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Context:Functional ankle instability (FAI) is difficult to identify and quantify.Objective:To compare joint position sense (JPS), time to stabilization (TTS), and electromy-ography (EMG) of ankle musculature in recreational athletes with and without FAI.Design:Case-control compared withttests and ANOVAs.Setting:Sports medicine research laboratory.Participants:20 recreational athletes.Main Outcome Measures:Passive angle reproduction, TTS, and mean EMG amplitude of the tibialis anterior, peroneals, lateral gastrocnemius, and soleus muscles during single-leg-jump landing.Results:No differences in JPS or medial-lateral TTS measures between groups. Significantly longer anterior-posterior TTS (P< .05) in the unstable ankle group. The stable ankle group had significantly higher mean EMG soleus amplitude after landing (P< .05). No other significant differences were found for mean EMG amplitudes before or after landing.Conclusions:Subjects with FAI demonstrated deficits in landing stability and soleus muscle activity during landing that may represent chronic adaptive changes following injury.

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Context: Long-term effects of ankle bracing on lower extremity kinematics and kinetics are unknown. Ankle motion restriction may negatively affect the body's ability to attenuate ground reaction forces (GRFs).Objective: To evaluate the immediate and long-term effects of ankle bracing on lower extremity kinematics and GRFs during a jump landing.Design Setting: Sports medicine research laboratory. Patients or Other Participants: A total of 37 healthy subjects were assigned randomly to either the intervention (n 5 11 men, 8 women; age 5 19.63 6 0.72 years, height 5 176.05 6 10.58 cm, mass 5 71.50 6 13.15 kg) or control group (n 5 11 men, 7 women; age 5 19.94 6 1.44 years, height 5 179.15 6 8.81 cm, mass 5 74.10 6 10.33 kg).Intervention(s): The intervention group wore braces on both ankles and the control group did not wear braces during all recreational activities for an 8-week period.Main Outcome Measure(s): Initial ground contact angles, maximum joint angles, time to reach maximum joint angles, and joint range of motion for sagittal-plane knee and ankle motion were measured during a jump-landing task. Peak vertical GRF and the time to reach peak vertical GRF were assessed also.Results: While participants were wearing the brace, ankle plantar flexion at initial ground contact (brace 5 356 6 136, no brace 5 386 6 156, P 5 .024), maximum dorsiflexion (brace 5 216 6 76, no brace 5 226 6 66, P 5 .04), dorsiflexion range of motion (brace 5 566 6 146, no brace 5 596 6 166, P 5 .001), and knee flexion range of motion (brace 5 796 6 166, no brace 5 826 6 166, P 5 .036) decreased, whereas knee flexion at initial ground contact increased (brace 5 126 6 96, no brace 5 96 6 96, P 5 .0001). Wearing the brace for 8 weeks did not affect any of the outcome measures, and the brace caused no changes in vertical GRFs (P . .05).Conclusions: Although ankle sagittal-plane motion was restricted with the brace, knee flexion upon landing increased and peak vertical GRF did not change. The type of lace-up brace used in this study appeared to restrict ankle motion without increasing knee extension or vertical GRFs and without changing kinematics or kinetics over time.

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Context: Computerized neuropsychological testing is commonly used in the assessment and management of sport-related concussion. Even though computerized testing is widespread, psychometric evidence for test-retest reliability is somewhat limited. Additional evidence for test-retest reliability is needed to optimize clinical decision making after concussion.Objective: To document test-retest reliability for a commercially available computerized neuropsychological test battery (ImPACT) using 2 different clinically relevant time intervals.Design: Cross-sectional study. Setting: Two research laboratories.Patients or Other Participants: Group 1 (n ¼ 46) consisted of 25 men and 21 women (age ¼ 22.4 6 1.89 years). Group 2 (n ¼ 45) consisted of 17 men and 28 women (age ¼ 20.9 6 1.72 years).Intervention(s): Both groups completed ImPACT forms 1, 2, and 3, which were delivered sequentially either at 1-week intervals (group 1) or at baseline, day 45, and day 50 (group 2). Group 2 also completed the Green Word Memory Test (WMT) as a measure of effort.Main Outcome Measures: Intraclass correlation coefficients (ICCs) were calculated for the composite scores of ImPACT between time points. Repeated-measures analysis of variance was used to evaluate changes in ImPACT and WMT results over time.Results: The ICC values for group 1 ranged from 0.26 to 0.88 for the 4 ImPACT composite scores. The ICC values for group 2 ranged from 0.37 to 0.76. In group 1, ImPACT classified 37.0% and 46.0% of healthy participants as impaired at time points 2 and 3, respectively. In group 2, ImPACT classified 22.2% and 28.9% of healthy participants as impaired at time points 2 and 3, respectively.Conclusions: We found variable test-retest reliability for ImPACT metrics. Visual motor speed and reaction time demonstrated greater reliability than verbal and visual memory. Our current data support a multifaceted approach to concussion assessment using clinical examinations, symptom reports, cognitive testing, and balance assessment.Key Words: intraclass correlation, concussions, mild traumatic brain injuries, neuropsychological testing, athletes Key PointsImPACT had strong to weak test-retest reliability over time, consistent with the results of previous studies. Reliability was greater for the visual motor speed and reaction time subscores than for the verbal and visual memory subscores. Computerized neuropsychological testing is only 1 component of a multifaceted concussion-management program that uses all appropriate tools in clinical decision making.

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Background: Ankle sprains are common injuries that often lead to functional ankle instability (FAI), which is a pathology defined by sensations of instability at the ankle and recurrent ankle sprain injury. Poor postural stability has been associated with FAI, and sports medicine clinicians rehabilitate balance deficits to prevent ankle sprains. Subsensory electrical noise known as stochastic resonance (SR) stimulation has been used in conjunction with coordination training to improve dynamic postural instabilities associated with FAI. However, unlike static postural deficits, dynamic impairments have not been indicative of ankle sprain injury. Therefore, the purpose of this study was to examine the effects of coordination training with or without SR stimulation on static postural stability. Improving postural instabilities associated with FAI has implications for increasing ankle joint stability and decreasing recurrent ankle sprains.