Purpose: This study investigated the effect of an individualized sodium bicarbonate (SB) supplementation-timing strategy on 200-m and 400-m freestyle swimming time-trial (TT) performance. Methods: Thirteen well-trained swimmers (8 men and 5 women; mean [SD] 22 [3] y, 1.76 [0.79] m, 73.4 [9.6] kg) had their time-to-peak bicarbonate (HCO3-) determined after ingestion of 0.3 g·kg-1 body mass SB in size 0 vegetarian capsules alongside a carbohydrate-high meal (1.5 g·kg-1 body mass). Following familiarization, participants performed 200-m and 400-m freestyle TTs after individualized timing (160 [36] min) of either SB or a placebo (PL; cornflour) on 4 separate occasions in a randomized, double-blind, crossover design. Completion times, blood lactate, and rating of perceived exertion (6-20 Borg) were measured. Results: SB did not improve completion times compared with PL during the 200-m (124.5 [7.3] vs 125.1 [6.2] s, P = .219, g = 0.09) or 400-m (263.4 [12.8] vs 264.7 [13.6] s; P = .192, g = 0.10) TTs. Blood lactate was elevated for SB compared with PL following the 200-m (12.99 [1.45] vs 10.98 [2.25] mmol·L-1; P = .042) and 400-m (13.05 [2.29] vs 10.44 [2.40] mmol·L-1; P = .017) TTs. SB reduced rating of perceived exertion after the TTs compared with PL (200 m: -0.9 [1.4] au, P = .033; 400 m: -1.2 [1.4] au, P = .012). Conclusions: SB consumed in capsules at individualized time-to-peak [HCO3-] did not improve 200-m or 400-m freestyle-swimming TT performance and might not be a worthwhile SB ingestion strategy for well-trained swimmers.
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