Sports Specialization, Part II: Alternative Solutions to Early Sport Specialization in Youth Athletes

Sprinting to the top: comparing quality of distance variety and specialization between swimmers and runners

Objectives

To compare performance progression and variety in race distances of comparable lengths (timewise) between pool swimming and track running. Quality of within-sport variety was determined as the performance differences between individual athletes' main and secondary race distances across (top-) elite and (highly-) trained swimmers and runners.

Methods

A total of 3,827,947 race times were used to calculate performance points (race times relative to the world record) for freestyle swimmers (n = 12,588 males and n = 7,561 females) and track runners (n = 9,230 males and n = 5,841 females). Athletes were ranked based on their personal best at peak performance age, then annual best times were retrospectively traced throughout adolescence.

Results

Performance of world-class swimmers differentiates at an earlier age from their lower ranked peers (15-16 vs. 17-20 year age categories, P < 0.05), but also plateaus earlier towards senior age compared to runners (19-20 vs. 23 + year age category, P < 0.05), respectively. Performance development of swimmers shows a logarithmic pattern, while runners develop linearly. While swimmers compete in more secondary race distances (larger within-sport variety), runners specialize in either sprint, middle- or long-distance early in their career and compete in only 2, 4 or 3 other race distances, respectively. In both sports, sprinters specialize the most (P < 0.05). Distance-variety of middle-distance swimmers covers more longer rather than sprint race distances. Therefore, at peak performance age, (top-) elite female 200 m swimmers show significantly slower sprint performances, i.e., 50 m (P < 0.001) and 100 m (P < 0.001), but not long-distance performances, i.e., 800 m (P = 0.99) and 1,500 m (P = 0.99). In contrast, (top-) elite female 800 m middle-distance runners show significantly slower performances in all their secondary race distances (P < 0.001). (Top-) elite female athletes specialize more than (highly-) trained athletes in both sports (P < 0.05).

Conclusions

The comparison to track running and lower ranked swimmers, the early performance plateau towards senior age, and the maintenance of a large within-sport distance variety indicates that (top-) elite sprint swimmers benefit from greater within-sport specialization.

Diving Into Sports Specialization: The Association of Early Specialization on Injury Rates in Youth to Young Adult Divers

OBJECTIVES

This study explored the link between early sports specialization and injury rates in youth divers, a relationship that remains largely unexplored within diving.

DESIGN

Cross-sectional survey.

SETTING

Members of the USA Diving Organization and collegiate male and female divers participated in an online survey, reporting their sports involvement and injury history.

PARTICIPANTS

One hundred eighty-two male and female divers aged 8 to 25 years were recruited through USA Diving or US collegiate team databases.

INDEPENDENT VARIABLES

Early/late specialization (based on age <12 or 12 years or older), gender (M/F), springboard and/or platform divers, experience (junior/senior, regional/zone/national/international), hours of dryland/water training, and prior sport exposure.

MAIN OUTCOME MEASURES

Injury history obtained on questionnaire.

RESULTS

One hundred eighty-two divers were surveyed; 70% female. Age to start diving and age to concentrate solely on diving were significantly associated with certain injuries (P < 0.05). Beginning diving before age 13 years of age was significantly associated with lower odds of injuries in the shoulder and wrist (P = 0.013 and 0.018, respectively), after adjusting for select covariates. Age of specialization was not significantly associated with injuries in any body part (P > 0.05), after adjusting for covariates. Greater years of diving experience was significantly associated with diving injuries in all 11 body parts (P < 0.05).

CONCLUSIONS

This study indicates that early sports specialization is associated with decreased injury rates in elite youth divers who specialized before age 13 years, particularly for head/neck, shoulder, and wrist injuries. Moreover, we observed a positive correlation between experience and injury rate. Further investigation should focus on distinguishing between acute and overuse injuries.

Acute effects of a vigorous-intensity warm-up on response suppression and decision-making of football referees

This study investigates the acute effect of physical exercise simulating a standard pre-competitive warm-up on the response suppression and decision-making of football referees. Thirty-four referees (n = 17 - regional level; n = 17 - national level) participated in the study. A Stop-Signal Task (SST) and a decision-making video test were used to evaluate the referees' perceptual-cognitive functions. The findings revealed that the vigorous aerobic exercise acutely impacted basic cognitive functions, as indicated by decreased reaction time and decreased choice accuracy. However, higher-order cognitive functions such as response suppression and decision-making did not exhibit significant changes post-exercise. Based on these results, there is no evidence to suggest that a vigorous-intensity warm-up is likely to favour response suppression and decision-making factors in the initial phases of the game. National referees showed superior response suppression abilities (shorter stop-signal reaction times and lower probability of responding to the stop-signal) than regional referees, indicating that higher-level referees possess enhanced perceptual-cognitive skills, likely influenced by their experience. Further studies are required to determine whether these variables can be acutely improved through physical exercise. In this regard, our results suggest the need for alternative strategies in pre-competitive referee warm-ups if aiming to improve perceptual-cognitive skills in the initial phases of the game.

Developing the Physical Performance in Youth Soccer: Short-Term Effect of Dynamic-Ecological versus Traditional Training Approach for Sub-Elite U13 Players-An Ecological Exploratory Cluster Randomised Trial

Currently, research in youth soccer consists of methodological choices that can raise activity volumes and exercise intensity to promote proper training for youth soccer demands. Therefore, the present cluster randomised trial aims to evaluate the effects of the dynamic-ecological approach on the physical performance parameters compared with a traditional one in a group of sub-elite U13 players. Thirty-five male children (age 12.16 ± 0.55 years; weight 45.59 ± 7.15 kg; height 145.5 ± 4.2 cm; BMI 15.8 ± 2.1 kg·m-2) were recruited for this trial from two teams belonging to sub-elite soccer schools and randomly assigned to a dynamic-ecological approach (DEA) or a traditional training (TTG) group. The training program lasted six weeks and consisted of 18 training sessions of 90 min each (3 sessions per week). The sample was evaluated by the standing long jump (SLJ), hop test (HT), 10 m sprint (10 m), 10 × 5 m shuttle run test (SRT), and leg raise test (LR). The DEA group showed significantly higher results in the SLJ (p < 0.001), HT left leg (p < 0.001), 10 m sprint (p < 0.001), and SRT (p < 0.001). In conclusion, the dynamic-ecological approach provides higher performance adaptations. Therefore, this approach can be considered a suitable method to optimise pre-pubertal player training, mainly when no fitness or strength coach is available.

Development of Field Tests for Cardiovascular Fitness Assessment in Wheelchair

It is essential to consider both physique and physical fitness factors to minimize the risk of injuries and optimize athletic performance among elite athletes. Athletes with disabilities face limitations in fitness assessments compared to their healthy counterparts. The aim of this study was to revalidate established cardiovascular fitness assessment methods and develop field tests for wheelchair athletes. As representatives registered at the Korea Paralympic Committee's Athletes Training Center in Icheon, athletes with physical disabilities participating in para ice hockey (n = 14), who were capable of wheelchair control, were volunteered. Prior to cardiovascular fitness assessments using an ergometer and a shuttle run, demographic characteristics were surveyed, and physical measurements and muscle strength (grip strength) were recorded. All the participants performed one ergometer test based on cardiovascular fitness criteria, and for shuttle run validation, two trials were conducted using existing audio cues (National Physical Fitness 100, 20 m shuttle run). For the development of the shuttle run, considering wheelchair turning, signal-to-sound intervals were increased by 1 s and 1.5 s, respectively, in two trials. An analysis of the correlation with the maximal oxygen consumption (VO2max) in comparison to the reference criterion, an ergometer, demonstrated high correlations in the first trial (r = 0.738) and the second trial (r = 0.780). Similarly, significant correlations were observed with the maximum heart rate (HRmax) in the first trial (r = 0.689) and the second trial (r = 0.896). Thus, the 15 m shuttle run is validated as a field test for assessing cardiovascular fitness in athletes with disabilities. Correlation analysis with maximal oxygen uptake (VO2max) compared to the reference criterion, an ergometer, revealed a correlation of 0.815 with a 1 s interval audio cue and 0.355 with a 1.5 s interval audio cue. A high correlation was observed with the 1 s interval audio cue. Regarding the maximum heart rate (HRmax), the correlations were 0.665 with a 1 s interval audio cue. Once again, a high correlation was noted with the 1 s interval audio cue. The field test selected for measuring cardiovascular fitness in wheelchair athletes involved performing a 15 m shuttle run while in the wheelchair. The test utilized an audio cue with a 1 s increased interval between the signal sounds.

