Objectives: The present study aimed to determine the effects of ischemic preconditioning on performance in three successive 50-m swimming trials and to measure stroke rate, stroke length and blood lactate accumulation. Design: Counterbalanced, repeated-measures cross-over study. Methods: On two separate days, eleven competitive male swimmers (20 ± 3 years, 182 ± 5 cm, 77 ± 5 kg) performed three successive 50-m trials in a 50-m swimming pool, preceded by intermittent bilateral cuff inflation (4× 5-min of blood flow restriction + 5-min of cuff deflation) at either 220 for thighs and 180 mmHg for arms (ischemic preconditioning) or 20 mmHg for both limbs (control-treatment). The 50-m trials were conducted 1-, 2-, and 8-h after the procedure. Results: While no ergogenic effect of ischemic preconditioning was observed for 1-h (0.4%, 95% confidence limits of ±0.6%, p = 0.215), there were clear beneficial effects of ischemic preconditioning on 2- and 8-h (1.0% and 1.2%, respectively; 95% confidence limits of ±0.6% in both cases, p = 0.002). Furthermore, ischemic preconditioning increased blood lactate accumulation in 2-(p < 0.001) and 8-h (p = 0.010) and stroke rate for 2- and 8-h in specific 10-m segments (p < 0.05). Conclusions: These findings suggest a time-dependent effect of ischemic preconditioning on 50-m swimming performance for competitive athletes, with the time window of the beneficial effect starting after about 2-h and lasting for at least 8-h after ischemic preconditioning. This change in performance was accompanied by an increase in blood lactate accumulation and faster strokes in front crawl.
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