Either Autonomy Support or Enhanced Expectancies Delivered Via Virtual-Reality Benefits Frontal-Plane Single-Leg Squatting Kinematics

Our purpose in this study was to determine the effects of a virtual reality intervention delivering specific motivational motor learning manipulations of either autonomy support (AS) or enhanced expectancies (EE) on frontal plane single-leg squatting kinematics. We allocated 45 participants (21 male, 24 female) demonstrating knee, hip, and trunk frontal plane mechanics associated with elevated anterior cruciate ligament injury risk to one of three groups (control, AS, or EE). Participants mimicked an avatar performing five sets of eight repetitions of exemplary single-leg squats. AS participants were given the added option of choosing the color of their avatar. EE participants received real-time biofeedback in the form of green highlights on the avatar that remained on as long as the participant maintained pre-determined 'safe' frontal plane mechanics. We measured peak frontal plane knee, hip, and trunk angles before (baseline) and immediately following (post) the intervention. The control group demonstrated greater increases in knee abduction angle (Δ = +2.3°) than did the AS (Δ = +0.1°) and EE groups (Δ = -0.4°) (p = .003; η2p = .28). All groups demonstrated increased peak hip adduction (p = .01, ηp2 = .18) (control Δ = +1.5°; AS Δ = +3.2°; EE Δ = +0.7°). Hip adduction worsened in all groups. AS and EE motivation strategies appeared to mitigate maladaptive frontal plane knee mechanics.

Concussion history and virtual reality metrics predict core or lower extremity injury occurrence among high school athletes

Introduction

A history of concussion is recognized as a risk factor for musculoskeletal injury, which is likely associated with physiological effects that warrant better understanding. This study aimed to assess the potential of measurements obtained from an immersive virtual reality (VR) test to identify a subtle perceptual-motor impairment that may be prospectively associated with the occurrence of a core or lower extremity sprain or strain.

Methods

A cohort of 68 high school athletes (41 female soccer players and 27 male football players) provided survey responses and completed an immersive VR test several days prior to the initiation of preseason practice sessions. Measurements of eye, neck, arm, and whole-body displacements were obtained during 40 successive lunging/reaching responses to visual stimuli moving horizontally across the VR headset display. Injury occurrences were electronically documented from the initial preseason practice session to the final game of the season.

Results

A statistically significant and intrinsically credible two-factor prediction model for core or lower extremity injury occurrence included an interaction between female sex and a self-reported history of two or more concussions, along with slow response time (RT) for arm reach (OR = 4.67; 95% CI, 1.51-14.43). Follow-up analyses identified sex-specific cut points for arm reach RT associated with elevated injury risk, which were ≥1.385 s for females and ≥1.257 s for males.

Discussion

High school female soccer players who have sustained more than one concussion appear to be highly vulnerable to core or lower extremity sprain or strain, with the risk of injury compounded by a slow arm reach RT. Male football players as a group demonstrated significantly faster arm reach RT than that of female soccer players, but slow perceptual-motor RT for arm reach was also identified as a potentially important injury risk factor for male players. Immersive VR appears to provide precise measurements of behavioral performance characteristics that depend on brain processing efficiency. Given that the speed, accuracy, and consistency of perceptual-motor responses may be modifiable, future research should explore the potential benefits of VR training for reducing the risk of sport-related injuries.

Assessment and Training of Perceptual-Motor Function: Performance of College Wrestlers Associated with History of Concussion

Concussion may affect sport performance capabilities related to the visual perception of environmental events, rapid decision-making, and the generation of effective movement responses. Immersive virtual reality (VR) offers a means to quantify, and potentially enhance, the speed, accuracy, and consistency of responses generated by integrated neural processes. A cohort of 24 NCAA Division I male wrestlers completed VR assessments before and after a 3-week VR training program designed to improve their perceptual-motor performance. Prior to training, the intra-individual variability (IIV) among 40 successive task trials for perceptual latency (i.e., time elapsed between visual stimulus presentation and the initiation of movement response) demonstrated strong discrimination between 10 wrestlers who self-reported a history of concussion from 14 wrestlers who denied ever having sustained a concussion (Area Under Curve ≥ 0.750 for neck, arm, and step movements). Natural log transformation improved the distribution normality of the IIV values for both perceptual latency and response time (i.e., time elapsed between visual stimulus presentation and the completion of movement response). The repeated measures ANOVA results demonstrated statistically significant (p < 0.05) pre- and post-training differences between groups for the IIV in perceptual latency and the IIV in response time for neck, arm, and step movements. Five of the six IIV metrics demonstrated a statistically significant magnitude of change for both groups, with large effect sizes. We conclude that a VR assessment can detect impairments in perceptual-motor performance among college wrestlers with a history of concussion. Although significant post-training group differences were evident, VR training can yield significant performance improvements in both groups.

Test-Retest Reliability of Immersive Virtual Reality Measures of Perceptual-Motor Performance

The duration, accuracy, and consistency of responses to various types of stimuli are widely accepted as indirect indicators of the efficiency of brain information processing, but current clinical tests appear to lack sufficient sensitivity to detect subtle impairments. Immersive virtual reality (VR) offers a new means to acquire measures of perceptual-motor responses to moving visual stimuli that require rapid conflict resolution, but their test-retest reliability has not yet been demonstrated. Repeated measures. We analyzed data from 19 healthy young adults who performed a 40-trial VR test on three consecutive days. We focused on response time (RT) and perceptual latency (PL) for eye, neck, arm, and whole-body step displacements involved in executing a reaching/lunging movement in a right or left direction toward a peripherally located virtual target. Measures of RT and PL included a 40-trial mean, an intra-individual variability (IIV) value, and a rate correct score (RCS) that incorporated both response duration and accuracy. Most mean and IIV values for PL and RT demonstrated a positive distributional skew that was substantially reduced by natural logarithm transformation. While a learning effect was evident between sessions 1 and 2 for 7 of 8 mean PL and RT measures, 3-session intraclass correlation coefficient (ICC) values were moderate to excellent for 15 of 16 transformed PL and RT measures (range: .618 to .922). The composite RCS metric did not require transformation for either PL or RT, whose respective 3-session ICC values were .877 and .851. This moderate to excellent test-retest reliability for various VR measures of perceptual-motor function, combined with evidence of their validity from both past and future research, suggest that these measures can advance clinical detection of impaired brain processing and longitudinal assessments of potentially modifiable performance deficiencies.

