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

Subsequent musculoskeletal injury after concussion in National Football League players

OBJECTIVE

To assess whether National Football League (NFL) players diagnosed with a concussion have an increased risk of injury after return to football.

METHODS

A retrospective cohort study analysed the hazard of subsequent time-loss lower extremity (LEX) or any musculoskeletal injury among NFL players diagnosed with a concussion in 2015-2021 preseason or regular season games compared with: (1) all non-concussed players participating in the same game and (2) players with time-loss upper extremity injury. Cox proportional hazards models were adjusted for number of injuries and concussions in the prior year, player tenure and roster position. Additional models accounted for time lost from participation after concussion.

RESULTS

There was no statistical difference in the hazards of LEX injury or any musculoskeletal injury among concussed players compared with non-concussed players, though concussed players had a slightly elevated hazard of injury (LEX injury: HR=1.12, 95% CI 0.90 to 1.41; any musculoskeletal injury: HR=1.08, 95% CI: 0.89 to 1.31). When comparing to players with upper extremity injuries, the hazard of injury for concussed players was not statistically different, though HRs suggested a lower injury risk among concussed players (LEX injury: HR=0.78, 95% CI: 0.60 to 1.02; any musculoskeletal injury: HR=0.82, 95% CI: 0.65 to 1.04).

CONCLUSION

We found no statistical difference in the risk of subsequent injury among NFL players returning from concussion compared with non-concussed players in the same game or players returning from upper extremity injury. These results suggest deconditioning or other factors associated with lost participation time may explain subsequent injury risk in concussed players observed in some settings after return to play.

Neurocognitive Function Domains Are Not Affected in Active Professional Male Footballers, but Attention Deficits and Impairments Are Associated with Concussion

OBJECTIVE

To determine the neurocognitive function of active professional male footballers, determine whether deficits/impairments exist, and investigate the association between previous concussion(s) and neurocognitive function.

METHODS

An observational cross-sectional study conducted via electronic questionnaires. The CNS Vital Signs online testing system was used to evaluate neurocognitive function.

RESULTS

Of the 101 participants, 91 completed the neurocognitive function testing. Neurocognitive function domain deficits or impairments were unlikely in 54.5-89.1%, slight in 5.9-21.8%, moderate in 1.0-9.9%, and likely in 4.0-14.9% of participants. A history of zero concussions found a significant association between the neurocognitive index (Odds Ratio [OR] 0.6; 95% CI 0.2-0.4) and complex attention domain (OR 0.3; 95% CI 0.1-0.9), with 40% and 70% less odds, respectively, of deficit/impairment. Among the 54.5% who reported any number of concussions, there were increased odds of neurocognitive domain deficits/impairments for complex attention (CA) [3.4 times more] and simple attention (SA) [3.1 times more].

CONCLUSION

In the active professional male footballer, most neurocognitive functions do not have significant deficits/impairments. The odds of neurocognitive function deficit/impairment were significantly increased threefold for CA and SA in those who reported a history of any concussion(s).

Monitoring cognitive function in the fatigued warfighter: A rapid review of cognitive biomarkers

OBJECTIVES

Decreases in cognitive function impair occupational performance, reduce occupational safety, and increase musculoskeletal injury risk. The aim of this paper was to identify measures that may be used to monitor cognitive function in the warfighter.

DESIGN

A rapid review.

METHODS

A rapid search of Academic Search Complete, MEDLINE, PsycINFO, and SPORTSDiscus databases was conducted.

ELIGIBILITY CRITERIA

original peer reviewed research articles, written in English, published between 2002 and 2022, and using human participants with no health issues in military training environments or active service.

RESULTS

Of the 248 articles screened, 58 full-text articles were assessed for eligibility and 29 included in the review. Of these, 16 papers presented data from multi-stressor military training environments, or experimental studies where simulated military tasks were being performed. Thirteen papers focused on an aspect of military work and the implications for cognitive function (i.e., physical load, periods of extended wakefulness or fatigue, and hypoxic conditions). The domains of cognitive function that were assessed (i.e. vigilance, reaction time, working memory, situational awareness, and decision-making) were somewhat consistent among studies.

CONCLUSIONS

Prolonged exposure to high-stress military environments compromises multiple aspects of cognitive function. These findings highlight the need for a suite of biomarkers to monitor cognitive function and assess the ability of military personnel to attend to and process mission-critical information and make appropriate decisions on the battlefield and other high-stress environments. Our findings suggest that a suite of common tests may provide useful information about cognitive function in the warfighter.

