Strengthening of the evertor muscles is widely advocated as a key component of lateral ankle sprain rehabilitation, but our clinical observation of impaired invertor muscle performance among many patients suggested the need for this study of isokinetic performance deficiencies. Subjects were 30 physically active adolescents, ages 14-19 years, who had recently sustained a lateral ankle sprain or who had symptoms of chronic lateral ankle instability. Eversion/inversion testing was performed on a Biodex isokinetic dynamometer at speeds of 30 and 120 degrees/sec. Analysis of variance results demonstrated significantly greater (p < .05) invertor deficits than evertor deficits for both peak torque and average power at both tests speeds. The findings of this study suggest that a lateral ankle ligament injury may be associated with an invertor muscle performance deficiency, and that restoration of a normal evertor/invertor strength relationship may be accomplished through performance of an isotonic ankle strengthening program.

Context: Prevention of a lower extremity sprain or strain requires some basis for predicting that an individual athlete will sustain such an injury unless a modifiable risk factor is addressed.Objective: To assess the possible existence of an association between reaction time measured during completion of a computerized neurocognitive test battery and subsequent occurrence of a lower extremity sprain or strain.Design: Prospective cohort study.Setting: Preparticipation screening conducted in a computer laboratory on the day prior to initiation of preseason practice sessions.Participants: 76 NCAA Division I-FCS football players.Main Outcome Measures: Lower extremity sprains and strains sustained between initiation of preseason practice sessions and the end of an 11-game season. Receiver operating characteristic analysis identified the optimal reaction time cut-point for discrimination between injured versus noninjured status. Stratified analyses were performed to evaluate any differential influence of reaction time on injury incidence between starters and nonstarters.Results: A total of 29 lower extremity sprains and strains were sustained by 23 of the 76 players. A reaction time cut-point of ≥ .545 s provided good discrimination between injured and noninjured cases: 74% sensitivity, 51% specificity, relative risk = 2.17 (90% CI: 1.10, 4.30), and odds ratio = 2.94 (90% CI: 1.19, 7.25).Conclusions: Neurocognitive reaction time appears to be an indicator of elevated risk for lower extremity sprains and strains among college football players, which may be modifiable through performance of exercises designed to accelerate neurocognitive processing of visual input.

Context: Neurocognitive reaction time has been associated with musculoskeletal injury risk, but visuomotor reaction time (VMRT) derived from tests that present greater challenges to visual stimulus detection and motor response execution may have a stronger association.Objective: To assess VMRT as a predictor of injury and the extent to which improvement may result from VMRT training.Design: Cohort study.Setting: University athletic performance center.Participants: 76 National Collegiate Athletic Association Division-I FCS football players (19.5 ± 1.4 y, 1.85 ± 0.06 m, 102.98 ± 19.06 kg).Interventions: Preparticipation and postseason assessments. A subset of players who exhibited slowest VMRT in relation to the cohort’s postseason median value participated in a 6-wk training program.Main Outcome Measures: Injury occurrence was related to preparticipation VMRT, which was represented by both number of target hits in 60 s and average elapsed time between hits (ms). Receiver operating characteristic analysis identified the optimum cut point for a binary injury risk classification. A nonparametric repeated-measures analysis of ranks procedure was used to compare posttraining VMRT values for slow players who completed at least half of the training sessions (n = 15) with those for untrained fast players (n = 27).Results: A preparticipation cut point of ≤85 hits (≥705 ms) discriminated injured from noninjured players with odds ratio = 2.30 (90% confidence interval, 1.05–5.06). Slow players who completed the training exhibited significant improvement in visuomotor performance compared with baseline (standardized response mean = 2.53), whereas untrained players exhibited a small performance decrement (group × trial interaction effect, L₂ = 28.74; P < .001).Conclusions: Slow VMRT appears to be an important and modifiable injury risk factor for college football players. More research is needed to refine visuomotor reaction-time screening and training methods and to determine the extent to which improved performance values can reduce injury incidence.

Context: Poor core stability is believed to increase vulnerability to uncontrolled joint displacements throughout the kinetic chain between the foot and the lumbar spine.Objective: To assess the value of preparticipation measurements as predictors of core or lower extremity strains or sprains in collegiate football players.Design: Cohort study.Setting: National Collegiate Athletic Association Division I Football Championship Subdivision football program.Patients or Other Participants: All team members who were present for a mandatory physical examination on the day before preseason practice sessions began (n = 83).Main Outcome Measure(s): Preparticipation administration of surveys to assess low back, knee, and ankle function; documentation of knee and ankle injury history; determination of body mass index; 4 different assessments of core muscle endurance; and measurement of step-test recovery heart rate. All injuries were documented throughout the preseason practice period and 11-game season. Receiver operating characteristic analysis and logistic regression analysis were used to identify dichotomized predictive factors that best discriminated injured from uninjured status. The 75th and 50th percentiles were evaluated as alternative cutpoints for dichotomization of injury predictors.Results: Players with ≥2 of 3 potentially modifiable risk factors related to core function had 2 times greater risk for injury than those with <2 factors (95% confidence interval = 1.27, 4.22), and adding a high level of exposure to game conditions increased the injury risk to 3 times greater (95% confidence interval = 1.95, 4.98). Prediction models that used the 75th and 50th percentile cutpoints yielded results that were very similar to those for the model that used receiver operating characteristic-derived cutpoints.Conclusions: Low back dysfunction and suboptimal endurance of the core musculature appear to be important modifiable football injury risk factors that can be identified on preparticipation screening. These predictors need to be assessed in a prospective manner with a larger sample of collegiate football players.

Ankle proprioception is widely regarded as an important factor that affects susceptibility to ankle sprain, but the precise mechanisms by which proprioceptive abilities may enhance ankle stability are not well understood. Pertinent literature is reviewed and theoretical interrelationships among factors that may affect dynamic ankle function are discussed. Topics addressed include mechanoreceptor function, muscle spindle function, postural balance, ankle edema, joint capsule distension, synovial hypertrophy, capsuloligamentous laxity, anterolateral rotary instability, ankle giving way, reflexive muscle splinting, articular deafferentation, neurogenic inflammation, muscular de-efferentation, and enhancement of compensatory neuromuscular mechanisms. Recommendations for future research are presented in the form of questions that cannot be adequately answered at present concerning the role of proprioceptively mediated mechanisms in the maintenance of dynamic ankle stability.

Relatively few studies have been performed to examine the effectiveness of different methods of treatment for the inversion ankle sprain. In this study, restoration of function following a grade II inversion sprain was compared among 34 subjects who received one of three methods of treatment, each of which incorporated an Air-Stirrup brace. The methods included uniform compression provided by elastic tape, focal compression provided by a U-shaped device, and focal compression with simultaneous cryotherapy. Although the results failed to demonstrate statistical significance at the .05 level (p = .055), the two groups that received focal compression attained each of nine levels of function in fewer days than the group that received uniform compression. The results of this study indicate that focal compression appears beneficial, but increased frequency and duration of cryotherapy does not appear to enhance the rate of recovery following an inversion ankle sprain.