Association between training volume and lower extremity overuse injuries in young female athletes: implications for early sports specialization

Background: Recent studies indicated greater risk of overuse injuries among young female athletes than their male counterparts. However, few studies have focused on female athletes and the effect of single-sport participation on lower extremity overuse injuries.

Objective: The objective of this study is to identify an independent risk variable for lower extremity overuse injuries based on status of sport participations (single- and multisports) in young female athletes.

Methods: In this cross-sectional study, 12–18-year-old female athletes were asked to complete electronic questionnaires describing their current sport participation and previous injury history. Range of motion (ROM), muscular strength, and performance parameters were measured at the time of completion of electronic questionnaires. Potential risk variables were compared between single- and multisport athletes and entered into a logistic regression model. Adjusted odds ratio (aOR), 95% confidence intervals (95% CIs), and p values were recorded to find an association with increased likelihood of lower extremity overuse injuries.

Results: The study cohort comprised 236 female young athletes (single-sport athletes: N = 60, multisport athletes: N = 176). A few variables including age, BMI, weekly hours of training for a sport, knee ROM, ankle ROM, and knee extensor strength were identified as potential risk variables. A logistic regression analysis showed an independent association between increased weekly hours of training for a sport and greater likelihood of histories of lower extremity overuse injuries (aOR = 1.091, 95% CIs: 1.007–1.183, p = .034).

Conclusion: Although status of single- or multisports participation was not a significant risk variable, increased training volume was found to be an independent contributing factor for greater likelihood of lower extremity overuse injury histories in 12–18 years female athletes. The current study identified that single-sport athletes trained nearly twice as many hours per week when compared to multisport athletes, which may explain an underlying mechanism of sports specialization.     

Youth sports specialization and musculoskeletal injury: a systematic review of the literature

Objectives: Early sports specialization is being seen with increasing frequency in children and adolescents in an attempt to achieve elite performance status. This phenomenon has attracted negative medical and lay media attention due, in part, to the possibility of an increased risk of acute and overuse injuries. The purpose of this study was to systematically review available research on youth sport specialization and musculoskeletal injury.

Methods: A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for studies evaluating sports specialization and injury rates in participants under age 18. Inclusion criteria were: (1) youth patient population (defined as <18 years of age), (2) peer-reviewed investigation of association(s) between sports specialization and incidence of injury, and (3) original research article (rather than a review, case report, or meta-analysis). Exclusion criteria were: (1) reliance on surrogate measure(s) of sports specialization (eg. hours of participation), (2) language other than English, and (3) not a clinically-based study. Rates of sport specialization, acute and overuse injuries, and frequency of organized training regimens were recorded.

Results: Three studies met final inclusion and exclusion criteria. Of these studies two were retrospective cohort studies and one was a case-control study. All three studies reported an increased risk of overuse injures (OR range: 1.27–4.0; P < 0.05) which varied by sport and anatomic pathology. One study noted an increased rate of withdrawal from tennis matches (OR = 1.55, P < 0.05) in athletes who participated only in tennis compared to multisport athletes who competed in tennis. Based on the consistency of the results from included studies, the strength of recommendation grade for the current evidence against early sports specialization is “B” (recommendation based on limited-quality patient-oriented evidence).

Conclusions: The primary evidence that currently exists with regard to early sport specialization is scarce, retrospective, and shows only modest associations between early sports specialization and overuse injury. Further prospective research is needed to more definitively determine if early sports specialization in children is associated with increased injury risk.

Level of Evidence: Systematic Review, Level III     

Epidemiology and Severity of Sports and Recreation Injuries Presenting to a Tertiary Adult Emergency Department

Objective: This study aims to evaluate all sports and recreation injuries that present to an emergency department, identify the activity and injury patterns associated with hospital admission, and determine injuries that could be better treated in alternative care settings.

Methods: This is a retrospective review of all sports injuries that presented to the emergency department of a high volume, urban, tertiary referral center from 1/1/2010 to 12/31/2011. These were identified by a sports term search algorithm applied to all emergency department records. The main outcome measured was hospital admission status after sports injury. Univariate and multivariate regression analysis was performed to identify risk factors for hospital admission in the sports injury population.

