The study assessed, at the intensity of 100% of the critical speed (CS), the behavior of blood lactate concentration ([La]), rating of perceived exertion (RPE), heart rate (HR), plasma concentrations of tryptophan [TRP] of prolactin ([PRL]) and free fatty acids ([FFA]). Fourteen swimmers performed two protocols: 1) trials of 200 and 400 m at maximum intensity (V200 and V400) for the CS, 2) CS series (trials of 400 m), and rest intervals of 40 s. The main results were: (1) [TRP] and [FFA] did not differ between rest and exhaustion (p> 0.05), (2) increased [PRL], the [La], HR and RPE (p <0.05) throughout the series CS. Thus the increase in [PRL] may indicate manifestation of central fatigue in intensity corresponding to the CS.
Front Crawl Stroke; Training; Tryptophan; Prolactin