Reactive postural responses predict risk for acute musculoskeletal injury in collegiate athletes

Identifying risk factors for musculoskeletal injury is critical to maintain the health and safety of athletes. While current tests consider isolated assessments of function or subjective ratings, objective tests of reactive postural responses, especially when in cognitively demanding scenarios, may better identify risk of musculoskeletal injury than traditional tests alone.

OBJECTIVES

Examine if objective assessments of reactive postural responses, quantified using wearable inertial measurement units, are associated with the risk for acute lower extremity musculoskeletal injuries in collegiate athletes.

DESIGN

Prospective survival analysis.

METHODS

191 Division I National Collegiate Athletic Association athletes completed an instrumented version of a modified Push and Release (I-mP&R) test at the beginning of their competitive season. The I-mP&R was performed with eyes closed under single- and dual-task (concurrent cognitive task) conditions. Inertial measurement units recorded acceleration and angular velocity data that was used to calculate time-to-stability. Acute lower extremity musculoskeletal injuries were tracked from first team activity for six months. Cox proportional hazard models were used to determine if longer times to stability were associated with faster time to injury.

RESULTS

Longer time-to-stability was associated with increased risk of injury; every 250 ms increase in dual-task median time-to-stability was associated with a 36% increased risk of acute, lower-extremity musculoskeletal injury.

CONCLUSIONS

Tests of reactive balance, particularly under dual-task conditions, may be able to identify athletes most at risk of acute lower extremity musculoskeletal injury. Clinically-feasible, instrumented tests of reactive should be considered in assessments for prediction and mitigation of musculoskeletal injury in collegiate athletes.

Preseason Prognostic Factors for Injuries and Match Loss in Collision Sports: A Systematic Review

This study aimed to identify which preseason factors had strong evidence of risks for physical injury during the season of collision sports including rugby, American football, and Australian rules football using qualitative synthesis. Pubmed, EMBASE, MEDLINE, SPORTDiscus, Scopus, and the Cochrane Library were reviewed. Eligibility criteria for selecting studies were: studies involving the collision sports; prospective cohort studies; and studies with outcomes of relative risks, odds ratios, and correlations between players' preseason conditions and injury during the season. The risk of bias based on the Scottish Intercollegiate Guidelines Network quality checklists for cohort studies was assessed in 57 studies. The current study identified strong evidence that 1) anthropometric characteristics (body mass index and estimated mass moment of inertia of the body around a horizontal axis through the ankle), which are calculated with weight and height; 2) physical function, in particular for the trunk and lower limb (trunk-flexion hold and wall-sit hold); and 3) Oswestry Disability Index disability, which is a patient-reported outcome measure for disability due to low back pain, were positive prognostic factors for injury during the collision sports season, regardless of playing experience.

Quantifying the Magnitude and Longevity of the Effect of Repetitive Head Impacts in Adolescent Soccer Players: Deleterious Effect of Long Headers Extend Beyond a Month

There is growing interest in the effects of sports-related repetitive head impacts (RHIs) on athletes' cognitive capabilities. This study examines the effect of RHIs in data collected from adolescent athletes to estimate the magnitude and longevity of RHIs on sensorimotor and cognitive performance. A non-linear regression model estimated the longevity of RHI effects by adding a half-life parameter embedded in an exponential decay function. A model estimate of this parameter allows the possibility of RHI effects to attenuate over time and introduces a mechanism to study the cumulative effect of RHIs. The posterior distribution of the half-life parameter associated with short-distance headers (<30 m) is centered around 6 days, whereas the posterior distribution of the half-life parameter associated with long-distance headers extends beyond a month. Additionally, the magnitude of the effect of each short header is around 3 times smaller than that of a long header. The results indicate that, on both tasks, response time (RT) changes after long headers are bigger in magnitude and last longer compared to the effects of short headers. Most important, we demonstrate that deleterious effects of long headers extend beyond 1 month. Although estimates are based on data from a relatively short-duration study with a relatively small sample size, the proposed model provides a mechanism to estimate long-term behavioral slowing from RHIs, which may be helpful to reduce the risk of additional injury. Finally, differences in the longevity of the effects of short and long RHIs may help to explain the large variance found between biomechanical input and clinical outcome in studies of concussion tolerance.

