Left Ventricular Twist Mechanics in Amateur Marathon Runners: A Speckle Tracking Echocardiographic Study

Objective: Long-term endurance exercise, such as marathon running, induces cardiac adaptations. However, the impact of different training durations on left ventricular (LV) structure and function remains incompletely understood. Methods: Marathon runners were categorized into three groups based on training duration: short-term (ST), more extended-term (MET), and long-term (LT), along with a control group of non-runners. Standard echocardiography and speckle tracking imaging were performed to assess LV structure and function. Diastolic function was evaluated via Doppler and Doppler tissue imaging parameters. LV mechanics were assessed by global longitudinal strain (GLS), apical rotation, LV twist, torsion, and untwisting rate (UTR), before and after the marathon. The distribution of Traditional Chinese Medicine (TCM) constitution types among amateur marathon runners of different ages was also investigated. Results: Compared with controls, LT runners showed increased interventricular septum diastolic (IVSd), LV end-diastolic diameter (LVEDD), LVEDD index (LVEDDi), posterior wall thickness (PW), relative wall thickness (RWT), end-diastolic volume (EDV), EDV index (EDVi), end-systolic volume (ESV), ESV index (ESVi), stroke volume (SV), stroke volume index (SVi), LV mass (LVM), and LVM index (LVMi) (p < 0.05). LT runners exhibited lower early diastolic velocity (E), E/A ratio, early diastolic annular velocity (E′a), and E/E′a ratio, but higher late diastolic atrial velocity (A) compared to ST, MET, and control groups (p < 0.01). Before the marathon, LT runners had higher absolute apical rotation, LV twist, LV torsion, and UTR, but lower GLS than other groups (p < 0.05). One hour post-marathon, LV twist and torsion showed similar trends across all runner groups (p > 0.05). Changes (Δ) in GLS, global circumferential strain (GCS), apical rotation, LV twist, torsion, and UTR were greater in LT runners compared to ST and MET groups (p < 0.05). A higher prevalence of the balanced Pinghezhi constitution (as defined by TCM) in the oldest age group (42-50 years). Conclusion: Amateur marathon runners demonstrate training duration-dependent cardiac remodeling, with long-term runners exhibiting more pronounced structural and functional adaptations. This was paralleled by a potential link between intrinsic physiological resilience and the capacity for long-term athletic adaptation.