultrasound to monitor joint health after musculoskeletal injuries.

Effects of gait training with auditory biofeedback on biomechanics and talar cartilage characteristics in individuals with chronic ankle instability: A randomized controlled trial.

BACKGROUND: Altered walking gait is a typical impairment following ankle sprains which may increase susceptibility to recurring injuries and development of posttraumatic osteoarthritis at the ankle. There is a lack of targeted gait training interventions focusing on specific modifications in individuals with chronic ankle instability (CAI). Additionally, there is a need to focus on cartilage health changes following gait training to mitigate osteoarthritis progression. RESEARCH QUESTION: To determine the immediate and retention effects of gait training using auditory biofeedback (AudFB) in patients with chronic ankle instability (CAI) on biomechanics and talar cartilage characteristics. METHODS: Eighteen participants with CAI were randomly assigned into Control (n = 7) or AudFB (n = 11) groups. Each group completed 8-sessions of 30-minute treadmill walking. The AudFB group received biofeedback through a pressure sensor fashioned to the lateral foot and instructions to walk while avoiding noise from the sensor. The Control group did not receive instructions during sessions. An in-shoe insole system measured peak pressure, maximum force, and center of the pressure gait line (COP) during walking. Ultrasonography captured talar cartilage thickness and echo intensity before and after walking. Biomechanics and ultrasound were measured at baseline, immediately, and 1-week after the intervention. Repeated measures mixed-methods analysis of variance assessed changes within groups across time. RESULTS: The AudFB group significantly reduced pressure and force in the lateral foot and medially shifted their COP at Immediate and 1-week Post. There were no observed changes in the Control group. In addition, neither group demonstrated changes in ultrasound measures at follow-up. SIGNIFICANCE: Implementation of auditory biofeedback during gait training can be a valuable tool for clinicians treating patients with CAI.

Utility of Gait Biofeedback Training to Improve Walking Biomechanics in Patients With Chronic Ankle Instability: A Critically Appraised Topic.

CLINICAL SCENARIO: Chronic ankle instability (CAI) is a condition that involves feelings of the ankle "giving way," pain, and decreased self-reported function. Individuals with CAI often demonstrate persistent biomechanical impairments during gait that are associated with repetitive lateral ankle sprains (LAS) and the development of early onset ankle posttraumatic osteoarthritis (OA). Traditional rehabilitation strategies have not successfully improved these reported aberrant gait biomechanics; thus, traditional rehabilitation may not effectively reduce the risk of recurrent LAS and ankle OA among individuals with CAI. Conversely, targeted gait training with biofeedback may be effective at decreasing the risk of recurring LAS and ankle OA if these rehabilitation strategies can promote individuals with CAI to develop a gait strategy that protects against subsequent LAS and ankle OA. CLINICAL QUESTION: Can targeted gait biofeedback interventions cause individuals with CAI to implement a walking gait pattern that is not associated with recurrent LAS and ankle OA? SUMMARY OF FINDINGS: Five studies assessed gait biofeedback interventions targeting plantar pressure and/or ankle kinematics involving visual biofeedback (n = 3), auditory biofeedback (n = 1), and haptic biofeedback (n = 1). Plantar pressure was medially shifted during a single session while receiving biofeedback (n = 2), immediately after biofeedback (n = 1), and 5 minutes after receiving biofeedback (n = 1) in 3 studies. One study demonstrated reduced ankle inversion after 8 sessions of biofeedback training. One study did not substantially improve plantar pressure while receiving visual feedback. CLINICAL BOTTOM LINE: Targeted gait training strategies appear effective in acutely altering gait biomechanics in individuals with CAI while receiving, and immediately after, biofeedback has been removed. Long-term outcomes are not currently established for gait training strategies in those with CAI. STRENGTH OF RECOMMENDATION: Limited evidence (grade B) suggests that targeted gait biofeedback strategies can alter specific CAI gait biomechanics to a strategy not associated with recurrent LAS, and ankle OA immediately, and after, multiple sessions of gait training.