Subtle impairments of perceptual-motor function and well-being are detectable among military cadets and college athletes with self-reported history of concussion

Introduction

A lack of obvious long-term effects of concussion on standard clinical measures of behavioral performance capabilities does not preclude the existence of subtle neural processing impairments that appear to be linked to elevated risk for subsequent concussion occurrence, and which may be associated with greater susceptibility to progressive neurodegenerative processes. The purpose of this observational cohort study was to assess virtual reality motor response variability and survey responses as possible indicators of suboptimal brain function among military cadets and college athletes with self-reported history of concussion (HxC).

Methods

The cohort comprised 75 college students (20.7 ± 2.1 years): 39 Reserve Officer Training Corp (ROTC) military cadets (10 female), 16 football players, and 20 wrestlers; HxC self-reported by 20 (29.2 ± 27.1 months prior, range: 3-96). A virtual reality (VR) test involving 40 lunging/reaching responses to horizontally moving dots (filled/congruent: same direction; open/incongruent: opposite direction) was administered, along with the Sport Fitness and Wellness Index (SFWI) survey. VR Dispersion (standard deviation of 12 T-scores for neck, upper extremity, and lower extremity responses to congruent vs. incongruent stimuli originating from central vs. peripheral locations) and SFWI response patterns were the primary outcomes of interest.

Results

Logistic regression modeling of VR Dispersion (range: 1.5-21.8), SFWI (range: 44-100), and an interaction between them provided 81% HxC classification accuracy (Model χ ²[2] = 26.03, p < .001; Hosmer & Lemeshow χ ²[8] = 1.86, p = .967; Nagelkerke R ²= .427; Area Under Curve = .841, 95% CI: .734, .948). Binary modeling that included VR Dispersion ≥3.2 and SFWI ≤86 demonstrated 75% sensitivity and 86% specificity with both factors positive (Odds Ratio = 17.6, 95% CI: 5.0, 62.1).

Discussion/Conclusion

Detection of subtle indicators of altered brain processes that might otherwise remain unrecognized is clearly important for both short-term and long-term clinical management of concussion. Inconsistency among neck, upper extremity, and lower extremity responses to different types of moving visual stimuli, along with survey responses suggesting suboptimal well-being, merit further investigation as possible clinical indicators of persisting effects of concussion that might prove to be modifiable.

Immersive Real-Time Biofeedback Optimized With Enhanced Expectancies Improves Motor Learning: A Feasibility Study

CONTEXT

An Optimizing Performance through Intrinsic Motivation and Attention for Learning theory-based motor learning intervention delivering autonomy support and enhanced expectancies (EE) shows promise for reducing cognitive-motor dual-task costs, or the relative difference in primary task performance when completed with and without a secondary cognitive task, that facilitate adaptive injury-resistant movement response. The current pilot study sought to determine the effectiveness of an autonomy support versus an EE-enhanced virtual reality motor learning intervention to reduce dual-task costs during single-leg balance.

DESIGN

Within-subjects 3 × 3 trial.

METHODS

Twenty-one male and 24 female participants, between the ages of 18 and 30 years, with no history of concussion, vertigo, lower-extremity surgery, or lower-extremity injuries the previous 6 months, were recruited for training sessions on consecutive days. Training consisted of 5 × 8 single-leg squats on each leg, during which all participants mimicked an avatar through virtual reality goggles. The autonomy support group chose an avatar color, and the EE group received positive kinematic biofeedback. Baseline, immediate, and delayed retention testing consisted of single-leg balancing under single- and dual-task conditions. Mixed-model analysis of variances compared dual-task costs for center of pressure velocity and SD between groups on each limb.

RESULTS

On the right side, dual-task costs for anterior-posterior center of pressure mean and SD were reduced in the EE group (mean Δ = -51.40, Cohen d = 0.80 and SD Δ = -66.00%, Cohen d = 0.88) compared with the control group (mean Δ = -22.09, Cohen d = 0.33 and SD Δ = -36.10%, Cohen d = 0.68) from baseline to immediate retention.

CONCLUSIONS

These findings indicate that EE strategies that can be easily implemented in a clinic or sport setting may be superior to task-irrelevant AS approaches for influencing injury-resistant movement adaptations.

Changes in dual-task cognitive performance elicited by physical exertion vary with motor task

Background

Integrated movement and cognitive load paradigms are used to expose impairments associated with concussion and musculoskeletal injury. There is currently little information on the discriminatory nature of dual-task complexity and the relative influence of physical exertion on cognitive outcomes.

Purpose

Assess cognitive performance while under motor conditions of increasing complexity before and after a standardized exercise protocol.

Methods

34 participants were recruited (17 male and 17 female; 24 ± 1.4 yrs). A modified Eriksen flanker test was used to assess cognitive performance under four conditions (seated, single-leg stance, walking, and lateral stepping) before and after a 20-min moderate-to vigorous intensity treadmill protocol. The flanker test consisted of 20 sets of 5-arrow configurations, appearing in random order. To complete the response to cognitive stimulus, participants held a smartphone horizontally and were instructed to respond as quickly and as accurately as possible by tilting the device in the direction corresponding to the orientation of the middle arrow. The metrics used for analysis included average reaction time (ms), inverse efficiency index (average reaction time penalized for incorrect responses), and conflict effect (the average time cost of responding to an incongruent repetition vs. a congruent repetition). Mixed effects (condition by time) RMANOVAs were conducted to examine the effects of motor task complexity and physical exertion on cognitive performance.

Results

There was a condition by time interaction for inverse efficiency index (p < 0.001), in which participants displayed higher cognitive efficiency for the pre-activity lateral stepping condition compared to the other three conditions (Cohen's d = 1.3–1.6). For reaction time and conflict effect, there were main effects for condition (p = 0.004 and 0.006, respectively), in which performance during lateral stepping was improved in relation to the seated condition (reaction time Cohen's d = 0.68; conflict effect Cohen's d = 0.64).

Conclusion

Participants tended to display better dual-task cognitive performance under more stimulating or complex motor tasks before physical exertion, likely associated with the inverted-U arousal-performance relationship. When using dual-task assessments, clinicians should be mindful of the accompanying motor task and baseline exertion levels and their potential to disrupt or optimize cognitive performance.

