Youth and adolescent athletes: training, injury and development

Training young athletes means training a moving target: bodies that are growing, maturing and specialising at different rates. This guide starts where the field agrees, the international consensus on youth athletic development, the position statement on youth resistance training, and the consensus on paediatric ACL injuries, which together push back on the myth that strength training stunts growth and set out how to load young athletes safely. It then layers on the individual studies we have appraised, from injury-prevention programmes to early specialisation. Along the way it defines the key terms and answers the questions clinicians and coaches ask most. Where the evidence is thin, particularly in the youngest age groups, we say so.

Updated as new evidence lands · last reviewed at Issue 9

youth-athlete

Foundations: consensus & guidelines

The international consensus statements this topic is built on. Start here, then read the appraised studies below against them.

WHO · 2020Physical activity and sedentary behaviour, WHO guidelines

Global guidelines on physical activity and sedentary behaviour across the lifespan and clinical populations.

  • Adults should do 150 to 300 minutes of moderate, or 75 to 150 minutes of vigorous, aerobic activity per week, plus muscle strengthening on two or more days.
  • Some physical activity is better than none, and any amount counts toward health benefits; sedentary time should be limited.
  • Recommendations extend across the lifespan and to pregnancy, older adults and people with chronic conditions or disability.

Our appraisal: A GRADE-informed guideline from a large evidence review, so the dose targets are among the better-grounded numbers in this field. Its limitation is deliberate breadth: it sets population activity doses, not sport-specific training prescriptions, and stops short of a firm sedentary-time threshold.

Read the statement ↗
IOC Injury and Illness Epidemiology Consensus Group · Bahr et al. (BJSM) · 2020IOC consensus on methods for recording and reporting epidemiological data on injury and illness in sport 2020 (STROBE-SIIS)

IOC consensus standardising how injury and illness are defined, recorded and reported in sport, and introducing the STROBE Extension for Sport Injury and Illness Surveillance.

  • Standardises definitions for injury and illness, their severity, and how athlete exposure is captured and reported.
  • Introduces the STROBE Extension for Sport Injury and Illness Surveillance (STROBE-SIIS) as a reporting guideline.
  • Recommends expressing risk as incidence and burden, that is severity combined with incidence, rather than injury counts alone.

Our appraisal: This is a methods consensus, not a clinical recommendation; its value is making injury and illness data comparable across studies and squads. It does not tell you how to prevent injury, but it defines the denominator and outcomes against which any prevention claim should be judged.

Read the statement ↗
IOC · Ardern et al. (BJSM) · 2018Paediatric ACL injuries: 2018 IOC consensus statement

International consensus on the prevention, diagnosis and management of anterior cruciate ligament injuries in skeletally immature patients.

  • Stresses that management in growing children must protect open growth plates and be individualised with the family.
  • Prioritises timely diagnosis, specialist involvement and shared decision-making over a one-size-fits-all surgical rule.
  • Highlights neuromuscular training as the mainstay of prevention in youth.

Our appraisal: Expert consensus addressing questions where randomised evidence in children is scarce; it frames a cautious, individualised approach rather than resolving graft or timing debates. Weight it as the best available structured guidance for a population that trials rarely study.

Read the statement ↗
IOC · BJSM · 2016Training/competition load and injury & illness risk, IOC consensus

IOC consensus on how training and competition load relate to injury and illness risk, and how to monitor it.

  • Load itself is not the enemy; appropriate, progressive load builds the capacity that protects athletes, whereas rapid changes relative to what an athlete is accustomed to are associated with raised injury risk.
  • Recommends monitoring both external load, what the athlete does, and internal load, the physiological and psychological response, alongside athlete wellbeing.
  • Presents the acute:chronic workload ratio as one monitoring concept, flagging rapid load increases as higher risk, and stresses individualised load progression.
  • Notes that many modifiers, including sleep, psychological stress and previous injury, shape the relationship between load and injury.

Our appraisal: Structured expert consensus rather than a trial, so it frames how to think about load rather than proving any threshold. Note that the acute:chronic workload ratio it helped popularise has since been heavily criticised on methodological grounds, including spurious correlation, arbitrary cut-offs and uncertain modelling, so treat specific ratios as a prompt for discussion, not a rule.

Read the statement ↗
IOC · Bergeron et al. (BJSM) · 2015Youth athletic development: IOC consensus statement

International consensus on developing healthy, resilient and capable young athletes, covering maturation, training, specialisation and wellbeing.

  • Emphasises that training and expectations should track biological maturation, not just chronological age.
  • Cautions against early single-sport specialisation for most youth, citing overuse injury and burnout risk.
  • Frames long-term athletic development around enjoyment, diverse movement and appropriate progressive loading.

Our appraisal: Consensus synthesis of expert opinion and observational evidence; it sets sound developmental principles rather than prescribing validated dose thresholds. It is most useful as a framework for age- and maturity-appropriate planning.

Read the statement ↗
IOC · Ljungqvist et al. (BJSM) · 2009IOC consensus on periodic health evaluation of elite athletes

IOC consensus recommending a structured periodic health evaluation for elite athletes, covering cardiovascular, musculoskeletal, general and mental health.

  • Recommends a structured, periodic health evaluation rather than a single one-off pre-participation examination.
  • Covers cardiovascular screening, musculoskeletal assessment, and general and mental health.
  • Positions the evaluation as a chance to educate athletes and establish baselines, while acknowledging limited evidence that screening prevents outcomes.