A National Survey on the Relationship of Youth Sport Specialization Behaviors to Self-Reported Anxiety and Depression in Youth Softball Players

BACKGROUND

There are little to no data on whether any associations exist between sport specialization and mental health in youth softball athletes.

HYPOTHESIS

Highly specialized youth softball athletes will have worse self-reported depression and anxiety symptom scores compared with low and moderate specialized athletes.

STUDY DESIGN

Cross-sectional survey.

LEVEL OF EVIDENCE

Level 4.

METHODS

An online cross-sectional survey was distributed in the fall of 2021 to a national sample of female youth softball athletes between the ages of 12 and 18 years. Sport specialization status was determined using a 3-point specialization scale that classifies either low, moderate, or high. The patient health questionnaire-9 (PHQ-9) and the 7-item general anxiety disorder scale (GAD-7) were used to assess self-reported symptoms of depression and anxiety. Comparison also included sports participation and specialization behaviors between specialization groups.

RESULTS

A total of 1283 subjects (mean age, 15.1 ± 1.7 years) fully completed the survey. After adjusting for covariates, lower scores were reported on both the PHQ-9 and GAD-7 by highly specialized athletes compared with moderate or low specialization athletes (PHQ-9, high = 8.6 ± 0.4; moderate = 11.2 ± 0.3; low = 10.9 ± 0.5; P < 0.01; GAD-7, high = 6.5 ± 0.4; moderate = 8.6 ± 0.3; low = 8.4 ± 0.4, P < 0.01). Conversely, higher scores were reported on both scales for athletes who received private softball coaching compared with those who did not (PHQ-9, 11.5 ± 0.3 vs 9.0 ± 0.3; P < 0.01; GAD-7, 8.8 ± 0.3 vs 6.9 ± 0.3, P < 0.01). Finally, athletes who reported an arm overuse injury in the previous year reported higher PHQ-9 scores (10.8 ± 0.3 vs 9.8 ± 0.3; P < 0.01).

CONCLUSION

While sport specialization, as measured by the validated 3-point scale, was not associated with increased anxiety and depression symptom scores, other aspects of specialization behavior such as private coaching or overuse injury history were associated with worse scores on these scales, indicating potential concern for anxiety and depression. However, although the differences we observed were statistically significant, they did not exceed the minimal clinically important difference values that have been established for the PHQ-9 (5 points) or GAD-7 (4 points).

CLINICAL RELEVANCE

This project is a first step toward understanding the sport specialization behaviors and their influence on the mental health of youth softball athletes. Focusing on investigating specialization behaviors further may reveal to be a better indicator of risk of developing anxiety and depression symptoms compared with utilizing the 3-point specialization scale.

Are Recreational Sports a Relic of the Past OR a Solution for the Future?

ABSTRACT

Children's participation in sport is a critical component to their physical and social development and as such, efforts should be made to provide all children with the opportunity to play. In recent years, there has been an observed shift in the focus of youth sports from that of participation for the health benefits of physical activity and fun to that of winning and competing. As a result, there has been a rise in club sports offerings and a subsequent reduction in recreational sports opportunities. This change presents unique challenges to children's access to sport and may not adequately support their overall physical, social, and emotional development. This commentary will discuss the benefits and barriers to increasing recreational sport opportunities using the Social Ecological Model as a framework. It also will propose solutions that can be implemented at the intrapersonal, interpersonal, organizational, community, and public policy levels to revive recreational sports.

Variation vs. specialization: the dose-time-effect of technical and physiological variety in the development of elite swimmers

OBJECTIVE

It is heavily discussed whether larger variety or specialization benefit elite performance at peak age. Therefore, this study aimed to determine technical (number of different swimming strokes) and physiological (number of different race distances) variety required to become an international-class swimmer (> 750 swimming points) based on 1'522'803 race results.

RESULTS

Correlation analyses showed lower technical variety in higher ranked swimmers (P < 0.001), yet with small effects (0.11-0.30). However, Poisson distribution revealed dose-time-effects and specified number of swimming strokes required during each age group. Specifically, freestyle swimmers showed highest chances when starting to compete in three to four swimming strokes but reduced their variety to three swimming strokes at the ages of 12/13yrs with another transition to two swimming strokes at the ages of 19/21yrs (female/male swimmers, respectively). Although both sexes showed similar specialization pattern throughout their career, earlier specialization was generally evident in female compared to male swimmers. At peak performance age, freestyle was most frequently combined with butterfly. Swimmers who either kept competing in all five swimming strokes or focused on only one at the beginning of their careers showed lowest probability of becoming an international-class swimmer. Physiological variety increased during junior age but declined again to three race distances towards elite age.

May the Force Be with Youth: Foundational Strength for Lifelong Development

ABSTRACT

Today's youth are weaker than previous generations, and measurable reductions in physical fitness are beginning to emerge. Without targeted initiatives that recognize the foundational importance of resistance training, weaker children and adolescents may be more likely to experience the inevitable consequences of neuromuscular dysfunction and less likely to experience the pleiotropic benefits of exercise and sport. Early exposure to strength-building activities is needed to prepare today's youth for ongoing participation in varied physical activities throughout this developmental phase of life. The novel iceberg of physical development is a metaphoric image that illustrates the sequential and cumulative influence of muscular strength on motor skills and physical abilities. Efforts to enhance the physical capacity of youth should include resistive skills that improve basic movement patterns and enhance motoric competence. A shift in our conceptual thinking about youth resistance training is needed to alter the current trajectory toward physical inactivity and related comorbidities.

Differential improvements between men and women in repeated CrossFit open workouts

INTRODUCTION

The CrossFit® Open (CFO) acts a preliminary round that qualifies men and women for later stages of its annual Games competition. The CFO typically consists of 4-6 workouts that variably challenge an athlete's weightlifting strength, gymnastic skill, and endurance capacity. Except for differences in prescribed intensity loads, workouts are designed the same for men and women to elicit a similar challenge. While all workouts within a single year are unique to each other, one has been repeated from a previous CFO each year between 2012 and 2021. Because previous CFO workouts are often integrated into training, improvements are expected when a workout is officially repeated. However, besides documented record performances, it is unclear whether most athletes are improving, if these improvements affect ranking, or if differences exist between men and women.

PURPOSE

To examine sex-division differences and performance changes across repeated CFO workouts, as well as their effect on CFO and workout ranking.

METHODS

Eleven separate samples of 500 men and 500 women, who were representative of the same overall percent rank within each year involving one of the nine repeated CFO workouts (2011-2021) were drawn for this study. Each athlete's age (18-54 years), rank (overall and within each workout), and reported workout scores were collected from the competition's publicly-available leaderboard. Each sample had excluded any athlete who had not met minimum performance criteria (e.g., at least one completed round) for all prescribed (Rx) workouts within a given year (including those not analyzed). Since some workouts could be scored as repetitions completed or time-to-completion (TTC), and because programming was often scaled between men and women, all scores were converted to a repetition completion rate (repetitions divided by TTC [in minutes]).

RESULTS

Separate sex-division x time analyses of variance with repeated measures revealed significant (p < 0.05) interactions in all but one repeated workout comparison. Initially, men were faster in four workouts (~18.5%, range = 3.9-35.0%, p < 0.001), women in two (~7.1%, range = 5.2-9.0%, p < 0.001), and they tied in the remaining three workouts. When workouts were repeated in subsequent years, men were faster in three workouts (~5.4%, range = 0.9-7.8%, p < 0.05), while women were faster in two (~3.8%, range = 3.5-4.1%, p < 0.01). Though performance improved in seven of the nine workouts (~14.3%, p < 0.001) and percentile rank was controlled, athletes earned a lower rank (overall and within workout) on each repeated workout (p < 0.001).

