Association of Competition Volume, Club Sports, and Sport Specialization With Sex and Lower Extremity Injury History in High School Athletes

Overuse Injury of the Epiphyseal Primary Physis

Year-round participation in youth sport that involves high levels of repetitive movement fosters an environment in which overuse injuries are likely to occur. Epiphyseal primary physeal stress injuries (PSIs), unique to skeletally immature athletes, are a particular concern, given their potential for growth disturbance. Initially observed in Little League baseball players, these injuries are now known to affect the long bones around the shoulder, elbow, wrist, hand, knee, ankle, and foot of skeletally immature athletes involved in a variety of sport activities.This article offers an epidemiological and radiologic perspective on the extent and distribution of epiphyseal PSIs in youth sport. We also review a novel framework for understanding the pathophysiologic mechanisms causing these injuries. This information is essential for the early identification of epiphyseal PSIs and devising preventive measures that can reduce a delayed diagnosis and long-term morbidity. Preventing and reducing injury to the epiphyseal growth plates is essential because impairment and dysfunction can result in lifelong morbidity and a risk of premature osteoarthritis.

High School Girls' Volleyball Athletes' Self-Reported Management of Pain, Intentions to Report Overuse Injuries, and Intentions to Adhere to Medical Advice for Treating Overuse Injuries

CONTEXT

Girls' high school volleyball is a popular sport with a high rate of overuse injuries and sport specialization. Health professionals perceive that high school athletes are reluctant to follow treatment plans involving sport activity reduction. This study's purpose was to describe high school girls' volleyball athletes' self-reported shoulder and knee pain, the likelihood of adhering to medical advice, and the association of factors that influence the likelihood of reporting overuse injuries and sport specialization.

STUDY DESIGN

Cross-sectional.

METHODS

Participants completed an online survey (demographics, sport participation measures, shoulder and knee pain information, medical adherence likelihood [4-point Likert: not at all likely to extremely likely], and factors influencing overuse injury reporting intentions). A 2 × 2 chi-square analysis compared factors that influence athletes' intentions to "not report an overuse injury" (eg, I thought my coach would get mad; yes/no) and sport specialization (nonhighly specialized/highly specialized athletes).

RESULTS

There were 150 participants (highly specialized = 56%, grade: ninth = 33%, 10th = 28%, 11th = 22%, 12th = 17%). At least 60% reported shoulder and knee pain related to an overuse mechanism. Most reportedly did not seek rehabilitation led by a medical provider (shoulder pain = 66%, knee pain = 60%). Only 11% of athletes reported they were "extremely likely" to rest from sporting activity during the regular season if advised by a medical professional. Highly specialized athletes were more likely to report the pursuit of a college scholarship as a factor that influences their intention to report an overuse injury compared to nonhighly specialized athletes (13% vs 3%, respectively, P = .04).

CONCLUSIONS

Most girls' volleyball athletes did not treat their pain with guided rehabilitation, which may increase their risk of a worse overuse injury or even acute injury. Clinicians, athletes, parents, and coaches need to work together to create a sport culture that empowers athletes to discuss their pain and overuse injuries with medical professionals.

Highly Active Middle School Athletes Demonstrate Poor Motor Skill Proficiency

BACKGROUND

Fundamental movement skills (FMS) are critical components to lifelong participation in sports and physical activity. With the rise in early sports specialization, mastery of motor skills may be limited in youth athletes. The purpose of this study was to assess FMS proficiency in highly active middle school athletes and determine whether proficiency differed between specialization levels and sex.

HYPOTHESIS

(1) Most athletes would fail to achieve proficiency in all domains of the Test of Gross Motor Development (TGMD-2), (2) highly specialized athletes would demonstrate lower proficiency in all domains of the TGMD-2, and (3) male athletes would demonstrate higher proficiency than female athletes.

STUDY DESIGN

Cross-sectional.

LEVEL OF EVIDENCE

Level 4.

METHODS

A total of 91 athletes were recruited (44 male, 12.6 ± 0.9 years). Activity level was quantified using the Hospital for Special Surgery (HSS) Pediatric Functional Activity Brief Scale (Pedi-FABS), specialization level was determined using the Jayanthi Specialization Scale, and the TGMD-2 was used to assess FMS proficiency. Descriptive statistics were used to describe gross motor, locomotor, and object control percentile rank. A 1-way analysis of variance (ANOVA) was used to assess differences in percentile rank between low, moderate, and high specialization groups and independent samples t tests were used to compare sexes (α < 0.05).

RESULTS

Mean Pedi-FABS score was 23.6 ± 4.9. In total, 24.2%, 38.5%, and 37.4% of athletes classified as low, moderate, and highly specialized, respectively. Mean percentile ranks were 56.2%, 64.7%, and 62.6% for locomotor, object control, and gross motor domains, respectively. No athlete achieved a percentile rank >99% in any domain of the TGMD-2, and there was no significant difference between specialization groups or sex.

CONCLUSION

Despite high activity levels, no athlete demonstrated proficiency in any domain of the TGMD-2, and there was no difference in proficiency between specialization levels or by sex.

CLINICAL RELEVANCE

Sport participation, regardless of level, does not ensure adequate mastery of FMS.

Reported Anterior Cruciate Ligament Injury Incidence in Adolescent Athletes Is Greatest in Female Soccer Players and Athletes Participating in Club Sports: A Systematic Review and Meta-analysis

PURPOSE

To identify the risk of anterior cruciate ligament (ACL) injury in adolescent athletes based on sex, sport, and sport affiliation.

METHODS

A literature search was performed using 3 online databases (PubMed, Cochrane Library, and EMBASE) from database inception to November 2023 per the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Included studies consisted of Level I or II studies reporting on ACL injury exposures in time (hours) or injuries per 1,000 athlete-exposures (AEs) (1 game or practice) in adolescent athletes. Exclusion criteria consisted of non-English studies, case reports, animal/cadaveric studies, and review articles. Methodological quality and bias assessment of the included studies was assessed using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. ACL injuries were analyzed and pooled to calculate incidence rates (IRs), per-season risk, and relative risk (RR) based on sex, sport, and sport affiliation (club sport participation vs school sport participation).

RESULTS

A total of 1,389 ACL injuries over 19,134,167 AEs were identified (IR, 0.075; 95% confidence interval [CI], 0.071-0.079). Of these, 670 ACL injuries were reported in female athletes over 7,549,892 AEs (IR, 0.089; 95% CI, 0.087-0.091) with 719 in males over 11,584,275 AEs (IR, 0.062; 95% CI, 0.058-0.067). The greatest RR for ACL injury in females was in soccer (RR, 3.12; 95% CI, 2.58-3.77) for AEs. The greatest per-season risk of ACL injuries reported in female athletes occurred in soccer (1.08%), basketball (1.03%), and gymnastics (1.01%). The greatest per-season risk of ACL injuries reported in male athletes occurred in football (0.82%), lacrosse (0.64%), and soccer (0.35%). Club sport participation, in both AEs (RR, 3.94; 95% CI, 3.19-4.87) and hours of exposure (RR, 1.57; 95% CI, 1.07-2.28), demonstrated an increased risk of ACL injury.

CONCLUSIONS

The risk of ACL injuries was 1.56-fold greater in adolescent female athletes compared with male athletes. The highest-risk sport for females was soccer. Participation in club sports possessed higher rates of injury compared with school sports.

LEVEL OF EVIDENCE

Level II; meta-analysis of Level I and II studies.

Injury Patterns in Highly Specialized Youth Athletes: A Comparison of 2 Pathways to Specialization

CONTEXT

Sport specialization, commonly defined as intensive year-round training in a single sport to the exclusion of other sports, has been associated with an increased risk for overuse injury. Two pathways to becoming highly specialized are recognized: (1) having only ever played 1 sport (exclusive highly specialized) and (2) quitting other sports to focus on a single sport (evolved highly specialized). Understanding the differences in injury patterns between these groups of highly specialized athletes will inform the development of injury-prevention strategies.

OBJECTIVE

To compare the distribution of injury types (acute, overuse, serious overuse) among evolved highly specialized athletes, exclusive highly specialized athletes, and low-moderately specialized athletes.

DESIGN

Cross-sectional study.

SETTING

Tertiary care pediatric sports medicine clinic between January 2015 and April 2019.

PATIENTS OR OTHER PARTICIPANTS

A total of 1171 patients (age = 12.01-17.83 years, 59.8% female) who played ≥1 organized sports, presented with a sport-related injury, and completed a sports participation survey.

MAIN OUTCOME MEASURE(S)

Distribution of injury types (acute, overuse, serious overuse).

RESULTS

The percentage of injuries due to overuse was similar between the exclusive and evolved highly specialized athletes (59.2% versus 53.9%; P = .28). Compared with low-moderately specialized athletes, exclusive and evolved highly specialized athletes had a higher percentage of overuse injuries (45.3% versus 59.2% and 53.9%, respectively; P = .001). Multivariate analysis of the highly specialized groups revealed sport type to be a significant predictor of a higher percentage of injuries due to overuse, with individual-sport athletes having increased odds of sustaining an overuse injury compared with team-sport athletes (odds ratio = 1.95; 95% CI = 1.17, 3.24).

CONCLUSIONS

The distribution of injury types was similar between evolved and exclusive highly specialized youth athletes, with both groups having a higher percentage of injuries due to overuse compared with low-moderately specialized athletes. Among highly specialized athletes, playing an individual sport was associated with a higher proportion of overuse injuries compared with playing a team sport.