Multi-axis destabilisation device influences plantar pressure distribution in adults with chronic ankle instability.

Patients with chronic ankle instability (CAI) walk with increased lateral plantar pressure, precipitating future injuries. Gait retraining to medially shift plantar pressure may prevent recurrent injury. We assessed if a multi-axis destabilisation device changed plantar pressure and muscle activity in patients with CAI during walking. Twelve adults with CAI (age: 23.6 ± 5.0 years; body mass index: 26.7 ± 4.5 kg/m2) participated. Insole plantar pressure and electro-myography were collected synchronously during treadmill walking. The destabilisation device had a half-sphere under both the rearfoot and forefoot. Two 30s walking trials were recorded at baseline, first without and second with the destabilisation device. After 20 min of walking with the destabilisation device, two 30s post-walking trials were collected, first with and second without the destabilisation device. The middle 10 steps of each trial were extracted, plantar pressure quantified, and data averaged across steps for repeated measures ANOVA analysis. Electromyographic data wereextracted from 50 ms pre- through 200 ms post-initial contact. The centre of pressure shifted medially during destabilisation device use (P < 0.002) versus baseline. This shift was notretained upon device removal. Thus, the device capably shifts plantar pressure while worn. Its effects beyond a single sessionare unknown.

Effects of rehabilitation on joint-coupling in patients with chronic ankle instability.

Chronic ankle instability (CAI) is associated with kinematic changes in the lower extremity. Alterations in joint-coupling have been identified during gait in patients with CAI. Rehabilitation remains the gold-standard for clinical treatment of CAI but little is known on the effects of rehabilitation on joint-coupling variability. Wearable destabilisation devices have shown an increase in muscle activity during functional tasks and may be useful in rehabilitation. The purpose of this study is to analyse the joint-coupling variability during gait prior to and following a rehabilitation programme performed with and without destabilisation devices. Twenty-six individuals with CAI were randomly assigned to receive 4 weeks of comprehensive rehabilitation with or without destabilisation devices. A 3D motion capture system was used to collect kinematics during walking. A vector-coding analysis was used to assess the joint-coupling variability of knee and hip motion to ankle motion. The destabilisation device group had decreases in joint-coupling variability during periods of walking gait. This decrease in joint-coupling variability may represent a change in sensorimotor organisation following rehabilitation. This decrease is indicative of an adaptation to the rehabilitation using destabilisation devices and may indicate an improvement in sensorimotor function.

External Focus of Attention Influences Cortical Activity Associated With Single Limb Balance Performance.

OBJECTIVE: External focus (EF) of attention leads to improved balance performance. Consideration of the neuromodulatory effects of EF may inform its clinical utility in addressing neuroplastic impairments after musculoskeletal injuries. This study aimed to determine whether electrocortical activity and balance performance changed with attentional foci that prioritized differing sensory feedback and whether changes in electrocortical activity and balance were associated. METHODS: Individuals who were healthy (n = 15) performed a single-limb balance task under 3 conditions: internal focus (IF), somatosensory focus (EF with a baton [EF-baton]), and visual focus (EF with a laser [EF-laser]). Electrocortical activity and postural sway were recorded concurrently using electroencephalography and a triaxial force plate. Electroencephalographic signals were decomposed, localized, and clustered to generate power spectral density in θ and α-2 frequency bands. Postural sway signals were analyzed with center-of-pressure sway metrics (eg, area, distance, velocity) and knee angle. The relationship between percent change in clustered brain activity and task performance metrics was assessed. RESULTS: Both EF conditions resulted in increased cortical activity and improved balance performance compared with IF. EF-laser had the largest effect, demonstrating increased frontal θ power (d = 0.64), decreased central θ power (d = -0.30), and decreased bilateral motor, bilateral parietal, and occipital α-2 power (d = -1.38 to -4.27) as well as a shorter path distance (d = -0.94) and a deeper (d = 0.70) and less variable (d = -1.15) knee angle than IF. Weak to moderate associations exist between increases in cortical activity and improved balance performance (ρ = 0.405-0.584). CONCLUSION: EF resulted in increased cortical activity associated with cognitive, motor, somatosensory, and visual processing. EF-laser, which prioritized visual feedback, had the largest and broadest effects. Changes in cortical activity resulting from EF were independently associated with improved balance performance. IMPACT: This study demonstrates that goal-oriented attention results in functional increases in brain activity compared with internally directed self-focus. These results suggest EF may target neurophysiologic impairments and improve balance in clinical populations.

