Cardiac responses to exercise in competitive child cyclists

Abstract

These findings indicate that 1) maximal stroke volume is the critical determinant of the high VO2max in child cyclists and 2) factors that influence resting stroke volume are important in defining VO2max differences between child endurance athletes and untrained boys.

Cardiovascular responses to endurance training in children: effect of gender

“…It can be argued that our aforementioned results were obtained during resting conditions and cannot therefore be extrapolated to maximal exercise. However, as previously reported in pediatric longitudinal [12] and cross-sectional [11,44] studies, SV max patterns from rest to maximal exercise in our experiment were not altered by training (Fig. 1).…”

“…VO 2max , maximal oxygen uptake; Q, cardiac output; SV, stroke volume; AVO-D, arterio-venous oxygen difference; SVR, systemic vascular resistances; E, peak velocity of early diastolic rapid inflow; A, peak velocity of late diastolic rapid inflow; LVEDd, end-diastolic left ventricular internal diameter; ST, interventricular septal thickness; PWT, end-diastolic posterior wall thickness; LVM, left ventricular mass. However, as previously reported in pediatric longitudinal [12] and cross-sectional [11,44] studies, SV max patterns from rest to maximal exercise in our experiment were not altered by training (Fig. We might postulate that the repetitive overload imposed on the ventricle after training could have caused the addition of myocardial fibres in series.…”

“…central and /or peripheral adaptations) by which V O 2max increases in children after training are however, not yet fully elucidated. Cross-sectional studies have reported higher V O 2max in endurance-trained children because of the higher maximal stroke volume (SV max ) only [10,11]. In healthy subjects, aerobic training increases V O 2max [4 -6] but the magnitude of improvement appears to be limited when compared with adults, even if training stimuli or initial physical fitness are taken into account [7].…”

“…In children, far less information is available on this topic. Cross-sectional studies have reported higher V O 2max in endurance-trained children because of the higher maximal stroke volume (SV max ) only [10,11]. However, whether these superior cardiac functional capacities reflect the effect of training or are simply the result of genetic factors cannot be easily determined from such studies.…”

Aerobic fitness and its relationship to sport, exercise training and habitual physical activity during youth

“…Cross-sectional studies have reported that trained young athletes of both sexes have higher peak VO 2 than their untrained peers44–46 and focused studies have reported higher peak VO 2 than untrained youth in trained cyclists,47–49 cross-country skiers,50 swimmers51–54 and canoeists 50. Young male athletes tend to have higher peak VO 2 than young female athletes and although this is probably due to the sex differences described earlier variations in training volume cannot be ruled out.…”