Left ventricular diastolic mechanics in trained athletes during submaximal exercise using speckle tracking echocardiography

Abstract

This thesis investigated sport specific responses of diastolic mechanics at rest and during submaximal exercise. Two-dimensional speckle tracking echocardiography (STE) was used to assess diastolic mechanics at rest and whilst triathletes (TRI, n=9, 32 ± 7 years), long distance runners (LDR, n=7, 34 ± 3 years), resistance trained (RT, n=5, 24 ± 5 years) and untrained controls (CON, n=5, 29 ± 5 years) performed dynamic and static exercise. Cycling consisted of 5 minute stages at 30% and 60% maximum workload (Wmax), and leg extension involved 15 second contractions at 40% and 75% maximal voluntary isometric contraction (MVIC). Peak untwisting velocity (PUV), apical and basal rotation velocities did not differ between groups at rest or during exercise (p>0.05). PUV increased in TRI from rest to 30% and 60% Wmax (p<0.01), remained unchanged in LDR, RT and CON from rest to 30% (p>0.05, p<0.05, p>0.05, respectively) and 60% Wmax (p=0.018, p>0.05, p>0.05, respectively). PUV did not change from rest to 40% (p>0.05) and 75% MVIC in TRI, LDR, CON (p>0.05) and RT (p<0.05). These findings suggest diastolic mechanics do not differ at rest or during exercise based on sport specificity, yet mixed training (TRI) athletes demonstrate augmented diastolic mechanics during dynamic exercise.