Effect of New Zealand blackcurrant extract on cycling performance across quartile distances and the final km of a 16.1 km time-trial.

Peripheral blood flow is increased by blackcurrant intake in humans, potentially via anthocyanin-induced vasorelaxation and vasodilation, which may affect performance and pacing strategy in a cycling time-trial (TT). We examined the effect of 7-days New Zealand blackcurrant (BC) extract on performance in each quartile and the last km of a 16.1 km TT. Fourteen trained male cyclists (>3 years experience; mean ± SD; age: 38 ± 13 years; height: 178 ± 4 cm; body mass: 77 ± 9 kg; V̇O2max: 53 ± 6 mL∙kg-1∙min-1, maximum power: 365 ± 36 W) completed two familiarization and two experimental time trials on an electronically braked ergometer (SRM ergometer, SRM International, Germany). Each experimental TT was preceded by 7-days supplementation of either New Zealand blackcurrant extract (300 mg∙day-1 CurraNZ™; containing 105 mg anthocyanin, Health Currancy Ltd, UK) or placebo (PL, 300 mg∙day-1 microcrystalline cellulose M102), in capsules. Experimental time-trials were separated by a 14-day washout period of the supplementation in a randomized, double-blind, cross-over design. Performance in each quartile and the last km was analyzed with paired t-tests and significance accepted at p ≤ .05. BC improved the 16.1 km TT performance by 2.4% (BC vs. PL: 1678 ± 108 vs. 1722 ± 131 s, p = .02) and allowed faster cycling speed in the 4-8 km (BC: 34.6 ± 2.2 vs. PL: 33.9 ± 2.4 km∙h-1, p = .02), 8-12 km (BC: 34.3 ± 2.3 vs.PL: 33.5 ± 2.7 km∙h-1, p = .04) and 12-16.1 km (BC: 35.2 ± 2.6 vs. PL: 34.2 ± 2.8 km∙h-1, p = .04) sectors. There was no difference in cycling speed between conditions for the last km (BC: 37.8 ± 4.1 vs. PL: 36.2 ± 3.1 km∙h-1, p > .05). Heart rate and cadence were similar between conditions in each sector and the last km of the 16.1 km TT. Intake of New Zealand BC extract allowed an increase in cycling performance for the last 75% of a 16.1 km TT. It is concluded that 7-days intake of New Zealand blackcurrant extract (CurraNZ™) has a favorable effect on overall cycling TT performance in endurance-trained athletes with implications for pacing strategy, as the performance improvement was not due to an enhanced final km