Results: 1,101 of the 191,259 encounters (0.6%) had 1,210 sports injuries. 84 were admitted (7.6%). Basketball injuries were most prevalent (31.6%). All-terrain vehicle (ATV) related injuries was most often admitted (46.4%). Logistic regression identified ATV riding (95% CI 6.15–23.37, p < 0.001) and age over 50 years-old (4.09–17.40, p < 0.001) as independent risk factors for admission while basketball (0.101–0.985, p = 0.047) and black race (0.17–0.77, p = 0.008) were independently protective. Isolated sprains/strains and soft tissue injuries (4/649, 0.6%) rarely required admission.

Conclusions: The 7.6% admission rate is higher than previously reported, likely because the study institution is a tertiary referral center. ATV riding is associated with higher severity injuries that are more likely to require hospital admission. Most sports injuries that present to an emergency department, specifically isolated soft tissue injuries of the extremities, may be more efficiently treated in a non-emergent setting.     

Autonomic modulations of heart rate variability are associated with sports injury incidence in sprint swimmers

Objectives: Young athletes’ participation in competitive sports is becoming increasingly common, and this increased involvement raises concerns about the occurrence of overtraining and sports injuries. Since these issues are poorly understood, this study analyzed heart rate variability, stress/recovery relationship, and sports injury incidence during a training macrocycle of young sprint and endurance swimmers.

Methods: Thirty teenage swimmers (aged 12 to 17 years) were divided into two groups as follows: Sprint (n = 17) and Endurance (n = 13). Subjects were evaluated over 20 weeks, based on the following three schedules: general, specific, and competitive. In addition to heart rate variability and sports injury incidence, the Recovery-Stress-Questionnaire of Athletes was used to analyse stress/recovery states in athletes. All procedures were developed at the initial moment and at the end of each periodization step.

Results: The Sprint group presented a reduced standard deviation of normal-normal beats (73.0 ± 6.6 vs. 54.1 ± 3.5 ms; p < 0.05) and root mean square of the successive differences (55.3 ± 6.2 vs. 42.0 ± 3.7 ms; p < 0.01) from the period of general preparation until the time of competition. Recovery-stress monitoring was affected only by the swimming training periodization (p < 0.05). During the general period, differences between recovery and stress scales were correlated directly with the root mean square of the successive differences (r = 0.576; p = 0.001), the standard deviation of instantaneous variability beat-to-beat (r = 0.521; p = 0.003) and the triangular index (r = 0.476; p = 0.008). Differences between general recovery and stress scales were inversely correlated with geometric indexes after the specific training period. Moreover, the Sprint group showed a higher incidence of sports injury than the Endurance group (0.0214 ± 0.0068 vs. 0.0136 ± 0.0050 cases/1000 hours).

Conclusion: Sprint training was associated with progressive activation of the sympathetic nervous system as well as a higher incidence of sports injury in comparison to endurance swimming during a training macrocycle.     

Poor sleep is related to lower general health,increased stress and increased confusion in elite Gaelic athletes

Objectives: Persistent poor sleep is associated with a range of adverse health outcomes. Sleep is considered the main method of recovery in athletes; however, studies report that a significant number of athletes are getting insufficient sleep. The purpose of this study was to assess the sleep profiles of elite Gaelic athletes and to compare wellbeing in those with poor sleep and those with good sleep.

Methods: 69 elite Gaelic athletes completed questionnaires, including the Pittsburgh Sleep Quality Index (PSQI), Subjective Health Complaints Inventory (SHC), Nordic Musculoskeletal Questionnaire (NMQ), stress subscale of the Depression Anxiety Stress Scale (DASS), the tension-anxiety, anger-hostility and confusion-bewilderment subscales of the Profile of Mood States (POMS) as well as the catastrophising subscale of the Coping Strategies Questionnaire (CSQ). Participants were categorised into poor sleepers (PSQI ≥5) and good sleepers (PSQI <5) and outcome measures of health and wellbeing were analysed between the two groups.

