Effects of Blackcurrant Supplementation on Exercise Performance in Resistance-Trained Athletes: A Randomized Crossover Placebo-Controlled Trial

Background: Blackcurrant (BC) supplementation may enhance resistance training performance through mechanisms such as improved vasodilation, increased nitric oxide synthesis, and antioxidant effects. These benefits can optimize blood flow, reduce oxidative stress, and aid recovery, potentially enhancing strength, endurance, and muscle recovery during resistance exercise. Methods: Twenty resistance-trained individuals (7 males and 13 females; age: 21.5 ± 0.6 years; height: 167.9 ± 7.66 cm; weight: 73.9 ± 16.2 kg) participated in a randomized crossover study to evaluate the effects of BC supplementation. The study included three conditions: low-dose BC (LBC: 250 mg/d of BC + 350 mg/d of maltodextrin), high-dose BC (HBC: 600 mg/d of BC), and placebo (PL: 600 mg/d of maltodextrin). Participants consumed each supplement for seven days, separated by a seven-day washout period, with baseline (BL) assessments conducted prior to interventions. Performance outcomes were analyzed using a two-way repeated measures ANOVA ( p ≤ 0.05) with post hoc Fisher's LSD tests. Results: Both BC doses significantly improved one-repetition maximum (1RM) in the bench press [BL: 60.2 ± 38.5 kg, PL: 60.6 ± 38.4 kg, LBC: 63.3 ± 38.3 kg, HBC: 62.5 ± 37.9 kg; ( p = 0.002)] and leg press [BL: 263.0 ± 103.3 kg, PL: 270.2 ± 109.4 kg, LBC: 296.1 ± 114.6 kg, HBC: 284.3 ± 116.2 kg; ( p < 0.001)]. Muscular endurance, assessed as 3 rd set lifting volume, showed significant improvements for LBC over BL and for HBC over PL in the bench press [BL: 511.4 ± 408.3 kg, PL: 543.3 ± 371.3 kg, LBC: 632.4 ± 355.6 kg, HBC: 648.9 ± 548.2 kg; ( p = 0.04)], and for both BC doses compared to BL and PL in the leg press [BL: 3122.9 ± 1881.5 kg, PL: 3679.6 ± 2081.6 kg, LBC: 5585.8 ± 3042.8 kg, HBC: 4147.8 ± 2539.6 kg; ( p = 0.001)]. Total lifting volume revealed significant gains for LBC in both the bench press [LBC: 1338. ± 804.4 kg vs. BL: 1225.8 ± 859.5 kg and PL: 1257.7 ± 822.1 kg; ( p = 0.04)] and the leg press (LBC: 8661.8 ± 4085.9 kg vs. BL: 6199.0 ± 2962.7 kg and PL: 6755.6 ± 3172.6 kg; ( p = 0.001)]. However, no significant differences were observed in bench press peak power, mean power, or velocity, nor in Wingate test outcomes (peak, mean, or minimum power) following BC supplementation. Conclusion: BC supplementation, particularly at low doses, significantly enhanced muscular strength and endurance in resistance-trained individuals, with notable improvements in resistance exercise performance. However, its effects on power output remain inconclusive. This study was entirely self-funded by the researchers, ensuring independence and minimizing potential biases from external funding or grants. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.