Biomechanical Response to External Biofeedback During Functional Tasks in Individuals With Chronic Ankle Instability.

CONTEXT: Altered biomechanics displayed by individuals with chronic ankle instability (CAI) is a possible cause of recurring injuries and posttraumatic osteoarthritis. Current interventions are unable to modify aberrant biomechanics, leading to research efforts to determine if real-time external biofeedback can result in changes. OBJECTIVE: To determine the real-time effects of visual and auditory biofeedback on functional-task biomechanics in individuals with CAI. DESIGN: Crossover study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Nineteen physically active adults with CAI (7 men, 12 women; age = 23.95 ± 5.52 years, height = 168.87 ± 6.94 cm, mass = 74.74 ± 15.41 kg). INTERVENTION(S): Participants randomly performed single-limb static balance, step downs, lateral hops, and forward lunges during a baseline and 2 biofeedback conditions. Visual biofeedback was given through a crossline laser secured to the dorsum of the foot. Auditory biofeedback was given through a pressure sensor placed under the lateral foot and connected to a buzzer that elicited a noise when pressure exceeded the set threshold. Cues provided during the biofeedback conditions were used to promote proper biomechanics during each task. MAIN OUTCOME MEASURE(S): We measured the location of center-of-pressure (COP) data points during balance with eyes open and eyes closed for each condition. Plantar pressure in the lateral column of the foot during functional tasks was extracted. Secondary outcomes of interest were COP area and velocity, time to boundary during static balance, and additional plantar-pressure measures. RESULTS: Both biofeedback conditions reduced COP in the anterolateral quadrant while increasing COP in the posteromedial quadrant of the foot during eyes-open balance. Visual biofeedback increased lateral heel pressure and the lateral heel and midfoot pressure-time integral during hops. The auditory condition produced similar changes during the eyes-closed trials. Auditory biofeedback increased heel pressure during step downs and decreased the lateral forefoot pressure-time integral during lunges. CONCLUSIONS: Real-time improvements in balance strategies were observed during both external biofeedback conditions. Visual and auditory biofeedback appeared to effectively moderate different functional-task biomechanics.

Effects of 4-week impairment-based rehabilitation on jump-landing biomechanics in chronic ankle instability patients.

OBJECTIVE: To determine effects of 4-weeks of impairment-based rehabilitation on lower extremity neuromechanics during jump-landing. DESIGN: Descriptive laboratory study. PARTICIPANTS: Twenty-six CAI subjects (age = 21.4 ± 3.1 sex=(M = 7,F = 19), height = 169.0 ± 8.8 cm, weight = 71.0 ± 13.8 kg) completed 15 jump-landing trials prior to and following 12 supervised rehabilitation sessions. MAIN OUTCOME MEASURES: Frontal and sagittal lower extremity kinematics and kinetics and sEMG amplitudes (anterior tibialis, peroneus brevis, peroneus longus, and medial gastrocnemius). Means and 90% confidence intervals (CIs) were calculated for 100 ms prior to and 200 ms following ground contact. Areas where pre- and post-rehabilitation CIs did not overlap were considered significantly different. Kinematic and kinetic peaks and kinematic excursion were compared with paired t-test (P ≤ 0.05). RESULTS: Following rehabilitation, CAI subjects exhibited less ankle (2.1° (0.8, 3.4), P < 0.01) and hip (2.0° (0.5, 3.7), P = 0.01) frontal plane excursion and lower peak hip abduction (2.5° (0.0, 5.0), P = 0.05). There was less ankle (5.0° (1.7, 8.3), P < 0.01) and knee (3.4° (0.8, 6.0), P = 0.01) sagittal plane excursion following rehabilitation. There was decreased peroneus longus activity from 9 ms to 135 ms post ground contact and decreased peak plantar flexion moment (0.08 N∗m/kg (0.01, 0.13), P = 0.02) following rehabilitation. CONCLUSION: Progressive impairment-based rehabilitation resulted in reductions in kinematic excursion and peroneus longus muscle activity, suggesting a more efficient landing strategy.

