Injuries are common in elite adolescent athletics, but few studies have addressed risk factors for injury. Growth and maturation are potential risk factors in this population; however, the current body of literature is both inconclusive and considered at high risk of bias. The aim of this study was therefore to examine whether growth rate, maturity status, and maturity tempo are associated with injury risk in an elite sports academy. Anthropometric, skeletal maturity and injury data collected prospectively over four seasons (117 athlete-seasons) were included in the analyses. Growth rate for stature was associated with greater risk of bone (incidence rate ratio (IRR): 1.5 per one standard deviation increase above the mean; 95% CI: 1.1-1.9) and growth plate injuries (IRR: 2.1; 1.5-3.1). Growth rate for leg length was associated with greater overall injury risk (IRR: 1.3; 1.0-1.7) as well as the risk of bone (IRR: 1.4; 1.0-1.9) and growth plate injuries (IRR: 2.1; 1.4-3.0). Athletes with greater skeletal maturity, expressed as skeletal age (IRR: 0.6 per year; 0.5-0.9) and percentage of predicted mature height (IRR: 0.8 per percent increase; 0.7-1.0), were less prone to growth plate injuries. Rate of change in skeletal age was associated with an increased risk of bone injuries (IRR: 1.5; 1.0-2.3). The results of this study suggest that rapid growth in stature and leg length, skeletal maturity status, and maturity tempo represent risk factors for certain injury types in adolescent athletics.

Skeletal maturation and growth rates are related to bone and growth plate injuries in adolescent athletics.

Limb symmetry index in competitive alpine ski racers: Reference values and injury risk identification according to age-related performance levels.

It is well established that differences in injury definition and recording methodology restrict comparisons between injury surveillance programmes. There is, however, little documentation of the variation that can exist between data recorders. The aim of this study was, therefore, to explore the effect on reported injuries when team recorders or supervisors are involved in research. Injury data collected prospectively over five seasons for the U16, U17, and U18 age groups in a youth football (soccer) academy were used to compare different recording settings based on the research involvement of the clinicians. A research-invested team physiotherapist reported an 8.8 times greater incidence (P < 0.001) of non-time-loss injuries and a 2.5 times greater incidence (P < 0.001) of minimal injuries (1-3 days lost) compared to a setting where neither the team physiotherapists nor the supervisor relied on the collected data for research purposes. When team physiotherapists were not invested in research themselves but were supervised by a researcher, the incidence of non-time-loss injuries and minimal injuries was 2.5 times (P < 0.001) and 2.0 times greater (P < 0.01) than in the non-invested setting, respectively. However, there were no differences between recording settings for overall incidence of time-loss injuries. The results from this study demonstrate that involving clinicians that are relying on the collected data for research purposes can significantly affect the reported rates of non-time-loss and minimal injuries. Time-loss injuries overall were not affected by research investment, and should therefore be preferred for comparisons between teams and seasons.

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Involving research-invested clinicians in data collection affects injury incidence in youth football

Objectives To describe the injury characteristics of male youth athletes exposed to year-round athletics programmes. Methods Injury surveillance data were prospectively collected by medical staff in a cohort of youth athletics athletes participating in a full-time sports academy from 2014–2015 to 2018–2019. Time-loss injuries (>1 day) were recorded following consensus procedures for athletics. Athletes were clustered into five event groups (sprints, jumps, endurance, throws and non-specialised) and the number of completed training and competition sessions (athletics exposures (AE)) were calculated for each athlete per completed season (one athlete season). Injury characteristics were reported overall and by event groups as injury incidence (injuries per 1000 AE) and injury burden (days lost per 1000 AE). Results One-hundred and seventy-eight boys (14.9±1.8 years old) completed 391 athlete seasons, sustaining 290 injuries. The overall incidence was 4.0 injuries per 1000 AE and the overall burden was 79.1 days lost per 1000 AE. The thigh was the most common injury location (19%). Muscle strains (0.7 injuries per 1000 AE) and bone stress injuries (0.5 injuries per 1000 AE) presented the highest incidence and stress fractures the highest burden (17.6 days lost per 1000 AE). The most burdensome injury types by event group were: bone stress injuries for endurance, hamstring strains for sprints, stress fractures for jumps, lesion of meniscus/cartilage for throws and growth plate injuries for non-specialised athletes. Conclusion Acute muscle strains, stress fractures and bone stress injuries were identified as the main injury concerns in this cohort of young male athletics athletes. The injury characteristics differed between event groups.