CONCLUSIONS

Performance (measured as repetition completion rate) has improved in most repeated CFO workouts, particularly for women. However, improvements seen among all athletes, along with increased participation, have made it more difficult for athletes to improve their overall rank. To rank higher, individual athletes must improve their pace to a greater degree than the average improvements seen across the competitive field.

Early single sport specialization does not improve pitching velocity, motion, strength, or utilization in high school baseball pitchers

Background

The impact of single-sport specialization on performance and injury risk in youth and adolescent athletes remains debated. The purpose of this study was to determine the incidence of single-sport specialization and its association with pitch velocity, pitcher utilization, range of motion, strength, and injury history.

Methods

High school pitchers in the Northeastern, Southeastern, Midwestern, and Western Regions of the United States were prospectively recruited. Prior to the season, pitchers were surveyed about their basic demographics, sport participation history, and injury history. At this timepoint, a standardized physical examination was performed and max pitch velocity was measured. They were then prospectively followed over the ensuing high school season, where pitch utilization and counts were followed and injuries were tracked.

Results

Across the study, 115 pitchers were recruited, of whom 53% played baseball as their only sport and 47% played other sports. Single- position specialization within baseball was uncommon as 90% of athletes played positions other than pitcher. There were no differences in range of motion, strength, or pitch velocity between multisport athletes and single-sport specialists. Within the multisport group, 26% reported a history of injury, while 38% of the single-sport specialists reported a history of injury (P = .179). There were no significant differences in pitcher utilization between multisport athletes and single-sport specialists. Only a single prospective injury occurred in the 115 players.

Conclusion

Although single-sport specialization is common, nearly half of all high school pitchers in this study were multisport athletes. While injury history was generally similar between the two groups, single-sport baseball players did not have the following: improved motion, increased strength, higher ball velocity, or greater pitching volumes during the high school baseball season compared to multisport athletes. Accordingly, single-sport specialization did not have a competitive advantage for these high school pitchers based on the performance factors studied. Further prospective studies are necessary to understand the association between single-sport specialization and injury risk in high school baseball players.

Youth Sport Specialization and Risk of Injury: A General Review

OBJECTIVE

The purpose of this literature review was to analyze, understand, and disclose prior empirical findings about the injury risks associated with youth sport specialization.

DATA SOURCES

Articles were included in this review if they examined the association between youth sport specialization status and injury. Nine articles from 5 journals met these criteria. All articles summarized the findings of cross-sectional (N = 5) or cohort studies (N = 4).

MAIN RESULTS

Each article included in this review indicated that specialized youth athletes are more susceptible to injury. Only 5 studies assessed the injury risks linked to specialization independent of sport training volume. These studies produced contradictory results.

CONCLUSIONS

Although specialized youth athletes are more prone to injury, future research is needed to determine the independent and inherent injury risk associated with specialization. Nevertheless, youth athletes should refrain from specialization until at least adolescence.

Developmental activities of elite junior hockey players: an analysis of early sport specialization

Early sport specialization is a popular and contentious topic in the scientific literature and popular media. The lure of extrinsic rewards has led to increasing rates of specialization among young athletes, while expert recommendations promote multisport participation. The purpose of this study was to describe and analyze developmental activities of a group of elite junior hockey players in Canada. Within this context, elements of specialization were investigated in accordance with existing theoretical frameworks and long-term athlete development models to enhance the literature. Fifteen participants from the Ontario Hockey League completed quantitative retrospective interviews, detailing past sport and recreational activities. Thirty-one developmental milestones were assessed. Accumulated hours of activity were categorized in accordance with Côté's (1999) Developmental Model of Sports Participation, along with the number and types of sports in which they participated during childhood. Jayanthi et al.'s (2015) continuum was utilized to determine the age at which the athletes became moderately and highly specialized. Accrued hours of deliberate practice reported by participants increased from ages 6 to 16 years, as did competition in organized hockey games. Reported hours of deliberate play peaked at 9 years of age and decreased thereafter. Participants played a combined 16 sports other than hockey, ranging from an average of 2.0 at age 6, to a maximum average of 5.6 at 12 years old, and decreasing each year to 2.3 by age 15. The greatest number of hours in other sports was accumulated at 12 years of age. Using a three-point scale, participants considered themselves "highly specialized" at 14 years old; however, other quantitative indicators suggested this may have occurred at 12 years of age. Relative to previous research on early sport specialization, participants in this study spent more time practicing hockey, while ceasing hockey-specific play and other sports at younger ages. Despite a diverse sport history, hockey competition was initiated earlier than recommended, showing high levels of sport commitment as young as 9 years old. The early specialization path remains a popular trajectory among coaches, parents, and athletes in Canadian ice hockey.

What makes a Grand Slam champion? Early engagement, late specialization and timely transition from having fun to dedication

In order to provide adequate support for young tennis players, it is important to understand the development path and factors which can have a positive or negative impact on the development of a player. The aim of this research was to determine the factors that affected sports specialization in tennis by means of qualitative analysis (early, optimal, or late). As well as to deepen the knowledge around the phenomenon of specialization in tennis among players of differing success levels through their personal experiences, in order to contribute to a better understanding of their specialization. The authors interviewed 30 tennis players of differing levels, including 10 participants from the most elite level (Grand Slam champions), exploring their contrasting experiences of development. The data set was analyzed using reflexive thematic analysis. Three topics were generated, which included the following: engaging in sport, decisions, and time of specialization. The obtained results offer a stimulus to reflect on numerous aspects of athlete development.

Beyond athletic development: The effects of parkour-based versus conventional neuromuscular exercises in pre-adolescent basketball players

The purpose of this study was to compare the effects of a parkour-based warm-up to a conventional neuromuscular training (NMT) warm-up on the athletic capabilities of youth basketball players. This was examined through two arms: In Investigation 1, the aims were to measure the effects of the two warm-ups on physical measures of athletic performance in prepubescent basketball players. Using post-intervention semi-structured interviews, Investigation 2 aimed to gain insights from the players in relation to the perceived benefits of the two warm-ups. Pre-adolescent children were recruited from two youth level basketball teams. Participants from one club were randomly assigned to either a conventional NMT warm-up group or a parkour warm-up group, while a control group was formed of participants from the second club. Participants of both experimental groups were required to complete a 15-minute warm-up once per week before their regular basketball practice across 8-weeks. For both groups, the coach adopted the same pedagogical approach, utilising a guided discovery strategy. Pre-post test measures of overhead squat performance, countermovement jump, and 10-metre sprint speed were recorded in all three groups. Additionally, pre-post measures were recorded for a timed parkour-based obstacle course for the two experimental groups. No significant between-group differences were found between pre- and post-test measures. However, analysis using Cohen's d effect sizes revealed improvements in both intervention groups versus the control. Moreover, between group effect size differences were observed between the two experimental groups. Following the intervention, participants from both experimental groups were also invited to take part in a post-intervention semi-structured interview to discuss their experiences. The thematic analysis of these semi-structured interviews revealed three higher order themes: Enjoyment; Physical literacy; and Docility; of which the two former themes appear to align to constructs relating to the wider concept of physical literacy. In summary, warm-ups designed to improve athleticism can include less structured and more diverse movement skills than are typical of conventional NMT warm-ups. Specifically, we provide evidence that advocates for warm ups that include parkour-related activities alongside conventional NMT exercises to preserve physical fitness qualities and to simultaneously evoke a sense of enjoyment, fun, and purpose. The benefit of such activities may extend beyond athletic development and, more broadly, contribute to the development of physical literacy.

