Adaptation of left ventricular twist mechanics in exercise-trained children is only evident after the adolescent growth spurt

The extent of structural cardiac remodelling in response to endurance training is maturity dependent. In adults, this structural adaptation is often associated with the adaptation of left ventricular (LV) twist mechanics. For example, an increase in LV twist often follows an expansion in end-diastolic volume, whereas a reduction in twist may follow a thickening of the LV walls. Whilst structural cardiac remodelling has been shown to be more prominent post-peak height velocity (PHV), it remains to be determined how this maturation-dependent structural remodelling influences LV twist. Therefore, we aimed to (I) compare LV-twist mechanics between trained vs. untrained children pre- and post-PHV, and (ii) investigate how LV structural variables relate to LV-twist mechanics pre- and post-PHV. LV function and morphology were assessed (echocardiography) in endurance-trained and untrained boys (n=38 and n=28, respectively) and girls (n=39 and n=34, respectively). Participants were categorised as either pre- or post-PHV using maturity offset to estimate somatic maturation. Pre-PHV, there were no differences in LV twist or torsion between trained vs. untrained boys (twist: P=0.630; torsion: P=0.382) or girls (twist: P=0.502; torsion: P=0.316), and LV-twist mechanics were not related with any LV structural variables (P>0.05). Post-PHV, LV twist was lower in trained vs. untrained boys (P=0.004), with torsion lower in trained groups, irrespective of sex (boys: P