Results: 47.8% of athletes were poor sleepers. Self-reported sleep duration was 7.5 ± 0.6 h per night. 63.7% of poor sleepers took >30 min to fall asleep, compared to 5.6% of good sleepers. Poor sleepers had significantly lower general health (SHC) (p = 0.029), increased stress (DASS) (p = 0.035) and increased confusion (POMS-subscale) (p = 0.005). There was no significant difference between groups for number of painful body parts (NMQ) (p = 0.052), catastrophising (CSQ) (p = 0.287), overall mood (POMS) (p = 0.059), or POMS subscales of anger (p = 0.346) or tension (p = 0.593).

Conclusion: Nearly 50% of elite Gaelic athletes report poor sleep. There is a significant relationship between poor sleep and lower general health, increased stress and increased confusion, and these factors may interact with each other. Monitoring of and interventions to enhance sleep may be required to improve athletes’ wellbeing.     

Risk factors associated with self-reported injury history in female youth soccer players

Background: studies that investigate risk factors for musculoskeletal injuries in female youth athletes are limited, especially related to training attributes and position status.

Objective: to determine risk factors including training attributes and position status for a self-reported musculoskeletal injury history in female youth soccer players.

Methods: we conducted a cross-sectional study of young female soccer players (mean age: 13.6 ± 2.3 years). we asked about their history of musculoskeletal injuries using an electronic questionnaire. the proportion of young female soccer players with and without a history of soccer-related musculoskeletal injuries were compared based on physical characteristics, training attributes, position status (single vs. multiple), lower extremity strength, and joint laxity. a binary logistic regression analysis was used to generate, and adjusted odds ratios adjusted for potential co-variates (aor). a 95% confidence interval (95%ci) that did not cross one or p < 0.05 were considered statistically significant.

Results: a total of 160 young female soccer players (mean age: 13.6 ± 2.3 years) participated in the study. an independent association was found between prior musculoskeletal injuries and older ages (aor: 1.60, 95%ci: 1.17, 2.20, p = 0.004), higher weight (aor: 1.10, 95%ci: 1.01, 1.20, p = 0.026), and greater bmi (aor: 1.43, 95%ci: 1.07, 1.90, p = 0.014).

Conclusions: musculoskeletal injuries were associated with age, weight, and bmi in female youth players. the current study indicates that maintaining proper body composition may be beneficial to reduce musculoskeletal injuries among female youth soccer players.     

Are professional handball players at risk for developing a glenohumeral internal rotation deficit in their dominant arm?

Objectives: Overhead athletes, such as baseball players, have been shown to have adaptive changes in the shoulder range of motion (ROM) of their dominant arm. Professional handball players are a unique subtype of overhead athletes with very different demands from baseball players. The aim of this study was to determine if professional handball players demonstrate differences in shoulder ROM between their dominant and non-dominant arm and try to relate them with new variables.

Methods: Fifty professional male handball players were included and completed a questionnaire regarding age at which they started to play, number of hours they practice a week, field position and arm dominance. ROM measurements were performed including forward flexion (FF), external rotation with the shoulder in abduction (ABER) and with adducted arm (ADER) and internal rotation with shoulder in abduction (IR). Statistical analysis was performed to determine differences in ROM between the dominant and non-dominant shoulder and if there is a relationship between these differences and shoulder load or field position.

Results: The dominant arm showed decreased internal rotation (47 vs. 56 degrees, p < 0.001) and increased external rotation both with the arm abducted (99 vs. 88 degrees, p < 0.001) and at the side (62 vs 57 degrees, p = 0.001). This was not correlated with shoulder load for any movement (FF, p = 0.980; ABER, p = 0.741; ADER, p = 0.803; IR, p = 0.085) but was dependent on field position with first line players showing the highest internal rotation deficit (13 degrees vs. 6–7 degrees in the other field positions, p = 0.013).

Conclusion: This study showed that professional male handball players with a first line position have a significant risk for developing a glenohumeral internal rotation deficit, similar to the phenomenon seen in baseball pitchers.     

Epidemiology of mental health conditions in incoming division I collegiate athletes

Objectives: The purpose of this study is to examine the epidemiology of mental health conditions in incoming American Division I collegiate athletes.

Methods: Pre-participation physical questionnaires from 1118 incoming student athletes at a Division I Institution were collected retrospectively from 2011–2017. Data collected included lifetime history of any mental health condition, musculoskeletal injuries, concussions, and post-concussion depression. History of any mental health condition was evaluated by gender and sport played. It was also evaluated in comparison to musculoskeletal injuries and concussions.