https://bjsm.bmj.com/content/bjsports/55/17/954.full.pdf

Injury characteristics in male youth athletics: a five-season prospective study in a full-time sports academy

This narrative review summarizes the current literature on early sport specialization and changes that occur in the musculoskeletal system throughout growth and maturation. It discusses the impact of development on the motor and sensory systems and how this contributes to movement and coordination in the young athlete. With the increasing number of youth athletes in organized sport and the popularization of early sport specialization, the purpose of this paper is to educate those involved with the youth and adolescent athlete to important changes that are occurring at this time in development and the implications they have on movement, performance and injury. It is important for coaches, parents and athletes to understand and acknowledge the changes that are occurring, and to expect some difficulty in adaptation, which may be evident as either a plateau or deterioration in performance, or typical overuse injuries that are seen in the adolescent athlete.

Developmental changes in the youth athlete: implications for movement, skills acquisition, performance and injuries.

The present investigation was carried out to examine the incidence and pattern of injuries in adolescent multisport athletes from youth sports academy. Injury data were prospectively collected from 166 athletes during the seasons from 2009 to 2014. A total of 643 injuries were identified, 559 (87.0%) were time-loss injuries. The overall injury incidence was 5.5 (95% confidence interval CI: 5.1–6.0), the incidence of time-loss injuries was 4.8 (95% CI: 4.4–5.2), the incidence of growth conditions was 1.2 (95% CI: 1.0–1.4) and incidence of serious injuries was 0.6 (95% CI: 0.5–0.8) per 1000 h of exposure. The prevalence of overuse injuries was 50.3%. Growth conditions represented 20.0%. Most of the injuries (67.0%) involved the lower extremities, and both foot and ankle were the most predominant injured body parts (22.0%). Knee injuries were mostly from overuse (50 vs. 23, p = .02), whereas foot and ankle injuries resulted from an acute mechanism (94 vs. 31, p < .0001). Minor and moderate injuries a...

Compelling overuse injury incidence in youth multisport athletes

Objectives To investigate the association of maturity status with injury incidence in Middle-Eastern youth athletes. Design Prospective cohort study. Setting Four consecutive seasons (2010–2014), Aspire Academy, Qatar. Participants Male athletes (age range: 11–18 years) representing four disciplines enrolled and grouped into two categories: individual sports and racquet sports. Outcome measures Injury data collected over four seasons. Athletes’ anthropometric characteristics assessed to calculate age at peak height velocity. Predicted mature heights (PMHs) collected and categorised into four quartiles. Athletes had wrist and hand radiographs for assessment of skeletal age (SA). Early and late maturers with an SA of >1 year older or younger than their chronological age (CA). Results For the sample (n=67) across all groups, 43 (64%) athletes had one or more injuries: total of 212 injuries, 4.9 injuries per athlete across study. Survival analysis of maturity status using SA found early maturing athletes had two-fold greater injury risk compared with late maturers (HR 2.04, 95% CI 1.15 to 3.61, p=0.015). PMH associated with injury risk (HR 1.05, 95% CI 1.01 to 1.08, p=0.006). Athletes in fourth quartile (≥184 cm) had up to two-fold injury risk (HR 2.41, 95% CI 1.42 to 4.08, p=0.001). Racquet and individual sports involved similar injury risk (HR 1.14, 95% CI 0.86 to 1.52, p=0.37). Conclusion SA early maturity and PMH gradient were significant predictors of injury in youths.

https://bmjopen.bmj.com/content/bmjopen/9/3/e023284.full.pdf

Sports injuries aligned to predicted mature height in highly trained Middle-Eastern youth athletes: a cohort study

Objectives To examine the association between generalised joint laxity (GJL) and injury rates in Middle Eastern male youth athletes. Design Prospective observational study consisting of GJL screen and injury audit (season 2009/2010). Setting Aspire Sports Academy Doha, Qatar. Participants A total of 226 adolescent male athletes (mean age: 14.2 years; SD: 1.7; range: 10–18) involved in 15 sporting activities were grouped into contact and non-contact sports. All available athletes were included in this study. Outcome measures A seasonal injury audit, athletes’ anthropometric characteristics, for example, weight, height and body mass index and screen for GJL to determine Beighton Score (BS). Results The 226 athletes sustained 596 injuries and 75% reported at least one injury over a seasonal injury audit. Players in contact sports were injured more often than players in non-contact sports (more frequent injuries than injury-free time in contact sports; 127 days (95% CI 93 to 160) vs 176 days in non-contact sports (95% CI 118 to 234) (p Conclusion Greater GJL, defined by gradient BS, plus involvement in contact sports together influence injury risk in youth athletes. Preseason documentation of GJL scoring should be considered specifically for contact sports as injury pre-emptive measure.

https://bmjopensem.bmj.com/content/bmjosem/5/1/e000482.full.pdf

Beighton scoring of joint laxity and injury incidence in Middle Eastern male youth athletes: a cohort study.