The associations of early specialization, sports volume, and maturity status with musculoskeletal injury in elite youth football players

Background: Youth football in schools has experienced rapid growth in China. Despite the increase of players engaging in more frequent, intensive, and organized sports training at their early ages, the controversy over early specialization (ES) still exists. This study aims to: a) investigate the training situation of players in the Chinese School Football Programme and b) examine the associations of early specialization, sports volume, and maturity status with musculoskeletal injury. Methods: A cross-sectional survey was used. Players who participated in the National School Football Winter Camp were invited to fill out a questionnaire that included the data of maturity, ES, sports volume, and injury history (n = 88 boys and n = 90 girls). Results: The results have shown that 80.3% of the athletes were classified as ES, while 19.7% of them were classified as non-ES. Almost all athletes (96%) participated in a sport for more than 8 months in a year. Most athletes (75.8%) spent more than twice of the time on organized sports than leisure activities. 30.3% of the athletes trained on average more hours per week than the number of their ages. Binomial logistic regression models reflected the significant differences in the odds ratios (OR) of reporting a history of injury among athletes with different levels of specialization (p = 0.024) and the OR of reporting a history of leg injury among players with different weekly sports volumes (p = 0.038). Significant differences were also shown in the OR of players reporting foot injuries between players with different maturity states (p = 0.046), and the Chi-squared test showed significant differences in the OR of reporting acute injuries between players with different levels of specialization (p = 0.048) and weekly activity (p = 0.022). No significant differences were found between the remaining variables. Conclusion: Most school football elite players follow the ES pathway even though ES increases the risk of injury, especially acute injury. Pre-pubertal and early pubertal players have a higher incidence of foot injuries. Players who train more hours per week than their ages have more leg injuries and acute injuries. Therefore, priority protection and intervention should be carried out for populations with a high risk of injury.

Difference Asymmetry between Preferred Dominant and Non-Dominant Legs in Muscular Power and Balance among Sub-Elite Soccer Players in Qatar

The objective of this study was to determine and compare leg asymmetry between preferred dominant and non-dominant legs in muscular power and balance among sub-elite soccer (football) players in Qatar. Thirty-two professional local soccer players from the Qatar Stars League (Second Division) participated in the study (23.1 ± 6.1 years). They were classified according to their preferred dominant leg (preferred leg to kick the ball). Twenty-two players had a right dominant leg, and the remaining ten had a left dominant leg. Countermovement jump (CMJ) was used to measure unilateral and bilateral vertical jump performances. The Y-balance test (YBT) was used to assess dynamic balance. No significant differences were found between the dominant and non-dominant leg for CMJ flight height (p > 0.05; asymmetry index (AI) = 1.83 ± 11.46) or the relative and absolute reach distance derived from the YBT (p > 0.05; AI (relative) = −0.45 ± 9.68, AI (absolute) = −0.60 ± 12.3). Bilateral asymmetry in dynamic balance was not significant for any of the anterior, posteromedial, or the posterolateral reaching directions (p > 0.05). The selected football players demonstrated an acceptable level of leg symmetry for power and dynamic balance. These findings may prove helpful for the assessment and evaluation of talents and should help to develop and optimize training regimes.

Athletic children: Guidelines and monitoring in pediatric orthopedic surgery

In day-to-day practice pediatric orthopedic surgeons often come up against the question of sport. The aim of the present study was to analyze the relationship between sport and childhood, with 3 questions: (1) What are the benefits of sport for children? (2) How to manage high-level child athletes? And (3) What sports are possible after major orthopedic surgery? Sports provide many benefits for children, and are to be encouraged. Sixty minutes' moderate to intense physical activity per day benefits motor development and bone mineralization and reduces the risk of obesity. On the other hand, excessive sports activity, as encountered in high-level sport, can be harmful for the child's development. The amount of training should not exceed a certain threshold in terms of hours per week according to age. Surgical treatment of sport-related traumatic lesions does not necessarily accelerate return to sport: indications need to be reasonable, despite pressure from the patient's circle. Sports are possible after major orthopedic surgery, although return to sport tends to be delayed and the level is lower than preoperatively.

Differences in Lower Extremity Coordination Patterns as a Function of Sports Specialization

The practice of early sport specialization, defined as intense year-round training in a single sport at the exclusion of others, is increasing in youth athletics. Despite potential benefits, sport specialization may be detrimental to the health of young athletes, as specialization may increase the risk of musculoskeletal injuries-particularly overuse injuries. However, there remains limited knowledge about how sports specialization uniquely alters underlying sports-related motor behavior. The purpose of this study was to compare the variability of movement patterns exhibited by highly sports specialized youth athletes to that of nonspecialized athletes during performance of a sport-specific, virtual reality based cutting task. It was hypothesized that highly specialized athletes would display different patterns of movement coordination compared to nonspecialized athletes during both the run-up phase and cut-and-decelerate phase. In support of the hypothesis, specialized athletes exhibited both intra- and inter-limb coordination that were significantly different than unspecialized athletes. Overall, the results indicate that the highly specialized athletes tended to exhibit greater degrees of coordination but also the ability to break the coordinated patterns of joint angle changes to execute a cutting maneuver, which requires asymmetric demands on the lower extremities while planting on one leg and changing direction.

Single and Especially Multisport Participation May Increase Physical Fitness in Younger Americans

BACKGROUND

We sought to examine the associations between sports participation and physical fitness in younger Americans.

METHODS

The analytic sample included 1108 Americans aged 6-15 years. Muscular fitness assessments included handgrip strength, leg extension strength, and plank position. Cardiorespiratory fitness was examined with graded treadmill tests.

RESULTS

Youth participating in any sports had increased physical fitness performance for each marker: 1.63 kg (CI: 0.91-2.35) for handgrip strength, 6.23 kg (CI: 3.15-9.32) for leg extension strength, 9.41 lbs. (CI: 4.51-14.31) for plank position held, and 3.02 mL/kg/min (CI: 1.23-4.80) for estimated maximal oxygen uptake. Participants engaging in a single sport had increased performance for most fitness markers: 1.52 kg (CI: 0.67-2.38) for handgrip strength, 5.16 kg (CI: 1.50-8.82) for leg extension strength, 5.98 s (CI: 0.17-11.78) for plank position held, and 2.67 mL/kg/min (CI: 0.58-4.77) for estimated maximal oxygen uptake. Youth engaging in multiple sports exhibited even steeper trends: 1.77 kg (CI: 0.83-2.70) for handgrip strength, 7.63 kg (CI: 3.62-11.65) for leg extension strength, 13.89 s (CI: 7.52-20.27) for plank position held, and 3.50 mL/kg/min (CI: 1.15-5.85) for estimated maximal oxygen uptake.

CONCLUSIONS

Any sports participation, including single and multiple sports, is linked to increased physical fitness in American youth.

Youth Sports Specialization and Its Effect on Professional, Elite, and Olympic Athlete Performance, Career Longevity, and Injury Rates: A Systematic Review

BACKGROUND

Limited data are available on the long-term consequences of early sports specialization in high-level athletes.

PURPOSE

To evaluate the existing literature on the effects of sports specialization among professional, Olympic, and other elite athletes.

STUDY DESIGN

Systematic review; Level of evidence, 3.

METHODS

We performed a systematic review of studies from 1990 to 2021 on youth sports specialization in professional, elite, and/or Olympic athletes following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. An elite athlete was defined as one who performed at the highest level of his or her sport, beyond college level. Data were summarized according to 6 objectives: (1) definitions of specialization, age at specialization, and participation in other sports; (2) motivation for specialization; (3) athlete perspectives on specialization; (4) performance data; (5) specialization and injury risk; and (6) career longevity.

RESULTS

From 8756 articles, 29 studies were included, of which 17 (58.6%) were survey-based studies. Of the 8 articles that commented on injury risk, all demonstrated reduction in injury risk in athletes who delayed specialization. Performance benefits were apparent with later specialization in 7 of 9 articles; the remaining 2 showed benefit with earlier specialization in marathon runners and soccer players. There were less definitive results on career longevity, with 5 of 9 articles finding no association between career longevity and sports specialization.