Visual-Spatial Attentional Performance Identifies Lower Extremity Injury Risk in Adolescent Athletes

OBJECTIVE

Strategies to identify lower extremity musculoskeletal (LEMSK) injury risk have been informed by prospectively identified biomechanical and neuromuscular risk factors. Emergent evidence suggests that cognitive and oculomotor performance may also contribute to LEMSK injury. The purpose of this study was to determine whether prospective cognitive and oculomotor measures identify adolescent athletes who sustain an in-season LEMSK injury.

DESIGN

Prospective longitudinal study.

SETTINGS

Controlled laboratory and athletic event settings.

PARTICIPANTS

Four hundred eighty-eight adolescent male football and female soccer athletes aged 13 to 18 years.

ASSESSMENT OF RISK FACTORS

Preseason baseline cognitive and oculomotor performance: Attention Network Task (ANT), cued task switching, King-Devick test, and near point of convergence.

MAIN OUTCOME MEASURE

Incidence of LEMSK sprains and strains during a single competitive season.

RESULTS

Attention Network Task-orienting network reaction time (RT) was the only cognitive or oculomotor measure significantly associated with LEMSK injury [B = 1.015, 95% confidence interval (CI): 1.01-1.024, P < 0.01]. Every 10 milliseconds increase in orienting network RT was associated with a 15% increased risk for LEMSK injury. Athletes demonstrating an orienting network RT ≥ 32.8 milliseconds had a higher risk for LEMSK injury relative to athletes below the cut-point (relative risk, 2.62; 95% CI, 1.52-4.52; odds ratio, 3.00; 95% CI, 1.63-5.52).

CONCLUSIONS

Deficits in visual-spatial components of attention were associated with 2.62 times greater risk for LEMSK injury in adolescent athletes. The present results add evidence to suggest that visual-spatial attentional processing contributes to LEMSK injury and may supplement previously established LEMSK injury risk assessments.

CORE STRENGTH TRAINING ON PHYSICAL CONDITIONING OF COLLEGE MALE SOCCER PLAYERS

ABSTRACT Introduction: The concept of CORE emerged in mechanical-neurological studies of rehabilitation in the 80s, referring to the central muscles of the human trunk, including the lumbar-pelvis-abdominal-perineal-hip complex responsible for the body orthostatic stability and support. Strengthening the CORE has received increasing attention from sports medicine specialists after the 2000s, and strength training is the subject of recent research in competitive sports. However, there is still a lack of conceptual studies of protocols for training focused on soccer athletes. Objective: Verify a CORE strength training protocol based on the analysis of the CORE training concept, its main functions, and introductory practical examples. Methods: Literature data collection, experimental and statistical-mathematical methods, and theoretical analysis about CORE training focused on explosive strength performance in soccer players are used. The developed protocol experiments with 44 athletes, divided into experimental and control groups, by sex. Information is collected on goal shooting, 30-meter pass, balance, stability, and symmetry. Results: The group experienced better results in both sexes(P<0.05). Conclusion: The explosion strength indicators of the players were significantly improved. Whether male or female athletes, the higher the skill level, the stronger the CORE stability in players. Therefore, the CORE stability and strengthening in athletes promote a benefit in the technical level of soccer players. Evidence Level II; Therapeutic Studies - Investigating the result.

Lower Kinetic Chain, Meet the Thinking Brain: A Scoping Review of Cognitive Function and Lower Extremity Injury Risk

The classic model of non-contact ACL injury includes environmental, anatomical, hormonal and biomechanical risk factors which directly impact either the amount of stress placed on the ligament or the relative capacity of ligament to withstand the forces placed on it. However, cognition also clearly plays a role in successful athletic performance, yet diminished cognitive function is rarely considered a risk factor for injury.

Objective

To examine the existing literature to determine the extent to which cognitive function (both cognitive ability and task cognitive load) influences non-contact lower extremity injury risk in male and female athletes with a broad variety of athletic expertise.

Study Design

Scoping Review.

Methods

An electronic search was conducted of CINAHL, SPORTDiscus, Google Scholar, and MEDLINE using the PRISMA method. Search terms included Boolean combinations of "cognition", "concussion", "ImPACT", "cognitive deficit", "mild traumatic brain injury (mTBI)", and "neuropsychological function" as cognitive descriptors and the terms "injury risk" and "lower extremity injury" as injury descriptors. Inclusion criteria included papers written in English published between 2000-2021. Exclusion criteria included neurological and cognitively atypical populations, except for concussion (included). Included articles were appraised using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies.