Sex Moderates the Relationship between Perceptual-Motor Function and Single-Leg Squatting Mechanics

To examine the isolated and combined effects of sex and perceptual-motor function on single-leg squatting mechanics in males and females. We employed a cross-sectional design in a research laboratory. Fifty-eight females (22.2 ± 3.5 yrs, 1.60 ± .07 m, 64.1 ± 13.0 kg) and 35 males (23.5 ± 5.0 yrs, 1.80 ± .06m, 84.7 ± 15.3 kg) free from time-loss injury in the six months prior, vertigo, and vestibular conditions participated in this study. Independent variables were sex, perceptual-motor metrics (reaction time, efficiency index, conflict discrepancy), and interaction effects. Dependent variables were peak frontal plane angles of knee projection, ipsilateral trunk flexion, and contralateral pelvic drop during single-leg squatting. After accounting for the sex-specific variance and perceptual-motor function effects on frontal plane squatting kinematics, female sex amplified the associations of: higher reaction time, lower efficiency index, and higher conflict discrepancy with greater right ipsilateral peak trunk lean (R² = .13; p = .05); higher reaction time, lower efficiency index, and higher conflict discrepancy with decreased right contralateral pelvic drop (R² = .22; p < .001); higher reaction time and lower conflict discrepancy with greater right frontal plane knee projection angle (R² = .12; p = .03); and higher reaction time with greater left frontal plane knee projection angle (R² = .22; p < .001). Female sex amplified the relationship between perceptual-motor function and two-dimensional frontal plane squatting kinematics. Future work should determine the extent to which perceptual-motor improvements translate to safer movement strategies.

A Neuro-Integrative Assessment of Perceptual-Motor Performance and Wellness in ROTC Cadets

Resting heart rate variability (HRV) may be a useful index of both brain-based executive function and general health. Our purpose in this study was to quantify relationships among HRV, perceptual-motor performance metrics, and wellness survey responses. A cohort of 32 male Reserve Officer Training Corp (ROTC) cadets completed a dual-task upper extremity reaction time (UERT) test, two tests of whole-body reactive agility, and a 10-item wellness survey that produced a 0-100 Overall Wellness Index (OWI). We averaged participants' resting HRV measurements twice per week over 10 weeks to derive an intra-individual grand mean (HRV-IIGM) and over a series of days we calculated an intra-individual coefficient of variation (HRV-IICV). We used median values for the two HRV metrics (HRV-IIGM and HRV-IICV) to separate the cadets into equal-sized high and low HRV groups to form the dependent variable for logistic regression analyses. We found a significant inverse relationship between HRV-IIGM and HRV-IICV (r = -0.723, p < .001). Differences in UERT in the left versus right visual hemifields (L-R Diff) and OWI scores were strongly related to both HRV-IIGM ≤ 4.49 and HRV-IICV ≥ 6.95%. Logistic regression models that included L-R Diff and OWI showed 71% classification accuracy for HRV-IIGM (Model χ2 [2] = 12.47, p = .002, Nagelkerke R² = 0.430) and 81% classification accuracy for HRV-IICV (Model χ2 [2] = 14.88, p = .001, Nagelkerke R² = 0.496). These findings suggest that resting HRV, perceptual-motor efficiency, and overall wellness are highly interrelated, supporting a multi-factor biopsychosocial assessment to guide the design and implementation of interventions to maximize operational effectiveness for ROTC cadets and other military personnel.

Whole-Body Reactive Agility Metrics to Identify Football Players With a Core and Lower Extremity Injury Risk

Clinical prediction models are useful in addressing several orthopedic conditions with various cohorts. American football provides a good population for attempting to predict injuries due to their relatively high injury rate. Physical performance can be assessed a variety of ways using an assortment of different tests to assess a diverse set of metrics, which may include reaction time, speed, acceleration, and deceleration. Asymmetry, the difference between right and left performance has been identified as a possible risk factor for injury. The purpose of this study was to determine the whole-body reactive agility metrics that would identify Division I football players who were at elevated risk for core, and lower extremity injuries (CLEI). This cohort study utilized 177 Division I football players with a total of 57 CLEI suffered who were baseline tested prior to the season. Single-task and dual-task whole-body reactive agility movements in lateral and diagonal direction reacting to virtual reality targets were analyzed separately. Receiver operator characteristic (ROC) analyses narrowed the 34 original predictor variables to five variables. Logistic regression analysis determined the three strongest predictors of CLEI for this cohort to be: lateral agility acceleration asymmetry, lateral flanker deceleration asymmetry, and diagonal agility reaction time average. Univariable analysis found odds ratios to range from 1.98 to 2.75 for these predictors of CLEI. ROC analysis had an area under the curve of 0.702 for any combination of two or more risk factors produced an odds ratio of 5.5 for risk of CLEI. These results suggest an asymmetry of 8-15% on two of the identified metrics or a slowed reaction time of ≥0.787 s places someone at increased risk of injury. Sixty-three percent (36/57) of the players who sustained an injury had ≥2 positive predictors In spite of the recognized limitation, these finding support the belief that whole-body reactive agility performance can identify Division I football players who are at elevated risk for CLEI.

Perceptual-Motor Efficiency and Concussion History Are Prospectively Associated With Injury Occurrences Among High School and Collegiate American Football Players

Background:

After a sport-related concussion (SRC), the risk for lower extremity injury is approximately 2 times greater, and the risk for another SRC may be as much as 3 to 5 times greater.

Purpose:

To assess the predictive validity of screening methods for identification of individual athletes who possess an elevated risk of SRC.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

Metrics derived from a smartphone flanker test software application and self-ratings of both musculoskeletal function and overall wellness were acquired from American high school and college football players before study participation. Occurrences of core or lower extremity injury (CLEI) and SRC were documented for all practice sessions and games for 1 season. Receiver operating characteristic and logistic regression analyses were used to identify variables that provided the greatest predictive accuracy for CLEI or SRC occurrence.

