Effect of Maturation on Anthropometrical and Fitness Variables in 13 Year-Old Girls

Abstract

Maturity can discriminate performance in individuals of similar age and because of this the use of maturity levels should be used to detect differences in fitness and body composition in youngsters. PURPOSE: To examine the differences in anthropometrical and fitness variables between different maturational stages in 13 year-old girls. METHODS: The sample was composed by 76 girls in the maturity level three (ML-3) and by 127 girls in the maturity level four (ML-4), in the age of 13 years old. The measurements of sexual maturation were made according to the procedures modified by FAULKNER (1996). Fat percentage was calculated by the equation of BOILEAU et al. (1985), blood pressure (BP) was collected by the procedures suggested by ACSM (2003), sit-and-reach test and hand grip test were performed according to JOHNSON and NELSON (1986) and VO2 max was estimated using 20-m Shuttle Run test developed by LÉGER et al (1986). Mann-Whitney U test was used to examine the difference between the means of anthropometric and fitness variables due to maturational levels. RESULTS: Chronological age was similar for ML-3 and ML-4 (13.4 ± 0.2 and 13.4 ±0.2 years). However, differences were found for body weight (45.9 ±7.1 and 51.7 ± 9.5 Kg), sitting height (82.2 ± 3.7 and 83.4 ± 3.1 cm), BMI (18.5 ± 2.6 and 20.4 ± 3.3 Kg/m2), fat percentage (25.1 ±5.7 and 28.5 ± 5.2%), lean body mass (34.1 ±4.2 and 36.7 ± 6.0 Kg), fat mass (11.7 ± 4.1 and 15.0 ± 4.7 Kg), grip strength of right hand (25.2 ± 3.3 and 26.9 ± 5.0 Kgf), grip strength of left hand (23.2 ± 4.1 and 25.2 ± 4.7 Kgf) and flexibility (23.4 ± 7.1 and 26.1 ± 7.6 cm), p<0.05. No difference was found for body height (157.3 ±6.0 and 158.7 ± 5.6 cm), systolic BP (106.7 ± 12.9 and 108.4 ± 12.7 mmHg), diastolic BP (66.0 ± 10.4 and 68.3 ± 8.8 mmHg) and predicted VO2 max (39.9 ± 4.1 and 39.5 ± 3.6 ml/kg/min). CONCLUSIONS: The self-assessment of the male reproductive tract development was useful to detect differences in anthropometric, body composition and fitness (muscular strength and flexibility) profiles in puberty girls in the age of 13 years old.