Youth Sport Specialization: Current Concepts and Clinical Guides

Abstract

The concept of youth sport specialization has evolved over the past decade, from a focus on the risk of overuse injury to a broader awareness of its effects on mental health, social well-being, quality of life, growth and maturation, sport performance, and long-term athletic success. This review article considers a recently revised definition of youth sport specialization, as well as guidelines and consensus statements from various sports medicine organizations, with practical applications for young athletes.

Introduction

As youth sports culture has evolved in the past decade, sport specialization has received significant research attention in pediatric sports medicine. An early focus on a single sport with a drive toward elite participation has shifted toward greater intensity and higher levels of competition in youth sports. Sports specialization is thought to have been first implemented in the training of young athletes in the mid-to-late 20th century in Eastern Europe [38]. In addition, it is thought that deliberate practice (ie, specific, focused, skill-based) for over 10 years is associated with achieving elite status in an activity, with the most significant physiologic benefit being the development of motor skills. Early research on deliberate practice was based on violinists, although the concept has been expanded to sports [10]. Yet in certain sports, physical demands pose injury risks or diminished mental health and quality of life (QOL). Sports medicine providers caring for young athletes have goals including to “keep kids safe” and to “keep kids in the game.”

In this article, we review the research on sport specialization, including its relationship with injury risk, mental health and emotional well-being, QOL, growth and maturation, sport performance, and long-term athletic success.

Defining Sport Specialization

In 2013, Jayanthi et al first defined “specialized” sport as including any 2 of the following 3 criteria: single-sport training, playing and/or training for more than 8 months of a year, and/or playing a single sport at the exclusion of other sports [23,28]. This definition was refined in 2015 to allow for a spectrum of sport specialization—including low, moderate, or high—based on how many criteria an athlete met. A specialized athlete may (1) choose a main sport, (2) participate for more than 8 months per year in 1 main sport, and (3) quit all other sports to focus on 1 sport [27,47]. This 3-point specialization scale has been linked with injury risk [4,26–28,40,47]. In recent years, as the science around sport specialization has developed, concerns arose about the applicability of this definition across sport settings and research study models. To address this, in 2021, Bell et al [5] conducted a Delphi study including 17 experts who came to consensus on the following definition of youth sport specialization: “intentional and focused participation in a single sport for a majority of the year that restricts opportunities for engagement in other sports and activities.”

Sport Specialization and Injury Risk

Sport injuries can have substantial impacts on physical and mental health. Recent research has suggested that sport specialization in young athletes may be associated with increased risk for certain injuries, including overuse injuries [3].

One of the earliest studies to analyze the relationship between sport specialization and athlete injury profile was a survey of self-reported injury rates in youth tennis players; Jayanthi et al reported that tennis specialization was associated with greater odds of having withdrawn from a match within the prior year due to injury [26]. This was followed by an important study by McGuine et al [40] on the association of low, moderate, or high levels of sport specialization with risk of lower-extremity injuries in 1544 high-school athletes over 2843 athletic seasons. They found that the incidence of lower-extremity injuries for moderate-level participants was higher than that for low-specialization participants (95% confidence interval [CI]: 1.04–2.20, P = .03), and the incidence of lower-extremity injuries for high-specialization participants was greater than that for low-specialization participants (95% CI: 1.12–3.06, P = .02). In addition, Post et al [56] surveyed 2011 athletes in the age range of 12 to 18 years who were recruited from athletic competitions. They found that highly specialized athletes, who played a primary sport 8 months per year or more, and athletes whose weekly hours of participation exceeded their age in years were more likely to report recent overuse injuries than their peers. Similarly, in a cohort of 546 adolescent female athletes participating in basketball, soccer, or volleyball, specialization in a single sport was associated with a 1.5-fold increase in relative risk (RR) of patellofemoral pain incidence (95% CI: 1.0–2.2, P = .038) [20]. Single-sport athletes had a 4-fold greater RR for specific diagnoses such as patellar tendinopathy or Sinding-Larsen-Johansson syndrome (95% CI: 1.5–10.1, P = .005) and Osgood-Schlatter disease (95% CI: 1.5–10.1, P = .005) than multisport athletes. There was no substantial increase in RR between single-sport and multisport participants for other knee pathologies including symptomatic plica, Hoffa fat pad impingement, pes anserine bursitis, and iliotibial band syndrome (P > .05).