Biomechanical Response to External Biofeedback During Functional Tasks in Individuals With Chronic Ankle Instability.

CONTEXT: Altered biomechanics displayed by individuals with chronic ankle instability (CAI) is a possible cause of recurring injuries and posttraumatic osteoarthritis. Current interventions are unable to modify aberrant biomechanics, leading to research efforts to determine if real-time external biofeedback can result in changes. OBJECTIVE: To determine the real-time effects of visual and auditory biofeedback on functional-task biomechanics in individuals with CAI. DESIGN: Crossover study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Nineteen physically active adults with CAI (7 men, 12 women; age = 23.95 ± 5.52 years, height = 168.87 ± 6.94 cm, mass = 74.74 ± 15.41 kg). INTERVENTION(S): Participants randomly performed single-limb static balance, step downs, lateral hops, and forward lunges during a baseline and 2 biofeedback conditions. Visual biofeedback was given through a crossline laser secured to the dorsum of the foot. Auditory biofeedback was given through a pressure sensor placed under the lateral foot and connected to a buzzer that elicited a noise when pressure exceeded the set threshold. Cues provided during the biofeedback conditions were used to promote proper biomechanics during each task. MAIN OUTCOME MEASURE(S): We measured the location of center-of-pressure (COP) data points during balance with eyes open and eyes closed for each condition. Plantar pressure in the lateral column of the foot during functional tasks was extracted. Secondary outcomes of interest were COP area and velocity, time to boundary during static balance, and additional plantar-pressure measures. RESULTS: Both biofeedback conditions reduced COP in the anterolateral quadrant while increasing COP in the posteromedial quadrant of the foot during eyes-open balance. Visual biofeedback increased lateral heel pressure and the lateral heel and midfoot pressure-time integral during hops. The auditory condition produced similar changes during the eyes-closed trials. Auditory biofeedback increased heel pressure during step downs and decreased the lateral forefoot pressure-time integral during lunges. CONCLUSIONS: Real-time improvements in balance strategies were observed during both external biofeedback conditions. Visual and auditory biofeedback appeared to effectively moderate different functional-task biomechanics.

Influence of Anticipation and Motor-Motor Task Performance on Cutting Biomechanics in Healthy Men.

CONTEXT: Biomechanical analyses of cutting tasks have demonstrated kinematic differences associated with the noncontact knee-injury risk when the movement direction is unanticipated. Motor-motor dual tasks occur within dynamic environments and change the demand for attentional resources needed to complete athletic maneuvers, which may contribute to injury risk. OBJECTIVE: To investigate the influence of anticipation and motor-motor task performance on cutting biomechanics. DESIGN: Cross-sectional study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 32 healthy, recreationally active men (age = 23.1 ± 3.6 years, height = 180.0 ± 7.0 cm, mass = 81.3 ± 17.3 kg) who self-reported regular participation in cutting sports. INTERVENTION(S): Participants performed a 45° side-step cut on the dominant limb in a random order of conditions: anticipation (anticipated, unanticipated) and task (no ball throw, ball fake, ball throw). MAIN OUTCOME MEASURE(S): Triplanar trunk, hip, and knee angles were assessed throughout the stance phase using 3-dimensional motion capture. Data were analyzed using a time series of means calculated from initial contact to toe-off (0%-100%) with 90% confidence intervals. Mean differences between conditions were identified as regions of nonoverlapping confidence intervals, and those that occurred during the region of peak vertical ground reaction force (0%-25%) are presented. RESULTS: Regardless of anticipation, attending to a ball (ball throw) resulted in more trunk extension (range = 2.9°-3.7°) and less lateral trunk flexion toward the cutting direction (range = 5.2°-5.9°). Planning to attend to a ball (ball fake) resulted in less lateral trunk flexion toward the cutting direction (4.7°). During unanticipated cutting, more trunk rotation away from the cutting direction was observed when attending to a ball (range = 5.3°-7.1°). The interaction of anticipation and task had a similar influence on sagittal- and frontal-plane trunk position. CONCLUSIONS: Motor-motor task performance and its interaction with anticipation induced an upright, neutral trunk position during side-step cutting, which has been associated with the risk for noncontact knee injury. Promoting task complexity during rehabilitation and injury-prevention programs may better prepare individuals to succeed when performing high-risk athletic maneuvers.

