A five-year follow-up study on cardiorespiratory function in adolescent elite endurance runners

It is not known whether the superior cardiorespiratory function in adolescent athletes is attributed to the effects of training or to genetic disposition. We re-examined 6 elite endurance runners and 7 boys with ordinary physical activity 5-6 years after the first examination. At the age of 14 years the two groups did not differ as regards height, weight, percent body fat and lean body mass (LBM). The runners had slightly superior cardiorespiratory characteristics but, with the exception of lower resting and maximal heart rates (HR) in the runners, the differences were not statistically significant. At the age of 19-20 years the runners had significantly higher maximal oxygen uptake (VO2 max) per kg body weight (74 vs. 61 ml/min/kg), VO2 max/LBM (85 vs. 74 ml/min/kg LBM), calculated work at a heart rate of 170 beats/min (W170) per kg body weight (3.9 vs. 2.7 W/kg), W170/LBM (4.5 vs. 3.3 W/kg LBM), larger relative heart volume (HV) (472 vs. 369 ml/m2) and lower resting HR (52 vs. 68 beats/min) than the controls. The runners also displayed greater increases in the growth-corrected percentage changes in cardiorespiratory variables, but the differences did not reach statistical significance. We conclude that the relative VO2 max, W170 and HV values in the runners had increased as a result of a prolonged endurance training.