Chronic Grape Extract in Crosstraining Athletes: A Randomized Crossover Trial

Supplementation with certain antioxidant nutrients is a feasible strategy to accelerate recovery from fatigue and prevent exercise-induced oxidative damage. Grape seed extract (GSE) contains flavonoids such as proanthocyanidins, which are potent antioxidants with numerous health benefits. Therefore, optimizing the recovery process after training is essential for athletes engaged in strength and power sports who aim to enhance performance.

Thirty trained CrossFit athletes consumed grape seed extract or a placebo for one week. The training session consisted of a 12-minute strength block, a 13-minute metabolic conditioning (MetCon), and a final 15-minute MetCon. The Rating of Perceived Exertion (RPE), Gastrointestinal Distress Score (GDS), blood pressure and the Perceived Recovery Status scale (RPS) were administered at the beginning of the session and at the end of each segment of the CrossFit session. DOMS was assessed using a visual analog scale at 24 and 48 hours after the CrossFit session.

Inclusion criteria

• Age: 18-35 years.
• Body mass index: 18.5-30 kg/m2.
• Ability to understand the instructions, objectives, and study protocol.
• Minimum of 3 years of experience in crosstraining, with at least 6 hours of weekly training over the past 3 months.
• Resident on the island of Tenerife.

Exclusion criteria

• History of a significant adverse cardiovascular event, renal insufficiency, cirrhosis, eating disorder, weight control surgical intervention, or type 2 diabetes mellitus.
• Any chronic pathology in which the intake of nutritional supplements, especially use of antioxidant supplements during the 4 weeks prior to the start of the study.
• Any condition that, in the investigator's judgment, would impair the ability to participate in the study or represent a personal risk to the participant.
• Use of medications that may affect the study results.
• Unstable body weight for 3 months prior to the start of the study (> 4 kg loss or gain in weight).
• Active tobacco abuse or illicit drug use, or history of treatment for alcohol abuse.
• On a special diet or prescribed for other reasons (e.g., celiac disease).