Results: The lifetime prevalence of any mental health condition was 14.0% for all athletes, 14.2% for male athletes, and 13.6% for female athletes. Individual sports reported a greater prevalence (17.2%) than did team sports (11.8%) (p = 0.010). The prevalence was also higher in contact sports (16.4%) than in non-contact sports (12.5%), although this difference was not statistically significant (p = 0.072). There was a significant association between mental health condition and all four major groups of injuries examined: upper extremity (p = 0.043), lower extremity (p = 0.007), axial skeletal (p < 0.001), and concussions (p = 0.039). Post-concussion depression occurred in 2.0% of all athletes reporting a concussion.

Conclusion: The lifetime prevalence of mental health conditions in this population (14.0%) is far less than estimates in the general population. This observation may be due to a combination of factors including exercise/athletic participation mitigating depressive symptoms, competitive selection, and underreporting. History of a mental health condition may be associated with injury, although causation cannot be determined.     

From which level of competition in clubs are adolescents at greater risk of injury compared with outside-of-clubs athletes? A school-based study

Objectives: Sport practice is a key factor in a person’s physical and mental health but, for adolescent athletes, some injuries lead to health problems in the long term. The literature provides multiple factors for understanding injury but does not give information about injury risk related to each level of play in a large sample of multisport athletes. This study investigates this relationship in 14- to 19-year-old adolescents.

Methods: The survey on adolescents and health was conducted in classrooms of France, from February to March 2015. Only sports players were included in the analyses (n = 986). The levels of play were divided into five categories: outside of a club/no competition, club player/no competition, club player/local level, club player/state level and club player/national and higher level. A three-step binary logistic regression analysis with age, sex, type of sport, weekly hours of exposure, and level of play was used.

Results: During the past year, 48.1% of the adolescents were injured. Age and sex were not risk factors. The injury risk associated with the increases in level of play is higher than those related to the hours of exposure per week or the type of sport. In clubs, adolescents who do not compete or play at a local level showed no evidence of greater injury risk whereas state-level and national- and higher-level athletes were at greater risk than outside-of-club players (OR = 2.18, 95%CI = 1.13–3.94 and OR = 3.89, 95%CI = 2.07–7.31, respectively).

Conclusion: Adolescents who play sports in clubs are clearly more exposed to injury than those who play outside of a club, mainly from state level. Age and sex are not related to injury. Future epidemiological studies should control adolescents’ level of play. Special attention should be accorded to the injury risk of athletes playing at these levels of competition.     

Epidemiology of injuries in Portuguese senior male rugby union sevens: a cohort prospective study

Objectives: To assess the incidence, type and location of injuries sustained during the Portuguese rugby union sevens circuit. To investigate the influence of players’ training loads on injury risk.

Methods: A prospective cohort study recording time-loss injuries was conducted with all teams competing in the Portuguese national rugby sevens circuit (eight from the top-tier and seven from the second-tier). Main outcome measures included: incidence rate, anatomical location, type, injury incident and severity. Data were also collected regarding players’ training loads. Fisher’s exact test was used to estimate the relative risk of suffering an injury during the sevens season and training sevens during the fifteens season.

Results: A total of 27 injuries were recorded corresponding to an incidence rate of 133.9 injuries per 1000 player match-hours. The average severity was 22.22 days. Contact events preceded 81.5% of injuries. Most injuries occurred in the lower limb (66.7%) and were joint/ligament or muscle/tendon injuries (85.1%). The association between injuries and lower volume of training during the sevens season was identified for the second-tier (p = 0.021). For the same level, an inverse relation between training hours and injury severity was also found (p = 0.008). Top-tier players training sevens and fifteens simultaneously during the year presented a significant increase of injury risk (relative risk = 3.2; p = 0.011).

Conclusions: Injury incidence in our study is similar to that reported for international sevens, although severity is lower. An association between training loads and the occurrence of injuries was found for both tiers, although with differential results, thus reinforcing the need to customize players’ preparation. Further studies at non-elite competitions are needed to gather significant data to accurately formulate future injury prevention protocols or recommend modifications to game laws or competition formats, aiming at players’ welfare.     