Background: It has been established that injury incidence data and training load in table tennis is somewhat limited.
Objectives: The purpose of this study was to analyze and report training load and injury incidence. This was established over a full season in highly trained youth table tennis athletes. We further aimed to establish what variables related to training load have a statistically significant effect on injury in youth table tennis.
Methods: Data was collected from eight male adolescent table tennis players of Arabic origin. Training and game time were monitored continuously throughout each training session and match. Heart rate was measured throughout and then subsequently analyzed to quantify internal training load.
Results: Players were subjected to an average of 1901 h 33 min ± 44 h 30 min of training time and 140 h 0 min ± 11 h 29 min of game time over the season. Overall injury incidence was 8.3 (95% CI: 4.6 - 12.0), time-loss injuries 4.4 (95% CI: 1.9 - 6.9) and growth conditions 2.0 (95% CI: 0.6 - 3.3) per 1000 hours. Internal training loads quantified via the Edwards training impulse equation were significantly different between training weeks (P = 0.001), with lowest values around competition periods (P < 0.05). For every extra auxiliary unit of relative training load per minute during training, a significant increase (P = 0.014) in injury occurrence was present.
Conclusions: Most of the injuries occurred during the first quarter of the year (65%), when training loads were highest. In conclusion, the results of this preliminary study showed that training loads increase during a season until competition period, with relative training load per minute being linked to the likelihood of injuries. The rate of overuse injuries and growth-related conditions were higher than previously reported in adolescents in other racket sports.

https://biblio.ugent.be/publication/8622941/file/8630441.pdf

Training Load and Injury Incidence Over One Season in Adolescent Arab Table Tennis Players: A Pilot Study

Background: Warm-up including dynamic stretching is a popular and widely accepted practice as a pre-exercise routine for athletes. However, a shortage of studies investigating the impact of dynamic stretching on linear repeated-sprint performance exists. Objectives: The present study aims to look at the effect of different volumes of dynamic stretching on 30 m linear repeated sprint performance in team sport athletes. Methods: Fifteen male university team-sport players [age (mean ± SD) 22.1 ± 0.6 years, stature 166.9 ± 6.6cm and body mass 67.5 ± 8.0kg] underwent 3 sessions in this within-subjects counterbalanced study. All sessions included a general warm-up (5-minutes self-paced), followed by a dynamic stretching protocol (one set-DSS1; two sets-DSS2; three sets-DSS3) comprised of five active dynamic exercises for lower body musculature (gastrocnemius, gluteals, hamstrings, quadriceps and hip extensor). A standardized specific warm-up was then undertaken followed by a repeated-sprint test (6 × 30-m sprint with 30 seconds active recovery). Results: Values for average sprint time (AST) and total sprint times (TST) were significantly faster (P = 0.005) following DSS2 compared to DSS1 and DSS3. Fatigue index (FI) was significantly lower in DSS2 compared to DSS1 and DSS3 (P 0.05) for best sprint time (BST), mean sprint time (MST) or rating of perceived exertion (RPE). Conclusions: In conclusion, a dynamic warm-up consisting of two sets resulted in improved performance in repeated-sprint. The exact mechanisms associated with this established ergogenic benefit is still unclear and requires more research.

Abdallah Rejeb

Papers

Compelling overuse injury incidence in youth multisport athletes

Sports injuries aligned to predicted mature height in highly trained Middle-Eastern youth athletes: a cohort study

Beighton scoring of joint laxity and injury incidence in Middle Eastern male youth athletes: a cohort study.

Training Load and Injury Incidence Over One Season in Adolescent Arab Table Tennis Players: A Pilot Study

Two Sets of Dynamic Stretching of the Lower Body Musculature Improves Linear Repeated-Sprint Performance in Team-Sports.