CONCLUSION

Although current data on sports specialization in elite, professional, and Olympic athletes are mostly retrospective and survey-based evidence, most sports demonstrate better performance after youth multisport engagement, and youth sports specialization was linked with increased injury risk in athletes at the highest levels of competition.

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.

Training, Wellbeing and Recovery Load Monitoring in Female Youth Athletes

Participation in youth sports is ever-increasing, along with training and competition demands placed upon youth athletes. Young athletes may experience high training loads due to playing several sports, as well as participating in school physical education. Therefore, monitoring youth athlete load is an emerging area of research that may help limit non-functional overreaching, injury, or illness and assist with long-term athlete development. This narrative review highlights that multiple measures have been explored to monitor both internal and external load. However, the validity, reliability and practicality of these measures are often not fully understood in female youth populations. The most commonly used external monitoring methods are GPS tracking and TRIMP whereas common internal monitoring tools are questionnaires, perceived exertion rating and heart rate measures. The reporting of injuries and menstrual cycles is also crucial for providing completeness when monitoring an athlete. It has been suggested that the combination of training load, recovery and wellbeing monitoring variables is the optimal way to monitor an athlete's fatigue levels. Whichever monitoring method is applied, in a youth population it is important that the protocol can be individualised, is inexpensive and can be easily implemented and reported so that the monitoring is sustainable.

Psychosocial aspects of sports medicine in pediatric athletes: Current concepts in the 21st century

Behavioral aspects of organized sports activity for pediatric athletes are considered in a world consumed with winning at all costs. In the first part of this treatise, we deal with a number of themes faced by our children in their sports play. These concepts include the lure of sports, sports attrition, the mental health of pediatric athletes (i.e., effects of stress, anxiety, depression, suicide in athletes, ADHD and stimulants, coping with injuries, drug use, and eating disorders), violence in sports (i.e., concepts of the abused athlete including sexual abuse), dealing with supervisors (i.e., coaches, parents), peers, the talented athlete, early sports specialization and sports clubs. In the second part of this discussion, we cover ergolytic agents consumed by young athletes in attempts to win at all costs. Sports doping agents covered include anabolic steroids (anabolic-androgenic steroids or AAS), androstenedione, dehydroepiandrostenedione (DHEA), human growth hormone (hGH; also its human recombinant homologue: rhGH), clenbuterol, creatine, gamma hydroxybutyrate (GHB), amphetamines, caffeine and ephedrine. Also considered are blood doping that includes erythropoietin (EPO) and concepts of gene doping. In the last section of this discussion, we look at disabled pediatric athletes that include such concepts as athletes with spinal cord injuries (SCIs), myelomeningocele, cerebral palsy, wheelchair athletes, and amputee athletes; also covered are pediatric athletes with visual impairment, deafness, and those with intellectual disability including Down syndrome. In addition, concepts of autonomic dysreflexia, boosting and atlantoaxial instability are emphasized. We conclude that clinicians and society should protect our precious pediatric athletes who face many challenges in their involvement with organized sports in a world obsessed with winning. There is much we can do to help our young athletes find benefit from sports play while avoiding or blunting negative consequences of organized sport activities.

Prospective evaluation of sport activity and the development of femoroacetabular impingement in the adolescent hip (PREVIEW): results of the pilot study

Background

The purpose of this pilot study was to validate the feasibility of a definitive study aimed at determining if high-intensity physical activity during adolescence impacts the development of femoroacetabular impingement (FAI).

Methods

This prospective cohort pilot study had a sample size target of 50 volunteers between 12 and 14 years old at sites in Canada, South Korea, and the Netherlands. Participants were evaluated clinically and radiographically at baseline and at 2 years. The participants’ sport and physical activity were evaluated using the Habitual Activity Estimation Scale (HAES) and the American Orthopaedic Society for Sports Medicine (AOSSM) criteria for sport specialization. The primary outcome was feasibility and secondary outcomes included the incidence of radiographic FAI and hip range of motion, function (Hip Outcome Score, HOS), and quality of life (Pediatric Quality of Life questionnaire, PedsQL) at 24 months. Study groups were defined at the completion of follow-up, given the changes in participant activity levels over time.

Results

Of the 54 participants enrolled, there were 36 (33% female) included in the final analysis. At baseline, those classified as highly active and played at least one organized sport had a higher incidence of asymptomatic radiographic FAI markers (from 6/32, 18.8% at baseline to 19/32, 59.4% at 24 months) compared to those classified as low activity (1/4, 25% maintained at baseline and 24 months). The incidence of radiographic FAI markers was higher among sport specialists (12/19, 63.2%) compared to non-sport specialists (8/17, 47.1%) at 24 months. The HOS and PedsQL scores were slightly higher (better) among those that were highly active and played a sport compared to those who did not at 2 years (mean difference (95% confidence interval): HOS-ADL subscale 4.56 (− 7.57, 16.70); HOS-Sport subscale 5.97 (− 6.91, 18.84); PedsQL Physical Function 7.42 (− 0.79, 15.64); PedsQL Psychosocial Health Summary 6.51 (− 5.75, 18.77)).

Conclusion

Our pilot study demonstrated some feasibility for a larger scale, definitive cohort study. The preliminary descriptive data suggest that adolescents engaged in higher levels of activity in sports may have a higher risk of developing asymptomatic hip deformities related to FAI but also better quality of life over the 2-year study period.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-022-01164-3.

Relationships Between Body Composition and Performance in the High-Intensity Functional Training Workout "Fran" are Modulated by Competition Class and Percentile Rank

This study examined relationships between body composition and high-intensity functional training (HIFT) workout performance. Fifty-seven men (31.4 ± 6.9 years, 177.2 ± 7.5 cm, 84.7 ± 8.5 kg) and thirty-eight women (29.2 ± 6.4 years, 166.6 ± 6.1 cm, 66.5 ± 7.7 kg) with HIFT experience (≥6 months) reported completing “Fran” (21-15-9 repetitions of barbell thrusters and pull-ups) in 4.78 ± 2.22 min and 6.05 ± 2.84 min, respectively, and volunteered to complete dual-energy X-ray absorptiometry assessments. Participants were grouped by competition class (men, women, master’s men, master’s women) and percentile rank in “Fran” (≤25th percentile, 25–75th percentiles, ≥75th percentile). Two-way analyses of variance revealed expected differences (p < 0.001) between men and women in non-bone lean mass (NBLM), fat-free mass index, and fat mass, and more NBLM (10.6–10.8 kg) and less fat mass (2.7–5.2 kg) in >75th percentile compared to other percentiles. Most body composition measures were significantly (p < 0.05) related to performance in men and women but limited in master’s men; no relationships were seen in master’s women. “Fran” time was negatively correlated to NBLM and fat-free mass index in all percentile groups (ρ = -0.37 to -0.64) and bone mineral characteristics for >25th percentile (ρ = −0.41 to −0.63), and positively correlated to fat mass in 25–75th percentiles (ρ = 0.33–0.60). No other relationships were seen in ≤25th percentile. The influence of body composition on “Fran” time appears to vary by both competition class and percentile rank. Though training to increase lean mass always seems relevant, reducing body fat only appears relevant in mid-skilled trainees and when it is outside healthy parameters.

The Role of Verbal Feedback in the Motor Learning of Gymnastic Skills: A Systematic Review

The main purpose of this study was to systematically review the effects of feedback on motor skill acquisition in gymnastic skills. A systematic literature search was conducted in the electronic databases MEDLINE (EBSCO), Scopus, SPORTDiscus (EBSCO), and Web of Science. Of the initial 743 search articles, 13 studies were included in the quantitative analysis. Studies were included if they met the following criteria: (a) healthy subjects, (b) studies with gymnastic, artistic gymnastic, or trampoline elements in the study protocol, (c) verbal feedback intervention, (d) the study compared verbal feedback intervention with other forms of feedback, instructional intervention, or with a control intervention, and (e) task performance evaluation. Methodological quality was identified using the PEDro scale. Combining verbal instructions with different forms of feedback is beneficial when learning complex gymnastic skills. Verbal feedback may be useful to improve the technical performance of a gymnastic element; in particular, information regarding the errors committed in a key element of the performance seems to be effective in the motor learning process.

