Commentary: Time for a paradigm shift in conceptualizing risk factors in sports injury research

Contact Breast Injuries Among Female Athletes: A Systematic Review

BACKGROUND

Robust surveillance of injury aetiology and epidemiology is recognised as fundamental for effective injury reduction and management programmes. However, while sex-specific differences in injury type and nature are noted in the literature, it is unclear if these are reflected in surveillance practices, and how the athlete is affected.

OBJECTIVE

Therefore, this study aimed to systematically review contact breast injuries (CBIs) among adult female athletes.

METHODS

The following databases were searched: PubMed, EMBASE, SPORTDiscus including MEDLINE, Web of Science and Scopus. The literature search was conducted in May 2023 and the search was limited to articles in the English and German language. Studies including female athletes, aged 18 years and above, in any sports (team or individual) at any level (amateur, semi-professional and professional), where an occurrence of CBI was documented were included. Studies were included irrespective of their investigated timeframes (e.g. the whole career, one or multiple seasons). Findings were categorised (e.g. sport, level of competition and investigated timeframe of the study) to enable possible comparisons. Case studies were excluded due to the non-generalisability of findings.

RESULTS

Of the six studies included, rugby codes (rugby union, rugby league and rugby sevens) had the highest occurrence rate (62.0%) of CBIs among eight different investigated sports (rugby codes 62.0%, softball 59.5%, Australian Football League (AFL) 51.0%, water polo 50.0%, soccer 46.7%, basketball 27.6-48.8%, volleyball 34.6%, boxing 0.0%). Between 25.6% and 62.0% of participants reported incurring a CBI and between 0.0% and 42.9% of CBIs were reported to a medical professional or support staff. The reported treatment rate for CBIs ranged between 0.0% and 2.1%, The main mechanisms for CBIs (where reported) were contact with another athlete (AFL 37.6%, rugby codes 56%) the ball (AFL 31.6%, rugby codes 25.5%) and the ground (AFL 6.6%, rugby codes 22%). Between 18.2% and 48% of the participants reported that CBIs negatively affected their performance. Risk factors increasing CBIs were positional differences, larger breast size and higher body mass index (BMI). In-season injury data collection and surveillance supported through education of both players and medical staff were identified to be of relevance for future CBI prevention. None of the studies reported incidence rate.

CONCLUSION

Despite the frequent occurrence of CBIs among female athletes, reporting and treatment remains low. Awareness and education of all stakeholders are fundamental to ensuring better breast safety in female sport. Identifying the mechanics, severity and risk factors of CBIs through thorough injury surveillance must be a focus of further research.

REGISTRATION

The study was preregistered on Open Science Framework (OSF).

Learning from fall-related interventions for older people at home: A scoping review

This scoping review aims to provide a better understanding about the fall-related interventions, and the conditions which stand out as effective in decreasing fall risks of older people at home. A total of 28 peer-reviewed papers were included when they reported interventions with an incidence of falls or fall-risk as a primary outcome for older people, focusing on the home environment, from 8 databases. Qualitative examination was complemented by quantitative risk ratio analysis where it was feasible. The interventions regarding incidence of falls had a mean risk rate of 0.75; moreover, interventions using multiple strategies were found relatively successful. The interventions regarding fall risk had a mean hazard rate of 0.66. A considerable number of no-effect ratios were evident. Combining education, home assessment or improvement, and use of technology with implementation by health service experts appears to be the most promising intervention strategy to reduce falls.

Association Between Landing Error Scoring System (LESS) Items and the Incidence Rate of Lower Extremity Stress Fracture

Background:

Lower extremity stress fracture injuries are a major cause of morbidity in physically active populations. The ability to screen for modifiable risk factors associated with injury is critical in developing injury-prevention programs.

