Longitudinal investigation of training status and cardiopulmonary responses in pre- and early-pubertal children.
OBJECTIVE
The presence of a maturational threshold that modulates children's physiological responses to exercise training continues to be debated, not least due to a lack of longitudinal evidence to address this question. The purpose of this study was to investigate the interaction between swim-training status and maturity in nineteen trained (T, 10 ± 1 years, -2.4 ± 1.9 years pre-peak height velocity, 8 boys) and fifteen untrained (UT, 10 ± 1 years, -2.3 ± 0.9 years pre-peak height velocity, 5 boys) children, at three annual measurements.


METHODS
In addition to pulmonary gas exchange measurements, stroke volume (SV) and cardiac output ([Formula: see text]) were estimated by thoracic bioelectrical impedance during incremental ramp exercise.


RESULTS
At baseline and both subsequent measurement points, trained children had significantly (P < 0.05) higher peak oxygen uptake (year 1 T 1.75 ± 0.34 vs. UT 1.49 ± 0.22; year 2 T 2.01 ± 0.31 vs. UT 1.65 ± 0.08; year 3 T 2.07 ± 0.30 vs. UT 1.77 ± 0.16 l min(-1)) and [Formula: see text] (year 1 T 15.0 ± 2.9 vs. UT 13.2 ± 2.2; year 2 T 16.1 ± 2.8 vs. UT 13.8 ± 2.9; year 3 T 19.3 ± 4.4 vs. UT 16.0 ± 2.7 l min(-1)). Furthermore, the SV response pattern differed significantly with training status, demonstrating the conventional plateau in UT but a progressive increase in T. Multilevel modelling revealed that none of the measured pulmonary or cardiovascular parameters interacted with maturational status, and the magnitude of the difference between T and UT was similar, irrespective of maturational status.


CONCLUSIONS
The results of this novel longitudinal study challenge the notion that differences in training status in young people are only evident once a maturational threshold has been exceeded.
College of Engineering, Swansea University, Singleton Park, Swansea, SA2 8PP, Wales, UK, m.mcnarry@swansea.ac.uk.
M A
MA
McNarry
K A
KA
Mackintosh
K
K
Stoedefalke
D000293:Adolescent; D002302:Cardiac Output; D016022:Case-Control Studies; D002648:Child; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011627:Puberty / Q000502:physiology*; D011659:Pulmonary Gas Exchange