Identifiable risk factors for thirty-day complications following arthroscopic rotator cuff repair

Objectives: Shoulder arthroscopy has increased in frequency over the past decade, with rotator cuff repair comprising the majority of cases performed. Prior studies have detailed risk factors for 30-day complications and readmission rates after arthroscopic shoulder surgery using the National Surgical Quality Improvement Program (NSQIP) database, but no study has specifically looked at arthroscopic rotator cuff repair. The purpose of the study is to evaluate the risk factors for 30-day complications following arthroscopic rotator cuff repair using the NSQIP database.

Methods: The NSQIP database was queried for all patients undergoing arthroscopic rotator cuff repair from 2006–2015. Demographics and thirty-day outcomes for these patients were analyzed using univariate analyses and multivariate regression analysis to determine the risk factors for complications.

Results: 21,143 patients underwent arthroscopic rotator cuff repair, with 147 patients (0.70%) having a complication within 30-days. Univariate analysis found age >65 (p = 0.0028), male gender (p = 0.0053), elevated BMI (p = 0.0054), ASA class >2 (p < 0.0001), history of chronic obstructive pulmonary disease (p < 0.0001), hypertension (p < 0.0002), dyspnea (p < 0.0001), steroid use (p = 0.0350), and operative time >90 min (p = 0.0316) to be associated with increased risk of complications. Multivariate analysis found female sex to be protective or complication (OR 0.56, p = 0.0017), while American Society of Anesthesiology (ASA) class >2 (OR 1.51, p = 0.0335) and history of COPD (OR 2.41, p = 0.0030) and dyspnea (OR 1.89, p = 0.0359) to be risk factors for complication. The most common complication is venothromboembolic events, accounting for 36.7% of all complications.

Conclusion: Male sex, ASA class > 2, and history of COPD and dyspnea were independent risk factors for thirty-day complications following arthroscopic rotator cuff repair.

Level of evidence: IV     

Lifetime prevalence of injuries in incoming division I collegiate football players

Objectives: The purpose of this study is to determine the lifetime prevalence of past injuries in incoming first year football players in a Division 1 college football team.

Methods: Pre-participation questionnaires from 605 first-year football players over 20 years (1996–2015) were examined to determine the prevalence of concussions, stingers, fractures, and musculoskeletal surgeries sustained before playing at the collegiate level. Players were grouped by position: wide receiver and defensive back (WR/DB), offensive and defensive linemen (OL/DL), all other positions (OP), and unknown (UKN). Prevalence of injuries by year and position was compared using Pearson’s χ² Test (p < 0.05).

Results: The reported lifetime prevalence is as follows: concussion (21%), stinger (23%), musculoskeletal surgery (23%), and fracture (44%). There were no significant differences in lifetime prevalence of concussions (p = 0.49), stingers (p = 0.31), fractures (p = 0.60), or musculoskeletal surgeries (p = 0.97) based on position. There were also no significant differences in the lifetime prevalence of concussions (p = 0.14), musculoskeletal surgeries (p = 0.50), or fractures (p = 0.59) based on year. However, there was a significant difference in the lifetime prevalence of stingers based on year (p < 0.001).

Conclusions: There was an expectation to observe an increase in injury prevalence by entering year, but this was not seen. A decrease in stingers was actually observed, but there was no significant difference among any other injury recorded. These results do not support the perception that football injuries are on the rise. Under reporting is a significant concern as players may fear disqualification or that they are evaluated by the coaching staff based on their medical history. More research is needed to confirm lifetime injury prevalence and evaluate differences over time among football players.     

Serum creatine kinase elevations in ultramarathon runners at high altitude

Objectives: Creatine kinase (CK) is a sensitive enzyme marker for muscle damage in athletes. Elevated CK levels have been reported in many endurance physical activities. The consequence and possible long-term sequela of the CK elevation in athletes is unknown. There is a paucity of literature stating actual numerical values of CK associated with competing in an ultramarathon with extreme environmental conditions. Our hypothesis was that the serum CK levels increase significantly as a result of running a 161 km ultramarathon at high altitude.

Methods: This was a prospective observational study of participants of the Leadville 100 ultramarathon race in Leadville, Colorado at high altitude (2800–3840 m) in August 2014. We collected blood samples from sixty-four volunteer runners before and eighty-three runners immediately after the race.