Sheppard et al [62] conducted a retrospective study that examined the effects of high, moderate, and low levels of sport specialization on subjective hip and groin dysfunction in collegiate ice hockey athletes. Highly specialized athletes reported more pain, lower QOL, and lower function scores during activities of daily living (ADLs) and sport/recreation. The moderate-specialization group reported more symptoms and functional problems during ADLs than the low-specialization group. An online survey of 246 Little League baseball players (241 boys; mean age, 9.5 ± 1.6 years) completed with their parents’ help showed that 10% met criteria for high specialization, with associated behaviors including year-round play and private coaching [55]. Highly specialized Little League players reported worse throwing arm health measures compared with low-specialization players.

Bell et al [3] conducted a systematic review and meta-analysis on sport specialization in young athletes (aged ≤18 years) and injury risk. Pooled estimates and data analysis of more than 3000 athletes showed that highly specialized athletes had a greater risk of overuse injury than moderate-specialized (RR: 1.18; 95% CI: 1.05–1.33) and low-specialized participants. Moderate-specialized participants had a greater risk of overuse injury versus low-specialized athletes (RR: 1.39; 95% CI: 1.04–1.87).

The role of volume of sport participation as a potential contributing risk factor for injury is a recent area of investigation. Prospective evaluation of injury incidence in 1190 athletes, 7 to 18 years, showed that specialized athletes were more likely (odds ratio [OR] = 1.36, P < .01) to sustain a serious overuse injury (eg, spondylolysis, stress fracture) than nonspecialized athletes, controlling for age and hours of participation [50]. A cohort of 236 young (12–18 years), female, single-sport athletes was found to have trained nearly twice as many hours per week compared with multisport athletes, and an independent association was identified between increased weekly hours of training for a sport and history of lower-extremity overuse injuries (OR = 1.091, 95% CIs: 1.007–1.183, P = .034) [65]. Survey data from 102 male and female middle- and high-school long-distance runners showed that highly specialized runners reported more months of competition per year, higher weekly running distance, more runs per week, higher average distance per run, and greater running enjoyment [14]. Unexpectedly, no association between sport specialization levels and running-related injury risk or QOL was found in this cohort. Although some have suggested that this may be due to the volume of sport exposure in specialized athletes, prospective data of McGuine et al [40] demonstrated that specialized athletes had increased risk of lower-extremity injuries compared with multisport athletes, even when controlling for competition volume.

Studies continue to seek to evaluate the risk-benefit profile for sport specialization. Carder et al [7] conducted a systematic review and meta-analysis that sought to determine if sport sampling in youths was associated with a lower sports injury rate than sport specialization. From the 6 studies included, data were pooled from 5736 young athletes, and of those, 2451 (42.7%) were classified as “sport samplers,” 1628 (28.4%) were classified as “sport specializers,” and 1657 (28.9%) were considered “others” (neither samplers nor specializers). Sport specializers had a higher injury risk than sport samplers (RR: 1.37; 95% CI: 1.19–1.57; P < .0001), and there was a higher risk of injury in the specializer group than in the others group (RR: 1.09; 95% CI: 1.04–1.14; P < .005). There was also a higher risk of injury found in the others group than in the sampler group (RR: 1.21; 95% CI: 1.14–1.29; P < .0001). The authors concluded that in young athletes, sport sampling was associated with a decreased risk of injury than sport specialization.

Sport Specialization and Growth

Sport specialization often happens while young athletes are still growing, including during the “growth spurt,” a time of sexual maturation and changes in endocrine function that promote rapid physical growth [37]; peak height velocity (PHV) generally occurs at 12 years in girls and 14 years in boys. If data from childhood physical examinations cannot be obtained, PHV can be calculated using chronological age, body mass index, standing height, and seated height [44]. Using this model, it is possible to determine “age at takeoff,” which is the start of the growth spurt and of sudden height development [25]. Other body composition changes, such as increases in body fat mass, are also common during the growth spurt [1].

Several studies suggest that musculoskeletal injuries often happen during the growth spurt. An epidemiological study showed a sharp increase in traumatic knee ligamentous injury in 10- to 14-year-olds [35]. A study comparing musculoskeletal injuries in the year before PHV to those in the year of PHV found more acute injuries in the year of PHV [67]. Researchers who investigated the relationship among growth spurt, training load, and musculoskeletal injuries concluded that both growth spurt and increased training load are associated with high musculoskeletal injury risk [52]. Furthermore, growth rate and injury incidence have been linearly correlated in adolescent male athletes; that study also found that the relationship between growth rate and injury burden was not linear, but significant [29]. This suggests that healthcare practitioners who work with young athletes need to monitor onset and rate of growth and consider this a risk factor for musculoskeletal injury [29].

