Saccharomyces boulardii supplementation does not affect anaerobic power gain induced by short-term sprint interval training in physically active individuals

Sprint interval training (SIT), which consists of vigorous-intensity exercise interspersed with periods of rest or low-intensity exercise, can improve human anaerobic performance. Probiotic strains, including yeasts (e.g. Saccharomyces boulardii; Sb), have beneficial effects on human health; however, evidence regarding the effects of probiotics on anaerobic performance is unavailable. The current study investigated whether Sb supplementation influences the SIT-induced changes to the following performance variables: peak (PPO) and mean (MPO) power output. Fifteen healthy individuals (twelve men and three women) were randomly divided into two groups: placebo (PLA; n=8) and Sb (n=7). The individuals performed six SIT sessions on a cycle ergometer (four to seven 30-s all-out sprints thrice weekly). During the training period, participants ingested a capsule containing PLA or at least 1×109 Sb cells daily for 14 days. Performance-related variables were compared between the first and last training sessions. Sb supplementation did not influence the changes in PPO and MPO across the two weeks of training (P>0.05); therefore, the data from both groups were analyzed collectively to assess performance changes induced by SIT. Training increased PPO, an index of anaerobic power, in the sixth session compared to the first session (by 8±11% in the first sprint; +1.0±1.2 W/kg; P=0.008) but did not change MPO. In conclusion, short-term SIT improved the participants' anaerobic performance (power), as evidenced by increased PPO. Sb supplementation did not affect the improved anaerobic power caused by SIT.