Relationships between myocardial deformation and vascular parameters in competitive adolescent swimmers: a cross-sectional group-comparative study

Background To investigate the association between global longitudinal strain (GLS) and vascular parameters in licensed adolescent swimmers and to determine whether these associations differ from those in sedentary controls. Myocardial performance index (MPI) was evaluated as a secondary exploratory measure. Methods This single-center cross-sectional study included 40 competitive adolescent swimmers (20 short-distance and 20 long-distance) and 20 healthy sedentary controls. All participants underwent 12-lead electrocardiography, transthoracic echocardiography with speckle-tracking-derived GLS assessment, and vascular ultrasonography. Vascular measures included carotid intima-media thickness (CIMT), aortic stiffness index, aortic distensibility, and brachial flow-mediated dilation (FMD) at 1 and 3 min. Between-group comparisons, total-sample and group-stratified correlation analyses, tests of correlation differences, interaction analyses, and exploratory multivariable models were performed. Results Sixty participants were analyzed. Compared with controls, swimmers had lower resting heart rate, lower 3-minute FMD, and lower aortic distensibility but higher aortic stiffness index and CIMT; these differences were most evident in long-distance swimmers. In the total sample, more negative GLS values were associated with higher FMD and aortic distensibility and with lower aortic stiffness and CIMT. In group-stratified analyses, the association between 3-minute FMD and GLS was significant only in swimmers ( r = -0.812, p < 0.001), not in controls ( r = 0.269, p = 0.251). The difference between correlation coefficients was significant ( p < 0.001), and the FMD-3 x swimmer status interaction term was independently significant ( p = 0.017). In exploratory multivariable analysis, 3-minute FMD remained independently associated with GLS. Conclusions Associations between GLS and vascular parameters may differ between adolescent swimmers and sedentary controls, with the GLS-FMD relationship appearing particularly pronounced in swimmers. These findings do not establish causality but suggest a closer link between myocardial deformation and vascular leftacteristics in swimmers. Larger prospective studies with standardized vascular assessment are needed.