Results: Out of 669 athletes who started the race, 352 successfully completed the race in less than the 30-hour cut-off time (52%). The majority of runners were male (84%). We were able to collect both pre- and post-race blood samples from 36 runners. Out of these 36 runners, the mean pre-race CK was increased from 126 ± 64 U/L to 14,569 ± 14,729 U/L (p < 0.001). There was a weak linear correlation between lower sodium levels and higher CK levels post-race (p = 0.003; R² = 0.10). Using a multiple regression model, other than a negative correlation between sodium and CK levels (p = 0.001), there were no statistically significant correlations between post-race CK levels and athletes’ age, BMI, or finishing time.

Conclusions: Significant elevation of CK level occurs as a result of running ultramarathons. The majority of athletes with significantly elevated CK levels were asymptomatic and required no major medical attention.     

Incidence of injury based on sports participation in high school athletes

Objectives: Youth participation in competitive athletics has significantly increased in the past two decades. There has also been a recent rise in the number of sports injuries that physicians are seeing in young athletes. The objective of this study was to assess the likelihood of sports injuries based on several risk factors in a general sample of athletes at a suburban-area high school.

Methods: This was a cross-sectional study. An online survey was distributed to 2,200 student-athletes at a local high school with a mean age of 15.9 years. Four hundred eighty four (22%) complete responses were received. Data collected in the survey included demographics, frequency of sports participation, level of participation, types of sports played, participation in cross-training, injuries incurred, use of non-steroidal anti-inflammatory drugs, and treatment for sports injuries.

Results: Athletes played an average of 1.6 different sports. The average number of hours of participation in sports annually was 504.3 ± 371.6 hours. The average total number of sports injuries experienced by athletes in our study was 1.7 per participant. 80.8% of respondents reported having sustained at least one sports injury.

A higher total number of hours per year of sports participation and playing a contact sport were significantly associated with more reported lifetime sports injuries. Older age, playing a contact sport, and playing on a travel/club team were associated with students using NSAIDs for sports injuries. Older age, playing a contact sport, and doing cross training are also associated with having had surgery for a sports injury.

Conclusions: Although more hours of participation and playing a contact sport may lead to an increased number of injuries, this risk must be weighed against the myriad of benefits that sports provide for young athletes.     

Return-to-play rates following arthroscopic treatment of femoroacetabular impingement in competitive baseball players

Objective: Femoroacetabular impingement (FAI) has been increasingly recognized in cutting sports including soccer, hockey and football. More recently, the prevalence among overhead athletes has also been recognized. The purpose of this study was to review impingement patterns, return-to-play rates and clinical outcome following arthroscopic treatment of FAI among high-level baseball players.

Methods: Between 2010 and 2014, 70 competitive baseball players (86 hips; age 22.4 ± 4.5 years) were identified. Demographics and return-to-play rates were recorded. Patient-reported outcome scores, including the Modified Harris Hip Score (mHHS), the Hip Outcome Score-Activity of Daily Living (HOS-ADL), the Sport-specific Subscale (HOS-SSS), and the International Hip Outcome Tool (iHOT-33), were collected pre-operatively at 6 months and 1year (n = 34, 49% of cohort).

Results: The cohort included professional (27.1%), college (57.1%), high-school (8.6%) and club-team athletes (7.1%). Infielder (37.5%), pitcher (22.9%) and catcher (16.7%) were the most common positions. Average follow-up was 16.8 months (range 12.1–34.2). There was no relationship between playing position and impingement pattern (p ≥ 0.459), or between symptom laterality and handedness, batting position or playing position (p ≥ 0.179). One patient required revision surgery (infection). Return to sport rate was 88%, at a mean of 8.6 ± 4.2 months, with 97.7% returning at/above their pre-injury level of play. There was significant improvement in all outcome measures: mHHS (60.1 ± 11.9 to 93 ± 9.5), HOS-ADL (71.3 ± 16.7 to 96.3 ± 3.6), HOS-SSS (51.3 ± 24.8 to 92.3 ± 8.2) and iHOT-33 (40.7 ± 19.9 to 85.9 ± 14) (p < 0.001).

Conclusion: Arthroscopic treatment of FAI in competitive baseball players resulted in high return-to-play rates at short-term follow-up, with significant improvements in clinical outcome scores.     