Inequalities in the Evaluation of Male Versus Female Athletes in Sports Medicine Research: A Systematic Review

BACKGROUND

Female sports participation continues to rise; however, inequalities between male and female athletes still exist in many areas and may extend into medical research.

PURPOSE

The purpose of this study was to (1) compare the number of published studies evaluating male versus female athletes in various sports and (2) identify which co-ed sports currently underrepresent female athletes in the sports medicine literature.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

All nonreview research studies published from 2017 to 2021 in 6 top sports medicine journals were considered for inclusion. Sports medicine studies were included that isolated athletes, reported study outcomes specific to male and/or female patients, provided study outcomes for specific sports, and evaluated ≤3 different sports. The total number of studies reporting on male and/or female athletes were compared for all sports, and odds ratios (ORs) were calculated. Comparisons of study design, level of sports participation, outcomes assessed, and study quality were also made according to participant sex.

RESULTS

Overall, 669 studies were included the systematic review. Most studies isolated male athletes (70.7%), while 8.8% isolated female athletes and 20.5% included male and female athletes. Female athletes were more frequently studied in softball and volleyball, while male athletes were more commonly researched in baseball, soccer, American football, basketball, rugby, hockey, and Australian football. Notably, male athletes were largely favored in baseball/softball (91% vs 5%; OR = 18.2), rugby (72% vs 5%; OR = 14.4), soccer (65% vs 15%; OR = 4.3), and basketball (58% vs 18%; OR = 3.2).

CONCLUSION

Sports medicine research has favored the evaluation of male athletes in most sports, including the majority of co-ed sports. Potential reasons for this inequality of research evaluation include availability of public data and database data, financial and promotional incentives, a high percentage of male sports medicine clinicians and researchers, and sex biases in sport. While the causes of these differences are multifaceted, researchers should consider both sexes for study inclusion whenever possible, and journals should support a more balanced representation of research publications regarding male and female athletes.

Early Sport Specialization and Long-term Throwing Arm Health in College Baseball Players

BACKGROUND

Early sport specialization is associated with increased risk of overuse injuries in several sports, including baseball. However, limited evidence exists evaluating how early sport specialization affects patient-reported outcome measures as they age. The purpose of this study was to determine differences in Kerlan-Jobe Orthopedic Clinic (KJOC) Shoulder and Elbow Scores among collegiate baseball players based on the grade when a participant first reported high specialization behaviors.

HYPOTHESIS

Baseball players who were highly specialized at a younger age will have worse throwing arm health while participating in college.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

A total of 752 college baseball players was contacted through their institution's athletic trainer. We measured baseball specialization and KJOC scores using the validated Baseball and Sport Experience survey. Data were summarized using means and SDs, medians and interquartile ranges (IQRs), and frequencies and percentages. A Kruskal-Wallis test was used to determine differences in mean KJOC scale scores based on the earliest time the participant reported high-level specialization.

RESULTS

A total of 294 baseball players completed the survey (response rate: 39.1%). Of the 294 participants, 280 completed the KJOC scale questions to generate a total KJOC score (median: 90.5; IQR: 76.6-97.2). No significant differences in KJOC total scores (P = 0.78) existed based on the grade period in which the athlete was first highly specialized.

CONCLUSION

Early baseball specialization as a youth baseball player may not impact throwing arm health in college baseball athletes.

CLINICAL RELEVANCE

Early specialization has been linked to increased risk for overuse injuries in certain sports, but may not lead to poorer throwing arm health in college baseball players. Sports medicine clinicians and researchers may use this information to educate various stakeholders about the benefits and risks associated with early sport specialization.

Methods of Monitoring Internal and External Loads and Their Relationships with Physical Qualities, Injury, or Illness in Adolescent Athletes: A Systematic Review and Best-Evidence Synthesis

BACKGROUND

With the increasing professionalisation of youth sports, training load monitoring is increasingly common in adolescent athletes. However, the research examining the relationship between training load and changes in physical qualities, injury, or illness in adolescent athletes is yet to be synthesised in a systematic review.

OBJECTIVE

The aim of this review was to systematically examine the research assessing internal and external methods of monitoring training load and physical qualities, injury, or illness in adolescent athletes.

METHODS

Systematic searches of SPORTDiscus, Web of Science, CINAHL and SCOPUS were undertaken from the earliest possible records to March 2022. Search terms included synonyms relevant to adolescents, athletes, physical qualities, injury, or illness. To be eligible for inclusion, articles were required to (1) be original research articles; (2) be published in a peer-reviewed journal; (3) include participants aged between 10 and 19 years and participating in competitive sport; (4) report a statistical relationship between a measure of internal and/or external load and physical qualities, injury or illness. Articles were screened and assessed for methodological quality. A best-evidence synthesis was conducted to identify trends in the relationships reported.

RESULTS

The electronic search yielded 4125 articles. Following screening and a review of references, 59 articles were included. The most commonly reported load monitoring tools were session ratings of perceived exertion (n = 29) and training duration (n = 22). Results of the best-evidence synthesis identified moderate evidence of positive relationships between resistance training volume load and improvement in strength, and between throw count and injury. However, evidence for other relationships between training load and change in physical qualities, injury, or illness were limited or inconsistent.

CONCLUSIONS

Practitioners should consider monitoring resistance training volume load for strength training. Additionally, where appropriate, monitoring throw counts may be useful in identifying injury risk. However, given the lack of clear relationships between singular measures of training load with physical qualities, injury, or illness, researchers should consider multivariate methods of analysing training load, as well as factors that may mediate the load-response relationship, such as maturation.

High Sport Specialization Is Associated With More Musculoskeletal Injuries in Canadian High School Students

OBJECTIVE

To describe levels of sport specialization in Canadian high school students and investigate whether sport specialization and/or sport participation volume is associated with the history of musculoskeletal injury and/or concussion.

DESIGN

Cross-sectional study.

SETTING

High schools, Alberta, Canada.

PARTICIPANTS

High school students (14-19 years) participating in various sports.

INDEPENDENT VARIABLES

Level of sport specialization (high, moderate, low) and sport participation volume (hours per week and months per year).

MAIN OUTCOME MEASURES

Twelve-month injury history (musculoskeletal and concussion).

RESULTS

Of the 1504 students who completed the survey, 31% were categorized as highly specialized (7.5% before the age of 12 years). Using multivariable, negative, binomial regression (adjusted for sex, age, total yearly training hours, and clustering by school), highly specialized students had a significantly higher musculoskeletal injury rate [incidence rate ratio (IRR) = 1.36, 95% confidence interval (CI), 1.07-1.73] but not lower extremity injury or concussion rate, compared with low specialization students. Participating in one sport for more than 8 months of the year significantly increased the musculoskeletal injury rate (IRR = 1.27, 95% CI, 1.02-1.58). Increased training hours significantly increased the musculoskeletal injury rate (IRR = 1.18, 95% CI, 1.13-1.25), lower extremity injury rate (IRR = 1.16, 95% CI, 1.09-1.24), and concussion rate (IRR = 1.31, 95% CI, 1.24-1.39).

CONCLUSIONS

Approximately one-third of Canadian high school students playing sports were categorized as highly specialized. The musculoskeletal injury rate was higher for high sport specialization students compared with low sport specialization students. Musculoskeletal injuries and concussion were also more common in students who train more and spend greater than 8 months per year in one sport.

Sports Specialization, Physical Literacy, and Physical Activity Levels in Young Adults

CONTEXT

Youth sport specialization may be associated with physical literacy and physical activity in young adulthood. The purposes of this study were to compare young adult (18-25 y) physical literacy and physical activity by high school sport specialization status and to examine the relationship between current physical activity and physical literacy.

DESIGN

Retrospective, cross-sectional study design.

METHODS

Participants were recruited from ResearchMatch, university classes, and social media posts. Participants (N = 172; aged 22.1 [2.1] y; 80.1% female) completed the following anonymous surveys on REDCap to assess: demographics and injury history, sport specialization, physical literacy (PLAYself), and physical activity (Godin Leisure-Time Exercise Questionnaire).

RESULTS

When controlling for age, there were no statistically significant differences in physical literacy (F2,166 = 2.02, P = .14) or moderate to vigorous physical activity (F2,161 = 0.24, P = .79) between sport specialization groups. There was a moderate, positive relationship between physical literacy and physical activity (r = .33, P < .001).

CONCLUSIONS

Young adult physical literacy and physical activity were similar regardless of youth sport specialization level. Young adult physical literacy was positively associated with physical activity. Future studies should consider physical literacy as a possible correlate of physical activity among young adults.

Sport Specialization Classification and Injury Risk in Female Athletes

BACKGROUND

Description of possible detrimental effects of sport specialization specific to adolescent female athletes is limited in current literature with no consensus on sport specialization classification.

HYPOTHESIS

Specialized female athletes will have higher rates of injury, body image issues, and menstrual dysfunction, regardless of the specialization classification utilized.

STUDY DESIGN

Cross-sectional.

LEVEL OF EVIDENCE

Level 3.

METHODS

Retrospective data was obtained from questionnaires from female athletes in local high schools (n = 229; 13-18 years of age). The 3-point specialization scale was used to analyze differences in injury rates, body image issues, and menstrual dysfunction within low, moderate, and highly specialized athletes. When comparing accuracy of specialization scales in identifying high risk athletes, three peer-reviewed specialization classification scales were utilized-a 3-point scale, a 6-point scale, and a binary self-selection scale. Odds ratios (OR) and 95% confidence intervals (CI) were calculated for studied variables (a priori p ≤ 0.05).