Using a Crossline Laser to Predict Peak Plantar Pressure During Walking.

CONTEXT: Developing low-cost assessment tools to quantify ankle biomechanics in a clinical setting may improve rehabilitation for patients with chronic ankle instability (CAI). OBJECTIVE: To determine whether a crossline laser can predict peak plantar pressure during walking. DESIGN: Descriptive laboratory study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Twenty-five participants with CAI (9 men, 16 women; age = 20.8 ± 2.3 years, height = 170.4 ± 10.4 cm, mass = 78.9 ± 22.4 kg). INTERVENTION(S): Participants completed 30 seconds of treadmill walking with a crossline laser fixed to their shoe while, simultaneously, a video camera recorded the laser projection on the wall and an in-shoe plantar-pressure system measured plantar pressure. MAIN OUTCOME MEASURE(S): Peak laser rotation and peak plantar pressure of the lateral midfoot and forefoot. RESULTS: With respect to peak plantar pressure, peak rotation of the laser during walking explained 57% of the variance in the lateral midfoot and 64% in the lateral forefoot. CONCLUSIONS: The crossline laser may be a valuable clinical tool for predicting lateral peak plantar pressure in patients with CAI during walking.

Prevalence and Impact of Chronic Ankle Instability in Adolescent Athletes.

BACKGROUND: The prevalence and impact of chronic ankle instability (CAI) in adolescent athletes are unknown. To better develop and justify prevention strategies of lateral ankle sprains and CAI, it is important to understand the origin and associated long-term impact of CAI within populations other than adults. PURPOSE/HYPOTHESIS: The purpose of this study was to determine the prevalence and impact of CAI on ankle function, health-related quality of life (HRQoL), and physical activity in adolescent athletes. The hypothesis was that the presence of CAI will be commonly reported among adolescent athletes and that participants with CAI will have lower self-reported ankle function, HRQoL, and physical activity when compared with participants without CAI. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A cohort of 1002 healthy (able to fully participate) adolescent athletes (50.4% female; mean age, 15.6 ± 1.6 years) across 8 club sport facilities and high schools completed paper-and-pencil surveys to establish the presence of CAI (Identification of Functional Ankle Instability [IdFAI]) and estimate perceived ankle function (Foot and Ankle Ability Measure [FAAM]-Activities of Daily Living and FAAM-Sport), HRQoL (Pediatric Quality of Life Inventory 4.0 [PedsQL]), and physical activity (Hospital for Special Surgery Pediatric Functional Activity Brief Scale [HSS Pedi-FABS]). RESULTS: The overall prevalence of CAI was 20.0%. Participants with unilateral CAI reported significantly lower (P < .001) ankle function (FAAM-Sport: 87.0 ± 14.8) and HRQoL (total PedsQL: 89.8 ± 9.8) than participants who did not have CAI (FAAM-Sport: 97.7 ± 6.0; total PedsQL: 93.5 ± 9.1). Physical activity was not different between participants with and without CAI. CONCLUSION: The prevalence of CAI was high among adolescent athletes. The presence of CAI negatively affected ankle function and HRQoL in adolescent athletes. Given the high prevalence and negative impact of CAI in an adolescent population, strategies to prevent ankle injuries and maintain physical activity are needed to alleviate future long-term consequences associated with developing CAI. These strategies should be implemented as soon as sport participation begins, as it appears that the origin of CAI may occur before adulthood.