Purpose:

To determine if baseline Landing Error Scoring System (LESS) scores are associated with the incidence rate of lower extremity stress fracture.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

A total of 1772 participants with no history of lower extremity stress fracture were included. At preinjury baseline, the authors conducted a lower extremity movement assessment during a jump-landing task using the LESS. Incident lower extremity stress fractures were identified during a 4-year follow-up period. Potential incident cases were reviewed by 2 sports medicine fellowship–trained orthopaedic surgeons blinded to baseline LESS data. Univariate and multivariable Poisson regression models were used to estimate the association between baseline total LESS scores, individual LESS items, and the incidence rate ratio (IRR) of lower extremity stress fracture.

Results:

A total of 94 incident lower extremity stress fractures were documented, for a 5.3% (95% CI, 4.3%-6.5%) cumulative incidence. The overall LESS score was associated with the incidence rate of lower extremity stress fracture. For every additional movement error documented at baseline, there was a 15% increase in the incidence rate of lower extremity stress fracture (IRR, 1.15 [95% CI, 1.02-1.31]; P = .025). In univariate analyses, ankle flexion, stance width, asymmetrical landing, and trunk flexion at initial contact, in addition to overall impression, were associated with the incidence rate of stress fracture. After controlling for sex and year of entry into the study cohort, participants who consistently landed flat-footed or heel-to-toe were 2.33 times (95% CI, 1.36-3.97; P = .002) more likely to sustain a lower extremity stress fracture. Similarly, participants who consistently demonstrated asymmetric landing at initial contact were 2.53 times (95% CI, 1.34-4.74; P = .004) more likely to sustain a stress fracture.

Conclusion:

Components of the LESS may be associated with increased lower extremity stress fracture risk and may be helpful in efficiently assessing high-risk lower extremity biomechanics in large groups.

Examining the Dynamic Nature of Anterior Cruciate Ligament Injury Risk Factors in Women's Collegiate Soccer

CONTEXT

Anterior cruciate ligament (ACL) injuries are a common and devastating injury in women's soccer. Several risk factors for ACL injury have been identified, but have not yet been examined as potentially dynamic risk factors, which may change throughout a collegiate soccer season.

DESIGN

Prospective cohort study.

METHODS

Nine common clinical screening assessments for ACL injury risk, consisting of range of motion, movement quality, and power, were assessed in 29 Division I collegiate women's soccer players. Preseason and midseason values were compared for significant differences. Change scores for each risk factor were also correlated with cumulative training loads during the first 10 weeks of a competitive soccer season.

RESULTS

Hip external rotation range of motion and power had statistically significant and meaningful differences at midseason compared with preseason, indicating they are dynamic risk factors. There were no significant associations between the observed risk factor changes and cumulative training load.

CONCLUSIONS

Hip external rotation range of motion and power are dynamic risk factors for ACL injury in women's collegiate soccer athletes. Serial screening of these risk factors may elucidate stronger associations with injury risk and improve prognostic accuracy of screening tools.

Anterior cruciate ligament injury: towards a gendered environmental approach

BACKGROUND

The anterior cruciate ligament (ACL) injury rate for girls/women has not changed in over 20 years, and they remain 3-6 times more likely to experience injury compared with boys/men. To date, ACL injury prevention and management has been approached from a sex-based biological point of view which has furthered our understanding of injury risk factors, mechanisms, and prevention and rehabilitation programmes. However, the traditional sex-based approach does not take into account the growing recognition of how sex and gender (a social construct) are 'entangled' and influence each other.

OBJECTIVE

This paper discusses the curious absence of gender as an influencer in the dialogue surrounding ACL injuries. We propose adding gender as a pervasive developmental environment as a new theoretical overlay to an established injury model to illustrate how gender can operate as an extrinsic determinant from the presport, training and competition environments through to ACL injury and the treatment environment.

APPROACH

We draw on social epidemiological theories of the embodiment of gender and health to provide plausible examples of how gender may influence ACL injury, and demonstrate the opportunity for new, interdisciplinary research in the field.

CONCLUSION

Over 20 years of research has failed to decrease the ACL injury rate disparity between girls/women and boys/men. Embedding gender in the study of ACL injury will heighten awareness of possible influences outside the traditional biological elements, challenge us to think about the inextricable 'entanglement' of sex and gender, and inform more effective approaches to ACL injury prevention and treatment.