A history of concussions is associated with symptoms of common mental disorders in former male professional athletes across a range of sports

Objective: Recent reports suggest that exposure to repetitive concussions in sports is associated with an increased risk of symptoms of distress, anxiety and depression, sleep disturbance or substance abuse/dependence (typically referred as symptoms of common mental disorders[CMD]) and of later development of neurodegenerative disease, in particular chronic traumatic encephalopathy (CTE). The primary aim of this study was to explore the relationship between sports career-related concussions and the subsequent occurrence of symptoms of CMD among former male professional athletes retired from football (soccer), ice hockey and rugby (union).

Methods: Cross-sectional analyses were performed on baseline electronic questionnaires from three prospective cohort studies among former male professional athletes retired from football (soccer), ice hockey and rugby (union). The number of confirmed concussions was examined through a single question, while symptoms of distress, anxiety and depression, sleep disturbance and adverse alcohol use were assessed using validated questionnaires.

Results: From 1,957 former professional athletes contacted, a total of 576 (29%) completed the questionnaire. Of these, 23% had not incurred a concussion during their career, 34% had two or three, 18% four or five, and 11% six or more concussions. The number of sports career-related concussions was a predictor for all outcome measures (β = 0.072–0.109; P ≤ 0.040). Specifically, former professional athletes who reported a history of four or five concussions were approximately 1.5 times more likely to report symptoms of CMD, rising to a two- to five-fold increase in those reporting a history of six or more sports career-related concussions.

Conclusions: These data demonstrate an association between exposure to sports concussion and subsequent risk of symptoms of CMD in former professional athletes across a range of contact sports. Further work to explore the association between sports concussion and symptoms of CMD is required; in the meanwhile, strategies for effective risk reduction and improved management appear indicated.     

Ultrasonography findings and physical examination outcomes in dancers with and without patellofemoral pain

Objectives: To identify whether a physical examination for patello-femoral pain (PFP) is related to ultrasonography findings at the knee, and to identify possible factors related to PFP in young dancers.

Methods: Sixty-seven young female dancers (7th grade, aged 12.8 ± 0.5) from three schools with identical special dance programs were included in the study. All the dancers were interviewed for demographic details, dance background, and training intensity; were evaluated for anthropometric measurements; underwent physical examination of both knees for PFP and for knee range of motion (ROM); and, had ultrasonography assessment for pathologies and of anatomical parts of their knees.

Results: PFP was found in 54.5% of the 134 knees physically examined. In ultrasonography assessment, infra-articular effusion was found in 46.2% of the knees examined. H/week of dance practice was significantly higher among dancers with PFP (in both knees) compared with dancers with no PFP (p < .05). Knees with PFP had a significantly higher prevalence of intra articular effusion (p = .018) and higher prevalence of genu-recurvatum (p = .042). Knees with PFP had significantly greater growth plate width-anterior tibial tuberosity (p = .022) and a greater bony trochlear groove angle (p = .048).

Conclusion: This study describes the relationship between physical examination for PFP and the sonographic findings, and the factors related to knee injuries. The results showed a high prevalence of PFP and intra articular knee effusion among young dancers at the age of 12–13 years; and, that the number of hours of practice and anatomical structure are related to PFP. Our results should alert physicians, physiotherapists, athletic trainers and dance teachers to the need for devising modifications of training and injury prevention strategies from a young age (<12 years old).     

The relationship of hip muscle performance to leg,ankle and foot injuries: a systematic review

Objectives: Hip control affects movement and muscle firing patterns in the leg, ankle and foot, and may contribute to overuse injuries. Muscle performance can be measured as strength, endurance or muscle activation patterns. Our objective was to systematically review whether hip muscle performance is associated with leg, ankle and foot injuries.

Data sources: A structured and comprehensive search of six medical literature databases was combined with forward and backward citation tracking (AMED, CINAHL, EMBASE, Medline, Scopus and SportDiscus).

Study selection: Eligible studies measured hip muscle performance in individuals with musculoskeletal injuries below the tibial tuberosity, using dynamometry or electromyography (EMG). All studies compared an injured group with a control group or compared the injured and non-injured limb in the same individual.