Results

Fifty-six studies utilizing across the spectrum of levels of evidence met inclusion criteria. Forty-one articles had good, fourteen had fair, and one had poor methodological quality. Studies examined baseline cognitive function in healthy athletes (n=7); performance during dual-task paradigms (n=13); and the impact of concussion on dual-task performance (n=4), LE injury risk (n=22), or post-concussion testing (n=10). Six articles examining cognitive function and all dual-task studies (including concussion studies) found altered biomechanics associated with injury or increased processing demands. Studies related to concussion and injury incidence consistently found an increased risk of LE injury following concussion. Half of the studies that examined concussion and post-concussion cognitive testing demonstrated significant effects.

Discussion

Consistent across participant demographics, tasks, and dependent measures, fifty-one of fifty-six assessed articles concluded that decreased cognitive ability or increased cognitive load led to risky LE mechanics or a direct increase in non-contact LE injury risk.

Conclusion

The robustness of results across gender, performance level, sport, cognitive ability, task cognitive load suggest that the inclusion of cognitive training in the design of optimal LE injury prevention programs warrants further study. Level of Evidence: Ia.

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.

Influence of Cognitive Performance on Musculoskeletal Injury Risk: A Systematic Review

BACKGROUND

While a large number of studies have investigated the anatomic, hormonal, and biomechanical risk factors related to musculoskeletal (MSK) injury risk, there is growing evidence to suggest that cognition is an important injury contributor in the athletic population. A systematic review of the available evidence regarding the influence of cognitive performance on MSK injury risk has yet to be published in the sports medicine literature.

PURPOSE/HYPOTHESIS

The purpose was to determine the effects of cognition on (1) MSK biomechanics during sports-specific tasks and (2) MSK injury occurrence in the athletic population. It was hypothesized that athletes with lower cognitive performance would demonstrate biomechanical patterns suggestive of MSK injury risk and that injured athletes would perform worse on baseline measures of cognition as compared with their noninjured counterparts.

STUDY DESIGN

Systematic review.

METHODS

PubMed and SPORTDiscus were searched from January 2000 to January 2020. Manual searches were performed on the reference lists of the included studies. A search of the literature was performed for studies published in English that reported MSK biomechanics as a function of cognitive performance and MSK injury occurrence after baseline measures of cognition. Two independent reviewers extracted pertinent study data in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2009 guidelines and assessed study quality using the Quality Assessment Tool for Observational Cohort and Cross-sectional Studies from the National Institutes of Health. A meta-analysis was not performed, owing to the heterogeneous nature of the study designs.

RESULTS

Ten studies met inclusion criteria: 4 cognition-MSK biomechanics studies and 6 cognition-MSK injury studies. All 4 cognition-MSK biomechanics studies demonstrated that worse performance on measures of cognition was associated with lower extremity MSK biomechanical patterns suggestive of greater risk for MSK injury. The majority of the cognition-MSK injury studies demonstrated that injured athletes significantly differed on baseline cognition measures versus matched controls or that cognitive performance was a significant predictor for subsequent MSK injury.

CONCLUSION

Although the literature exploring cognitive contributions to MSK injury risk is still in its infancy, it is suggested that sports medicine personnel conduct baseline assessments of cognition-in particular, reaction time and working memory-to identify which athletes may be at elevated risk for future MSK injury.

Relationship Between Cognitive Performance and Lower Extremity Biomechanics: Implications for Sports-Related Concussion

Background

Collegiate athletes with prior sports-related concussion (SRC) are at increased risk for lower extremity (LE) injuries; however, the biomechanical and cognitive mechanisms underlying the SRC-LE injury relationship are not well understood.

Purpose

To examine the association between cognitive performance and LE land-and-cut biomechanics among collegiate athletes with and without a history of SRC and to determine the association among multiple cognitive testing batteries in the same athlete cohort.

Study Design

Controlled laboratory study.

Methods

A cohort of 20 collegiate athletes with prior SRC (9 men, 11 women; mean ± standard deviation [SD] age, 20.5 ± 1.3 years; mean ± SD time since last SRC, 461 ± 263 days) and 20 matched controls (9 men, 11 women; mean ± SD age, 19.8 ± 1.3 years) completed land-and-cut tasks using the dominant and nondominant limbs. LE biomechanical variables and a functional visuomotor reaction time (FVMRT) were collected during each trial. Athletes also completed the Immediate Post-Concussion Assessment and Cognitive Test (ImPACT) and Senaptec Sensory Station assessments.

