Abstract
BACKGROUND: In addition to the well-known cardiac structural adaptation to exercise training, little work examined changes in LV mechanics. With new regional and global indices available we sought to determine the effect of 24 weeks endurance versus resistance training on LV mechanics. METHODS AND RESULTS: 23 male subjects were randomly allocated to either a 24-week endurance- or resistance-training program. Pre- and post-training 2D echocardiographic images were acquired. Global LV mechanics (strain [epsilon]) were recorded in longitudinal, circumferential and radial planes. Rotation was assessed at apical and basal levels. In addition, longitudinal epsilon-volume loops, across the cardiac cycle, were constructed from simultaneous LV epsilon (longitudinal and transverse strain) and volume measurements across the cardiac cycle as a novel measure of LV mechanics. Marginal differences in epsilon and rotation data were found between groups. Post-training, we found no change in global peak epsilon data. Peak basal rotation significantly increased after training with changes in the endurance group (-2.2+/-1.9(o) to -4.5+/-3.3(o)) and the resistance group (-2.9+/-3.0(o) to -3.4+/-2.9(o)) . LV epsilon-volume loops revealed a modest rightward shift in both groups. CONCLUSIONS: Whilst most global and regional indices of LV mechanics were not significantly altered, 24 weeks of intense supervised exercise training increased basal rotation. Further studies that assess LV mechanics in larger cohorts of subjects and those with cardiovascular disease and risk factors may reveal important training impacts.