RESULTS

Of 229 athletes surveyed, 219 (95.6%) completed the 3-point specialization classification questions and were included in the study. 91 athletes (41.6%) were categorized as low specialization (LS), 59 (26.9%) were moderately specialized (ModS), and 69 (31.5%) were highly specialized (HS). ModS athletes were more likely to have a history of stress fractures (SFx) compared to LS athletes (p = 0.02; OR 3.62; 95% CI 1.27-10.26). Compared to LS athletes, HS athletes were more likely to have injury history (p = 0.01; OR 2.93; 95% CI 1.38-6.24) and a history of concussion (p < 0.01; OR 5.00; 95% CI 1.86-13.42).

CONCLUSION

Among female high school athletes, higher levels of specialization are associated with greater risk of injuries overall, and greater risk of concussions and SFx. This study did not demonstrate significant associations between specialization and body image issues or menstrual dysfunction.

CLINICAL RELEVANCE

This study further strengthens the association between injury and sport specialization and suggests that combining specialization scales better improves risk stratification which overall aids in preventing athlete injury.

Sport specialization, sleep, fatigue, and psychosocial ratings: do highly specialized athletes differ from their less specialized peers?

OBJECTIVES

To determine if sleep quality, fatigue, anxiety, depressive symptoms, or perceptions of sport participation differ between high-, moderate-, and low-specialized high school athletes with or without prior injuries.

METHODS

During pre-participation physical examinations (PPE), high school athletes completed questionnaires on sport specialization level, history of time-loss orthopedic injury, perceptions of sport participation, as well as sleep quality (Pittsburgh Sleep Quality Index (PSQI)), fatigue, anxiety, and depressive symptoms (Patient-Reported Outcomes Measurement Information System (PROMIS®)). Athletes were grouped according to sport specialization level and history of prior time-loss orthopedic injury.

RESULTS

A total of 186 athletes completed the study: 49% (n = 92; mean age = 15.3 ± 2.0 yrs; 50% female) were low specialized, 34% (n = 64; mean age = 15.3 ± 1.3 yrs; 47% female) were moderately specialized, and 16% (n = 30; mean age = 15.7 ± 1.1 yrs; 57% female) were highly specialized. Groups were similar for demographics, training volume, and injury history. Compared to the moderate-specialization group, highly specialized athletes reported higher levels of fatigue (3.1 ± 3.7 vs. 1.5 ± 2.2; p = 0.02), anxiety (3.6 ± 4.1 vs. 1.8 ± 2.6; p = 0.02), and depressive symptoms (2.4 ± 4.0 vs. 0.8 ± 2.0; p = 0.02). No differences in psychometric ratings, sleep quality, or perceptions of sport participation were observed between the low/moderate- or low/high-specialization groups. We did not observe any significant differences between groups who did and did not report a history of prior time-loss orthopedic injury.

CONCLUSIONS

Highly specialized high school athletes report higher levels of fatigue, more anxiety symptoms, and more depressive symptoms than their moderately specialized peers, despite no differences in training volume or injury history. Low specialized athletes did not differ from moderately specialized or highly specialized athletes in the aforementioned domains, and there were no differences in sleep quality across specialization groups. These findings add to the current body of literature on early sport specialization by illustrating the distinctive psychosocial implications of sport specialization and demonstrating the need for further prospective research.

Association of Sports Participation and Training Frequency with Injury in Japanese Students Majoring in Physical Education: A Retrospective Analysis

Objectives: This study evaluated prior sports participation and training frequency during elementary to high school and their association with acute and overuse injuries in Japanese college students currently majoring in physical education.Methods: This retrospective study included 292 students who completed questionnaires that assessed their type of sport participation (single sport or multiple sports), training frequency (number of days per week), and injury history (acute and overuse) during the elementary, junior high, and high school periods.Results: In total, 47.9% (95% confidence interval [CI]: 38.2–57.7) of elementary school-aged athletes played multiple sports; this decreased to 22.3% (95% CI: 14.1–30.4) in junior high school and 5.5% (95% CI: 1.0–9.9) in high school. There was a significant difference in the training frequency between those who had overuse injuries and not in elementary (p < 0.05), and junior high school (p < 0.05).Conclusions: The results of this study suggest that participating in multiple sports through junior high school may lead to improved sports levels (i.e., participation in higher levels of competition). In addition, appropriate management of training frequency may help reduce the incidence of overuse injuries.

Effects of Pre-Collegiate Sport Specialization on Cognitive, Postural, and Psychological Functions: Findings from the NCAA-DoD CARE Consortium

Background: Early sport specialization has been associated with an increased risk of musculoskeletal injuries and unfavorable psychological outcomes; however, it is unknown whether sport specialization is associated with worse cognitive, postural, and psychological functions in first-year collegiate student-athletes. Methods: First-year collegiate multisport (MA) and single-sport (SA) student-athletes were identified using a pre-collegiate sport experience questionnaire. The cognitive, postural, and psychological functions were assessed by the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), Standardized Assessment of Concussion (SAC), Balance Error Scoring System (BESS), and Brief Symptom Inventory 18 (BSI-18). Results: MA student-athletes performed higher in cognitive outcomes (e.g., higher ImPACT visual memory composite scores [ß = 0.056, p < 0.001]), but had higher psychological distress (e.g., higher BSI-18 global severity index [ß = 0.057, p < 0.001]) and no difference in postural stability (p > 0.05) than SA student-athletes. Conclusions: This study indicated first-year collegiate athletes with a history of sport specialization demonstrate lower cognitive performance but decreased psychological distress and no differences in static postural stability as compared to their MA counterparts. Future studies should consider involving different health measures to better understand the influence of sport specialization on overall physical and mental health.

Athlete Resilience Trajectories Across Competitive Training: The Influence of Physical and Psychological Stress

Competitive sport involves physical and psychological stressors, such as training load and stress perceptions, that athletes must adapt to in order to maintain health and performance. Psychological resilience, one’s capacity to equilibrate or adapt affective and behavioral responses to adverse physical or emotional experiences, is an important topic in athlete training and performance. The study purpose was to investigate associations of training load and perceived sport stress with athlete psychological resilience trajectories. Sixty-one collegiate club athletes (30 females and 31 males) completed self-reported surveys over 6 weeks of training. Athletes significantly differed in resilience at the beginning of competitive training. Baseline resilience differences were associated with resilience trajectories. Perceived stress and training load were negatively associated with resilience. Physical and psychological stressors had a small but statistically significant impact on resilience across weeks of competitive training, indicating that both types of stressors should be monitored to maintain athlete resilience.

Comparing High School Sport Specialization Trends Between Division I and Club Collegiate Athletes

BACKGROUND

Adolescent athletes report that sports specialization improves their ability to receive a collegiate athletics scholarship, though this is not well-understood. The purpose of this study was to examine self-reported trends in high school specialization and influences for sport participation between Division I (D-I) and college-aged club (club) athletes.

HYPOTHESIS

There would be no difference in high school sport specialization or sport participation influences between D-I and club athletes.

STUDY DESIGN

Retrospective cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

A survey included specialization classification (low, moderate, and high) for 9th to 12th grade, age that the athlete started organized sport and his or her collegiate sport, and several influential factors for participation in one's primary high school sport (1 = no influence to 5 = extremely influential). Chi-square analyses were used to compare specialization classifications between groups. Nonparametric tests were used to determine significant differences in age-related variables and influential factors between D-I and club athletes. All analysis were also conducted with boys and girls separately.

RESULTS

Participants included 266 D-I (girls, 155; 58%) and 180 club (girls, 122; 68%) athletes. Club athletes were more likely to be classified as low specialization at every grade in high school, and this difference was more pronounced between D-I and club female athletes than male athletes. The number of years an athlete was classified as highly specialized in high school was not different between D-I and club athletes. Club athletes were more influenced by playing with friends than D-I athletes and D-I athletes were more influenced by pursuing a collegiate scholarship than club athletes.

CONCLUSION

High levels of specialization in high school sport may not be necessary for playing at the collegiate level, though some level of specialization in high school might be necessary.

CLINICAL RELEVANCE

Clinicians should advocate for healthy long-term athlete development, which does not support high specialization in high school sports.

Gamifying App-Based Low-Intensity Psychological Interventions to Prevent Sports Injuries in Young Athletes: A Review and Some Guidelines

Sports injuries have become a real health concern. Particularly noticeable is the increasing number of severe sports injuries among young people. Sports injury (SI) is a multifactorial event where many internal and external, proximal and remote factors play a role in a recursive way, including physical and psychological variables. Accordingly, many voices expressing the need of tackling that and several prevention programs have arisen. Nevertheless, different barriers and limitations prevent a wide extension of well-controlled programs, closely monitored by highly specialized professionals in ordinary sports grass-root organizations. These have helped flourishing different low intensity (LI)-interventions and e-Health apps focusing on both physical warmup, training and fitness, and mental skills aimed at reducing athlete’s vulnerability to SIs. This kind of intervention usually uses self-administered techniques and/or non-specialized staff that can effectively monitoring the program. In fact, LI-interventions have shown to be effective coping with different health and psychological issues. However, these interventions face an important challenge: the lack of engagement people usually show. The current paper proposes how gamification can contribute to the engagement to such interventions. Based on the mechanics–dynamics–aesthetics framework to analyze game design, the paper suggests a set of guidelines app- and web-LI interventions aimed at preventing SIs should include to foster motivation and reduce attrition.

