Training the Adolescent Athlete

In mid-2021, we celebrated the world’s best athletes as they competed in the Tokyo Olympics. Although these international sporting events are traditionally held for adult athletes, competitors are often mere teenagers. In fact, they are often young teens. For example, some competitors from diving and swimming were only 14 years old, and skateboarding had competitors as young as 13 years old. The youngest competitor was a table tennis player, aged 12 years! Similar examples exist in elite sporting academies and competitions all around the world. With these young athletes pushing their bodies to the limit to prepare for the demands of their respective sports, it is reasonable to question if such specialized, intense training is healthy and whether the risks outweigh the benefits.

The challenges of training adolescent athletes are well-established. ¹² The different rates of biological maturation ⁷ and psychosocial development ⁸ among athletes of the same age means that a “one-size-fits-all” training approach is clearly inappropriate. Equally, adolescents are not “small adults”—a skeletally immature adolescent athlete with minimal training history will not tolerate the same training and competition loads of a highly trained and experienced adult athlete. So as health professionals, we need to provide adolescent athletes with the most informed advice to enhance their sporting experiences and maximize their chances of long-term success.

In this special issue of Sports Health, we address the scientific evidence relating to “Training the Adolescent Athlete” with 16 articles ranging in topic from addressing current thought around early sport specialization, to athlete development models, sleep considerations, and the specific injuries of competitive adolescent athletes. The following topics are covered:

• Early sport specialization, injury, and well-being

• Long-term athlete development

• Athlete monitoring

• Strength training and weight lifting

• Biological maturation

• Integrated neuromuscular training

• Training load and injury risk

Mosher and colleagues ¹¹ lead the issue with a clinical review, “Revisiting Early Sport Specialization: What’s the Problem?” They highlight the risks associated with early sport specialization, acknowledging that the mechanisms driving these effects are poorly understood. They also provide possible solutions to minimize risk and ensure recommendations provided by sports medicine practitioners are evidence based. Varghese and colleagues ¹⁴ discuss different models of youth athlete development, highlighting the strengths and limitations of each. Importantly, these authors provide a long-term athlete development framework for early childhood, middle childhood, and adolescence that considers growth rate and maturational status alongside the targeted training adaptations. Meisel et al ¹⁰ investigate early specialization, competitive volume, injury, and sleep habits in adolescent basketball players. The authors highlight the high competition workloads of these adolescents, with almost 50% of players competing in over 50 games in a 12-month period. A total 55% of players reported feeling physically exhausted, and 45% reported feeling mentally exhausted from basketball. These first articles set the stage for the rest of the issue by outlining and reviewing where thought lies today around sport specialization and the specific considerations for this population.

Given the importance of muscular strength to performance, recovery, and injury risk, 3 papers address the role of strength training/weight lifting in the physical preparation of adolescent athletes. Pierce et al ¹³ highlight the benefits of an age-appropriate, supervised weight-lifting program on both physical and psychosocial health. Other studies^2,6 highlight the benefits of strength training on movement competency. These results have clear implications for minimizing lower limb injury risk, demonstrating that under adequate supervision, age-appropriate strength training is associated with positive physical and psychosocial outcomes in adolescents.

Monitoring the athlete’s response to specific interventions, training, and competition is a critical role of sport scientists. Uthoff et al ¹⁹ investigate the effect of wearable resistance on external and internal training load in elite adolescent soccer players. The authors conclude that wearable resistance may offer a novel method of “micro-dosing” strength training without negatively affecting subsequent training sessions. Szigeti et al ¹⁷ quantify the training and competition demands of national-level adolescent soccer players. The cumulative training load performed in the 3 days prior to international matches is of particular interest; players performed up to 4 times more cumulative training load than the load experienced in matches. These findings highlight the intense physical demands placed on adolescents representing their country.

With the ongoing COVID-19 pandemic still a major concern, Seijo-Bestilleiro and colleagues ¹⁵ demonstrate that for a wide range of playing ages (4-19 years), participation in organized soccer is associated with lower rates of infection than that experienced in the general population for all ages and both sexes. Furthermore, Suppiah and colleagues ¹⁶ round out the athlete monitoring articles by using feature reduction techniques to identify key variables to predict sleep quality in adolescent athletes. Specific sport participation, training, and sleep hygiene habits were the variables with the greatest influence on sleep quality. Collectively, these articles demonstrate the high competition workloads of adolescent athletes, while also providing practical and evidence-based approaches to optimizing recovery and performance.

The relationships among chronic workload, changes in workload, and injury are explored by Johansson et al ⁵ in their study of tennis players, and Mehta et al ⁹ discuss similar implications in their study of baseball players. In the largest cohort to date, adolescent tennis players who experienced rapid changes in workload were at increased risk of back pain, shoulder complaints, and shoulder injuries. However, the evidence for high chronic workloads contributing to injury/pain is equivocal with 1 study ⁹ showing greater injury risk and others ⁴ showing no effect. Clearly, more research is needed to understand the complex relationships between workloads and injury in adolescent athletes.

In our final articles, Tenforde et al ¹⁸ and Herman et al ¹ provide a detailed analysis of health and sport organization guidelines on youth early sport specialization. Jayanthi and colleagues ³ summarize the evidence around early sport specialization, biological maturation, neuromuscular training, competition:training ratios, and workload progressions for adolescent athletes. They also provide a practical framework for coaches and parents to use when determining the load tolerance of their athletes.

This collection of clinical research, reviews, and guidelines provides practitioners with a wide range of considerations surrounding care of the young athlete and is meant to provide a compendium of the state of science as it relates to monitoring, management, and training of young athletes. Our appreciation is extended to all the authors who contributed their work to this special issue of Sports Health. We trust you will enjoy this issue and hope that it helps guide your clinical decision making with the adolescent athletes under your care.

—Tim Gabbett, PhD
Associate Editor, Sports Science