Epidemiology of Pediatric Gymnastics Injuries Reported in US Emergency Departments: Sex- and Age-Based Injury Patterns

Background:

Despite increasing participation rates in youth gymnastics, the majority of epidemiologic literature focuses on older elite athletes or stratifies athletes by level of competition.

Hypothesis:

The authors hypothesized that sex- and age-based patterns in youth gymnastics–related injuries exist, which are otherwise overlooked in an unstratified population.

Study Design:

Descriptive epidemiology study.

Methods:

Publicly available injury data from the National Electronic Injury Surveillance System were collected on pediatric gymnastics injuries presenting to emergency departments in the United States. Participation data from the National Sporting Goods Association were used to calculate national injury incidence rates in 7- to 11-year-olds (childhood) and 12- to 17-year-olds (adolescence) from January 1, 2012, to December 31, 2018. Z tests were conducted for the comparison of injury rates between girls and boys within each age group and for overall injury rate across age groups.

Results:

Girls participated in gymnastics at a frequency 6.5 times that of boys in childhood and 13.5 times that of boys in adolescence. An estimated 72,542 youth gymnastics–related injuries were reported in US emergency departments each year. A large proportion (61.3%) occurred in childhood, with female predominance in both age groups. Overall, there was no difference in weighted annual injury rate (injuries per 100,000 athlete-days per year) by age group (6.9 [childhood] vs 8.8 [adolescence]; P = .19) or sex (7.4 [girls] vs 8.1 [boys]; P = .65). In adolescence, boys were more likely than girls to experience injury (16.47 vs 8.2; P = .003). Wrist and lower arm fractures were more common in childhood than adolescence (1.07 vs 0.43; P = .002) and specifically in girls (childhood vs adolescence, 1.06 vs 0.37; P = .001). Ankle injuries and concussions were more common in adolescence vs childhood (P = .01 and .0002).

Conclusion:

Upper extremity injuries predominated among childhood gymnasts, particularly girls. In adolescence, girls and boys experienced increases in concussions and foot and ankle injuries. Although representing a lower overall number of training gymnasts as compared with girls, adolescent boys experience a higher rate of injuries overall.

Effects of Integrative Neuromuscular Training on Motor Performance in Prepubertal Soccer Players

ABSTRACT

Menezes, GB, Alexandre, DR, Pinto, JC, Assis, TV, Faigenbaum, AD, and Mortatti, AL. Effects of integrative neuromuscular training on motor performance in prepubertal soccer players. J Strength Cond Res 36(6): 1667-1674, 2022-The present study examined the effects of integrative neuromuscular training (INT) on motor performance in prepubertal soccer players. Subjects were randomly assigned to the experimental group (INT; n = 20, age: 8.2 ± 1.2 years; body mass: 28.4 ± 6.4 kg; height: 1.3 ± 0.1 m) or the control group (CON; n = 18, age: 8.5 ± 1.3 years; body mass: 32.8 ± 8.9 kg; height: 1.3 ± 0.1 m). Integrative neuromuscular training program was performed twice per week during the 12-week training intervention. Balance, flexibility, countermovement vertical jump height (CVJH), sprint speed, and change of direction speed (CODS) were assessed in both groups at baseline, sixth week and 12th week. A mixed model repeated measures analysis of variance was used to examine the group changes in performance for each variable. There was a time effect for balance in the INT from pre to 12th weeks (p < 0.001, g = 0.72), and from 6th to 12th weeks (p = 0.005, g = 0.34). An interaction effect for balance was also observed between INT and CON after the 12th week. A time effect in flexibility was observed in INT from baseline to 6th and 12th weeks (p = 0.02; g = 0.45 and p < 0.001; g = 0.71) and from 6 to 12th weeks (p = 0.003; g = 0.24). There was a time effect in CVJH, from baseline to 12th week and from 6th to 12th weeks (p < 0.05; g = 0.34 and g = 0.53, respectively). There was no significant between-group speed performance change. A time effect was found in CODS in INT, but only from baseline to 12th week (p = 0.02; g = 0.31). There were significant improvements in the percent change (Δ%) from baseline to 12 weeks (p < 0.05) for balance, flexibility, and CVJH in INT. These findings indicate that the addition of an INT program to soccer practice can improve selected motor performance skills in prepubertal soccer players.

CrossFit® open performance is affected by the nature of past competition experiences

Purpose

To examine the relationships between past competition performances and 2020 CrossFit® Open (CFO) performance.

Methods

A random selection from the top one thousand athletes (n = 220, 28.5 ± 4.4 years, 178 ± 7 cm, 87.5 ± 10.2 kg) were selected for this study. Overall and weekly performances (including ranks and scores) of the 2020 CFO, as well as overall ranks from all previous CFO, regional, and Games™ competitions in which they competed, were recorded from their publicly available online profile. The highest, lowest, average, and standard deviation (SD) of past rankings, as well as participation statistics (i.e., years since first appearance, total and consecutive appearances, and participation rate), were calculated for each competition stage. Relationships were then assessed between 2020 CFO performance and all past competition experience variables by calculating Kendall’s tau (τ) correlation coefficients and Bayes factors (BF₁₀).

Results

Overall and weekly ranking of the 2020 CFO was extremely favored (p < 0.001, BF₁₀ > 100) to be related to the athlete’s highest previous CFO rank (τ = 0.26–0.39) and individual regional appearances (τ = − 0.26 to − 0.34), as well as individual Games™ appearances (overall and for weeks 1, 3, and 4; τ = − 0.20 to − 0.22, p < 0.001, BF₁₀ > 100). Evidence for all other significant relationships ranged from moderate to very strong (p < 0.05, BF₁₀ = 3–100) and varied among specific 2020 CFO workouts. Few associations were noted for team competition experience, and these were generally limited to Games™ appearances (τ = − 0.12 to − 0.18, p < 0.05, BF₁₀ = 3.3–100).

Conclusions

Although specific relationships were found between 2020 CFO performance and individual appearances at regional and Games™ competitions, the most consistent relationships were seen with participation and ranking in past CFO competitions.

Pediatric Back Pain: A Scoring System to Guide Use of Magnetic Resonance Imaging

BACKGROUND

The prevalence of back pain in the pediatric population is increasing, and the workup of these patients presents a clinical challenge. Many cases are selflimited, but failure to diagnose a pathology that requires clinical intervention can carry severe repercussions. Magnetic resonance imaging (MRI) carries a high cost to the patient and health care system, and may even require procedural sedation in the pediatric population. The aim of this study was to develop a scoring system based on pediatric patient factors to help determine when an MRI will change clinical management.

METHODS

This is a retrospective cohort analysis of consecutive pediatric patients who presented to clinic with a chief complaint of back pain between 2010 and 2018 at single orthopaedic surgery practice. Comprehensive demographic and presentation variables were collected. A predictive model of factors that influence whether MRI results in a change in management was then generated using cross-validation least absolute shrinkage and selection operator logistic regression analysis.

RESULTS

A total of 729 patients were included, with a mean age of 15.1 years (range: 3 to 20 y). Of these, 344 (47.2%) had an MRI. A predictive model was generated, with nocturnal symptoms (5 points), neurological deficit (10 points), age (0.7 points per year), lumbar pain (2 points), sudden onset of pain (3.25 points), and leg pain (3.75 points) identified as significant predictors. A combined score of greater than 9.5 points for a given patient is highly suggestive that an MRI will result in a change in clinical management (specificity: 0.93; positive predictive value: 0.92).

CONCLUSIONS

A predictive model was generated to help determine when ordering an MRI may result in a change in clinical management for workup of back pain in the pediatric population. The main factors included the presence of a neurological deficit, nocturnal symptoms, sudden onset, leg pain, lumbar pain, and age. Care providers can use these findings to better determine if and when an MRI might be appropriate.