Results:

Overall, there were 87 high school and 74 American college football players included in this study. At least 1 CLEI was sustained by 45% (39/87) of high school players and 55% (41/74) of college players. Predictors of CLEI included the flanker test conflict effect ≥69 milliseconds (odds ratio [OR], 2.12; 90% CI, 1.24-3.62) and a self-reported lifetime history of SRC (OR, 1.70; 90% CI, 0.90-3.23). Of players with neither risk factor, only 38% (29/77) sustained CLEI compared with 61% (51/84) of players with 1 or both of the risk factors (OR, 2.56; 90% CI, 1.50-4.36). SRC was sustained by 7 high school players and 3 college players. Predictors of SRC included the Overall Wellness Index score ≤78 (OR, 9.83; 90% CI, 3.17-30.50), number of postconcussion symptoms ≥4 (OR, 8.35; 90% CI, 2.71-25.72), the Sport Fitness Index score ≤78 (OR, 5.16; 90% CI, 1.70-15.65), history of SRC (OR, 4.03; 90% CI, 1.35-12.03), and the flanker test inverse efficiency ratio ≥1.7 (OR, 3.19; 90% CI, 1.08-9.47).

Conclusion:

Survey responses and smartphone flanker test metrics predicted greater injury incidence among individual football players classified as high-risk compared with that for players with a low-risk profile.

A Novel Approach to Assessment of Perceptual-Motor Efficiency and Training-Induced Improvement in the Performance Capabilities of Elite Athletes

Standard clinical assessments of mild traumatic brain injury are inadequate to detect subtle abnormalities that can be revealed by sophisticated diagnostic technology. An association has been observed between sport-related concussion (SRC) and subsequent musculoskeletal injury, but the underlying neurophysiological mechanism is not currently understood. A cohort of 16 elite athletes (10 male, 6 female), which included nine individuals who reported a history of SRC (5 male, 4 female) that occurred between 4 months and 8 years earlier, volunteered to participate in a 12-session program for assessment and training of perceptual-motor efficiency. Performance metrics derived from single- and dual-task whole-body lateral and diagonal reactive movements to virtual reality targets in left and right directions were analyzed separately and combined in various ways to create composite representations of global function. Intra-individual variability across performance domains demonstrated very good SRC history classification accuracy for the earliest 3-session phase of the program (Reaction Time Dispersion AUC = 0.841; Deceleration Dispersion AUC = 0.810; Reaction Time Discrepancy AUC = 0.825, Deceleration Discrepancy AUC = 0.794). Good earliest phase discrimination was also found for Composite Asymmetry between left and right movement directions (AUC = 0.778) and Excursion Average distance beyond the minimal body displacement necessary for virtual target deactivation (AUC = 0.730). Sensitivity derived from Youden's Index for the 6 global factors ranged from 67 to 89% and an identical specificity value of 86% for all of them. Median values demonstrated substantial improvement from the first 3-session phase to the last 3-session phase for Composite Asymmetry and Excursion Average. The results suggest that a Composite Asymmetry value ≥ 0.15 and an Excursion Average value ≥ 7 m, provide reasonable qualitative approximations for clinical identification of suboptimal perceptual-motor performance. Despite acknowledged study limitations, the findings support a hypothesized relationship between whole-body reactive agility performance and functional connectivity among brain networks subserving sensory perception, cognitive decision-making, and motor execution. A complex systems approach appears to perform better than traditional data analysis methods for detection of subtle perceptual-motor impairment, which has the potential to advance both clinical management of SRC and training for performance enhancement.

Reliability and concurrent validity of TRAZER compared to three-dimensional motion capture

BACKGROUND

Efficient neural processing of visuospatial and proprioceptive input appears to be crucial for avoidance of sport injury. As such, clinically-feasible tests are needed to identify deficiencies found by advanced neuroimaging and electrophysiological tests. Three-dimensional motion capture in a laboratory setting is currently the gold standard for measurement of human movement parameters but is costly and requires extensive training. Non-immersive virtual reality systems with body motion tracking, such as TRAZER, may provide a clinically-feasible and portable means of acquiring similar variables. Test-retest reliability and concurrent validity of these systems are currently lacking.

AIM

The aim of the study was to assess the concurrent validity of the TRAZER single-camera system with 3D motion capture system and to assess the test-retest reliability of TRAZER's whole-body reactive agility metrics.

METHODS

Participants - For validity, 13 healthy individuals (24.8±3.1 years, 170.0±7.7 cm, 70.0±14.2 kg); for reliability, 18 healthy individuals (23.3±2.5 years, 168.2±11.2 cm, 78.2±17.8 kg). Design - Validity was a single-session cross-sectional study. Reliability was a 3 consecutive day test-retest study. Setting-Controlled laboratory study. Intervention - Assessments utilized randomized movements in eight directions for forty total repetitions as designated by the TRAZER system. TRAZER protocol was simultaneously tracked by Vicon Motion Capture and the TRAZER system. Reliability data were captured on three consecutive days by the TRAZER system. Main Outcome Measures - Maximum acceleration, maximum velocity, and total distance were recorded for validation. In addition to these measures, maximum deceleration, average velocity, average acceleration, average deceleration, and average reaction time were collected for reliability.

RESULTS

Overall, a lack of agreement exists between maximum outputs for TRAZER and 3D motion capture (velocity r=0.808, acceleration r=-0.090), but total distance correlation was high (r =.961). ICC values between days 1-2-3 for average measures were high (average velocity=0.847, average acceleration=0.919, and average deceleration=0.948) with the exception of average reaction time being fair (ICC=0.536). ICCs for maximum measures showed a much smaller correlation between days (velocity=0.654, acceleration=0.171, and deceleration=0.416).

CONCLUSIONS

Even though there is a lack of strong concurrent validity between measures obtained from TRAZER and 3D motion capture systems, there is strong test-retest reliability of the TRAZER system. The applicability of these findings makes TRAZER clinically relevant in scenarios requiring pre- and post-testing for return to play decisions, or monitoring of a training regimen where demonstration of validation to a gold standard measurement is not relevant.

RELEVANCE FOR PATIENTS

When test-retest capability is desired, such as in return-to-play protocols following an injury, Trazer is a reliable option.

