Effect of aerobic training and detraining on left ventricular dimensions and diastolic function in prepubertal boys and girls

Purpose: The purpose of this study was to determine the effect of an aerobi c training prog ram on the left ventricular (LV) cardiac morphology and fun ction of prepubertal children. Methods: Twenty-nine 10-11 year old boys and girls (TG) participated in a 13-week running program (3 x 1 h/week, intens ity: >80% HRmax), 26, of the same age, served as a control group (CG). M-mo de, 2-dimensional and pulsed-wave Doppler analyses were performed, during r esting conditions, before and after the training period (T) as well as, for TG only, after 2 months of detraining (D). Results: LV internal chamber di mension increased (+ 4.6 %, p < 0.01) while wall thicknesses concomitantly decreased (- 10.7 %, p < 0.05) as a result of T. All cardiac morphological parameters returned to pretraining values after D. Doppler-derived measurem ents of LV diastolic filling performance were also significantly altered by T and D. A significant enhancement in the early diastolic passive LV filli ng with a concomitant reduction in the late diastolic active LV filling wer e in fact obtained after T. The training-induced bradycardia (-7 beats(.)mi n(-1) p<0.01) was probably responsible for the changes in the late characte ristics of the diastolic active filling. All diastolic filling indexes retu rned to pretraining values after D. Systolic function indexes were not modi fied after either T or D. No changes were obtained for the overall LV morph ological and functional variables after 13 weeks of normal life for CG. Con clusion: These findings indicate that cardiac morphological adaptations can occur in prepubertal children after several months of aerobic training. Th ese alterations differ however, in some areas, to those classically reporte d in adults following endurance training programs where both an increase in LV size and mass exist. Our data likewise demonstrate that endurance train ing is able to induce favourable LV diastolic filling modifications, direct ed principally towards an enhancement in the early rapid filling inflow and a corresponding reduction in the atrial contribution to the total diastoli c inflow.