LEVEL OF EVIDENCE

Level III-diagnostic study.

Age and Gender Differences in Injuries and Risk Factors in Elite Junior and Professional Tennis Players

BACKGROUND

Elite tennis athletes experience injuries throughout the entire body. Impairments in trunk stability, lower limb flexibility, and hip range of motion (ROM) are modifiable risk factors that can impact injuries and performance. Information on nonmodifiable risk factors such as age and gender is limited. The purpose of this investigation was to provide information on risk factors to direct clinical decision-making and injury prevention and rehab programming in this population.

HYPOTHESIS

Prevalence and location of injuries will differ by age group and gender. Trunk stability, lower limb flexibility, and hip ROM will differ by age group and gender.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

A de-identified database (n = 237; females = 126) from the United States Tennis Association High Performance Profile (HPP) 2014-2015 was used for the analysis. Subjects were elite junior and professional tennis players (mean age 14.6 [range, 9-27] years). The HPP is a tennis-specific assessment and questionnaire that includes retrospective information on injury history. Subjects were categorized by injury, gender, and age. Injury locations were classified by region. Trunk stability measures included drop vertical jump (DVJ), single-leg squat, and prone and side planks. Lower limb measures included hamstring, quadriceps and hip flexor flexibility, and hip rotation ROM.

RESULTS

A total of 46% of athletes reported an injury. Significant differences were found for injury prevalence and location by age group. Adolescent athletes (age 13-17 years) had more trunk injuries, while adult athletes (age ≥18 years) had more lower limb injuries. Adolescent athletes performed worse on DVJ, dominant side plank, and hamstring flexibility compared with young (age ≤12 years) and adult athletes. Significant gender differences in hip ROM included internal rotation on both the dominant and nondominant sides.

CONCLUSION

Impairments in trunk stability, lower limb flexibility, and hip rotation ROM may affect both health and performance outcomes in this population. Elite tennis athletes may benefit from additional off court programming to address trunk and lower limb impairments.

CLINICAL RELEVANCE

Adolescent elite tennis athletes may be at higher risk of trunk injuries. Age, gender, injury history, and impairments should be considered with all assessments and programming.

Genetic characteristics of competitive swimmers: a review

A successful swimming performance is a multi-factorial accomplishment, resulting from a complex interaction of physical, biomechanical, physiological and psychological factors, all of which are strongly affected by the special medium of water as well as by genetic factors. The nature of competitive swimming is unique, as most of the competitive events last less than four minutes. Yet training regimens have an endurance nature (many hours and many kilometres of swimming every day), which makes it impossible to classify swimming by definitions of aerobic-type or anaerobic-type events, as in track and field sports. Therefore, genetic variants associated with swimming performance are not necessarily related to metabolic pathways, but rather to blood lactate transport (MCT1), muscle functioning (IGF1 axis), muscle damage (IL6) and others. The current paper reviews the main findings on the leading 12 genetic polymorphisms (located in the ACE, ACTN3, AMPD1, BDKRB2, IGF1, IL6, MCT1, MSTN, NOS3, PPARA, PPARGC1A, and VEGFR2 genes) related to swimming performance, while taking into consideration the unique environment of this sport.

Validity and reliability study of the Turkish version of the 'A Sport Fitness Index'

BACKGROUND

The aim of this study was to adapt the 'Sport Fitness Index' into Turkish and to ensure its validity and reliability.

METHODS

After obtaining the necessary permissions, the Sports Fitness Index was independently translated from its English original to Turkish by four different physicians specialising in sports medicine. The content validity of index v.1 was calculated using the Davis technique in sample 1 of 20 people regularly participating in sports. In sample 2 consisting of 104 athletes who had a sports-related ligament/muscle injury or applied to the sports medicine clinic for general medical examination; the validity and reliability of index v.2 were examined. ROC analysis was applied to determine the cut-off point value of the score obtained from the Turkish version of the index.

RESULTS

The calculated I-CVI (lowest: 0.80, highest: 0.95) and S-CVI/Ave values (0.87) showed that the index provided content validity. Item 1 and item 10 were removed from the Turkish version of the index, as it caused a decrease in the Cronbach's alpha coefficient of the index v.2. Thus, the Cronbach's alpha coefficient of the index was calculated as 0.925. In the Turkish version of index v.2, the single-factor structure (explained variance rate 66.22%; eigenvalue 5.29) was preserved. The index provided confirmatory factor analysis model fit indices. The index provided a high level of negative correlation (r ˃ -.60; P = .0001) with the total score of the Physical Activity Inadequacy Scale Short Form-10 and the sub-scores of all summary components (r ˃ -.60; P = .0001). According to the ROC curve, the best cut-off point was 70 points with 96.6% sensitivity and 75% specificity in the Turkish version of the index.

CONCLUSION

The Sports Fitness Index-TR provided its Turkish validity and reliability with its 8-item and single-factor structure. The cut-off point is accepted as 70 points.

Weightlifting for Children and Adolescents: A Narrative Review

The involvement of youth in the sport of weightlifting and the use of weightlifting methods as part of training for youth sport performance appears to be increasing. Weightlifting for children and adolescents has been criticized in some circles and is a controversial aspect of resistance training for young people. Although injuries can occur during weightlifting and related activities, the incidence and rate of injury appear to be relatively low and severe injury is uncommon. A number of performance, physical, and physiological variables, such as body composition, strength, and power, are improved by weightlifting training in children, adolescents, and young athletes. Manipulating program variables, when appropriate, can have a substantial and profound influence on the psychological, physiological, physical, and performance aspects of weightlifters. An understanding of the sport, scientific training principles, and musculoskeletal growth development is necessary to properly construct a reasonable and appropriate training program. A scientific background aids in providing an evidenced basis and sound rationale in selecting appropriate methods and directing adaptations toward more specific goals and enables the coach to make choices about training and competition that might not otherwise be possible. If weightlifting training and competition are age group appropriate and are properly supervised, the sport can be substantially safe and efficacious.

Developmental Training Model for the Sport Specialized Youth Athlete: A Dynamic Strategy for Individualizing Load-Response During Maturation

CONTEXT

Most available data on athletic development training models focus on adult or professional athletes, where increasing workload capacity and performance is a primary goal. Development pathways in youth athletes generally emphasize multisport participation rather than sport specialization to optimize motor skill acquisition and to minimize injury risk. Other models emphasize the need for accumulation of sport- and skill-specific hours to develop elite-level status. Despite recommendations against sport specialization, many youth athletes still specialize and need guidance on training and competition. Medical and sport professionals also recommend progressive, gradual increases in workloads to enhance resilience to the demands of high-level competition. There is no accepted model of risk stratification and return to play for training a specialized youth athlete through periods of injury and maturation. In this review, we present individualized training models for specialized youth athletes that (1) prioritize performance for healthy, resilient youth athletes and (2) are adaptable through vulnerable maturational periods and injury.

EVIDENCE ACQUISITION

Nonsystematic review with critical appraisal of existing literature.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

A number of factors must be considered when developing training programs for young athletes: (1) the effect of sport specialization on athlete development and injury, (2) biological maturation, (3) motor and coordination deficits in specialized youth athletes, and (4) workload progressions and response to load.

CONCLUSION

Load-sensitive athletes with multiple risk factors may need medical evaluation, frequent monitoring, and a program designed to restore local tissue and sport-specific capacity. Load-naive athletes, who are often skeletally immature, will likely benefit from serial monitoring and should train and compete with caution, while load-tolerant athletes may only need occasional monitoring and progress to optimum loads.

STRENGTH OF RECOMMENDATION TAXONOMY (SORT)

B.

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.

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.

The Effects of Physical Activity on Physeal and Skeletal Development

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There is increasing evidence in the literature regarding the important health impact of and risk factors for injury in youth sport.

