Effect of swimming intensity on performance in subsequent sprint triathlon: a sex-based analysis in amateur athletes

Abstract

Purpose Generally, triathletes participating in short events should aim to finish the swim stage with the leading group to improve their chances in the subsequent cycling and running stages. However, the fatigue associated with very intense swimming can impair subsequent split times. This study aimed to investigate the impact of swimming bout intensity on performance in subsequent cycling, running, and overall racing among well-trained male and female amateur triathletes. Methods Twenty athletes (12 men and 8 women) participated in this study. Critical velocity (CV) was estimated for swimming using a simple linear model. Body composition and maximal oxygen uptake were measured. Participants visited the laboratory three times to swim 750 m at intensities below CV, at CV, and above CV (in randomized order), before they cycled 20 km and ran 5 km as fast as they could to simulate a sprint triathlon. Heart rate, blood lactate level, perceived exertion, muscle pain, and dyspnea levels were measured at the end of each modality. Results For women, on the day on which swimming intensity was below the CV, the overall race time was higher than on the day on which swimming intensity was at the CV (p = 0.041) or faster than the CV (p = 0.002). For men, there was no significant difference in the overall race time among the three intensities (p > 0.05). Conclusion The results showed that, for men, swimming at higher intensity did not significantly change total time, whereas for women, lower intensity was associated with poorer performance.