New Zealand blackcurrant extract enhances muscle oxygenation during repeated intermittent forearm muscle contractions in advanced and elite rock climbers

Abstract

Anthocyanin-rich New Zealand blackcurrant (NZBC) may improve forearm muscle oxygenation and enhance performance in high-level rock climbers. As such, using a double-blind, randomized, crossover design study, twelve participants performed an oxidative capacity assessment, and two successive exhaustive exercise trials (submaximal forearm muscle contractions at 60 % of their maximal volitional contraction). Each visit was conducted following 7-days intake of 600 mg•day -1 NZBC extract or placebo. Oxidative capacity was estimated by calculating the oxygen half time recovery using near infrared spectroscopy. Time to exhaustion (s), impulse (kg•s), and minimum tissue saturation index (min-TSI %) were assessed during both the exercise trials. Muscle oxidative capacity was greater with NZBC (mean difference [MD] = 5.3 s, 95% confidence intervals [95% CI] = 0.4 -10.2 s; p = 0.036; Cohen's d = 0.94). During the exercise trials, there was an interaction for min-TSI % (time x condition, p = 0.046; ηp 2 = 0.372), which indicated a greater level of oxygen extraction during trial two with NZBC extract (MD = 9 %, 95% CI = 2-15 %) compared to the placebo (MD = 2 %, 95% CI = 1 -7 %). There was a decrease in time to exhaustion (p <0.001, ηp 2 =0.693) and impulse (p = 0.001, ηp 2 =0.672) in exercise trial two, with no effect of NZBC extract. In high level rock climbers 7days NZBC extract improves forearm muscle oxygenation with no effect on isolated forearm muscle performance.

Does Flavonoid Consumption Improve Exercise Performance? Is It Related to Changes in the Immune System and Inflammatory Biomarkers? A Systematic Review of Clinical Studies since 2005

“…As shown in Table 2 , since 2005, 38 articles have reported the effects of flavonoid-enriched extracts on sports performances [ 26 , 28 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 ], mainly using cycling and running performances but, also, strength testing, vertical jump, taekwondo, and the climbing test. These 38 articles referred to 37 clinical trials, because the articles by Nieman et al [ 97 ] and Ahmed et al [ 98 ] used the same clinical trial.…”

“…All of them were randomized controlled trials and double-blinded. Seven studies [ 73 , 75 , 76 , 78 , 79 , 80 , 83 ] had a crossover design, and the other six [ 77 , 82 , 83 , 84 , 86 , 87 ] had a parallel design.…”

“…Around 80% of the participants were male; specifically, there were 217 males out of 263 participants. In six studies [ 76 , 78 , 79 , 81 , 83 , 84 ], the mean age was between 19 and 25 years old. There were three studies [ 77 , 80 , 82 ] with people aged between 26 and 30 years, one [ 75 ] between 31 and 35, and three [ 73 , 86 , 87 ] with subjects aged between 36 and 40.…”

“…In eight trials [ 73 , 75 , 76 , 77 , 78 , 79 , 80 , 81 ], blackcurrants was the food source of anthocyanins, and, except for one [ 75 ], it was specifically New Zealand blackcurrants (CurraNZ™). Three studies [ 82 , 83 , 84 ] were performed with Montmorency tart cherries, one [ 86 ] with purple grapes, and one [ 87 ] with blueberries.…”

“…The dosage varied among studies between 105 mg/day [ 73 , 76 ] and 10 mL/kg/day, containing 52.6 mg/L of anthocyanins [ 86 ]. The most common dosage was between 200 and 300 mg/day [ 75 , 77 , 78 , 79 , 80 , 81 , 83 ], with only two studies using a dosage higher than 300 mg/day [ 87 , 103 ]. The length of the intervention in nine studies [ 73 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 ] was one week, with the four remaining studies being 10 days and two, three, and four weeks, respectively [ 75 , 84 , 86 , 87 ].…”