Wellness Survey Responses and Smartphone App Response Efficiency: Associations With Remote History of Sport-Related Concussion

Recent research findings have strongly suggested that sport-related concussion (SRC) increases risk for subsequent injury of any type, as well as a potential for long-term adverse effects on neurological and psychological well-being. The primary purpose of this study was to explore the reliability and discriminatory power of clinical testing procedures for detecting persisting effects of SRC. We used a cross-sectional study design to assess both self-reported symptoms commonly associated with post-concussion syndrome, and the effects of mental or physical activity on metrics derived from a smartphone app designed to test perceptual-motor responses. Among 30 physically active college students, 15 participants reported a SRC occurrence prior to testing (M time-since-injury = 4.0 years, SD = 3.1, range = 5 months to 11 years). We found good test-retest reliability for key metrics derived from the smartphone app (ICC ≥ .70); and the internal consistency for the Overall Wellness Index (OWI) for 10 categories of 82 post-concussion symptoms was ideal (Cronbach's α ≥ .80). Moderate intensity treadmill running demonstrated the strongest differential effect on perceptual-motor responses between participants with a history of SRC (HxSRC) and those with no such history (No SRC), which was best represented by the speed-accuracy trade-off quantified by the inverse efficiency index (IEI: group X trial interaction p = .055). Self-reported OWI symptoms ≥4 and post-physical activity IEI ≥ 568 ms provided the strongest discrimination between HxSRC and NoSRC participants (≥1 versus 0: OR = 9.75). Our findings suggest that persisting effects from a remote SRC occurrence can be detected by easily administered screening procedures that have the potential to identify individual athletes who might derive benefit from interventions to restore their optimal function and well-being.

Concussion History and Neuromechanical Responsiveness Asymmetry

CONTEXT

Detection of subtle changes in brain sensorimotor processes may enable clinicians to identify athletes who would derive the greatest benefit from interventions designed to reduce the risk for future injury and progressive neurologic or musculoskeletal dysfunction.

OBJECTIVE

To develop a generalizable statistical model for identifying athletes who possess subtle alterations in sensorimotor processes that may be due to previous concussion.

DESIGN

Cross-sectional study.

SETTING

Residential Olympic Training Center sports medicine clinic.

PATIENTS OR OTHER PARTICIPANTS

A primary cohort of 35 elite athletes and a secondary cohort of 40 elite athletes who performed identical tests the preceding year.

INTERVENTION(S)

Two upper extremity tests of visual-motor reaction time and 2 tests of whole-body reactive agility were administered. The whole-body tests required lateral or diagonal responses to virtual-reality targets, which provided measures of reaction time, speed, acceleration, and deceleration.

MAIN OUTCOME MEASURE(S)

Sport-related concussion history, which was reported by 54% (n = 19) of the athletes in the primary cohort and 45% (n = 18) of the athletes in the secondary cohort.

RESULTS

Univariable analyses identified 12 strong predictors of sport-related concussion history, which we combined to create a composite metric with maximum predictive value. Composite lateral asymmetry for whole-body reactive movements and persisting effects of previous musculoskeletal injury yielded a logistic regression model with exceptionally good discrimination (area under the curve = 0.845) and calibration (predicted-observed probabilities within 7 subgroups: r = 0.959, P = .001). Application of the derived model to compatible data acquired from another cohort of elite athletes demonstrated very good discrimination (area under the curve = 0.772) and calibration (within 8 subgroups: r = 0.849, P = .008).

CONCLUSIONS

Asymmetry in whole-body reactive movement capabilities may be a manifestation of a subtle abnormality in the functional connectivity of brain networks that might be relevant to previously reported associations between sport-related concussion history and musculoskeletal injury occurrence.

Risk Factors for Initial and Subsequent Core or Lower Extremity Sprain or Strain Among Collegiate Football Players

CONTEXT

Exposure to game conditions and previous injury are known to increase the risk of injury, but little available evidence pertains to modifiable factors that may mediate dynamic control of body segments, such as core muscle endurance and neurocognitive capabilities.

OBJECTIVE

To identify potentially modifiable factors associated with the occurrence of a core or lower extremity sprain or strain during participation in football.

DESIGN

Prospective cohort study.

SETTING

National Collegiate Athletic Association Division I Football Bowl Subdivision football program.

PATIENTS OR OTHER PARTICIPANTS

All team members who participated for the duration of 1 season or both of 2 consecutive seasons (n = 142).

MAIN OUTCOME MEASURE(S)

Predictors of injury occurrence were derived from analysis of preparticipation data that included the results of front plank hold (FPH) and neurocognitive tests. Receiver operating characteristic analysis was used to establish binary classifications of injury risk. Logistic regression analyses were conducted to build multivariable injury-prediction models for optimal discriminatory power.

RESULTS

Exceptionally good discrimination between injured and noninjured participants was provided by models that included the results of the FPH and ImPACT neurocognitive tests. A high level of exposure to game conditions and injury during the preceding year magnified the effects of other risk factors. A model for identifying players with an elevated risk for injury occurrence during both of 2 consecutive seasons included FPH ≤120 seconds, verbal memory score ≤87, composite reaction time ≥560 milliseconds, and starter status. Having ≥2 of the 4 risk factors demonstrated 44% sensitivity and 91% specificity, with an odds ratio = 8.40.

CONCLUSIONS

Core muscle endurance and neurocognitive processes may both play important roles in generating anticipatory muscle stiffness during participation in collegiate football. These factors may be particularly important for players who sustained an injury during the previous year and those who have a high level of game exposure.

Detection of Persisting Concussion Effects on Neuromechanical Responsiveness

PURPOSE

Assessment of various indices of neuromechanical responsiveness for association with concussion history.

METHODS

An observational cohort study included 48 elite athletes (34 males: 23.8 ± 4.4 yr; 14 females: 25.4 ± 4.5 yr) who performed visuomotor reaction time (VMRT) tests involving rapid manual contact with illuminated target buttons that included two dual-task conditions: 1) simultaneous oral recitation of scrolling text (VMRT+ST) and 2) simultaneous verbal responses to identify the right or left direction indicated by the center arrow of the Eriksen flanker test (VMRT+FT). A whole-body reactive agility (WBRA) test requiring side-shuffle movements in response to visual targets was used to assess reaction time, speed, acceleration, and deceleration.

RESULTS

Concussion occurrence at 2.0 ± 2.3 yr before testing was reported by 21 athletes. Strong univariable associations were found for VMRT+FT left minus right difference ≥15 ms (odds ratio [OR], 7.14), VMRT+ST outer two-ring to inner three-ring ratio ≥1.28 (OR, 4.58), and WBRA speed asymmetry ≥7.7% (OR, 4.67). A large VMRT+FT by VMRT+ST interaction effect was identified (OR, 25.00). Recursive partitioning identified a three-way VMRT+FT by VMRT+ST by WBRA interaction that had 100% positive predictive value for identification of athletes with concussion history, whereas negative status on all three factors had 90% negative predictive value.