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Increasing pediatric and adolescent activity intensity, such as is seen in earlier single-sport focus and specialization, may be associated with morphological changes in the growing skeleton.

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Chronic subacute injury to the developing physes in the active child can lead to stress on the growth plate and surrounding tissues that induces developmental morphological changes in the joint.

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There is evidence to suggest that frequent participation in sports that place particular stress across the physes of the proximal humerus, the proximal femur, and the distal radius can be associated with an increased risk of inducing developmental and morphological changes that could lead to future joint dysfunction and premature degeneration.

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Additional research is necessary to better define the pathoetiology of activity-mediated morphological changes, as well as to create and validate parameters for safe involvement in competitive physical activities.

Exploring the importance of diversified physical activities in early childhood for later motor competence and physical activity level: a seven-year longitudinal study

BACKGROUND

Research indicates that childhood motor competence (MC) can predict physical activity (PA) levels later in life and it has been argued that frequently engaging in a wide diversity of physical activities will eventually improve children's MC. However, no longitudinal or experimental studies have confirmed this theoretical rationale. The aims of this study are to explore the longitudinal associations between diversified physical activities at age six and later MC and PA (time spent in moderate-to-vigorous PA) (age nine and 13). Furthermore, we explore to what extent the longitudinal association between diversified physical activity and PA is mediated by MC.

METHODS

Longitudinal data from the Copenhagen School Intervention Study were used for this analysis, where 704 participated (69% response rate). Diversified physical activity (self-reported), MC (The Körperkoordinationstest für Kinder battery of postural stability and locomotor skills) and PA (accelerometer) were assessed in the children at age six, age nine and age 13. A total of 654 participated in at least two of the measures and, therefore, were included in the analysis. Two structural equation models were constructed, with diversified physical activity at age six and MC and PA at age nine as predictors of PA and MC at age 13.

RESULTS

The data from both models demonstrated good model fit. Diversified physical activity at 6 years of age was significantly associated with physical activity and MC at age 13, when adjusting for sex, age, intervention, weight, height, and previous levels of PA and MC. Diversified physical activity at age six was also positively associated with PA and MC at age nine, which were, in turn, positively related to PA at age 13 but to a lesser degree than diversified PA at age six. The association between diversified physical activity at age six and PA at age 13 was not mediated by MC at age nine.

CONCLUSIONS

The results of this study indicate that diversified physical activity at age six is important for the development of MC and PA in adolescence. Increasing the diversity of children's daily physical activities, not only the amount and intensity, seems important for future PA behavior and thereby health promotion in a life course perspective.

Early Specialization and Critical Periods in Acquiring Expertise: A Comparison of Traditional Versus Detection Talent Identification in Team GB Cycling at London 2012

The aim of this study was to compare two methodologies employed by the British Cycling talent identification program. Specifically, the authors investigated cyclists selected to represent GB cycling team at the London 2012 Olympics using (a) a traditional talent identification methodology (British Cycling Olympic Development Program), where selection is based upon race results and (b) a detection talent identification methodology (U.K. Sport Talent Team Program), which is a multi-Olympic event initiative that identifies athletic potential from physical and skill-based tests. To facilitate this comparison, the authors calculated the speed with which expertise was acquired. A Mann–Whitney U test (U = 16.0, p = .031) indicated that the speed of acquiring expertise was quicker in detection talent identification (Mdn = 5.4) than traditional talent identification (Mdn = 7.2). Practice started later with detection talent identification than with traditional talent identification (14.12 years vs. 11.23 years, respectively), which affected the period to excellence. Thus, detection talent identification resulted in an absence of early specialization, which suggests a critical period for attaining cycling expertise. The authors hypothesize a genetic basis of talent and propose that critical periods are important in detection talent identification programs.

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.

Talent development environments in elite Taekwondo population: a study within an Italian context

BACKGROUND

The aim of this study was to analyze the quality perception of the main talent development environments within the elite taekwondo population, through the Talent Development Environment Questionnaire (TDEQ-5).

METHODS

The TDEQ-5 was given to 107 top level athletes from the Italian National Team and from 12 domestic clubs. An exploratory factor analysis (EFA) was carried out and the descriptive statistics were measured for all the individual item scores; for each factor the independent t-Tests were carried out to identify differences in scores between the National and the Club environments.

RESULTS

The EFA revealed four principal components (56.68%). These four factors reported good reliability values (α = from 0.63 to 0.93) and significant correlations. The development environments were positively perceived by the athletes, with Factor 1 being the highest performing component and Factor 2 the weakest. Factor 1 was identified as the strength of the Club environment, while Factor 2 as the area of improvement for the National environment. The scale values of Factors 1, 2 and 3 were significantly higher (p < 0.01) in the Club environment. The item-by-item analysis revealed the presence of three strengths and six areas of improvement in the national environment, eleven strengths and no areas of improvement in the Club environment.

CONCLUSIONS

Our study highlights the strengths and weaknesses of the different development environments surveyed and may allow to plan targeted interventions to increase the perception of quality of the talent development environments, thus allowing the stakeholders to optimize their work.

Risk Factors, Diagnosis and Management of Bone Stress Injuries in Adolescent Athletes: A Narrative Review

Physical activity is known to be beneficial for bone; however, some athletes who train intensely are at risk of bone stress injury (BSI). Incidence in adolescent athlete populations is between 3.9 and 19% with recurrence rates as high as 21%. Participation in physical training can be highly skeletally demanding, particularly during periods of rapid growth in adolescence, and when competition and training demands are heaviest. Sports involving running and jumping are associated with a higher incidence of BSI and some athletes appear to be more susceptible than others. Maintaining a very lean physique in aesthetic sports (gymnastics, figure skating and ballet) or a prolonged negative energy balance in extreme endurance events (long distance running and triathlon) may compound the risk of BSI with repetitive mechanical loading of bone, due to the additional negative effects of hormonal disturbances. The following review presents a summary of the epidemiology of BSI in the adolescent athlete, risk factors for BSI (physical and behavioural characteristics, energy balance and hormone disruption, growth velocity, sport-specific risk, training load, etc.), prevention and management strategies.

Functional Movement Screen Detected Asymmetry & Normative Values Among College-Aged Students

BACKGROUND

The Functional Movement Screen (FMS™) is a popular test used by sports medicine professionals to identify dysfunctional movement patterns by analyzing mobility and stability during prescribed movements. Although the FMS™ has been a popular topic of research in recent years, normative data and asymmetries in college-aged students have not been established through research.

PURPOSE

The objective was to determine normative FMS™ scores, report frequency counts for FMS™ asymmetries, and determine if the number of sports seasons and number of different sports an individual participated in during high school varied between university students that showed FMS™ identified asymmetries.

STUDY DESIGN

Cross-sectional Study.

METHODS

One hundred university students completed the FMS™ and an associated survey to determine which sport(s) and for how many seasons they participated in each sport(s) during high school. Total FMS™ scores were assessed as well as identifying the presence of an asymmetry during a FMS™ screen. An asymmetry within the FMS™ was defined as achieving an unequal score on any of the screens that assessed right versus left movements of the body.

DATA ANALYSIS

Data analysis included descriptive statistics, Pearson correlation was utilized to investigate the relationship between number of sports played and number of sport seasons. Shapiro Wilk test for normality, and Mann Whitney U test was employed to investigate group differences in number of sports played. All analyses were conducted using SPSS software.

RESULTS

Statistically significant correlations (r = .286, r2 = .08, p < 0.01) were found for both number of sport seasons and number of sports with FMS™ total score. In addition, participants without FMS™-detected asymmetries played significantly more seasons and more sports than their peers that presented asymmetries (U = 946.5, z = -1.98, p = 0.047). Finish with the actual p-value in parenthesis.

CONCLUSION

Participating in multiple sports and multiple sport seasons during high school was associated with higher FMS™ total scores. Results suggest that participating in multiple sports and multiple sport seasons was associated with fewer asymmetries, which may decrease subsequent injury risk.

LEVEL OF EVIDENCE

3b.