High School Sport Specialization and Injury in Collegiate Club-Sport Athletes

CONTEXT

Sport specialization during adolescence may affect future injury risk. This association has been demonstrated in some professional sport athletes.

OBJECTIVE

To determine the association between adolescent sport specialization levels in high school and injuries sustained during collegiate club sports.

DESIGN

Cross-sectional study.

SETTING

Paper and online surveys.

PATIENTS OR OTHER PARTICIPANTS

Collegiate club-sport athletes.

MAIN OUTCOME MEASURES(S)

An anonymous survey was administered from September 2019 to May 2020. The survey included sport specialization classification via a commonly used 3-point scale (low, moderate, high) for each high school year (9th-12th), high school sports participation, and collegiate club-sport injury history. The number of years (0-4) an individual was highly specialized in high school was calculated. Individuals who participated in the same sport in high school and college were compared with individuals who played a different sport in college than in high school. An injury related to sport club activities was classified as arising from a contact, noncontact, or overuse mechanism required and the individual to seek medical treatment or diagnosis. Injuries were classified into overuse and acute mechanisms for the upper extremity, lower extremity (LE), and head/neck.

RESULTS

Single-sport participation and the number of years highly specialized in high school sport were not associated with college club-sport injuries (P > .1). Individuals who played a different collegiate club sport than their high school sport were more likely to report an LE or head/neck acute injury compared with athletes who played the same collegiate and high school sport (LE = 20% versus 8%, χ2 = 7.4, P = .006; head/neck = 16% versus 3%, χ2 = 19.4, P < .001).

CONCLUSIONS

Adolescent sport specialization was not associated with reported injuries in collegiate club-sport athletes. Collegiate club-sport athletic trainers should be aware that incoming students exploring a new sport may be at risk for LE and head/neck acute injuries.

Sport Specialization, Physical Performance and Injury History in Canadian Junior High School Students

BACKGROUND

Youth sports participation is encouraged for proposed physical and psychological benefits. However early sport specialization and the potentially negative consequences may be a cause for concern.

PURPOSE

To describe sport specialization in Canadian youth and investigate associations with previous injury and physical performance.

STUDY DESIGN

Cross-sectional study.

METHODS

Junior high school students (grades 7-9, ages 11-16) were invited to participate. All participants completed a questionnaire capturing specialization level (low, moderate, high; based on year-round training, exclusion of other sports, and single-sport training) and injury history in the previous 12-months. Additionally, all participants completed physical performance measures including vertical jump (cm), predicted VO2max (mL/kg/min), single-leg balance (secs) and Y-Balance composite score (%). Logistic regression examined the association between school grade, school size, sex and sport specialization (Objective 1) and the association between sport specialization and injury history (Objective 2). Multivariable linear regression analyses (4) assessed associations between sport specialization category and physical performance measures (Objective 3).

RESULTS

Two hundred and thirty-eight students participated in the study. Eighteen percent of participants reported high specialization, with no significant associations between sex, grade or school size and specialization category. There was no significant difference in the odds of sustaining previous injury between participants reporting moderate (odds ratio [OR]=1.94, 95% CI 0.86-4.35) or high (OR=2.21, 95% CI 0.43-11.37) compared to low specialization. There were no significant differences in vertical jump height (mean diff [MD] = -0.4 to 2.1cm), predicted VO2max (MD = 2.2 to 3.1mL/kg/min), single leg balance (MD = 0.5 to 1.9sec) or Y-balance (MD = 0.6 to 7.0%) between sport specialization categories.

CONCLUSIONS

Sport specialization exists in Canadian junior high schools but may be less common than previously reported and it was not associated with sex, grade, or school size. Level of specialization was not associated with history of injury nor a range of physical performance measures.

LEVEL OF EVIDENCE

Level 3.

Sport specialization of female figure skaters: cumulative effects on low back injuries

Objective: 1) to determine the proportion of sport specialization among female figure skaters, 2) to compare proportion of low back injuries between specialized female figure skaters and non-specialized female figure skaters, and 3) to identify an independent risk factor(s) for low back injuries in female figure skaters.Methods: A cross-sectional questionnaire study was used. Young female figure skaters were asked questions related to sport specialization and any history of low back injuries. The primary outcome variables were status of sport specialization, weekly training hours, and low back injury. Descriptive statistics, t-test, chi-square analyses, and binary logistic regressions were used.Results: Responses from 132 female figure skaters (mean age: 16.3 ± 2.7 years, age range: 8-22 years) were analyzed. Sixty-two percent (82/132) of figure skaters were specialized. Specialized female figure skaters spent more time in training (11.3 ± 6.5 hours/week) than non-specialized skaters (7.6 ± 4.9 hours/week, p = 0.001). No statistical differences were found in proportion of low back injury history between specialized (25.6%) and non-specialized female figure skaters (24.0%, p = 0.836). Chronological age was also identified as an independent risk factor for low back injuries in female figure skaters (aOR: 1.24, 95%CI: 1.00, 1.54, p = 0.048).Conclusions: The majority of female figure skaters in this cohort were specialized. An association between chronological age and low back injuries, found in the current study, may be a result of cumulative effects of participating in figure skating over time.

Changes in U.S. girls' participation in high school sports: implications for injury awareness

CONTEXT

The number of female athletes has grown exponentially since Title IX. However, little data exists on the proportion of women and girls who play each sport.

OBJECTIVE

To quantify changes in female sports participation in high school sports from 1973 to 2018.

DESIGN

Retrospective analysis of data from the National Federation of State High School Associations Participation Survey.

SETTING

US high schools.

PARTICIPANTS

US high school athletes from 1973 to 2018.

MAIN OUTCOME MEASURES

Percentage of female participation for each high school sport in 5-year intervals; and changes in rates of participation by player gender and sport at designated intervals.

RESULTS

From 1973 to 2018, the percentage of high school sports played by girls increased from 24.2% to 42.9% ([95%CI, 18.6,18.8], p < 0.0001). In the 14 sports included in our study, all had an increase in the percentage of female participation between 1973 and 2018. >80% of the increases occurred between 1973 and 1998 for all sports except lacrosse, ice hockey, football, and wrestling. Between 1998 and 2018, the percentage of girls playing each sport increased by less than 5% in all sports, except for ice hockey (11.5%, 95% CI 11.0, 12.0, p < 0.001) and wrestling (7.1%, 95% CI 6.9, 7.1, p < 0.001).

CONCLUSIONS

Girls' participation in high school sports continues to grow not only in numbers but in the types of sports played. Between 1998 and 2018, the greatest increases were noted in ice hockey and wrestling, which had fewer than 1% female participation before 1998. Physicians providing care for female athletes should be aware of these changes and understand the potential injuries associated with these sports.

Systematic Review of Health Organization Guidelines Following the AMSSM 2019 Youth Early Sport Specialization Summit

CONTEXT

Youth sport specialization may place young athletes at increased risk for negative impacts to their physical and/or psychological health. In response to these health concerns, several health organizations have created guidelines and position statements to guide parents and practitioners toward best practices for management of the young athlete.

OBJECTIVE

To systematically review and synthesize current organizations' recommendations and guidelines regarding youth sport specialization.

DATA SOURCES

English-language articles from January 1, 2000, to December 31, 2018, in the NCBI Pubmed, Embase, Cochrane, CINAHL, and SPORTDiscus databases.

STUDY SELECTION

Articles that reported on recommendations or interventions by health organizations or health representatives of sports organizations. A total of 56 articles were assessed, with 11 meeting inclusion eligibility criteria.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

Two investigators independently identified all recommendations within the results that fit within a 15-item framework encompassing 4 domains: Psychological Development/Approach, Physical Development/Load, Facilities and Resources, and Timing and Monitoring of Specialization.

RESULTS

Recommendations across organizations were primarily clustered in the Physical Development/Load (43%), Facilities and Resources (48%), and Sport Specialization (55%) domains. In contrast, the Psychological Development/Approach domain had fewer recommendations (20%). The most common recommendations endorsed concepts: "Monitor athlete well-being," "Youth athletes need access to well-trained, quality coaches," "Multi-sport participation," "Limit early organized participation and/or training," and "Parents require awareness of training, coaching, and best practices." The level of evidence provided to support a given recommendation varied significantly. The level of detail and the consistency of terms used throughout the results were typically low. Recommendations were frequently made without reference to potential outcome measures or specific strategies that could be used for practical implementation in the community.

CONCLUSION

There was broad representation of different aspects of specialization but limited consistency between health organization guidelines. Adopting a framework for recommendations as used in this review could assist organizations in structuring future recommendations that are specific, measurable, and framed in a manner that will promote action in the youth sport community.

Current Sport Organization Guidelines From the AMSSM 2019 Youth Early Sport Specialization Research Summit

CONTEXT

Youth athletes may be at elevated risk for adverse health due to sport specialization. Sport organizations have developed guidelines for participation during growth and development.

OBJECTIVE

To assess youth sport development guidelines using a 15-item framework across sport organizations and governing bodies in soccer, basketball, ice hockey, and swimming.

