Growth, Maturation and Health Profiles of Youth Triathletes; Associations with Training Load, Injury and Illness

To examine the health history, growth and maturation profiles, and current health status of youth triathletes prior to entry into a National Institute Network (NIN); and determine associations between growth, training load, and health problem severity to inform developmental training strategies.

Youth triathletes (ages 12-18) were monitored over one year. Data was collected on athletic health history, growth (height, weight, arm spam) and maturation (bone age (BA); peak height velocity (PHV), predicted adult height (PAH), PAH%). Over 10 weeks the Oslo Sports Trauma Research Centre questionnaire (OSTRC-H2 questionnaire), training load and rate of perceived exertion (RPE) were recorded across triathlon disciplines.

Estimated PHV occurred later than population norms (Female 12.5 ± 0.7; Male 13.3 ± 0.6). Estimated BA exceeded chronological age (CA) in both sexes. Males showed higher height tempo (B = 0.09, PD = 0.85), and arm span tempo than females (B = 0.20, PD = 0.96). Higher maturity offset was associated with greater total health problem severity (B = 0.23, PD = 0.98), reflecting a 25% increase per 1-year in maturity offset, and males typically had higher total severity (B = 0.52, PD = 0.90). Illnesses (n = 22) exceeded injuries (n = 14) and resulted in more total time-loss (3 vs 2 weeks). Swimming had the highest training volume, 24% higher than the bike (B = -0.28, PD = 0.99) and 44% higher than the running (B = -0.58, PD = 1.00), although more lower limb injuries were reported.

Sex-based maturation differences in youth triathletes require tailored training; high illness and injury prevalence identify the need for growth monitoring and balanced training to support long term athlete performance progression.