Influence of sex-specific concurrent changes in age, maturity status, and morphological covariates on the development of peak ventilatory variables in 10–17-year-olds

PURPOSES: (i) To investigate the influence of concurrent changes in age, maturity status, stature, body mass, and skinfold thicknesses on the development of peak ventilatory variables in 10–17-year-olds; and, (ii) to evaluate the interpretation of paediatric norm tables of peak ventilatory variables. METHODS: Multiplicative multilevel modelling which allows both the number of observations per individual and the temporal spacing of the observations to vary was used to analyze the expired ventilation (peak [Formula: see text] ) and tidal volume (peak V(T)) at peak oxygen uptake of 420 (217 boys) 10–17-year-olds. Models were founded on 1053 (550 from boys) determinations of peak ventilatory variables supported by anthropometric measures and maturity status. RESULTS: In sex-specific, multiplicative allometric models, concurrent changes in body mass and skinfold thicknesses (as a surrogate of FFM) and age were significant (p < 0.05) explanatory variables of the development of peak [Formula: see text] , once these covariates had been controlled for stature had no additional, significant (p > 0.05) effect on peak [Formula: see text] . Concurrent changes in age, stature, body mass, and skinfold thicknesses were significant (p < 0.05) explanatory variables of the development of peak V(T). Maturity status had no additional, significant (p > 0.05) effect on either peak [Formula: see text] or peak V(T) once age and morphological covariates had been controlled for. CONCLUSIONS: Elucidation of the sex-specific development of peak [Formula: see text] requires studies which address concurrent changes in body mass, skinfold thicknesses, and age. Stature is an additional explanatory variable in the development of peak V(T), in both sexes. Paediatric norms based solely on age or stature or body mass are untenable.