DATA SOURCES

English-language results from January 1, 2000, to December 31, 2018, from published sport organization guidelines and athlete development plans.

STUDY SELECTION

Two investigators independently reviewed publications identified from sport organizations. A total of 23 guidelines were incorporated, including 5 general sport organizations and 18 sport-specific guidelines.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

Two investigators independently identified all recommendations that fit within a predetermined rubric of recommendations encompassing 4 domains: Psychological Development/Approach, Physical Development/Load, Facilities and Resources, and Timing and Monitoring of Specialization. Sport-specific guidelines on volume were summarized.

RESULTS

Sport organizations and sport-specific guidelines had consensus on 2 items out of the 15-item: emphasis on early skill development and access to well-trained coaches. While recommended by all sports organization, multisport participation was emphasized by 3 of 4 sports, excluding soccer. Volume recommendations were inconsistent between and within sports. No group proposed methods to monitor athlete well-being.

CONCLUSION

This review highlights areas of agreement within sport organizations and governing bodies. Creating a framework to guide youth sport specialization may lead to specific and consistent guidelines.

Effects of chronic betaine supplementation on performance in professional young soccer players during a competitive season: a double blind, randomized, placebo-controlled trial

OBJECTIVE

Various nutritional strategies are adopted for athletes to maintain and to improve performance during the competition season. Betaine may enhance performance during a competitive season by increasing the testosterone to cortisol ratio and reducing systemic inflammation. The aim of this study was to investigate the effect of betaine supplementation on the bio-motor abilities in young professional soccer players.

METHODS

Twenty-nine young professional soccer players (age, 15.5±0.3 years) were matched by position and randomly assigned to one of two groups for 14 weeks: betaine (BG, 2 g/day; n=14) or placebo (PG n=15). Diet was standardized by a nutritionist, and measures of muscular power (countermovement jump: CMJ), change of direction: modified 5-0-5), acceleration (10 m sprint), sprint performance (30 m sprint time: SpT), muscular strength (leg press and bench press one repetition maximum: 1-RM), repeated sprint ability (running-based anaerobic sprint test: RAST), and aerobic capacity (30-15 intermittent fitness test) were assessed in the pre (P1), mid (P2) and post (P3) season over the course of 5 days. All subjects participated in one soccer match and five training sessions per week.

RESULTS

Significant (p < 0.05) group x time interactions were found for maximal oxygen uptake (VO2max), anaerobic peak power, and muscular strength favoring BG at P2 and P3 compared to P1. There were meaningful (p < 0.05) group x time interactions for CMJ, SpT, and peak power during the RAST that favored the BG.

CONCLUSIONS

14-week of betaine supplementation increased predicted 1-RM, VO2max, and repeated sprint ability performance in youth professional soccer players. Betaine supplementation seems to be a useful nutritional strategy to improve and to maintain performance during a competitive soccer season.

Sport Specialization and Quality of Life among Middle- and High-School Long-Distance Runners of Different Injury Status: A Retrospective Study

Running-related injuries are prevalent in adolescent long-distance runners. The aim of our retrospective study was to compare differences in sport specialization, running habits,quality of life, and sleep habits among middle-and high-school long-distance runners of different injury statuses. Middle- and high-school long-distance runners across the United States were recruited via cross-country coaches and athletic directors between January and May 2020. Participants completed an online survey with questions related to demographics, sport specialization, running habits, quality of life, sleep, and self-reported injury history. Overall, 306 participants completed the survey (male = 107, female = 176, unspecified = 23; age = 15.7 ± 1.1 years). Of the participants, 178 (58.2%) reported no history of injury, 101 (33.0%) reported a previous injury, and 27 (8.8%) reported a current injury. Middle- and high-school runners with a current injury reported significantly lower overall health (p= .01) and average distance per run (p = .05) than uninjured runners. No significant differences were found among injury status and sport specialization level, quality of life, sleep habits, or running volume (p> .05). Runners with a self-reported previous or current injury do not appear to be classified as high-specialized runners more frequently than uninjured runners.

Early sports specialisation and the incidence of lower extremity injuries in youth athletes: current concepts

Year-round intensive, single-sport training beginning at an young age is an increasingly common trend in the youth athlete population. Early sport specialisation may be ineffective for long-term athletic success and contribute to an increased risk of physical injury and burn-out. The medical community has noted that repetitive movement patterns may occur in non-diversified activity and this may contribute to overuse injury in young athletes. Studies have begun to identify an association between early sport specialisation and lower extremity injuries in the youth athlete population that is independent of training volume. Recent literature has suggested that sport diversification, not specialisation, is a better path for athletic success and minimised lower extremity injury risk.

Age Is More Predictive of Safe Movement Patterns Than Are Physical Activity or Sports Specialization: A Prospective Motion Analysis Study of Young Athletes

BACKGROUND

Movement quality and neuromuscular balance are noted predictors of acute injury. Early sports specialization and extremely high activity levels have been linked to elevated risk of injury.

PURPOSE

To investigate for any relationships among quality of physical movement, quantity of physical activity, and degree of sports specialization in a healthy cohort of active children and adolescents.

STUDY DESIGN

Cross-sectional study with prospectively collected data.

METHODS

Healthy children between the ages of 10 and 18 years were recruited and completed the Hospital for Special Surgery Pediatric Functional Activity Brief Scale to assess quantity of physical activity and the Jayanthi scale to assess degree of sports specialization (high, score of 2 or 3; low, score of 0 or 1). Movement quality was assessed using motion analysis sensors during 5 repetitions of 4 different jumping and squatting motions, with a maximum score of 100 per participant. Independent-samples t tests were used to compare participants with high versus low specialization on physical activity and movement quality. A Spearman correlation was used to determine the relationship between quantity of physical activity and movement quality, and linear regression was used to assess for the effect of participant age on relevant covariables.

RESULTS

Final analyses included 147 participants (72% male) with a mean ± SD age of 13.4 ± 2.2 years. Participants who were highly specialized displayed better movement quality than did participants with low sports specialization (27.6 ± 14.0 vs 19.8 ± 10.1; P < .01). Participants who were highly specialized had significantly higher activity levels (24.6 ± 5.9 vs 18.1 ± 6.9; P < .001). Movement quality was moderately correlated with physical activity level (r = 0.335; P < .001). Physical activity; hours of organized sports activity; hours of free, unorganized physical activity; and specialization level were not significant predictors of movement quality when controlling for age. Age alone predicted 24.2% of the variance in the overall movement quality score (R² = 0.242; B = 3.0; P < .001).

CONCLUSION

This study found that sports specialization and physical activity levels were not associated with movement quality when controlling for age, which was the most important variable predicting athletic movement quality. Although all participants displayed movement patterns that were associated with high risk for injury, overall movement quality improved with advancing chronological age.

CLINICAL RELEVANCE

All young athletes should ensure that neuromuscular training accompanies sport-specific training to reduce risk of injury.

The Relationships Between Sport Specialization, Sleep, and Quality of Life in Female Youth Volleyball Athletes

BACKGROUND

Although sport specialization may be associated with stress and burnout among youth athletes, the relationship with quality of life (QOL) remains unknown. The purpose of this study was to evaluate the relationship between sport specialization, sleep, and QOL in female youth athletes.

HYPOTHESIS

Higher levels of specialization are associated with increased daytime sleepiness and worse QOL.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 4.

METHODS

Female high school volleyball players completed preseason surveys to determine sport specialization (low, moderate, high), injury history, QOL, sleep duration, and daytime sleepiness. QOL and sleep variables were compared across specialization groups. Multivariable linear regression models were developed to evaluate the associations between sleepiness, QOL, specialization, grade in school, and injury history.

RESULTS

Of 1482 participants, 591 (40%), 436 (29%), and 455 (31%) were categorized as low, moderate, and high specialization, respectively. Highly specialized athletes demonstrated worse QOL (median 91.3 [interquartile range 86-96]) than low (92.4 [88-97], P = 0.05) and moderate (93.5 [88-99], P = 0.05) specialization groups and greater daytime sleepiness (11 [7-15]) than low (10 [6-14], P < 0.001) and moderate (10 [6-14], P < 0.001) specialization groups. In the multivariable model, QOL was negatively associated with prior injury occurrence (β = -1.1 ± 0.5, P = 0.02), but not grade in school (β = -0.08 ± 0.2, P = 0.71) or specialization (moderate: β = 0.08 ± 0.5, P = 0.88; high: β = -0.70 ± 0.5, P = 0.18). Daytime sleepiness increased with high specialization (β = 1.12 ± 0.3, P < 0.001) and grade (β = 0.76 ± 0.1, P < 0.001), but not prior injury (β = 0.51 ±0.3, P = 0.10).

CONCLUSION

Highly specialized female volleyball athletes demonstrate decreased QOL, perhaps because of higher rates of prior injury. Specialization is also associated with increased daytime sleepiness.

CLINICAL RELEVANCE

Sport participation patterns and injury may have implications for QOL in youth athletes.

