Physical Fitness Changes in Adolescent Norwegians From Age 13 to 15

Abstract

PURPOSE: To describe changes in multiple components of physical fitness in Norwegian adolescents over a 2 year period corresponding with the male pubertal growth spurt. METHODS: 1059 adolescents (529 male, 530 females) from 12 public schools were invited to testing at age 13, 14, and 15 (8th-10th grade). Test participation was 75-80%. Participants performed the following tests each test period: Physical fitness: Standard or modified Push-ups to failure (upper body strength), standing broad jump (lower body strength and power), Sit & Reach (flexibility), Flamingo balance test (static balance), side-to-side hop (coordination), Multi Stage Fitness Test (aerobic capacity). Anthropometrical measures; height, weight and BMI. RESULTS: At 13 yrs, there was no significant gender difference in bodyweight females 51.5 + 9.4 kg, males 51+ 10 kg) or height (females 162 + 7 cm, males 163 +8 cm). At 15 yrs males were both significantly heavier (females 59 + 9 kg, males 65 + 11 kg, p<0.001) and taller (females 167 + 6 cm, males 176 + 7,9 cm, p<0.001). Means±SD for fitness tests are presented below:TableCONCLUSIONS: As expected, gender differences in fitness expand during puberty. Strength and power relative to bodyweight increases more in males than females. Aerobic capacity increases slightly in males while remaining stable or tending to decline in females. However, balance and gross motor coordination improve identically in males and females from age 13 to 15 yrs. Correlations among fitness components were modest (Pearson's r = 0.2-0.5), supporting the need for a multi-component index of fitness. Summation of test results as a combined Z score, with equal weighting, yields a normal distribution for fitness index in males and females.