title: Changes in anthropometry and performance, and their interrelationships, across three seasons in elite youth rugby league players.
abstract: This study investigated the changes in anthropometry and performance, and their interrelationships, across 3 consecutive seasons (under-15 to under-17 age groups) in elite youth rugby league players. Each player participated in annual anthropometrical and performance assessments, comprising measurements of stature; body mass; limb lengths and circumference; skinfolds; predicted muscle cross-sectional area (CSA); 20-m speed, countermovement jump height, vertical power, and aerobic power. Lean body mass percentage changed (p ≤ 0.05) between the under-15 (70.9 ± 5.9%), under-16 (72.0 ± 5.8%), and the under-17 age groups (74.1 ± 5.7%). Likewise, predicted quadriceps muscle CSA also changed (p ≤ 0.05) between each age group (under-15 = 120.9 ± 37.8 cm; under-16 = 133.2 ± 36.0 cm; under-17 = 154.8 ± 28.3 cm). Concomitant changes between the under-15 and under-16 groups were found for 20-m speed (3.5 ± 0.1 cf. 3.4 ± 0.2 seconds; p = 0.008) and predicted jumping power (3,611.3 ± 327.3 W cf. 4,081.5 ± 453.9 W; p = 0.003). Both lean body mass and quadriceps muscle CSA consistently, related to both 20-m sprint time and jumping power, with r values ranging between -0.39 and -0.63 (20-m sprint time) and 0.55 to 0.75 (jumping power). Our findings demonstrate the importance of gains in lean body mass across later adolescence that support the ability to generate horizontal speed and predicted vertical power. This information informs the expectations and subsequent training programs of elite rugby league practitioners.
authors.affiliation: 1Department of Exercise and Sport Science, School of Science and Technology, University of New England, Armidale, New South Wales, Australia; and 2Department of Sport and Exercise Sciences, University of Chester, Parkgate Road, Chester, United Kingdom.
authors.forename: Mark
authors.initials: M
authors.lastname: Waldron
authors.forename: Paul
authors.initials: P
authors.lastname: Worsfold
authors.forename: Craig
authors.initials: C
authors.lastname: Twist
authors.forename: Kevin
authors.initials: K
authors.lastname: Lamb
mesh_terms: D000293:Adolescent; D000328:Adult; D000886:Anthropometry; D054874:Athletic Performance / Q000502:physiology*; D001827:Body Height; D001835:Body Weight; D005538:Football / Q000502:physiology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000033:anatomy & histology; D010809:Physical Fitness / Q000502:physiology; D012885:Skinfold Thickness