Defining a research agenda for youth sport specialisation in the USA: the AMSSM Youth Early Sport Specialization Summit

Sport specialisation is becoming increasingly common among youth and adolescent athletes in the USA and many have raised concern about this trend. Although research on sport specialisation has grown significantly, numerous pressing questions remain pertaining to short-term and long-term effects of specialisation on the health and well-being of youth, including the increased risk of overuse injury and burnout. Many current elite athletes did not specialise at an early age. Methodological and study design limitations impact the quality of current literature, and researchers need to prioritise pressing research questions to promote safe and healthy youth sport participation. The American Medical Society for Sports Medicine hosted a Youth Early Sport Specialization Summit in April 2019 with the goal of synthesising and reviewing current scientific knowledge and developing a research agenda to guide future research in the field based on the identified gaps in knowledge. This statement provides a broad summary of the existing literature, gaps and limitations in current evidence and identifies key research priorities to help guide researchers conducting research on youth sport specialisation. Our goals are to help improve the quality and relevance of research on youth sport specialisation and to ultimately assure that opportunities for healthy and safe sport participation continue for all youth.

High Specialization among Female Youth Soccer Players Is Associated with an Increased Likelihood of Serious Injury

PURPOSE

This study aimed to assess the associations between serious injury (≥3-month time loss) and level of specialization among high-level female soccer players and to compare the specialization and college commitment ages of female youth soccer players to Division I college and professional soccer athletes.

METHODS

Youth, college, and professional female soccer players in the United States playing in the top league at each level were recruited to complete an anonymous online survey. The survey collected information about player demographics, soccer specialization and training patterns, history of serious injuries from soccer, and perceptions surrounding soccer specialization. Comparisons between groups were performed using two-sample t-tests, χ2 analyses, and multiple logistic regression models controlling for differences in age. A P value of less than 0.05 was set as significant.

RESULTS

A total of 1,018 (767 youth, 251 college/professional) athletes completed the survey. Serious injuries affected 23.6% of youth and 51.4% of college/professional athletes. Anterior cruciate ligament tears were more prevalent in college/professional players compared with youth athletes (18.3% vs 4.0%; P < 0.001). Highly specialized youth athletes (66.5%) were more likely to have sustained a serious injury from soccer compared with athletes with low specialization (odds ratio, 2.28 (1.38-3.92); P = 0.008) but not moderate specialization (odds ratio, 1.37 (0.83-2.27); P = 0.43). A higher proportion of youth athletes specialized at a young age (≤10 yr) compared with college/professional players (44.2% vs 25.9%; P < 0.001).

CONCLUSIONS

High specialization in female youth soccer players is associated with an increased likelihood of sustaining a serious injury. Current youth soccer players are specializing earlier and committing to play college soccer at a younger age compared with when current college and professional players did.

Changes in the Health of Adolescent Athletes: A Comparison of Health Measures Collected Before and During the CoVID-19 Pandemic

CONTEXT

In the spring of 2020, schools closed to in-person teaching and sports were cancelled to control the transmission of CoVID-19. The changes that took place to the physical and mental health among young athletes during this time remain unknown, however.

OBJECTIVE

Identify changes in the health (mental health, physical activity and quality of life) of athletes that occurred during the CoVID-19 pandemic.

DESIGN

Cross-sectional study.

SETTING

Sample recruited via social media.

PATIENTS OR OTHER PARTICIPANTS

3243 Wisconsin adolescent athletes (age=16.2±1.2 yrs., female=58% female) completed an online survey in May 2020 (DuringCoVID-19). Health measures for this cohort were compared with previously reported data for Wisconsin adolescent athletes (n=5231, age=15.7±1.2, 47% female) collected in 2016-2018 (PreCoVID-19).

MAIN OUTCOME MEASURE(S)

Demographic information included: sex, grade and sports played. Health assessments included the Patient Health Questionnaire-9 Item (PHQ-9) to identify depression symptoms, the Pediatric Functional Activity Brief Scale (PFABS) for physical activity, and the Pediatric Quality of Life Inventory 4.0 (PedsQL) for health related quality of life (HRQoL). Univariable comparisons of these variables between groups were made via t-tests or chi-square tests. Means and 95% confidence intervals (CI) for each group were estimated by survey weighted ANOVA models.

RESULTS

Compared to PreCoVID-19, a larger proportion of the During-CoVID-19 participants reported rates of moderate to severe levels of depression (9.7% vs 32.9%, p<0.001). During-CoVID-19 participants reported 50% lower (worse) PFABS scores (mean:12.2 [95%CI: 11.9, 12.5] vs 24.7 [24.5, 24.9] p<0.001) and lower (worse) PedsQL total scores compared to the PreCoVID-19 participants (78.4 [78.0, 78.8] vs. 90.9 [90.5, 91.3] p<0.001).

CONCLUSIONS

During the CoVID-19 pandemic, adolescent athletes reported increased symptoms of depression, decreased physical activity and decreased quality of life compared to adolescent athletes in previous years.

Financial and medical burdens of youth sports specialization - survey of pediatric sports patients

BACKGROUND

The trend towards youth sports specialization has led to increased costs from higher injury rate and from private club fees. The objectives were to characterize the financial and medical burdens of sports specialization with single sport participation or club sports involvement.

METHODS

An 18-item survey on sports participation and musculoskeletal injury was administered to parents of patients visiting the clinic of a pediatric sports medicine orthopaedic surgeon over a three-month period. Comparisons were made between groups to identify differences in medical and financial burdens. Logistic regressions were performed to evaluate odds ratios for binary outcomes.

RESULTS

Club athletes were significantly younger than non-club athletes (12.9 ± 3.1 years versus 14.9 ± 2.8 years, p = .0002) with club athletes starting sports at average of 7.2 ± 3.1 years. Club sports participation (adjusted OR 5.88, 95% CI: 1.10, 31.4) and female sex (adjusted OR 3.47, 95% CI: 1.12, 10.74) were significant predictors of spending > $1000 USD on sports annually. Multisport participation (OR 5.72, 95% CI: 1.21, 26.96) and spending > $1000 on sports annually (OR 17.21, 95% CI: 1.49, 199.25) were significant predictors of presenting to clinic for a sports-related injury. Single sport athletes had a higher number of medical appointments for sports injuries (18.6 ± 23.0 versus 9.3 ± 10.0 for multisport, p = .0042).

CONCLUSIONS

Youth sports specialization is of substantial financial and medical burden to families. This data can help identify areas of intervention to mitigate injury risk and reduce financial barriers to youth sports participation.

Defining a Research Agenda for Youth Sport Specialization in the United States: The AMSSM Youth Early Sport Specialization Summit

ABSTRACT

Sport specialization is becoming increasingly common among youth and adolescent athletes in the United States and many have raised concern about this trend. Although research on sport specialization has grown significantly, numerous pressing questions remain pertaining to short- and long-term effects of specialization on the health and well-being of youth, including the increased risk of overuse injury and burnout. Many current elite athletes did not specialize at an early age. Methodological and study design limitations impact the quality of current literature, and researchers need to prioritize pressing research questions to promote safe and healthy youth sport participation. The American Medical Society for Sports Medicine hosted a Youth Early Sport Specialization Summit in April 2019 with the goal of synthesizing and reviewing current scientific knowledge and developing a research agenda to guide future research in the field based on the identified gaps in knowledge. This statement provides a broad summary of the existing literature, gaps and limitations in current evidence, and identifies key research priorities to help guide researchers conducting research on youth sport specialization. Our goals are to help improve the quality and relevance of research on youth sport specialization and to ultimately assure that opportunities for healthy and safe sport participation continue for all youth.

Early Sport Specialization Among Former National Collegiate Athletic Association Athletes: Trends, Scholarship Attainment, Injury, and Attrition

BACKGROUND

Many youth athletes focus on 1 sport to gain a competitive advantage, but early sport specialization may increase risk of overuse injuries and burnout. College athletes have successfully achieved advanced status; therefore, the study of their specialization patterns is a method to assess how specialization affects an athletic career.

PURPOSE

To determine trends in sport specialization by sex, sport, and decade of participation in National Collegiate Athletic Association (NCAA) athletes and assess the effect of specialization on scholarship attainment, injury, and attrition.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

An electronic survey was distributed to NCAA athletes who participated from 1960 to 2018. Survey topics included sex, sport, decade of participation, scholarship status, ≥30-day time-loss injuries sustained in college, orthopaedic surgery in college, career length, and age of single-sport specialization. Early specialization was defined as specialization in a single sport before age 15 years. Rates of early specialization were calculated for each sport, sex, individual and team sports, and decade of participation. Rates of scholarship attainment, injury, and attrition were compared between groups. Univariate associations were queried with logistic regression analysis to determine predictors of specialization, scholarship attainment, injury, and early attrition.

RESULTS

Of 1550 athletes who participated (17% response rate), 544 (35.1%) were women. Overall, 18.1% of athletes specialized before age 15 years (n = 281). Athletes in gymnastics, tennis, swimming and diving, and soccer were significantly more likely to specialize early, whereas football and baseball athletes were more likely to specialize late (P < .05 for all groups). Early specialization was more common among women (23.4% vs 15.2%; odds ratio, 1.72; P < .01). There was a trend toward earlier specialization for recent college graduates, with graduates from the last decade more likely to be classified as early specialization than those from previous decades (P = .036). Scholarship attainment was overall equivalent between groups. Time-loss injuries, lower extremity injuries, and orthopaedic surgery in college were not statistically different between groups. Career lengths were similar, but burnout was more common among early specialization athletes (10.5% vs 7.0%; odds ratio, 3.76; P < .01).

CONCLUSION

Less than one-fifth of NCAA athletes surveyed specialized before age 15 years, and neither scholarship attainment nor time-loss injury rate was affected by early specialization. Early specialization is on the rise but is associated with increased burnout.