CONCLUSIONS

Performance on dual-task VMRT tests and the WBRA test identified neuromechanical responsiveness deficiencies among elite athletes who reported a history of concussion.

Daily Heart Rate Variability before and after Concussion in an American College Football Player

This case report demonstrates the effects of sport-related concussion (SRC) on heart rate variability (HRV) in an American college football player. Daily measures of resting, ultra-short natural logarithm of the root mean square of successive differences (LnRMSSD), subjective wellbeing, and Player Load were obtained each training day throughout a 4-week spring camp and 4 weeks of preseason training. SRC occurred within the first 2 weeks of the preseason. During spring camp and preseason pre-SRC, the athlete demonstrated minimal day-to-day fluctuations in LnRMSSD, which increased post-SRC (LnRMSSD coefficient of variation pre-SRC ≤ 3.1%, post-SRC = 5.8%). Moderate decrements in daily-averaged LnRMSSD were observed post-SRC relative to pre-SRC (Effect Size ± 90% Confidence Interval = −1.12 ± 0.80), and the 7-day rolling average fell below the smallest worthwhile change for the remainder of the preseason. LnRMSSD responses to SRC appeared similar to trends associated with stress and training fatigue. Therefore, performance and sports medicine staff should maintain regular communication regarding player injury and fatigue status so that HRV can be interpreted in the appropriate context. Detection and monitoring of autonomic dysregulation post-SRC may require near-daily assessment, as LnRMSSD showed greater daily fluctuations rather than chronic suppression following the head injury.

The First Decade of Web-Based Sports Injury Surveillance: Descriptive Epidemiology of Injuries in United States High School Football (2005-2006 Through 2013-2014) and National Collegiate Athletic Association Football (2004-2005 Through 2013-2014)

CONTEXT:

The advent of Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided the acquisition of football injury data.

OBJECTIVE:

To describe the epidemiology of injuries sustained in high school football in the 2005-2006 through 2013-2014 academic years and collegiate football in the 2004-2005 through 2013-2014 academic years using Web-based sports injury surveillance.

DESIGN:

Descriptive epidemiology study.

SETTING:

Online injury surveillance from football teams of high school boys (annual average = 100) and collegiate men (annual average = 43).

PATIENTS OR OTHER PARTICIPANTS:

Football players who participated in practices and competitions during the 2005-2006 through 2013-2014 academic years in high school or the 2004-2005 through 2013-2014 academic years in college.

MAIN OUTCOME MEASURE(S):

Athletic trainers collected time-loss injury (≥24 hours) and exposure data. Injury rates per 1000 athlete-exposures (AEs), injury rate ratios (IRRs) with 95% confidence intervals (CIs), and injury proportions by body site and diagnosis were calculated.

RESULTS:

The High School Reporting Information Online system documented 18 189 time-loss injuries during 4 539 636 AEs; the National Collegiate Athletic Association Injury Surveillance Program documented 22 766 time-loss injuries during 3 121  476 AEs. The injury rate was higher among collegiate than high school (7.29 versus 4.01/1000 AEs; IRR = 1.82; 95% CI = 1.79, 1.86) athletes. Most injuries occurred during competitions in high school (53.2%) and practices in college (60.9%). The competition injury rate was higher than the practice injury rate among both high school (IRR = 5.62; 95% CI = 5.46, 5.78) and collegiate (IRR = 6.59; 95% CI = 6.41, 6.76) players. Most injuries at both levels affected the lower extremity and the shoulder/clavicle and were diagnosed as ligament sprains and muscle/tendon strains. However, concussion was a common injury during competitions among most positions.

CONCLUSIONS:

Injury rates were higher in college than in high school and higher for competitions than for practices. Concussion was a frequent injury sustained during competitions, which confirms the need to develop interventions to mitigate its incidence and severity.

Neuromechanical Considerations for Postconcussion Musculoskeletal Injury Risk Management

Recent epidemiological studies have documented increased susceptibility to musculoskeletal injury after sport-related concussion, which raises questions about the adequacy of current clinical practices to ensure safe return to sport. A growing body of evidence derived from advanced neuroimaging and neurological assessment methods strongly suggests that mild traumatic brain injury has long-lasting adverse effects that persist beyond resolution of clinical symptoms. Plausible interrelationships among postconcussion changes in brain structure and function support the rationale for specific methods of clinical assessment and training to target the interaction of cognitive and motor function for reduction of musculoskeletal injury risk after concussion. The findings of preliminary clinical studies are presented to support suggested strategies for reduction of postconcussion musculoskeletal injury risk, and to identify novel approaches that we consider worthy areas for further research.

A Growing Consensus for Change in Interpretation of Clinical Research Evidence

CONTEXT

  The paradigm of evidence-based practice (EBP) is well established among the health care professions, but perspectives on the best methods for acquiring, analyzing, appraising, and using research evidence are evolving.

BACKGROUND

  The EBP paradigm has shifted away from a hierarchy of research-evidence quality to recognize that multiple research methods can yield evidence to guide clinicians and patients through a decision-making process. Whereas the "frequentist" approach to data interpretation through hypothesis testing has been the dominant analytical method used by and taught to athletic training students and scholars, this approach is not optimal for integrating evidence into routine clinical practice. Moreover, the dichotomy of rejecting, or failing to reject, a null hypothesis is inconsistent with the Bayesian-like clinical decision-making process that skilled health care providers intuitively use. We propose that data derived from multiple research methods can be best interpreted by reporting a credible lower limit that represents the smallest treatment effect at a specified level of certainty, which should be judged in relation to the smallest effect considered to be clinically meaningful. Such an approach can provide a quantifiable estimate of certainty that an individual patient needs follow-up attention to prevent an adverse outcome or that a meaningful level of therapeutic benefit will be derived from a given intervention.

CONCLUSIONS

  The practice of athletic training will be influenced by the evolution of the EBP paradigm. Contemporary practice will require clinicians to expand their critical-appraisal skills to effectively integrate the results derived from clinical research into the care of individual patients. Proper interpretation of a credible lower limit value for a magnitude ratio has the potential to increase the likelihood of favorable patient outcomes, thereby advancing the practice of evidence-based athletic training.