Laboratory-based research has been conducted on musculoskeletal injury risk during growth spurt [31,44,53,57]. A study tested static and dynamic postural control abilities in early teen athletes and concluded that physical maturation and growth have considerable implications on static and dynamic postural control [31]. Another study reported that growth and maturation-related motor disruption happens approximately 6 months prior to PHV [44]. (“Adolescent awkwardness” has been described as temporary dysfunction of motor coordination during physical growth and maturation [53,57].) Also reported in both boys and girls during the growth spurt are certain mechanical alternations affecting movement [58,72]. A longitudinal study that followed 315 pediatric and adolescent athletes found that girls demonstrated at-risk jump-landing mechanics related to a traumatic knee injury during the rapid growth phase, but this was not detected in boys [13].

Long-Term Effects

On the question of long-term athletic success, German researchers found that only 0.3% of young athletes who specialized in a single sport became international-level athletes [18]. Also, Russian researchers followed 35,000 specialized youth athletes chosen to be in a high-level training institution and found that only 0.14% became elite athletes [36]. These studies suggest that only a very small percentage of young athletes who specialize in one sport achieve elite status.

So does performing multiple sports during childhood and adolescence enhance future success for an athlete? A study that examined 1558 top-level athletes in Germany found that world-class athletes (those who ranked in the top 10 in Olympic competition and/or world championships) performed more additional sports than did national-class athletes (those who ranked in the top 10 nationally but did not reach international competition) [18]. This study also found that world-class athletes began focusing on a single sport later than national-level athletes; the average age of focus was 14.4 years in world-class athletes and 12.1 years in national-level athletes. The same research team compared specialization status between medalists and nonmedalists in international competitions in individual sports (swimming, weightlifting, and skiing), game sports (basketball, handball, and field hockey), combat sports (wrestling, boxing, and judo), and artistic composition sports (gymnastics and platform diving) and found that medalists in international competitions performed multiple sports in their childhood and that age of specialization was later than that for nonmedalists [17]. Another study found that multisport high-school athletes had longer professional careers than those who specialized in a single sport during high school [59]. Another study reported that male professional quarterbacks in American football who took part in multiple sports in high school demonstrated better in-season performance and career success [2]. Finally, a recent systematic review that synthesized 29 studies concluded that young athletes who performed multiple sports demonstrated better athletic performance [41].

Mental Health

The association between mental health and sports in young athletes has been investigated with mixed findings. Pluhar et al [54] included a survey of 756 athletes of ages 6 to 18 years and found that a higher proportion of individual-sport athletes reported anxiety or depression than team-sport athletes (13% vs. 7%, P < .01). Survey data on the mental health of 326 elite German athletes of ages between 12 and 18 years, most enrolled at elite sport schools, showed that 7% met criteria for possible anxiety, 3% for probable anxiety, 10% for possible depression, and 4% for probable depression [70]. These findings did not differ by sex or age, and the study did not include a control group. In a Norwegian study, rates of psychological distress were compared between participants in elite sport high schools (n = 611, representing 50 sports) and a control population of general high-school students (n = 355) [59]. Symptom checklists demonstrated higher levels of psychological distress in the control group (18.9%) than among the elite athletes (7.1%). Sex differences were identified, with higher rates of distress in female athletes (13.2%) than in male athletes (3.6%); these rates were 11% higher in both male and female controls than that in elite athletes. Perfectionistic traits were the greatest predictors of psychological distress in this population and have been associated with burnout in other studies as well [19]. These studies speak to the complicated interplay among sport participation, competitive level, personality traits, and the natural selection process that drives success in sport.

