CHANGES IN BMI AND PHYSICAL FITNESS DURING EARLY ADOLESCENCE IN A NORWEGIAN SAMPLE

1. CHANGES IN BMI AND PHYSICAL FITNESS DURING EARLY ADOLESCENCE IN A NORWEGIAN SAMPLE Faculty of Health and Sport Haugen, T., Møll, Ø., Seiler, S. University of Agder INTRODUCTION 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). Females increased their performances in all fitness-tests, except ESR, from age 13 to 15. Males improved in PU, SBJ, and SS. There were also improvements in ESR, SAR, and FLB, but only from age 13 to 14. The Scandinavian countries have not escaped the trend towards decreased physical activity (PA) and increased prevalence of overweight and obesity among both children and adults (Anderssen et al., 2008) . Given the potential connections among PA, overweight, and future risk of disease, considerable attention has been given to increasing physical activity to improve cardiovascular fitness and reduce or maintain a healthy body composition. Current data quantifying different components of fitness in Norwegian children is scarce, making longitudinal assessment in the adolescent population difficult. Table Percentiles: Mean percentiles for the flamingo balance (FLB), standing broad jump (SBJ), sit-and-reach (SAR), and endurance shuttle run (euroESR) for 13-15 year old boys and girls from Norway relative to their age and sex matched peers from 23 other European countries (Tomkinson et al., 2007). Note, for the endurance shuttle run, Norwegian boys and girls were also compared to their age and sex matched peers from 37 countries around the world (worldESR) (Olds et al., 2006). PURPOSES The purposes of this study were; 1) to provide normative data quantifying the current physical fitness level of 13-to 15 year old Norwegian youth using a multi-component fitness assessment, 2) to quantify longitudinal changes in fitness in adolescents during this period of rapid physical growth, and 3) to compare the fitness of Norwegian teenagers with available European and International fitness data. DISCUSSION METHODS As expected, gender differences in fitness expand during puberty. Strength and power relative to bodyweight increases more in males than females. Aerobic capacity increases in males while remaining stable or tending to decline in females. However, balance and 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. When FLB-, SBJ-, SAR, and ESR results were compared with matched peers from 23 other European countries (from Tomkinson et al., 2007), and the ESR test with matched peers from 37 countries around the world (from Olds et al., 2006) our Norwegian sample performed superior in ESR, FLB, and SBJ, but inferior in SAR. Summation of test results as a combined Z score, with equal test weighting yields a normal distribution for fitness index in both males and females. 1059 adolescents (529 male, 530 females) from 12 public schools were invited to testing at age 13, 14, and 15. Test participation was 75-80%. The participants performed the following tests each test period: Physical fitness: Standard or modified Push-ups (PU, upper body strength) to failure, standing broad jump (SBJ, strength legs), Sit & Reach (SAR, flexibility), Flamingo balance test (FLB) (static balance), side to side hop (SS, coordination), Multi Stage Fitness Test (ESR, aerobic capacity). Anthropometrical measures; height, weight and BMI. References Anderssen, SA, Engeland, A, Søgaard, AJ, Nystad, W, Graff-Iversen, S, Holme, I. (2008). Scand J Med Sci Sports, 18:309-317. Olds, TS, Tomkinson, GR, Léger, LA, & Cazorla, G. (2006). J Sports Sci. 24:1025-1038. Tomkinson, GR, Olds, TS, & Borms, J. In G.R. Tomkinson & T.S. Olds. (Eds) (2007). 50:104-128. Medicine and Sport Science Series. Basel: Karger. 14th annual Congress of the ECSS, 24-27 June 2009, Oslo - Norway