Risk Factors for Lower-Extremity Injuries in Female Ballet Dancers: A Systematic Review

BACKGROUND

Ballet dancers have a high prevalence of injuries to the lower extremity. Many studies have investigated the relationship between dance injury and risk factors. However, risk factors for lower-extremity injury comparing recreational- and elite-level ballet dancers are scarce.

OBJECTIVE

To systematically review available original studies to assess risk factors for lower-extremity injury in female ballet dancers between recreational and elite ballet dancers.

DATA SOURCES

Five online databases [Web of Science, PubMed, OVID (Medline), EBSCO, and ProQuest] were searched systematically.

STUDY SELECTION

Included studies had an analytic study design published in the past 11 years and investigated an association between potential risk factors and lower-extremity injury in female ballet dancers.

STUDY APPRAISAL

Assessed independently by 2 reviewers using the Downs and Black (DB) criteria and Oxford Centre of Evidence-Based Medicine.

RESULTS

Seventeen studies were included. Alignment was a risk factor for lower-extremity injury in both recreational and elite ballet dancers. In elite ballet dancers, poor lumbopelvic movement control, inappropriate transversus abdominis contraction, decreased lower-extremity strength, and poor aerobic fitness were risk factors for lower-extremity injury. In recreational ballet dancers, hypermobility of the hip and ankle and longer training hours were risk factors for lower-extremity injury. Mean DB score was 15.94 (SD 1.57). The majority of studies were retrospective cohort studies or had poor follow-up, with 7 level 2b studies, 6 level 3b studies (cross-sectional), and 4 level 1b studies (prospective cohort with good follow-up).

CONCLUSIONS

Alignment was identified as a common risk factor for recreational and elite ballet dancers. Other risk factors differed between recreational ballet dancers and elite ballet dancers. Future studies are warranted to use a prospective study design, identify dance level-specific risk factors, and implement evidence-based prevention strategies.

Predicting self-esteem in informal caregivers of people with dementia: Modifiable and non-modifiable factors

While informal caregivers often feel burdened by the care for a person with dementia, they can also experience positive consequences due to caregiving; caregiver gains. One of these, relatively overlooked, caregiver gains is heightened self-esteem. We assessed the predictive ability of non-modifiable (caregiver sociodemographic- and dementia related-) and modifiable (psychological-) factors for caregiver self-esteem). A cross-sectional study in which 201 caregivers, who spent at least eight hours a week on caring for a community-residing person with dementia, completed a semi-structured interview and five questionnaires. One two-block (1: non-modifiable-; 2: modifiable variables) hierarchic multiple regression analysis was used to assess which variables predicted self-esteem. None of the non-modifiable variables significantly predicted self-esteem. Regarding the modifiable variables, depression and relationship quality with the person with dementia significantly predicted self-esteem (adjusted R² = .460, β = -.207, p = .015 and β = .632, p < .001 respectively). Caregivers who experience a better relationship quality with the person with dementia, and fewer depression symptoms, experience a higher level of self-esteem. Interventions focused on heightening self-esteem should strive to optimize these factors to enhance the lives of informal dementia caregivers.

The Role of the Accessory Malleolar Ossicles and Malleolar Avulsion Fractures in Lateral Ankle Ligament Reconstruction

While it is well known that ankle sprains are one of the most common injuries in the United States, predictive factors regarding failure of conservative treatment are not well known. There are many biomechanical and epidemiological factors that play a role in recurrence and failure of conservative treatment, but most cases are able to be treated with immobilization and/or rest, ice, elevation, physical therapy, and bracing. We propose that one important risk factor is often overlooked simply due to the fact that a vast majority of these cases resolve without the need for surgery. Accessory ossicles and avulsion fractures of the malleoli or talus may represent a predisposition or marker for ligamentous damage that may lead to the need for lateral ankle ligament repair or reconstruction in the future. We have identified 61 consecutive patients who underwent lateral ankle ligament repair or reconstruction by the primary surgeon from the years 2007 to 2017. Out of those patients who met our inclusion and exclusion criteria, 66% had the presence of osseous pathology consisting of accessory ossicles or avulsion fractures of the medial or lateral malleolus or talus. The proportion of osseous pathology seen with lateral ankle ligament repair or reconstruction was higher than what has been previously reported in both operative and nonoperative settings. This may help identify a risk factor for failure of conservative treatment in patients presenting with acute ankle sprains or ankle instability especially in the active cohort.