It is well established that physical activity/exercise has a positive effect on mental health. For example, in a cross-sectional study of 481 adolescents, those who reported more than 60 minutes of physical activity per day, 5 to 7 days per week, had 56% reduced odds of depression and 47% reduced odds of trait anxiety compared with adolescents who reported physical activity 0 to 2 days per week [39]. Sport-specialized athletes tend to have higher training volumes [12,64], and the mental health of young athletes regarding sport specialization may be linked to training volume. For example, a Swiss survey distributed to 1245 participants aged 16 to 20 years showed that peak mental well-being was evident at a mean of 14 hours of sports per week, whereas athletes at the high or low level of exercise patterns—over 17.5 hours per week, or less than 3.5 hours per week—had greater odds of poorer mental well-being (OR = 2.29 and OR = 2.33, respectively) [42].

Sleep is also closely linked to physical and mental health. Found that middle-school boys practicing more than 10 hours/week for any sport in which they participate over the course of the year slept over half an hour less than their peers who practiced fewer hours. The interaction between sleep duration and mental health in adolescents is significant, with insufficient sleep and daytime sleepiness having a close relationship with mood disorders [43]. Sleep quality has been associated with an increased risk of injury in young athletes, who are at an increased risk of sleep problems compared to nonathletes, potentially due to competing demands of academics, socializing, and athletics [8,43]. Watson et al [68] prospectively evaluated the independent relationships between sport specialization, sleep, and subjective well-being in female youth soccer players, while adjusting for the influence of training load and age. Specialized athletes reported significantly worse sleep quality during the season, although there was not a significant difference in total hours of sleep between specialized soccer players and multisport athletes. Poor sleep quality has been demonstrated to be an independent predictor of decreased competitive success in athletes and is associated with worse subjective well-being [30].

For young athletes specializing in a single sport, the sport environment and interpersonal dynamics between athletes and coaches can affect athlete mental health, with supportive environments helping to bolster resilience and mental toughness [15]. Conversely, mental health can be compromised in athletic environments that are less supportive and focus on success and performance over wellness [46]. Consequently, the specialized athlete may be involved in intensive training environments that increase risk of emotional abuse and burnout.

Well-Being and QOL

Quality of life is an important health endpoint used by clinicians, researchers, and the Department of Health and Human Services [22]. While, in general, athletes have higher health-related QOL than nonathletes, important risk factors can be detrimental to an athletes’ QOL [63,66]. In adjusted analysis for age, former female collegiate athletes were more likely to exercise and to view themselves in good/great health and were less likely to have smoked or used recreational drugs. Jayanthi et al in a qualitative parent-child study of single and multisport young athletes found no differences in health-related QOL outcomes; importantly, QOL outcomes were high across the board for all athletes [51]. Similarly, in a recent cross-sectional study of young pre-professional female dancers of ages 8 to 17 years (about 70% were specialized), QOL outcome measures were generally higher for this cohort than existing data on young nonathletes.

Studies have shown that injuries can have a significant psychosocial effect and can negatively impact QOL in athletes; furthermore, some injuries can ultimately result in symptoms consistent with post-traumatic stress disorder [21,49]. In fact, specialized athletes who had physically recovered from recent injuries reported continued lower QOL, which is consistent with prior studies showing that injuries’ impact on QOL persists long after physical recovery [6].

Sport specialization has been associated not only with overuse injuries as previously mentioned but also with increased risk of burnout [6]. Highly sport-specialized athletes have demonstrated worse subjective well-being in terms of fatigue, mood, and soreness compared with multisport athletes, even after controlling for confounding factors including age, sleep, and training load [68]. Watson et al [69] evaluated QOL among high-school female volleyball players and determined that highly sport-specialized athletes were more likely to report increased daytime sleepiness and decreased QOL, when compared to athletes with low sport specialization. Decreased QOL scoring among specialized athletes was primarily driven by lower ratings on physical QOL. Highly specialized athletes were more likely to report an injury, and when both injury history and sport specialization were incorporated into multivariable model analysis, specialization was no longer significantly associated with QOL—suggesting that the negative association between sport specialization and QOL was due to higher rates of injuries. The persistent negative impact on athlete QOL may be due to residual and long-lasting effects on athletes’ social environment and athletic identity that may be slow to return to pre-injury baseline.

Finally, Edison et al [9] has recently shown that athletic identity is higher in athletes who are more sport specialized, and while sport specialization may confer some advantages in terms of coping skills in young athletes, specialized athletes may be at heightened risk for worry than less-specialized athletes.