A Refined Prediction Model for Core and Lower Extremity Sprains and Strains Among Collegiate Football Players

CONTEXT

Researchers have identified high exposure to game conditions, low back dysfunction, and poor endurance of the core musculature as strong predictors for the occurrence of sprains and strains among collegiate football players.

OBJECTIVE

To refine a previously developed injury-prediction model through analysis of 3 consecutive seasons of data.

DESIGN

Cohort study.

SETTING

National Collegiate Athletic Association Division I Football Championship Subdivision football program.

PATIENTS OR OTHER PARTICIPANTS

For 3 consecutive years, all 152 team members (age = 19.7 ± 1.5 years, height = 1.84 ± 0.08 m, mass = 101.08 ± 19.28 kg) presented for a mandatory physical examination on the day before initiation of preseason practice sessions.

MAIN OUTCOME MEASURE(S)

Associations between preseason measurements and the subsequent occurrence of a core or lower extremity sprain or strain were established for 256 player-seasons of data. We used receiver operating characteristic analysis to identify optimal cut points for dichotomous categorizations of cases as high risk or low risk. Both logistic regression and Cox regression analyses were used to identify a multivariable injury-prediction model with optimal discriminatory power.

RESULTS

Exceptionally good discrimination between injured and uninjured cases was found for a 3-factor prediction model that included equal to or greater than 1 game as a starter, Oswestry Disability Index score equal to or greater than 4, and poor wall-sit-hold performance. The existence of at least 2 of the 3 risk factors demonstrated 56% sensitivity, 80% specificity, an odds ratio of 5.28 (90% confidence interval = 3.31, 8.44), and a hazard ratio of 2.97 (90% confidence interval = 2.14, 4.12).

CONCLUSIONS

High exposure to game conditions was the dominant injury risk factor for collegiate football players, but a surprisingly mild degree of low back dysfunction and poor core-muscle endurance appeared to be important modifiable risk factors that should be identified and addressed before participation.

Cohort study design: an underutilized approach for advancement of evidence-based and patient-centered practice in athletic training

OBJECTIVE

Providing patient-centered care requires consideration of numerous factors when making decisions that will influence a patient's health status.

BACKGROUND

Clinical decisions should be informed by relevant research evidence, but the literature often lacks pertinent information for problems encountered in routine clinical practice. Although a randomized clinical trial provides the best research design to ensure the internal validity of study findings, ethical considerations and the competitive culture of sport often preclude random assignment of patients or participants to a control condition.

CLINICAL ADVANTAGES

A cohort study design and Bayesian approach to data analysis can provide valuable evidence to support clinical decisions. Dichotomous classification of both an outcome and 1 or more predictive factors permits quantification of the likelihood of occurrence of a specified outcome.

CONCLUSIONS

Multifactorial prediction models can reduce uncertainty in clinical decision making and facilitate the individualization of treatment, thereby supporting delivery of clinical services that are both evidence based and patient centered.

Prediction of core and lower extremity strains and sprains in collegiate football players: a preliminary study

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.

Identification of cardiometabolic risk among collegiate football players

CONTEXT

Excessive fat mass clearly has adverse effects on metabolic processes that can ultimately lead to the development of chronic disease. Early identification of high-risk status may facilitate referral for definitive diagnostic tests and implementation of interventions to reduce cardiometabolic risk.

OBJECTIVE

To document the prevalence of metabolic syndrome among collegiate football players and to develop a clinical prediction rule that does not require blood analysis to identify players who may possess a high level of cardiometabolic risk.

DESIGN

Cross-sectional cohort study.

SETTING

University athletic training research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Sixty-two National Collegiate Athletic Association Division I Football Championship Subdivision football players (age = 19.9 +/- 1.2 years, height = 182.6 +/- 6.1 cm, mass = 97.4 +/- 18.3 kg).

MAIN OUTCOME MEASURE(S)

Anthropometric characteristics associated with body fat, isokinetic quadriceps strength, and biometric indicators associated with metabolic syndrome were measured. Participants were classified as high risk or low risk for future development of type 2 diabetes and cardiovascular disease.

RESULTS

The prevalence of metabolic syndrome in the cohort was 19% (12 of 62), and 79% (49 of 62) of the players exceeded the threshold for 1 or more of its 5 components. A 4-factor clinical prediction rule that classified individuals on the basis of waist circumference, blood pressure, quadriceps strength, and ethnic category had 92% sensitivity (95% confidence interval = 65%, 99%) and 76% specificity (95% confidence interval = 63%, 86%) for discrimination of high-risk or low-risk status.

CONCLUSIONS

The risk for developing type 2 diabetes and cardiovascular disease appears to be exceptionally high among collegiate football players. A lack of race-specific criteria for the diagnosis of metabolic syndrome almost certainly contributes to an underestimation of the true level of cardiometabolic risk for African American collegiate football players.

Effects of the subtalar sling ankle taping technique on combined talocrural-subtalar joint motions

BACKGROUND

The findings of research on the effectiveness of ankle taping for protection against ligament injury have been inconsistent, and the topic remains controversial. The precise orientation of the force vectors created by tension within the various tape strip components of an ankle taping procedure may be a critical factor influencing the degree of motion restraint that is provided. We hypothesized that the addition of the subtalar sling component to the widely recognized standard (Gibney) ankle taping procedure would enhance restraint of ankle motion. This was a controlled laboratory study, with fully repeated measures (subjects served as their own controls).

METHODS

An ankle arthrometer was used to quantify anteroposterior (AP) translation and frontal plane inversion-eversion (I-E) tilt of the talocrural-subtalar joints under untaped and taped conditions in normal subjects. A 15-minute exercise session was conducted to loosen the tape before measurement of its effect on motion restraint.

RESULTS

The ankle taping procedure that incorporated the subtalar sling provided significantly greater restriction of postexercise AP translation (p < 0.001, eta(2) = 0.63) and postexercise I-E tilt (p < 0.001, eta(2) = 0.66).

CONCLUSIONS

The subtalar sling ankle taping procedure provides greater restriction of motions associated with ankle instability than the more widely used Gibney procedure.