Results

In the SRC cohort, Pearson correlation coefficients indicated slower FVMRT was moderately correlated with decreased dominant limb (r = -0.512) and nondominant limb (r = -0.500) knee flexion, while increased dominant limb knee abduction moment was moderately correlated with decreased ImPACT Visual Memory score (r = -0.539) and slower ImPACT Reaction Time (r = 0.515). Most computerized cognitive measures were not associated with FVMRT in either cohort (P > .05).

Conclusion

Decreased reaction time and working memory performance were moderately correlated with decreased sagittal plane knee motion and increased frontal plane knee loading in collegiate athletes with a history of SRC. The present findings suggest a potential unique relationship between cognitive performance and LE neuromuscular control in athletes with a history of SRC injury. Last, we determined that computerized measures of cognitive performance often utilized for SRC management are dissimilar to sport-specific cognitive processes.

Clinical Relevance

Understanding the relationship between cognitive performance and LE biomechanics in athletes with prior SRC may inform future clinical management strategies. Future research should prospectively assess cognitive and biomechanical measures, along with LE injury incidence, to identify mechanisms underlying the SRC-LE injury relationship.

Epidemiology of Injuries in National Collegiate Athletic Association Men's Lacrosse: 2014-2015 Through 2018-2019

CONTEXT

The popularity of National Collegiate Athletic Association (NCAA) men's lacrosse has been steadily increasing since the early 1980s.

BACKGROUND

Injury surveillance is an important tool to aid in identifying emerging patterns of sport-related injury in NCAA men's lacrosse.

METHODS

Injury data collected from a sample of men's lacrosse teams through the NCAA Injury Surveillance Program for the academic years 2014-2015 through 2018-2019 were analyzed. Athlete exposures were estimated and computed based on collected exposure data. Injury counts, rates, and proportions were used to describe injury characteristics, and injury rate ratios (IRRs) with 95% confidence intervals (CIs) were calculated to estimate differences in injury rates.

RESULTS

The overall injury rate was 4.90 per 1000 athlete exposures (AEs), and the competition injury rate was higher than the practice injury rate (IRR = 2.59; 95% CI = 2.35, 2.84). The overall preseason injury rate was higher than the regular and postseason injury rates. The most reported injuries were concussions (8.0%), ankle sprains (7.7%), and hamstring tears (6.9%).

CONCLUSIONS

Study findings were comparable with existing epidemiological evidence. The overall burden of concussions and lower extremity injuries warrant further attention in this population.

Neurocognitive function and musculoskeletal injury risk in sports: A systematic review

OBJECTIVES

A variety of modifiable risk factors has been suggested to predict musculoskeletal injury in sports. Screening paradigms and exercise-based prevention programs, so far, frequently focused on physical parameters such as strength, balance or flexibility. However, less is known with regard to the impact of brain function. We investigated the relation between cognition and the occurrence of injury in athletes.

DESIGN

Systematic review.

METHODS

Database searches using Pubmed, Web of Science and Google Scholar returned nine cohort and case-control studies, which almost exclusively examined college athletes engaging in open skill sports. Methodological quality, rated by means of a modified Downs and Black checklist, was moderate (12/17 points).

RESULTS

Seven out of the nine included studies suggested that lower-order cognitive function (i.e. visuomotor reaction time) is systematically associated with the occurrence of injury. No paper examined the impact of executive function.

CONCLUSIONS

Despite initial evidence pointing towards a potentially injury-predictive role of lower-order cognitive function, several issues including the use of more variable populations and outcomes remain to be addressed before definitive recommendations for clinicians can be made.

Test-Retest Reliability of a Functional Reaction Time Assessment Battery

CONTEXT

Reaction time is commonly assessed postconcussion through a computerized neurocognitive battery. Although this measure is sensitive to postconcussion deficits, it is not clear if computerized reaction time reflects the dynamic reaction time necessary to compete effectively and safely during sporting activities. Functional reaction time assessments may be useful postconcussion, but reliability must be determined before clinical implementation.

OBJECTIVE

To determine the test-retest reliability of a functional reaction time assessment battery and to determine if reaction time improved between sessions.

DESIGN

Cohort.

SETTING

Laboratory.

PARTICIPANTS

Forty-one participants (21 men and 20 women) completed 2 time points. Participants, on average, were 22.5 (2.1) years old, 72.5 (11.9) cm tall, had a mass of 71.0 (13.7) kg, and were mostly right leg and hand dominant (92.7%).

INTERVENTIONS

Participants completed 2 clinical reaction time tests (computerized Stroop and drop stick) and 5 functional reaction time tests (gait, jump landing, single-leg hop, anticipated cut, and unanticipated cut) across 2 sessions. Drop stick and functional reaction time assessments were performed in single (motor task only) and dual task (motor task with cognitive task).

