Ninety-eight young male soccer players were investigated for differences between elite players (E) and non-elite players (NE) in height, weight, BMI, skinfold, maturation, genetic potential for height, and birth weight and length. The subjects were included in the study at the age of 10-12 years and then examined three times with half-year intervals. Maturation was evaluated by testicular volumes. In addition, serum testosterone and insulin-like growth factor-I were measured. Adjustment for age was carried out because of a difference in age (11.9 [E] vs. 11.6 [NE] years) between the two groups. The players selected for the elite group were taller (152.7, 155.7, and 160 cm (E) vs. 147.4, 150.1, and 154.3 cm (NE), p = .015; MANOVA), had lower values for skinfolds (27.6, 28.3, and 27.5 mm (E) vs. 33.7, 35.1, and 36.1 mm (NE), p = .005), and greater testicular volume, compared with non-elite players (5.8, 7.6, and 9.3 ml (E) vs. 3.9, 5.0, and 6.6 ml (NE), p < .05). A tendency for higher values of serum testosterone in the elite group was present (p = .076), but no difference in IGF-I was found (p = .796). No differences in the genetic constitution for height was found. The present data shows that young soccer players selected for the best teams are taller, leaner, and more mature compared to young soccer players at a lower level.
L. Hansen, K. Klausen, and J. Bangsbo are with the Institute of Exercise and Sport Sciences in the Department of Human Physiology at the University of Copenhagen, DK-2100 Copenhagen, Denmark. J. Müller is with Department of Growth and Reproduction at Rigshospitalet, Copenhagen, Denmark.