LEVELS OF EVIDENCE

Level IV: Case series.

Risk and Protective Factors for Middle- and Long-Distance Running-Related Injury

BACKGROUND

Despite a rapidly growing body of research, a systematic evidence compilation of the risk and protective factors for middle- and long-distance running-related injury (RRI) was lacking.

OBJECTIVES

Our objective was to compile the evidence about modifiable and non-modifiable training-related and behavioral risk and protective factors for middle- and long-distance RRI.

METHODS

We searched five databases (PubMed, CINAHL, MEDLINE, SPORTDiscus, and PsycINFO) for the dates 1 January 1970 to 31 December 2015, inclusive, for original peer-reviewed articles. The eligible designs were cross-sectional, case-control, longitudinal observational studies, and randomized controlled trials involving runners competing at distances from ≥800 m to ≤42.2 km. Outcomes were any specific and/or general RRI, and exposures included training-related and behavioral factors. We extracted authors and date, study design, injury type(s), descriptors and comparators for each exposure, and results and measures of association from the selected studies. Methodological quality was independently appraised using two separate checklists: a modified checklist for observational study designs and the Physiotherapy Evidence Database (PEDro) scale for randomized controlled trials.

RESULTS

Among 73 articles eligible for inclusion, 19 (26.0%) and 30 (41.0%) were of high or satisfactory methodological quality, respectively. As a non-modifiable exposure, a history of previous injury was found to be associated with an increased risk of both general and specific RRI. In terms of modifiable exposures, irregular and/or absent menstruation was found to be associated with an increased risk of stress fracture development, whereas the use of oral contraceptives was found to be associated with a decreased risk. High clinical, methodological, and statistical heterogeneity meant it was not feasible to estimate a pooled effect size across similar studies.

CONCLUSIONS

A history of previous injury was associated with an increased risk of both general and specific RRI. The use of oral contraceptives was found to be associated with a decreased risk of skeletal stress fracture. Conversely, irregular and/or absent menstruation was associated with an increased risk. The varied effect directions and/or a number of statistically insignificant results associated with the majority of factors hindered our ability to draw any definitive conclusions about their relationship to RRI risk.

Run Clever - No difference in risk of injury when comparing progression in running volume and running intensity in recreational runners: A randomised trial

Background/aim

The Run Clever trial investigated if there was a difference in injury occurrence across two running schedules, focusing on progression in volume of running intensity (Sch-I) or in total running volume (Sch-V). It was hypothesised that 15% more runners with a focus on progression in volume of running intensity would sustain an injury compared with runners with a focus on progression in total running volume.

Methods

Healthy recreational runners were included and randomly allocated to Sch-I or Sch-V. In the first eight weeks of the 24-week follow-up, all participants (n=839) followed the same running schedule (preconditioning). Participants (n=447) not censored during the first eight weeks entered the 16-week training period with a focus on either progression in intensity (Sch-I) or volume (Sch-V). A global positioning system collected all data on running. During running, all participants received real-time, individualised feedback on running intensity and running volume. The primary outcome was running-related injury (RRI).

Results

After preconditioning a total of 80 runners sustained an RRI (Sch-I n=36/Sch-V n=44). The cumulative incidence proportion (CIP) in Sch-V (reference group) were CIP_{2 weeks} 4.6%; CIP_{4 weeks} 8.2%; CIP_{8 weeks} 13.2%; CIP_{16 weeks} 28.0%. The risk differences (RD) and 95% CI between the two schedules were RD_{2 weeks}=2.9%(−5.7% to 11.6%); RD_{4 weeks}=1.8%(−9.1% to 12.8%); RD_{8 weeks}=−4.7%(−17.5% to 8.1%); RD_{16 weeks}=−14.0% (−36.9% to 8.9%).