Current Recommendations

To minimize the risks of sport specialization, many sports associations have issued guidelines, such as those from the National Athletic Trainer Association in 2022 [48]. In 2019, the American Medical Society for Sports Medicine (AMSSM) hosted the Youth Early Sports Specialization Summit with 2 goals: identify deficiencies in research and review recommendations by major sports organizations [32]. Research gaps identified included a lack of prospective, population-based studies following athletes throughout their careers, including sport specialization; limited information on gender and family influence; disparities on how parents understood specialization; and little evidence showing that intervention would alter the course of sport specialization. Current recommendations are for broad-based prospective studies to determine the effect of sport specialization on academic and psychological outcome measures, as well as athletic development and skill. Further research is also needed to measure outcome differences between multisport and early specialized athletes.

Recommendations from major sports organizations [24,65] were divided into 4 categories: psychological development, physical development, environmental (facilities), and timing and monitoring of systems. Each of these should be addressed in a specific and quantified manner. For instance, specific ages should be identified for inclusion in an activity [33].

Clinicians should monitor all youth as noted in the 2019 AMSSM guidelines [32], which encourage multisport involvement for athletes under the age of 14 years. While there is minimal evidence that early specialization leads to elite sports, some young athletes safely choose to specialize early, and several steps have been proposed to manage their sport specialization [45].

The first step is to maintain an appropriate environment, in which expectations and responsibilities are clearly delineated and understood by staff. Gradual skill and fitness training should be provided, and total psychosocial wellness encouraged [16]. This means focusing on the athlete’s individual needs, not on competitive outcomes. Next, growth and maturation should be monitored and activities limited during some rapid growth periods. Assessments should include those for burnout, perfectionism, and academic development. Providing neuromuscular training is also essential. It integrates general sport training with biomechanics and is particularly important in early youth specialization [11]. In addition, psychological skill training helps young athletes develop the mental capacity to handle coping and multitasking [34]. Finally, the volume and intensity of training should be monitored, enabling adequate rest and recovery and time for social and educational needs. Limiting numbers of coaches and teams reduces athlete confusion and overuse [60].

In summary, an active life including exercise is important to develop in youth. With the rise in early sport specialization (defined as engaging in more than 8 months of a single sport before the age of 14 years), research has suggested that it is associated with increased risk of injury in various sports, for both boys and girls, as well as burnout and sport dropout. Clinicians are therefore encouraged to support multisport participation in childhood and adolescence. Some athletes with proper motivation may specialize early but require careful monitoring to ensure their individual developmental needs are met. Future research will aid in characterizing the mechanisms for injury risk according to sex, age, and sport contexts. Furthermore, guidance from clinicians for all athletes and for specialized athletes during periods of rapid growth or high-volume training will promote adequate time for neuromuscular training, rest, and adequate nutrition.

Supplemental Material

sj-docx-1-hss-10.1177_15563316241237526 – Supplemental material for Youth Sport Specialization: Current Concepts and Clinical Guides

Supplemental material, sj-docx-1-hss-10.1177_15563316241237526 for Youth Sport Specialization: Current Concepts and Clinical Guides by Dai Sugimoto, Kristin E. Whitney, Pierre A. d’Hemecourt and Andrea Stracciolini in HSS Journal®

Supplemental Material

sj-docx-2-hss-10.1177_15563316241237526 – Supplemental material for Youth Sport Specialization: Current Concepts and Clinical Guides

Supplemental material, sj-docx-2-hss-10.1177_15563316241237526 for Youth Sport Specialization: Current Concepts and Clinical Guides by Dai Sugimoto, Kristin E. Whitney, Pierre A. d’Hemecourt and Andrea Stracciolini in HSS Journal®

Supplemental Material

sj-docx-3-hss-10.1177_15563316241237526 – Supplemental material for Youth Sport Specialization: Current Concepts and Clinical Guides

Supplemental material, sj-docx-3-hss-10.1177_15563316241237526 for Youth Sport Specialization: Current Concepts and Clinical Guides by Dai Sugimoto, Kristin E. Whitney, Pierre A. d’Hemecourt and Andrea Stracciolini in HSS Journal®

Supplemental Material

sj-docx-4-hss-10.1177_15563316241237526 – Supplemental material for Youth Sport Specialization: Current Concepts and Clinical Guides

Supplemental material, sj-docx-4-hss-10.1177_15563316241237526 for Youth Sport Specialization: Current Concepts and Clinical Guides by Dai Sugimoto, Kristin E. Whitney, Pierre A. d’Hemecourt and Andrea Stracciolini in HSS Journal®