Effects of a 25-km trial on psychological, physiological and stroke characteristics of short- and mid-distance swimmers

Aim: The aim of this paper was to evaluate the effects of a very long distance swimming task on psychological, biomechanical and physiological responses. Eight swimmers (age 21.0±1.2 years; stature 1.80±0.07 m; body mass 76.7±11.0 kg; means±SD) participated in a 25-km trial in a swimming pool. Methods: Before and immediately after the trial, swimmers underwent a 50-m sprint test, during which we assessed velocity, stroke rate (SR), stroke length (SL) and psychological condition (rate of perceived exertion [RPE] and profile of mood state [POMS] questionnaire). During the 25-km trial we determined also elbow angle, heart rate (HR) and lactate concentration ([La]). Results: Velocity, SR and SL during the sprint test after the trial decreased compared to before from 1.91±0.01 m·s-1, 0.94±0.01 cycles·s-1 and 1.99±0.02 m·cycle-1 to 1.45±0.01 m·s-1, 0.78±0.01 cycles·s-1 and 1.84±0.03 m·cycle-1, respectively (P<0.05). During the 25-km trial, velocity and SL decreased significantly, while SR and elbow angle did not change. Velocity and SR during the sprint test after the trial were significantly higher than those during the trial. RPE and fatigue (POMS subscale) increased significantly, while the other negative POMS subscales and vigor decreased significantly. HR decreased significantly at 20 km, then increasing significantly at 25 km, while [La] did not change. Conclusion: These results suggest that, despite the occurrence of fatigue, as evidenced by the drop in velocity and changes in psychological profile, swimmers were able to complete the 25-km trial by adopting a conservative pacing, unveiling also a reserve in maximum performance.