Conclusion

A similar proportion of runners sustained injuries in the two running schedules.

Lower extremity stress fractures in the military

Stress fractures of the lower extremities are common among the military population and, more specifically, military recruits who partake in basic training. Both intrinsic and extrinsic factors play a role in the development of these injuries, and it is important to identify those individuals at risk early in their military careers. Some of these factors are modifiable, so they may become preventable injuries. It is important to reiterate that one stress fracture places the soldier at risk for future stress fractures; but the first injury should not be reason enough for separation from the military, as literature would support no long-term deficits from properly treated stress fractures. Early in the process, radiographic analysis is typically normal; continued pain may warrant advanced imaging, such as scintigraphy or MRI. Most stress fractures that are caught early are amendable to nonoperative management consisting of a period of immobilization and NWB followed by progressive rehabilitation to preinjury levels. Complete or displaced fractures may require operative intervention as do tension-sided FNSF. Improving dietary and preaccession physical fitness levels may play a role in reducing the incidence of stress fractures in the active-duty military population. It is important to keep in mind when evaluating soldiers and athletes who present with activity-related pain that stress fractures are not uncommon and should be given significant consideration.

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.

Management and prevention of acute and chronic lateral ankle instability in athletic patient populations

Acute and chronic lateral ankle instability are common in high-demand patient populations. If not managed appropriately, patients may experience recurrent instability, chronic pain, osteochondral lesions of the talus, premature osteoarthritis, and other significant long-term disability. Certain populations, including young athletes, military personnel and those involved in frequent running, jumping, and cutting motions, are at increased risk. Proposed risk factors include prior ankle sprain, elevated body weight or body mass index, female gender, neuromuscular deficits, postural imbalance, foot/ankle malalignment, and exposure to at-risk athletic activity. Prompt, accurate diagnosis is crucial, and evidence-based, functional rehabilitation regimens have a proven track record in returning active patients to work and sport. When patients fail to improve with physical therapy and external bracing, multiple surgical techniques have been described with reliable results, including both anatomic and non-anatomic reconstructive methods. Anatomic repair of the lateral ligamentous complex remains the gold standard for recurrent ankle instability, and it effectively restores native ankle anatomy and joint kinematics while preserving physiologic ankle and subtalar motion. Further preventative measures may minimize the risk of ankle instability in athletic cohorts, including prophylactic bracing and combined neuromuscular and proprioceptive training programs. These interventions have demonstrated benefit in patients at heightened risk for lateral ankle sprain and allow active cohorts to return to full activity without adversely affecting athletic performance.

Injuries in runners; a systematic review on risk factors and sex differences

BACKGROUND

The popularity of running continues to increase, which means that the incidence of running-related injuries will probably also continue to increase. Little is known about risk factors for running injuries and whether they are sex-specific.

OBJECTIVES

The aim of this study was to review information about risk factors and sex-specific differences for running-induced injuries in adults.

SEARCH STRATEGY

The databases PubMed, EMBASE, CINAHL and Psych-INFO were searched for relevant articles.

SELECTION CRITERIA

Longitudinal cohort studies with a minimal follow-up of 1 month that investigated the association between risk factors (personal factors, running/training factors and/or health and lifestyle factors) and the occurrence of lower limb injuries in runners were included.

DATA COLLECTION AND ANALYSIS

Two reviewers' independently selected relevant articles from those identified by the systematic search and assessed the risk of bias of the included studies. The strength of the evidence was determined using a best-evidence rating system. Sex differences in risk were determined by calculating the sex ratio for risk factors (the risk factor for women divided by the risk factor for men).

MAIN RESULTS

Of 400 articles retrieved, 15 longitudinal studies were included, of which 11 were considered high-quality studies and 4 moderate-quality studies. Overall, women were at lower risk than men for sustaining running-related injuries. Strong and moderate evidence was found that a history of previous injury and of having used orthotics/inserts was associated with an increased risk of running injuries. Age, previous sports activity, running on a concrete surface, participating in a marathon, weekly running distance (30-39 miles) and wearing running shoes for 4 to 6 months were associated with a greater risk of injury in women than in men. A history of previous injuries, having a running experience of 0-2 years, restarting running, weekly running distance (20-29 miles) and having a running distance of more than 40 miles per week were associated with a greater risk of running-related injury in men than in women.

