Abstract: To explore the developmental pattern of body shape, physical, and nervous system of individuals with different maturity status during puberty, and to compare the advantages and disadvantages of assessing adolescents' physical development by chronological age or biological age. Method: 551 young male swimmers were recruited in this study. Among them, 94 athletes received followed-up observation for two years since 12 years old. Cross-sectional anthropometric and fitness assessments were conducted on the rest personals (N=457),and the standard score method was used to calculate Z-scores for the early- maturing group and the late- maturing group. All subjects received tests on body shape, maturity status, physical fitness, nervous system, and testosterone. 34 athletes were further divided into early maturing (EM), normal maturing (NM), and late maturing (LM) groups according to their maturation status. Results:(1)The height growth value in EM, NM, and LM group over two years were 8.96 cm, 14.23cm, 16.64 cm respectively. The other anthropometric characteristics showed a similar pattern as height.(2)The VO₂max growth value in EM, NM, and LM group over two years were 1.22 l/min, 0.27 l/min, 0.41 l/min respectively. The other fitness characteristics showed a similar pattern as VO₂max.(3)The testosterone growth value in EM, NM, and LM group over two years were 29.43 ng/dl, 232.40 ng/dl, and 154.61 ng/dl respectively.(4)The difference between "CA" and "BA" based Z scores in 12s, 13s, and 14s for EM were-1.16, -0.94 and -0.40(P<0.05)respectively. The difference between "CA" and "BA" based Z scores in 12s, 13s, and 14s for LM were 0.70, 1.02 and 0.84(P<0.05)respectively. Conclusion: LM and NM catch up with EM in anthropometric characteristics and testosterone but not in fitness characteristics and nervous system.

Key words: adolescent, growth, maturation, talent identification, catch-up growth, swim