External ankle taping does not alter lower extremity side-step cut and straight sprint biomechanics in young adult males.

Lateral ankle sprains (LAS) are one of the most common musculoskeletal injuries and as a response, clinicians often use external ankle taping prophylactically to reduce the prevalence of injuries. External ankle taping techniques have been shown to significantly reduce passive ankle range of motion; however, there is limited research on the effects of external ankle taping on lower extremity kinematics or kinetics during sport specific tasks. Therefore, our objective was to compare the effects of external ankle taping on ankle, knee and hip kinematics and kinetics compared to no taping during an anticipated sidestep cutting task and a straight sprint task. We conducted a cross-over laboratory study with 16 healthy males. Three-dimensional kinematics and kinetics were collected with a motion capture system and in-ground force plate during 5 trials of a sprint and anticipated side-step cut with or without external ankle taping. Group means and associated 90% confidence intervals were plotted across 100 data points for each task, significance being identified when the confidence intervals did not overlap for three consecutive data points. No significant kinetic or kinematic differences were identified between conditions for the tasks. External ankle taping does not influence lower extremity biomechanics during a control cutting task.

The Effects of Blood Flow Restriction on Muscle Activation and Hypoxia in Individuals With Chronic Ankle Instability.

CONTEXT: Muscle dysfunction is common in patients with chronic ankle instability (CAI). Blood flow restriction (BFR) may enhance muscle responses during exercise and provide an opportunity to enhance muscle adaptations to ankle rehabilitation exercises; however, there is no evidence examining the effect of BFR on muscle function in CAI patients. OBJECTIVE: Examine the effects of BFR on muscle activation and oxygen saturation during submaximal ankle eversion and dorsiflexion exercises in individuals with CAI. DESIGN: Cross-over study design. SETTING: Laboratory setting. Patients (or Other Participants): Nineteen young adults with a history of CAI. INTERVENTIONS: Participants performed 4 sets (30, 15, 15, and 15) of eversion and dorsiflexion resistance exercises at 30% of maximum voluntary isometric contraction during 2 conditions, BFR and control. For BFR, a cuff was applied above the knee at 80% of blood flow occlusion. For control, the cuff was not inflated. MAIN OUTCOME MEASURES: Fibularis longus and tibialis anterior electromyography muscle activation, lower-leg muscle oxygen saturation, and ratings of perceived exertion were recorded during exercises. RESULTS: Average grand mean muscle activation was 5.6% greater during eversion (P = .03) and 7.7% greater during dorsiflexion (P = .01) resistance exercises with BFR compared with control; however, the magnitudes of the effects of BFR were only clinically important during the dorsiflexion exercises. Lower-leg muscle oxygen saturation was 31% to 44% lower (P < .001) during BFR exercises. Ratings of perceived exertion were significantly higher during BFR exercises (P < .001). CONCLUSIONS: Greater muscle activation and hypoxia were present during submaximal resistance exercise with BFR in participants with CAI. Greater muscle activation and hypoxia during BFR exercises may be important acute responses mediating the training-related muscle adaptations that have been observed with BFR. The presence of these acute responses in CAI patients supports further research examining BFR as a potential ankle rehabilitation tool.

A Perceptual Framework for Conservative Treatment and Rehabilitation of Ankle Sprains: An Evidence-Based Paradigm Shift.