CONCLUSIONS

Previous injury and use of orthotic/inserts are risk factors for running injuries. There appeared to be differences in the risk profile of men and women, but as few studies presented results for men and women separately, the results should be interpreted with caution. Further research should attempt to minimize methodological bias by paying attention to recall bias for running injuries, follow-up time, and the participation rate of the identified target group.

Summer training factors and risk of musculoskeletal injury among high school cross-country runners

STUDY DESIGN

Prospective cohort.

OBJECTIVES

To examine the relationship between summer training practices and risk of injury during the first month of a high school interscholastic cross-country season.

BACKGROUND

Several prospective studies have reported a high incidence of injury in adolescent cross-country runners. However, limited reports exist on the role of summer training practices and risk of injury among these runners.

METHODS

Four hundred twenty-one athletes (186 girls, 235 boys) who competed in interscholastic cross-country were followed during a cross-country season. At the start of the season, all participants completed a questionnaire regarding summer training routines. Time-loss, running-related injuries were tracked during the subsequent season. Logistic regression analysis was used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for the risk of initial injury during the first month of the season associated with summer training variables.

RESULTS

Sixty-seven runners (15.9%) had a confirmed injury during the first month of the season, with a higher percent among girls (19.4%) than boys (13.2%) (P = .06). Overall, 60.1% of the participants ran during the summer prior to the season, with a significantly higher percent among girls (71.5%) than boys (51.1%) (P<.0001). Overall, no significant association (OR = 0.9; 95% CI: 0.5, 1.5; P = .90) was found between not running sometime during the preceding summer and increased risk of initial injury during the first month of the season. Among only the runners who ran during the summer, after adjusting for sex and prior injury, first-month injuries were more common among those who did not frequently alternate short and long mileage on different days (OR = 3.0; 95% CI: 1.4, 6.4; P = .005), and/or who ran 8 weeks or fewer (OR = 2.7; 95% CI: 1.2, 5.8; P = .01) during their summer training. Running 8 weeks or fewer (P = .03), not frequently alternating mileage on different days (P = .01), and running a higher percentage of time on predominantly hill (P = .001) and irregular terrains (P = .004) were associated with increased risk of injury for girls.

CONCLUSION

These findings suggest that injuries during the first month of the high school cross-country season may be reduced if runners who participate in summer training activities run a greater number of weeks and frequently vary their daily running mileage during the summer. For girls, training programs that reduce mileage on hills and irregular terrains may help to minimize the occurrence of running-related injury.

LEVEL OF EVIDENCE

Prognosis, level 1b-.

Management of chronic lateral ankle instability in military service members

Chronic lateral ankle instability is a condition frequently encountered by orthopedic surgeons treating highly active patient populations, particularly military service members. Providers treating military service members must have a high index of suspicion for this condition when signs and symptoms of functional or mechanical instability exist. Stress testing and ankle MRI, although not definitive in sensitivity for detecting instability or other concomitant injuries, should be considered during the treatment decision-making process. Appropriate nonoperative treatment should be attempted initially; however, when nonoperative treatment fails, surgical management is warranted to prevent untoward long-term sequelae. Proper surgical treatment and subsequent postoperative management are at the discretion of the individual surgeon but must account for the concomitant diseases frequently associated with chronic lateral ankle instability. Low recurrence of lateral instability can be achieved even in high-demand military patient populations with a focused treatment plan.

Weekly running volume and risk of running-related injuries among marathon runners

PURPOSEBACKGROUND: The purpose of this study was to investigate if the risk of injury declines with increasing weekly running volume before a marathon race.

METHODS

The study was a retrospective cohort study on marathon finishers. Following a marathon, participants completed a web-based questionnaire. The outcome of interest was a self-reported running-related injury. The injury had to be severe enough to cause a reduction in distance, speed, duration or frequency of running for at least 14 days. Primary exposure was self-reported average weekly volume of running before the marathon categorized into below 30 km/week, 30 to 60 km/week, and above 60 km/week.

