Acute effects of beetroot juice and caffeine co-ingestion during a team-sport-specific intermittent exercise test in semi-professional soccer players: a randomized, double-blind, placebo-controlled study

• Published in: BMC sports science, medicine & rehabilitation medicine & rehabilitation, 2022-03, Vol.14 (1), p.52-52, Article 52
• Main Authors: Berjisian, Erfan, McGawley, Kerry, Saunders, Bryan, Domínguez, Raúl, Koozehchian, Majid S, de Oliveira, Caio Victor Coutinho, Rafiei, Ramin, Miraftabi, Hossein, Sarshin, Amir, Naderi, Alireza
• Format: Article
• Language: English
• Subjects: Beverages; Caffeine; Clinical trials; Cognitive ability; Comparative analysis; Countermovement jump; Decision making; Dietary supplements; Double-blind studies; Ergogenic aids; Exercise; Exercise tests; Heart beat; Nitrate; Nitrates; Physiology; Questionnaires; Soccer; Soccer players; Team-sport performance; Yo–Yo test
• ISSN: 2052-1847; 2052-1847
• DOI: 10.1186/s13102-022-00441-1

Beetroot juice (BJ) and caffeine (CAF) are considered as ergogenic aids among athletes to enhance performance, however, the ergogenic effects of BJ and CAF co-ingestion are unclear during team-sport-specific performance. This study aimed to investigate the acute effects of BJ and CAF co-ingestion on team-sport-specific performance, compared with placebo (PL), BJ, and CAF alone. Sixteen semi-professional male soccer players (age: 19.8 ± 2.2 years, body mass: 69.2 ± 6.1 kg, height: 177.3 ± 6.0 cm) completed four experimental trials using a randomized, double-blind study design: BJ + CAF, CAF + PL, BJ + PL, and PL + PL. Countermovement jump with arm swing (CMJAS) performance and cognitive function by Stroop Word-Color test were evaluated before and after the Yo-Yo Intermittent Recovery Test level 1 (YYIR1). Also, rate of perceived exertion (RPE), heart rate, and gastrointestinal (GI) discomfort were measured during each session. No significant differences were shown between test conditions for total distance covered in YYIR1 (BJ + CAF: 1858 ± 455 m, CAF + PL: 1798 ± 422 m, BJ + PL: 1845 ± 408 m, PL + PL 1740 ± 362 m; p = 0.55). Moreover, CMJAS performance, cognitive function, and RPE during the YYIR1 were not significantly different among conditions (p > 0.05). However, the average heart rate during the YYIR1 was higher in CAF + PL compared to PL + PL (by 6 ± 9 beats/min; p