Lateral ankle sprains are the most common injuries sustained during physical activity. The epidemiologic trends associated with chronic ankle instability (CAI) suggest that current rehabilitation approaches may be inadequate. We sought to synthesize best-practices evidence for the rehabilitation of patients with acute ankle sprains and CAI through the integration of emerging paradigms in perception, the dynamics of skill acquisition, and the biopsychosocial model of function, disability, and health. From the best available evidence, 4 key factors emerged for effective treatment and rehabilitation strategies: pain reduction, external ankle support for up to 1 year, progressive return to motion, and coordination training. We combined these factors into a meta-theoretical framework that centers on the perceptual interdependence of the cellular, local, and global functioning levels by linking insights from the body-self neuromatrix, the dynamics of skill acquisition, and the biopsychosocial model. Based on the best-practice recommendations from systematic reviews, ankle-sprain rehabilitation represents a multidimensional phenomenon governed by perception. The impairments, activity limitations, and participation restrictions associated with CAI may be linked to perceptual-interdependence alterations. Pain and edema reduction, the use of external ankle support for up to 1 year, progressive return to motion, and coordination training foster enhanced perceptual interdependence from cells to society. Using the perceptual-interdependence framework for ankle-sprain rehabilitation, we offer new insights for charting the course of effective strategies for enhancing function, reducing disability, and preventing the long-term sequelae associated with CAI.

Effect of Impairment-Based Rehabilitation on Lower Leg Muscle Volumes and Strength in Patients With Chronic Ankle Instability: A Preliminary Study.

Context: Patients with chronic ankle instability (CAI) have demonstrated atrophy of foot and ankle musculature and deficits in ankle strength. The effect of rehabilitation on muscle morphology and ankle strength has not previously been investigated in patients with CAI. Objective: Our objective was to analyze the effect of impairment-based rehabilitation on intrinsic and extrinsic foot and ankle muscle volumes and strength in patients with CAI. Design: Controlled laboratory study. Setting: Laboratory. Patients: Five young adults with CAI. Intervention: Twelve sessions of supervised impairment-based rehabilitation that included range of motion, strength, balance, and functional exercises. Main Outcome Measures: Measures of extrinsic and intrinsic foot muscle volume and ankle strength measured before and after 4 weeks of supervised rehabilitation. Novel fast-acquisition magnetic resonance imaging was used to scan from above the femoral condyles through the entire foot. The perimeter of each muscle was outlined on each axial slice and then the 2-dimensional area was multiplied by the slice thickness (5 mm) to calculate muscle volume. Plantar flexion, dorsiflexion, inversion, and eversion isometric strength were measured using a hand-held dynamometer. Results: Rehabilitation resulted in hypertrophy of all extrinsic foot muscles except for the flexor hallucis longus and peroneals. Large improvements were seen in inversion, eversion, and plantar flexion strength following rehabilitation. Effect sizes for significant differences following rehabilitation were all large and ranged from 1.54 to 3.35. No significant differences were identified for intrinsic foot muscle volumes. Conclusion: Preliminary results suggest that impairment-based rehabilitation for CAI can induce hypertrophy of extrinsic foot and ankle musculature with corresponding increases in ankle strength.

External feedback during walking improves measures of plantar pressure in individuals with chronic ankle instability.

BACKGROUND: Individuals with chronic ankle instability (CAI) commonly present with an altered walking gait which favors the lateral aspect of their foot. Current rehabilitative protocols are unable to address these gait modifications which are potentially hindering improvements in patient-reported outcomes. Protocols for gait retraining are scarce, thus there is a need to develop intervention strategies and instruments to specifically target foot motion to address gait deficits in individuals with CAI. RESEARCH QUESTION: To determine the ability of a novel laser device providing external visual feedback (ExFB) during real-time to cause alterations in plantar pressure measures in individuals with CAI. METHODS: Twenty-six participants with CAI walked on a treadmill while real-time plantar pressure measures were being recorded during a baseline and feedback condition. Baseline trials were compared with ExFB trials within each subject. RESULTS: The ExFB condition was able to significantly reduce plantar pressures on the lateral midfoot and forefoot compared to baseline. A statistically significant medial shift in center of pressure trajectory was also observed in the ExFB condition compared to baseline. SIGNIFICANCE: Real-time external feedback provided by a novel laser device has the ability to reduce lateral column plantar pressures during walking in individuals with CAI.