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Luke Donovan, Joseph M. Hart and Jay Hertel


Ankle-destabilization devices are rehabilitation tools that may improve neuromuscular control by increasing lower-extremity muscle activation. Their effects should be tested in healthy individuals before being implemented in rehabilitation programs.


To compare EMG activation of lower-extremity muscles during walking while wearing 2 different ankle-destabilization devices.






15 healthy young adults (5 men, 10 women).


Surface EMG activity was recorded from the anterior tibialis, peroneus longus, lateral gastrocnemius, rectus femoris, biceps femoris, and gluteus medius as subjects walked on a treadmill shod, with an ankle-destabilization boot (ADB), and an ankle-destabilization sandal (ADS).

Main Outcome Measures:

Normalized amplitudes 100 ms before and 200 ms after initial heel contact, time of onset activation relative to initial contact, and percent of activation time across the stride cycle were calculated for each muscle in each condition.


The precontact amplitudes of the peroneus longus and lateral gastrocnemius and the postcontact amplitudes of the lateral gastrocnemius were significantly greater in the ADB and ADS conditions. In the ADB condition, the rectus femoris and biceps femoris postcontact amplitudes were significantly greater than shod. The peroneus longus and lateral gastrocnemius were activated significantly earlier, and the anterior tibialis, lateral gastrocnemius, and rectus femoris were activated significantly longer across the stride cycle in the ADB and the ADS conditions. In addition, the peroneus longus was activated significantly longer in the ADB condition when compared with shod.


Both ankle-destabilization devices caused an alteration in muscle activity during walking, which may be favorable to an injured patient. Therefore, implementing these devices in rehabilitation programs may be beneficial to improving neuromuscular control.

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Brian Killinger, Jakob D. Lauver, Luke Donovan and John Goetschius

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.

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Anna M. Ifarraguerri, Danielle M. Torp, Abbey C. Thomas and Luke Donovan

Individuals with chronic ankle instability (CAI) have been shown to have increased lateral plantar pressure during walking which is thought to contribute to symptoms associated with CAI. The objective of this study was to determine whether real-time video feedback can reduce lateral plantar pressure in individuals with CAI. Twenty-six participants with CAI completed 30 s of treadmill walking while plantar pressure was measured using an in-shoe plantar pressure system (baseline). Next, participants completed an additional 30 s of treadmill walking while receiving video feedback (VID FB). During the VID FB condition, participants had a significant decrease in medial forefoot peak pressure and medial midfoot pressure-time integral; however, both changes were associated with small effect sizes. Real-time video feedback did not reduce lateral plantar pressure in individuals with CAI; therefore, other gait retraining strategies should be considered when treating patients with CAI.

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Mark A. Feger, Luke Donovan, C. Collin Herb, Geoffrey G. Handsfield, Silvia S. Blemker, Joseph M. Hart, Susan A. Saliba, Mark F. Abel, Joseph S. Park and Jay Hertel

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.

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John McCleve, Luke Donovan, Christopher D. Ingersoll, Charles Armstrong and Neal R. Glaviano

Altered arthrokinematics are present in individuals with chronic ankle instability, which may influence their walking biomechanics. The objective of this study was to determine if fibular reposition tape (FRT) has any effect on lower extremity kinematics, kinetics, and vertical ground reaction forces (vGRFs) during gait in individuals with chronic ankle instability (CAI). Twenty active individuals with bilateral CAI received three conditions: FRT, sham FRT, and no tape. Ten trials of walking were collected for each condition to evaluate lower extremity kinematics, kinetics, and vGRF. Curve analyses were used to compare conditions by plotting group means and 90% confidence intervals. There were no significant differences in lower extremity biomechanics between any tape conditions. Application of FRT did not have any effect on triplanar kinematics, kinetics, or vGRF during gait in individuals with CAI.