Our appraisal: Expert consensus from 2009, so both the evidence and some recommendations, particularly around cardiac screening, have moved on and remain debated. It is useful as a template for what a periodic health review can cover, but it is not evidence that screening changes injury or illness outcomes.

Read the statement ↗
NSCA · Faigenbaum et al. (Journal of Strength and Conditioning Research) · 2009Youth resistance training: NSCA position statement

National Strength and Conditioning Association position statement on the safety, benefits and prescription of resistance training for children and adolescents.

  • Concludes that supervised, appropriately prescribed resistance training is safe and effective for children and adolescents.
  • Finds no evidence that resistance training damages growth plates or stunts growth when technique and progression are sound.
  • Recommends qualified supervision, correct technique and gradual progression as the conditions for safe training.

Our appraisal: A position statement drawing on a broad literature review; it settled the growth-plate myth and remains a practical reference, though it predates some newer long-term athletic development work. It tells you youth lifting is safe and beneficial when coached well, not the optimal programme for a given child.

Read the statement ↗

The evidence, appraised

Individual studies we have appraised, read against the consensus above, newest first.

Worth knowingEffects of Strength Training on Cognitive Function, Brain-Derived Neurotrophic Factor and Insulin-Like Growth Factor 1 in Highly-Trained Young Female Soccer PlayersAdding strength training helped teen female players get stronger, pass better and score higher on a Stroop test, but their BDNF and IGF-1 levels didn't move, so skip the 'rewires the brain' pitch.OverhypedThe Effects of Exergames on Fundamental Movement Skills in Childhood: A Systematic Review and Meta-analysisA 'meta-analysis' built only from significant comparisons claims exergames match traditional activity for kids' movement skills, but no pooled effect size is reported.Watch this spaceSex-Specific Adolescent Development of the Trochlea and Distal Femoral Physis: A 3D Shape Modeling StudyDeep learning 3D modeling maps sex-specific trochlear and growth plate development in teens, useful groundwork, but no effect sizes given and no surgical protocol yet.Watch this spacePersonalizing the Quadriceps Tendon Graft in Anterior Cruciate Ligament Reconstruction: A Novel, Continuous Method to Predict Graft Size Using Preoperative MRI. A new MRI formula predicts QT graft diameter within 1mm in 90% of cases, but the screening cutoff for 'small grafts' has only 39% specificity.Watch this spaceUnderstanding Anterior Cruciate Ligament Adaptation: Structural, Mechanical, and Healing ConsiderationsThe ACL looks trainable like tendon and bone, but this review is a conceptual framework, not proof any specific training dose cuts injury risk.Not yetPrevious Hamstring Injury Does Not Impact Biceps Femoris Long Head Fascicle Length and Eccentric Knee Flexion Strength Changes Following a Low-Volume Resistance Training Intervention in Elite Under-20-Year-Old Male Gaelic FootballersA small, uncontrolled 9-week Nordic/RDL study in youth Gaelic footballers found modest fascicle-length gains but no strength gains, and was too underpowered to say whether prior hamstring injury blunts adaptation.Practice-changingWorld Health Organization 2020 guidelines on physical activity and sedentary behaviourWHO's 2020 update gives clinicians concrete activity dose targets for every population, including pregnancy and chronic disease, but still won't say how much sitting is too much.Worth knowingThe Epidemiology of Catastrophic Head and Neck Injuries in High School and College Non-Football Sports: A 4-Decade ReviewCatastrophic head/neck injuries in non-football sports have fallen roughly 10-fold since the 1980s, but high school gymnasts and hockey players remain the highest-risk group today.

Key terms in this topic

Frequently asked

Is resistance training safe for children?

Yes. The NSCA position statement concludes that supervised, well-designed resistance training is safe and beneficial for children and adolescents, and that it does not damage growth plates when technique and progression are appropriate. The old fear that lifting stunts growth is not supported by the evidence. Competent supervision, appropriate loads and sound technique are the conditions that make it safe.

Does early sport specialisation improve long-term success?

The IOC youth development consensus cautions against early single-sport specialisation for most young athletes, linking it to higher rates of overuse injury and burnout without reliable long-term performance gains. Diverse, multi-sport participation is generally favoured through childhood. This is expert consensus drawing on observational evidence, so it is a well-reasoned steer rather than proof.

How are paediatric ACL injuries managed differently from adults?

The 2018 IOC paediatric ACL consensus highlights that skeletally immature patients need surgical techniques and decisions that respect open growth plates, and that management should be individualised with families involved in shared decisions. It stresses prevention, timely diagnosis and specialist involvement. As with other consensus statements, it frames the approach rather than settling every technical question.

Can injury-prevention programmes reduce injuries in young athletes?

Neuromuscular training programmes that combine strength, balance and landing technique, such as FIFA 11+, reduce injury rates in youth sport, and consensus supports their use. The effect varies with how well and how consistently programmes are delivered, and adherence is the main practical barrier. They lower risk; they do not eliminate it.

Should training load follow biological maturity rather than age?

Consensus favours accounting for biological maturity, not just chronological age, because children of the same age can differ markedly in development. This matters for grouping, load and expectations. The principle is well supported in consensus; the practical tools for measuring maturity in everyday settings remain imperfect.

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