MAIN OUTCOME MEASURES

Reaction time (in seconds) was calculated during all assessments. Test-retest reliability was determined using 2-way mixed-effects intraclass correlation coefficients (3, k). Paired samples t tests compared mean reaction time between sessions.

RESULTS

Test-retest reliability was moderate to excellent for all reaction time outcomes (intraclass correlation coefficients [3, k] range = .766-.925). Several statistically significant between-session mean differences were observed, but effect sizes were negligible to small (d range = 0.05-0.44).

CONCLUSIONS

The functional reaction time assessment battery displayed similar reliability to the standard computerized reaction time assessment battery and may provide important postinjury information, but more research is needed to determine clinical utility.

Impaired motor control after sport-related concussion could increase risk for musculoskeletal injury: Implications for clinical management and rehabilitation

This review presents a conceptual framework and supporting evidence that links impaired motor control after sport-related concussion (SRC) to increased risk for musculoskeletal injury. Multiple studies have found that athletes who are post-SRC have higher risk for musculoskeletal injury compared to their counterparts. A small body of research suggests that impairments in motor control are associated with musculoskeletal injury risk. Motor control involves the perception and processing of sensory information and subsequent coordination of motor output within the central nervous system to perform a motor task. Motor control is inclusive of motor planning and motor learning. If sensory information is not accurately perceived or there is interference with sensory information processing and cognition, motor function will be altered, and an athlete may become vulnerable to injury during sport participation. Athletes with SRC show neuroanatomic and neurophysiological changes relevant to motor control even after meeting return to sport criteria, including a normal neurological examination, resolution of symptoms, and return to baseline function on traditional concussion testing. In conjunction, altered motor function is demonstrated after SRC in muscle activation and force production, movement patterns, balance/postural stability, and motor task performance, especially performance of a motor task paired with a cognitive task (i.e., dual-task condition). The clinical implications of this conceptual framework include a need to intentionally address motor control impairments after SRC to mitigate musculoskeletal injury risk and to monitor motor control as the athlete progresses through the return to sport continuum.

Clinical utility of measuring the size of the lumbar multifidus and quadratus lumborum muscles in the Australian football league setting: A prospective cohort study

OBJECTIVES

Test the odds of factors previously associated with lower limb injury (decreased size of the multifidus (MF) and increased size of the quadratus lumborum (QL) muscle) in an independent sample of Australian Rules Football (ARF) players.

DESIGN

Prospective cohort study.

SETTING

Professional ARF.

PARTICIPANTS

Forty-three male ARF players.

MAIN OUTCOME MEASURES

Cross-sectional areas (CSAs) of MF and QL muscles measured from pre-season ultrasound images. Playing season injuries were recorded by club personnel. A multivariable logistic regression model was used to evaluate the usefulness of MF and QL muscle size for predicting playing season lower limb injuries.

RESULTS

Fifteen players (35%) sustained a playing season lower limb injury. The multivariable model indicated that the odds of sustaining a lower limb injury during the season was 2.38 (95% CI: 1.18, 5.00; P = 0.017) times less likely for a one cm² increase from the mean value in MF muscle CSA at the L5 vertebral level after adjusting for CSA of the QL, age and BMI. The main effect and interaction models positively predicted 75% of players that sustained a lower limb injury during the season (sensitivity 80%, specificity 85%).

CONCLUSION

Future studies could examine the efficacy, feasibility and adherence of 'at risk' players to a pre-season training program aimed at increasing MF muscle size and monitor playing season injuries.

Males with chronic ankle instability demonstrate deficits in neurocognitive function compared to control and copers

The purpose of this study was to determine if there were neurocognitive deficits among controls, copers and those with chronic ankle instability (CAI). Participants included those without history of ankle injury (n = 14), ankle sprain copers (n = 13) and patients with self-reported CAI (n = 14). They completed a battery of valid and reliable computer-based neurocognitive tests. The differences between neurocognitive domain scores were compared across the Control, Coper and CAI groups. Patients with CAI had lower composite memory, visual memory and simple attention compared to controls. In males with CAI, large differences in memory and attention were found relative to control participants. These differences may contribute to uncontrolled episodes of giving way through deficits in spatial awareness and/or an inability to identify environmental obstacles. Clinicians should explore ways to provide additional stimuli through innovative rehabilitation protocols aimed at maximizing neurocognitive abilities in patients with CAI.