Differences in Lower Extremity Movement Quality by Level of Sport Specialization in Cadets Entering a United States Service Academy

BACKGROUND

Sport specialization in youth athletes is associated with increased risk for musculoskeletal injury; however, little is known about whether sport specialization is associated with lower extremity movement quality. The purpose of this study was to examine differences in lower extremity movement quality by level of sport specialization in US Service Academy cadets.

HYPOTHESIS

Cadets who report an increased level of sport specialization would have a lower level of movement quality than those who are less specialized.

STUDY DESIGN

Cross-sectional analysis from an ongoing prospective cohort study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Cadets completed the Landing Error Scoring System (LESS) and a baseline questionnaire evaluating level of sport specialization during high school. Data were analyzed using separate 1-way analysis of variance models.

RESULTS

Among all participants (n = 1950), 1045 (53.6%) reported low sport specialization, 600 (30.8%) reported moderate sport specialization, and 305 (15.6%) reported high sport specialization at the time of data collection during the first week. Ages ranged from 17 to 23 years. Men (1491) and women (459) reported comparable specialization levels (P = 0.45). There were no statistically significant differences in lower extremity movement quality by level of specialization for all subjects combined (P = 0.15) or when only men were included in the analyses (P = 0.69). However, there were statistically significant differences in movement quality by level of specialization in women (P = 0.02). Moderately specialized women had the best movement quality (mean, 4.63; SD, 2.21) followed by those with high specialization (mean, 4.90; SD, 2.08) and those with low levels of specialization (mean, 5.23; SD, 2.07).

CONCLUSION

Women reporting moderate sport specialization had improved movement quality and significantly better LESS scores compared to those with high/low specialization.

CLINICAL RELEVANCE

Athletes, especially women, should be encouraged to avoid early sport specialization to optimize movement quality, which may affect injury risk.

Prevalence and Consequences of Sport Specialization Among Little League Baseball Players

BACKGROUND

Baseball is one of the most popular boy's youth sports, and there has been a rise in the rates of certain overuse injuries among players. Specialization has been identified as a risk factor for overuse injury in high school athlete populations, but there is little understanding of the prevalence or consequences of sport specialization in Little League baseball players.

HYPOTHESIS

Sport specialization will be highly prevalent among Little League baseball players and specialization will be associated with worse throwing arm health.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

A total of 246 Little League baseball players (male; N = 241; age, 9.5 ± 1.6 years) between 7 and 12 years old completed an anonymous, online questionnaire with their parent's assistance. The questionnaire consisted of participant demographics and baseball participation information, including sport specialization status and the Youth Throwing Score (YTS), a valid and reliable patient-reported outcome measure for youth baseball players.

RESULTS

Only 29 (11.8%) players met the criteria for high specialization. Approximately one-third of all players (n = 77; 31.3%) reported participating in baseball year-round or receiving private coaching outside of their league (n = 81; 32.9%). Highly specialized athletes demonstrated worse scores on the YTS on average compared with low-specialization athletes (mean [SE]: 56.9 [1.6] vs 61.1 [1.2]; P = 0.01). Similarly, pitching in the previous year (P < 0.01) or traveling overnight regularly for showcases (P = 0.01) were associated with a worse score on the YTS.

CONCLUSION

While the prevalence of high sport specialization was low among Little League baseball players, other behaviors associated with specialization such as year-round play and the receiving of private coaching were more common. Highly specialized Little League players demonstrated worse throwing arm health compared with low-specialization players.

CLINICAL RELEVANCE

Little League players and their parents may represent a potential target audience for dissemination campaigns regarding sport specialization.

Different Perceptions of Parents and Children on Factors Influencing Sport Specialization

Context: Sport specialization among youth athletes has been associated with increased risk of overuse injuries. Previous research demonstrates that children perceive specialization to be beneficial in making their high school team and receiving athletic college scholarships. Previous research demonstrates that parents play a significant role in their child’s sport experience. However, it is unknown if parents and children answer questions related to specialization factors in a similar manner. Objective: To evaluate the beliefs of youth athletes and parents on factors related to sport specialization and evaluate the level of agreement between dyads on sports specialization. Design: Cross-sectional. Setting: Online and paper surveys. Patients or Other Participants: Aim 1: 1998 participants (993 children and 1005 parents). Aim 2: 77 paired parent–child dyads. Interventions: Self-administered survey. Main Outcome Measures: The responses were summarized via frequency and proportions (%). Chi-squares were calculated between parent and child responses. Kappa coefficients were calculated for dyads to determine level of agreement. Sport specialization was classified using a common 3-point scale. Results: The parents were more concerned about risk of injury in sports compared with children (P < .001, χ2 = 231.4; parent: extremely: 7.1%; child: extremely: 3.7%). However, children were more likely to believe that specialization was associated with their chances of obtaining an athletic college scholarship compared with parents (P < .001, χ2 = 201.6; parent: very/extremely likely: 13.7%; child: very/extremely likely: 15.8%). Dyad subanalysis indicated a moderate level of agreement for “quitting other sports to focus on one sport” (κ = .50) and a low level of agreement for “identifying a primary sport” (κ = .30) and “training >8 months per year in primary sport” (κ = .32). Conclusions: Parents and youth athletes had differing beliefs on the factors related to sport specialization. Dyad analysis shows that parents and children answer sport specialization classification questions differently. Health care providers should be aware of these differences, and messaging should be individualized to the audience.

Sport Specialization in Middle- and High-School Long-Distance Runners

CONTEXT

Previous reports suggest high-specialized adolescent athletes may be at a higher risk of injury, worse sleep quality, and lower sport enjoyment than low-specialized athletes. Currently, sport specialization literature is primarily composed of adolescent athletes from a variety of sports. However, it is unknown if the findings on sport specialization from predominantly non-running athletes are generalizable to adolescent long-distance runners.

OBJECTIVE

Compare injury history, running volume, quality of life, sleep habits, and running enjoyment among male and female middle- and high-school long-distance runners from different sport specialization levels.

DESIGN

Cross-sectional.

SETTING

Online survey.

PARTICIPANTS

A total of 102 male (age=15.8±0.9 years) and 157 female (age=15.6±1.4 years) uninjured middle- and high-school athletes who participated in long-distance running activities (completion rate=50.7%).

MAIN OUTCOME MEASURE(S)

Participants were stratified by sex and sport specialization level (low, moderate, high). Group differences in self-reported running-related injuries, EQ-5D-Y quality of life, Pittsburgh Sleep Quality Index sleep quality, sleep duration, running habits, and running enjoyment were assessed.

RESULTS

High-specialized male and female middle- and high-school long-distance runners reported competing more months per year (p<0.001), higher weekly run distance (p<0.001), more runs per week (p<0.001), higher average distance per run (p<0.001), and higher running enjoyment (p<0.001) than low-specialized runners. Males reported higher average weekly run distance (p=0.01), higher average distance per run (p=0.01), and better sleep quality (p=0.01) than females. No differences among sport specialization were found for running-related injuries (p=0.25), quality of life (p=0.07), sleep quality (p=0.19), or sleep duration (p=0.11) among male or female middle- and high-school runners.

CONCLUSIONS

High-specialized male and female middle- and high-school long-distance runners reported higher running volumes and running enjoyment than low-specialized runners. However, high-specialized runners did not report a greater number of running-related injuries, lower quality of life, or lower sleep quality or duration as expected.

Family Affluence Relationship to Sports Specialization in Youth Athletes

Our objective was to examine the association between participant-reported family affluence and sport specialization level. We conducted a cross-sectional investigation of adolescent athletes. Specifically, participants completed a level of sport specialization (low/moderate/high) questionnaire and the Family Affluence Scale. The majority (52%) of the 195 youth athlete participants reported low, 33% reported moderate, and 15% reported high sport specialization. Sport specialization groups were similar in age (mean = 15.3 ± 1.6 years), proportion of females (49%), and time spent training (mean = 11.9 ± 5.0 hours per week). The high sport specialization group reported significantly greater family affluence than the low sport specialization group (Family Affluence Scale = 10.4 ± 1.7 vs 9.2 ± 1.9; P = .005). After covariate adjustment, higher levels of sport specialization remained significantly associated with greater family affluence (β = 0.48, 95% confidence interval = 0.11-0.86). Understanding the relationship between family affluence and sports specialization affords an opportunity to better identify and monitor populations likely to specialize in a single sport during high school.

Situations and mechanisms of non-contact knee injury in adult netball: A systematic review

OBJECTIVES

Noncontact knee injuries in netball are a concern due to a range of negative consequences. To reduce the number of injuries, identifying the situation and mechanism of injury is important. This systematic review examined the literature reporting the situation and mechanism of noncontact knee injury in netball.

DESIGN

Systematic Review.

METHODS

PRISMA guidelines were followed and specific key-term combinations used to search databases. Descriptive and analytic-observational studies reporting the situation or mechanism of noncontact knee injury in females playing netball were included (evaluated using frequency counts).

RESULTS

Six articles were included (combined sample 11,401). Players self-reported the situation of injury in five studies, only one study reported both the situation and mechanism of injury. Landing was the most reported situation of knee injury, representing 46.6% of all knee injuries whilst knee abduction (valgus) collapse was the most observed mechanism. Situation and mechanism of noncontact knee injury in netball were not adequately reported.

