Purpose <p>Increased left atrial (LA) stiffness has been associated with atrial arrhythmias in athletes; however, data regarding the LA stiffness index in sprint athletes are limited. This study aimed to evaluate left atrial stiffness and mechanical function in competitive sprinters.</p> Methods <p>Fifty elite sprinters and thirty-five age- and sex-matched healthy sedentary controls were included. Conventional echocardiography and two-dimensional speckle-tracking echocardiography were performed. LA reservoir strain (PALS), contraction strain (PACS), and LA stiffness index (E/e′/PALS) were calculated.</p> Results <p>There were no significant differences between sprinters and controls in LA volume index (20.92 ± 5.66 vs 19.30 ± 4.29&#xa0;mL/m², <i>p</i> = 0.159), LA global PALS (40.01 ± 7.74% vs 41.67 ± 8.04%, <i>p</i> = 0.343), LA global PACS (13.63 ± 4.42% vs 15.22 ± 4.40%, <i>p</i> = 0.106), or LA stiffness index (0.14 ± 0.03 vs 0.15 ± 0.04, <i>p</i> = 0.147). LV filling pressures assessed by E/e′ ratio were also similar between groups (<i>p</i> = 0.380).</p> Conclusion <p>Long-term sprint training does not appear to affect LA stiffness or mechanical function adversely.</p>