Neuromuscular Changes in Female Collegiate Athletes Resulting From a Plyometric Jump-Training Program

OBJECTIVE: To assess performance changes induced by a 6- week plyometric jump-training program. DESIGN AND SETTING: We used a quasiexperimental design to compare groups formed on the basis of team membership. Testing was conducted in an athletic training research laboratory, both before and after a 6-week period of preseason basketball conditioning. SUBJECTS: Nineteen female collegiate basketball players from a National Collegiate Athletic Association Division I program (8 subjects) and a National Association of Intercollegiate Athletics Division II program (11 subjects) who had no history of anterior cruciate ligament injury and who had no history of any lower extremity injury during the preceding 6 months. MEASUREMENTS: The variables of primary interest were hamstrings and quadriceps isokinetic peak torque. Of secondary interest were 5 variables derived from step-down and lunging maneuvers performed on a computerized forceplate system and 4 variables derived from tracking the position of the body core during performance of a T-pattern agility drill with a computerized infrared tracking system. RESULTS: A significant group x trial interaction was found for hamstrings peak torque at 60 degrees.s(-1) (F(1,17) = 9.16, P =.008.), and the proportion of total variance attributable to the treatment effect produced by the jump-training program was relatively large (eta(2) =.35, omega(2) =.30). None of the other variables demonstrated statistically significant changes. CONCLUSIONS: Our primary results support plyometric jump training as a strategy for improving neuromuscular attributes that are believed to reduce the risk of anterior cruciate ligament injury in female college basketball players. They also provide the basis for reasonable isokinetic strength goals.

Biomechanical and Neuromuscular Effects of Ankle Taping and Bracing

OBJECTIVE: An extensive review of clinically relevant research is provided to assist clinicians in understanding the underlying mechanisms by which various ankle-support systems may provide beneficial effects. Strategies for management of different types of ankle ligament conditions are also discussed. BACKGROUND: Much of the literature pertaining to ankle instability and external support has focused on assessment of inward displacement of the hindfoot within the frontal plane. Some researchers have emphasized the importance of (1) pathologic rotary displacement of the talus within the transverse plane, (2) the frequent presence of subtalar joint ligament lesions, and (3) the interrelated effects of ankle support on deceleration of inversion velocity and facilitation of neuromuscular response. DESCRIPTION: The traditional method for application of adhesive tape to the ankle primarily restricts inward displacement of the hindfoot within the frontal plane. The biomechanical rationale for a method of ankle taping that restricts lower leg rotation and triplanar displacement of the foot associated with subtalar motion is presented. CLINICAL ADVANTAGES: The lateral subtalar-sling taping procedure may limit strain on the anterior talofibular ligament associated with subtalar inversion, restrain anterolateral rotary subluxation of the talus in the presence of ligament laxity, and protect the subtalar ligaments from excessive loading. The medial subtalar sling may reduce strain on the anterior-inferior tibiofibular syndesmosis and enhance hindfoot-to-forefoot force transfer during the push-off phase of the gait cycle.

Invertor vs. evertor peak torque and power deficiencies associated with lateral ankle ligament injury

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.

Comparison of DonJoy ankle ligament protector and subtalar sling ankle taping in restricting foot and ankle motion before and after exercise

Clinicians often must select an appropriate prophylactic ankle support system for their patients from a variety of ankle orthoses and ankle taping configurations. The purpose of this study was to compare the effectiveness of the DonJoy Ankle Ligament Protector and a newly developed ankle taping procedure in restricting foot and ankle motion before and after exercise. Subjects were eight males and eight females who reported no history of ankle injury during the 6 months prior to testing, neurological condition, lower extremity arthritis, lower extremity fracture, or cardiac or balance problems. A Biodex dynamometer and computer were used to impose passive moments and to measure eversion and inversion prior to application of the ankle support systems, following application, and following 10 minutes of figure-of-eight running and 20 unilateral toe raises. Both ankles of each subject were assessed for each ankle support system. Subjects also compared the support systems for comfort, stability, and cosmetic acceptability. Both ankle support systems significantly reduced eversion and inversion following application and following exercise compared with preapplication measurements. Eversion measurements increased significantly following exercise for both ankle support systems compared with postapplication measurements. Inversion displacement following application was greater for the Ankle Ligament Protector than the ankle taping system. The two ankle support systems did not differ significantly following exercise for eversion or inversion measurements. The results may assist clinicians in selecting either of these ankle support systems for use in protection against ankle sprain injury.

Treatment of the inversion ankle sprain: comparison of different modes of compression and cryotherapy

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.

Comparative biomechanical effects of the standard method of ankle taping and a taping method designed to enhance subtalar stability

The purpose of this study was to compare the restrictive effects of the widely recognized standard method of ankle taping with those of a modified ankle taping method that incorporates an additional component, the subtalar sling. Both ankles of 30 college football players were measured for maximal passive motion before taping, immediately after taping, and after a 2 to 3 hour football practice session. Downward and inward motions of the foot within the sagittal and frontal planes were induced separately and in combination with each other to allow quantification of four ankle motions. The data were analyzed by a 2 x 4 x 2 multivariate analysis of variance, a separate 2 x 3 analysis of variance for each of the four ankle motions, and the Newman-Keuls method of multiple comparisons of cell means. The results of this study suggest that the incorporation of the subtalar sling greatly enhances the protective function of ankle taping, but may impede performance of certain athletic skills.

Treatment of Ankle Sprains With External Compression and Early Mobilization

In brief: Edema associated with the inversion ankle sprain can be minimized by using a U- shaped compression pad held in place against the soft tissue around the fibular malleolus by an elastic wrap or tape. Control of edema allows earlier mobilization of the ankle joint, which reduces recovery time and permits the earliest possible return to sports participation. Factors to be considered in the construction of a compression pad include shaping, firmness, and conformability to the contours of the ankle and foot. Optimal results are obtained through continuous use of a U-shaped pad beneath an adjustable form of compression for as long as the potential for edema exists.

External Compression for Controlling Traumatic Edema

In brief: External compression is widely advocated for treating acute sports injuries. However, the rationale for using it is seldom discussed. Maintaining joint function and reducing pain and secondary hypoxic tissue death lead to more rapid and complete recovery of edema associated with sprains and strains. Poorly managed edema may contribute to the development of restricted range of motion, muscle atrophy, reduced ligament tensile strength, and joint laxity-all of which predispose an athlete to reinjury. The mechanism of action of external compression in controlling edema may be explained on the basis of its effect on capillary filtration and lymphatic drainage.