CONCLUSIONS

Despite the variations in reporting methods, landing is the most common situation of injury. As only one study reported mechanism of injury, it is difficult to draw conclusions but the mechanism of noncontact knee injury in netball appears similar to those identified in other female athletes.

The Incidence and Risk Factors for Injuries in Girls Volleyball: A Prospective Study of 2072 Players

CONTEXT

Girls high school volleyball is very popular across the United States. There is limited prospective data regarding the incidence and risk factors of time loss (TL) and non-time loss (NTL) injuries sustained in this population.

OBJECTIVES

To estimate the incidence and describe the characteristics of injuries (TL and NTL) sustained in a girls' high school volleyball season.

DESIGN

Descriptive epidemiology study.

SETTING

Convenience sample of 78 high school interscholastic volleyball programs.

PATIENTS OR OTHER PARTICIPANTS

High school volleyball players participating during the 2018 interscholastic season.

MAIN OUTCOME MEASURES

TL and NTL injury rates, proportions, rate ratios, and with 95%CI.

RESULTS

A total of 2,072 girls enrolled in the study with 468 subjects (22.5%) sustaining 549 injuries (NTL=28.4%, TL=71.6%) for an overall injury rate of 5.31 [4.89, 5.79] per 1000 AEs. The competition injury rate was greater than the practice injury rate for all injuries (IRR: 1.19, [1.00, 1.41]) and TL injuries (IRR: 1.31, [1.07, 1.60]). Players with a previous musculoskeletal injury had a higher rate of TL than NTL injuries (IRR; 1.36 [1.12, 1.65]). Ankle injuries accounted for the greatest proportion of TL injuries (n=110, 28%), while the greatest proportion of NTL injuries occurred in the hand/fingers (n=34, 22%). Moreover, ligament sprains accounted for 40% of TL injuries (n=156), whereas muscle/tendon strains (n=79, 51%) accounted for over half of all NTL injuries.

CONCLUSIONS

While the majority of injuries sustained by adolescent girls' volleyball athletes were TL in nature, nearly a third of all injuries were NTL injuries. Injury characteristics differed widely between TL and NTL injuries. Understanding the most common types and characteristics of injury among high school volleyball players is critical for the development of effective injury prevention programs.

Parents' Awareness and Perceptions of Sport Specialization and Injury Prevention Recommendations

OBJECTIVE

To conduct a survey of parents to determine their knowledge of sport volume recommendations and examine their perceptions toward sport specialization.

DESIGN

Cross-sectional survey.

SETTING

Youth sport athletic tournaments, competitions, and practices.

PATIENTS OR OTHER PARTICIPANTS

Parents (n = 1000, 614 women, age: 44.5 ± 6.7 years) of youth athletes completed the survey. Parents had to have a child between 10 and 18 years of age who participated in organized sport in the previous 12 months.

INTERVENTIONS

The survey was anonymous and consisted of yes/no and Likert-scale questions and consisted of background of parent and child and perceptions and knowledge of safe sport recommendations. An expert panel validated the survey.

MAIN OUTCOME MEASURES

Data were summarized by frequencies, proportions (%), and mean values and SDs, when appropriate. Chi-square analyses were used to determine if parent sex influenced distributions.

RESULTS

Over 80% of parents had no knowledge of sport volume recommendations regarding h/wk (84.5%), mo/yr (82.2%), or simultaneous participation in multiple leagues (89.9%). Twenty-four percent of parents considered it appropriate to participate in multiple leagues in the same sport, whereas 60.5% considered it appropriate to participate in multiple leagues of a different sport. Thirty-four percent of parents indicated that they were concerned about the risk of injury in youth sports. Although 55% of parents considered sport specialization a problem in youth sports, only 43.3% thought that year-round sport participation increased the chances of sustaining an overuse injury. Female parents were more likely to be concerned about injury and believe that year-round sport participation results in overuse injury compared with men.

CONCLUSIONS

Recommendations associated with youth sport participation are not well known. However, parents are concerned about the risk of injury and consider sport specialization a problem.

Youth running consensus statement: minimising risk of injury and illness in youth runners

Despite the worldwide popularity of running as a sport for children, relatively little is known about its impact on injury and illness. Available studies have focused on adolescent athletes, but these findings may not be applicable to preadolescent and pubescent athletes. To date, there are no evidence or consensus-based guidelines identifying risk factors for injury and illness in youth runners, and current recommendations regarding suitable running distances for youth runners at different ages are opinion based. The International Committee Consensus Work Group convened to evaluate the current science, identify knowledge gaps, categorise risk factors for injury/illness and provide recommendations regarding training, nutrition and participation for youth runners.

What Defines Early Specialization: A Systematic Review of Literature

Introduction: While practitioners and organizations advise against early specialization, the lack of a consistent and clear definition of early specialization reduces the impact of recommendations and policies in youth sport. An important first step in understanding the consequences of early specialization is establishing what early specialization is. Objectives: This PRISMA-guided systematic review aimed to determine the types, characteristics, and general content of early specialization papers within the literature, and examine how early specialization has been defined and measured in order to advance knowledge toward a clear and consistent definition of early specialization. Data sources: Four different electronic databases were searched (SPORTDiscus, Web of Science, Sports Medicine and Education Index, and Scopus). Both non data-driven and data-driven studies were included to ensure a comprehensive understanding of the literature. Eligibility Criteria: In order to be included in the review, the paper must: (a) Focus on specialization and explicitly use the term "specialization" (b) Focus on sport and athletes (c) Be papers from a peer-reviewed (d) Be in English. And finally, (e) be available in full text. Results: One thousand three hundred and seventy one articles were screened resulting in 129 articles included in the review after applying inclusion/exclusion criteria. Results indicated a clear discrepancy between key components of early specialization and the approaches used to classify early specializers. Conclusion: Future research should work toward developing a valid and reliable approach to classifying early specializers and establishing a consistent definition across studies.

Awareness of Concussion-Education Requirements, and -Management Plans and Concussion Knowledge in High School and Club Sport Coaches

Context

A growing number of high-school–aged athletes participate on club sport teams. Some, but not all, state concussion laws apply to both interscholastic and private sport organizations. However, concussion education, management plans, and knowledge have not been examined in club coaches who coach high school-aged athletes.

Objective

To determine if differences in concussion education, management plans, and knowledge exist between high school coaches and coaches of club sport teams.

Design

Cross-sectional study.

Setting

Online survey.

Patients or Other Participants

A total of 769 coaches (497 high school coaches, 272 club coaches coaching high school-aged athletes; 266 women [34.6%], 503 men [65.4%]) completed an anonymous online questionnaire.

Main Outcome Measure(s)

The questionnaire consisted of demographic and team information, requirements for concussion-education and -management plans, and concussion knowledge.

Results

High school coaches were more likely than club coaches to report that their organizing bodies or leagues required them to receive concussion-education information (97.4% versus 80.4%; P &lt; .001) and that their organizing bodies or leagues had a concussion-management plan (94.0% versus 70.2%; P &lt; .001). High school coaches were more likely than club coaches to correctly agree that most concussions resolve in 7 to 10 days (48.6% versus 40.1%; P = .02) and disagree that loss of consciousness is required to diagnose a concussion (87.1% versus 80.9%; P = .02).

Conclusions

Club coaches were less likely to be aware of requirements for concussion-education and -management plans from their parent organizations and scored lower on specific concussion-knowledge questions than high school coaches despite the same education requirements across groups under their state concussion laws. These results raise concerns regarding the proper management of concussions in club sports and suggest a need for greater oversight and enforcement of state laws in the club sport setting.

Training Load and Injury Among Middle School-Aged Athletes

CONTEXT

Young athletes are encouraged to participate in high-intensity sport programs. However, most research on the association between training volume (TV) and injury has been performed on adult or professional athletes.

OBJECTIVE

To evaluate the association between acute and chronic TV (hours/week) and reported injury (yes/no) and evaluate the relationship between acute : chronic TV and injury while controlling for sex, age, and prior injury in young athletes.

DESIGN

Cohort study.

SETTING

Online surveys.

PATIENTS OR OTHER PARTICIPANTS

Middle school-aged adolescents.

MAIN OUTCOME MEASURE(S)

We conducted a baseline survey at the start of the 2017-2018 academic year. The baseline survey solicited information regarding demographics, injury history, and primary sport. Subsequent surveys were delivered electronically at the start of each week. Information obtained with the weekly survey included weekly TV and injuries sustained the previous week. Injuries were reported and classified (eg, acute or gradual onset) by the participants. Weekly TV was aggregated as rolling averages over the prior 2, 3, and 4 weeks. Acute:chronic TV was calculated for each participant for every week as the prior week TV divided by the TV during the prior 2 (1 : 2), 3 (1 : 3), and 4 (1 : 4) weeks of the study period.

RESULTS

A total of 244 recruits participated. Higher average TV over the prior 4 weeks (odds ratio [OR] = 0.97; 95% confidence interval [CI] = 0.93, 1.00; P = .05) was associated with fewer reported injuries. Additionally, higher average TV over the prior 2 (OR = 0.96; 95% CI = 0.93, 0.99; P = .04), 3 (OR = 0.95; 95% CI = 0.91, 0.99; P = .02), and 4 (OR = 0.95; 95% CI = 0.91, 0.99; P = .05) weeks was associated with fewer reported acute injuries the following week. Acute:chronic TV and any injury type were not related.

CONCLUSIONS

Consistent, higher levels of physical activity may offer protection against acute injury in young athletes.