Stimulus-specific functional remodeling of the left ventricle in endurance and resistance-trained men

Left ventricular (LV) structural remodeling following athletic training has been evidenced through training-specific changes in wall thickness and geometry. Whether the LV response to changes in hemodynamic load also adapts in a training-specific manner is unknown. Using echocardiography, we examined LV responses of endurance-trained (n=15), resistance-trained (n=14), and non-athletic males (n=13) to (i) 20%, 40%, and 60% one-repetition-maximum (1RM) leg-press exercise, and (ii) intravascular Gelofusine infusion (7ml·kg-1) with passive leg-raise. While resting heart rate was lower in endurance-trained vs. controls (P=0.001), blood pressure was similar between groups. Endurance-trained individuals had lower wall thickness, but greater LV mass relative to body surface area vs. controls, with no difference between resistance-trained and controls. Leg-press evoked a similar increase in blood pressure; however, resistance-trained preserved stroke volume (SV; -3±8%) vs. controls at 60% 1RM (-15±7%, P=0.001). While the maintenance of SV was related to the change in longitudinal strain across all groups (R=0.537; P=0.007), time-to-peak strain was maintained in resistance-trained but delayed in endurance-trained individuals (1% vs. 12% delay; P=0.021). Volume infusion caused a similar increase in end-diastolic volume (EDV) and SV across groups, but leg-raise further increased EDV only in endurance-trained individuals (5±5% to 8±5%; P=0.018). Correlation analysis revealed a relationship between SV and longitudinal strain following infusion and leg-raise (R=0.334, P=0.054), however, we observed no between-group differences in longitudinal myocardial mechanics. In conclusion, resistance-trained individuals better maintained SV during pressure loading, whereas endurance-trained individuals demonstrated greater EDV reserve during volume loading. These data provide novel evidence of training-specific LV functional remodeling.