Data extraction: Data was extracted from each study independently by two authors.

Data synthesis: Twenty case-control and four prospective studies (n = 24) met the inclusion criteria. Injury classifications included chronic ankle instability (n = 18), Achilles tendinopathy (n = 2), medial tibial stress syndrome and tibial stress fracture (n = 1), posterior tibial tendon dysfunction (n = 1), and exertional medial tibial pain (n = 2). Eleven of the studies revealed differences in hip muscle performance indicating less strength, delayed onset activation and decreased duration of activation in the injured groups. Two studies found evidence for differences between groups only in some of their measurements. Three out of the four prospective studies revealed that hip muscle performance was not a risk factor for leg, ankle and foot injuries.

Conclusions: This review provides limited evidence that hip muscle performance variables are related to leg, ankle and foot injuries. Emerging evidence indicates this might be a result of the injury rather than a contributor to the injury.     

Isolated ACL versus multiple knee ligament injury: associations with patient characteristics,cartilage status,and meniscal tears identified during ACL reconstruction

Objectives: The objectives of this study were to determine (1) if patients undergoing reconstruction of an isolated anterior cruciate ligament (ACL) tear had different characteristics (age, gender, body mass index [BMI]) than patients undergoing ACL reconstruction (ACLR) with multiple knee ligament (MKL) tears and (2) whether there was a difference in prevalence of articular cartilage injury and meniscus tears between these two groups.

Methods: Patients undergoing primary ACLR between February 2005 and June 2013 were identified through an ACLR registry. Patients were grouped by whether they had an isolated ACL tear or an ACL tear associated with another knee ligament tear. The study cohort was analyzed to identify differences in patient characteristics and cartilage/meniscus injury patterns between the groups.

Results: Of the 21,377 ACLR cases enrolled in the registry during the study period, 2.5% (n = 549) had MKL tears. The MKL group had more males (73.2% vs. 62.8%, p < 0.001) than the isolated ACL group. The MKL group also had a higher percentage of patients with a BMI greater than 30 (31.1% vs. 22.7%, p = 0.0002). When adjusting for these variables, any articular cartilage injury was equal in the two groups (OR = 1.01, CI 0.82–1.25, p = 0.922), while medial femoral condyle injury was less common in the MKL group (OR = 0.73, CI = 0.56–0.07, p = 0.28). The likelihood of any meniscus tear was lower in the MKL group (OR = 0.56, CI = 0.47–0.67, p < 0.001) as was the likelihood of medial meniscus tears (OR = 0.53, CI = 0.44–0.65, p < 0.001).

Conclusions: When comparing patients with MKL tears versus isolated ACL tears at ACLR, there was a higher percentage of males and patients with BMI over 30 in the MKL group. Medial femoral condyle articular cartilage injury, any meniscus tear, and medial meniscus tears were less common in patients with MKL injury compared to patients with isolated ACL tears.     

Range of motion and ankle injury history association with sex in pediatric and adolescent athletes

Background: Ankle sprain is one of the most common musculoskeletal injuries among young athletes, and there remains a gap in the literature regarding susceptibility to such injuries among physically active youth.

Objective: The primary purpose of this study was to determine the associations between sex, a history of ankle sprain, and ankle range of motion (ROM) in pediatric and adolescent athletes.

Methods: Athletes under the age of 18 years old who presented to a sports injury prevention center underwent ankle ROM measurements including plantarflexion (PF), inversion (IV), and eversion (EV). A two-way analysis of covariance (ANCOVA) was performed to examine effect of sex and a history of ankle sprain on ROMs. Also, a binary logistic regression was performed to investigate variables that are associated with a history of ankle injury.

Results: Among 452 pediatric and adolescent athletes [268 females (13.6 ± 2.3 years old) and 184 males (13.3 ± 2.5 years old)], 128 reported a history of previous ankle sprain. Females demonstrated significantly increased ROMs (PF and IV bilaterally, and right EV) compared to males while there was no effect of a history of ankle sprain on ROMs. Female sex was independently associated with a history of ankle sprain.

Conclusion: There was a strong effect of female sex on ROMs rather than a history of ankle injury history. Additionally, pediatric and adolescent females have greater odds of a history of ankle sprain when compared to their male counterparts.