RESULTS

A total of 68 of the 662 respondents sustained an injury. When adjusting for previous injury and previous marathons, the relative risk (RR) of suffering an injury rose by 2.02 [95% CI: 1.26; 3.24], p < 0.01, among runners with an average weekly training volume below 30 km/week compared with runners with an average weekly training volume of 30-60 km/week. No significant differences were found between runners exceeding 60 km/week and runners running 30-60 km/week (RR=1.13 [0.5;2.8], p=0.80).

CONCLUSIONS

Runners may be advised to run a minimum of 30 km/week before a marathon to reduce their risk of running-related injury.

LEVEL OF EVIDENCE

2b.

History of shoulder instability and subsequent injury during four years of follow-up: a survival analysis

BACKGROUND

Little is known about the risk factors for glenohumeral joint instability. We hypothesized that a prior history of instability would be a significant risk factor for subsequent injury.

METHODS

We conducted a prospective cohort study over a four-year period within a high-risk group of young athletes to address the research hypothesis. Subjects were freshmen entering the U.S. Military Academy in June of 2006. Part of the baseline assessment included documenting a prior history of glenohumeral instability on entry into the study. All subjects were followed for subsequent glenohumeral joint instability events until graduation in May of 2010. The primary outcome of interest in this study was time to glenohumeral instability event during the follow-up period. We examined injury outcomes, looking for any instability, anterior instability, and posterior instability events. Cox proportional-hazards regression models were used to analyze the data.

RESULTS

Among the 714 subjects, eight shoulders were excluded from the analyses due to prior surgical stabilization, leaving 1420 shoulders, of which 126 had a self-reported prior history of instability. There were forty-six (thirty-nine anterior and seven posterior) acute instability events documented in the cohort during the follow-up period. Subjects with a prior history of instability were over five times (p < 0.001) more likely to sustain an acute (anterior or posterior) instability event during the follow-up period. Subjects with a history of instability were also 5.6 times (p < 0.001) more likely to experience a subsequent anterior instability event and 4.6 times (p = 0.068) more likely to experience a posterior instability event during follow-up. Similar results were observed in multivariable models after controlling for the influence of demographic and baseline physical examination findings.

CONCLUSIONS

Despite meeting the rigorous physical induction standards for military service, subjects with a prior history of glenohumeral joint instability were approximately five times more likely to experience a subsequent instability event, regardless of direction, within this high-risk athletic population.

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.

Neurocognitive Reaction Time Predicts Lower Extremity Sprains and Strains

Context:

Prevention of a lower extremity sprain or strain requires some basis for predicting that an individual athlete will sustain such an injury unless a modifiable risk factor is addressed.

Objective:

To assess the possible existence of an association between reaction time measured during completion of a computerized neurocognitive test battery and subsequent occurrence of a lower extremity sprain or strain.

Design:

Prospective cohort study.

Setting:

Preparticipation screening conducted in a computer laboratory on the day prior to initiation of preseason practice sessions.

Participants:

76 NCAA Division I-FCS football players.

Main Outcome Measures:

Lower extremity sprains and strains sustained between initiation of preseason practice sessions and the end of an 11-game season. Receiver operating characteristic analysis identified the optimal reaction time cut-point for discrimination between injured versus noninjured status. Stratified analyses were performed to evaluate any differential influence of reaction time on injury incidence between starters and nonstarters.

Results:

A total of 29 lower extremity sprains and strains were sustained by 23 of the 76 players. A reaction time cut-point of ≥ .545 s provided good discrimination between injured and noninjured cases: 74% sensitivity, 51% specificity, relative risk = 2.17 (90% CI: 1.10, 4.30), and odds ratio = 2.94 (90% CI: 1.19, 7.25).

Conclusions:

Neurocognitive reaction time appears to be an indicator of elevated risk for lower extremity sprains and strains among college football players, which may be modifiable through performance of exercises designed to accelerate neurocognitive processing of visual input.