Original articles  EXERCISE PHYSIOLOGY AND BIOMECHANICS 

The Journal of Sports Medicine and Physical Fitness 2004 September;44(3):219-23

Copyright © 2009 EDIZIONI MINERVA MEDICA

language: English

Development of aerobic power in pubescent male soccer players related to hematocrit, hemoglobin and maturation. A longitudinal study

Hansen L. ¹, Klausen K. ²

¹ Institute of Medical Anatomy University of Copenhagen, Copenhagen, Denmark 2 Institute of Sports Science University of Copenhagen, Copenhagen, Denmark

Aim. ­More ­than ­ever ­young ath­letes are ­training inten­sively and com­pete at ­high ­levels. As ado­les­cent ath­letes are ­training in a ­period asso­ciated ­with ­many ­changes in ­growth and mat­u­ra­tion lon­gi­tu­dinal ­studies are impor­tant to elu­ci­date the devel­op­ment in phys­ical param­e­ters. The aim of ­this ­study was to eval­uate the devel­op­ment in ­aerobic ­power in ­elite as ­well as non-­elite ­soccer ­players ­during the ­years of ­puberty and to ­relate it to mat­u­ra­tion as ­well as he­mog­lobin and he­ma­tocrit.
­Methods. ­Forty-­nine ­young ­male ­soccer ­players at ­elite and non-­elite ­levels (10.5-13 y) ­were ­recruited as sub­jects. All sub­jects ­were ­tested 4 ­times ­over a ­period of 3.5 ­years. Anthro­po­met­rical param­e­ters ­including skin­fold ­were meas­ured. V.O2max was ­assessed ­during tread­mill run, tes­tic­ular ­volume and tes­tos­te­rone ­levels ­were ­used to esti­mate mat­u­ra­tion, and he­mog­lobin (Hb) as ­well as he­ma­tocrit (Htc) was meas­ured ­from ­blood sam­ples.
­Results. A lon­gi­tu­dinal devel­op­ment in V.O2max (l/min) was ­found for all ­players ­together. The ­elite ­players ­have ­higher ­values and ­steeper ­increase com­pared to non ­elite-­players. ­This dif­fer­ence was ­still ­present ­when V.O2max was ­adjusted for ­body ­weight (ml/kg/min).
Con­clu­sion. The gen­eral devel­op­ment in V.O2max was sig­nif­i­cantly cor­re­lated to the devel­op­ment in Hb and Htc as ­well as mat­u­ra­tion, but the dif­fer­ence ­between ­elite and non-­elite ­players ­could not be ­explained ­from dif­fer­ences in ­these var­i­ables. As ­elite ­players ­often are ­selected at a ­very ­young age it is pos­sible ­that ­training ­effect is ­present but it ­cannot be ­excluded ­that ­genetic fac­tors may ­play an impor­tant ­role.