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.
Study Goal
The researchers aimed to investigate the acute effects of beetroot juice and caffeine co-ingestion on team-sport-specific performance compared to placebo, beetroot juice alone, and caffeine alone.
Results Summary
The study found no significant differences in team-sport-specific performance, cognitive function, or perceived exertion between beetroot juice, caffeine, their combination, and placebo. However, beetroot juice and caffeine co-ingestion increased gastrointestinal distress, and caffeine alone elevated heart rate compared to placebo.
Population
Sixteen semi-professional male soccer players (age 19.8 ± 2.2 years).
Effective Dosage
Not specified in the abstract.
Duration
Acute (single-dose intervention).
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Beetroot juice and caffeine co-ingestion | no change | total distance covered in Yo-Yo Intermittent Recovery Test level 1 | sixteen semi-professional male soccer players | no significant change | no significant differences were shown | #1 |
Caffeine alone | no change | total distance covered in Yo-Yo Intermittent Recovery Test level 1 | sixteen semi-professional male soccer players | no significant change | no significant differences were shown | #2 |
Beetroot juice alone | no change | total distance covered in Yo-Yo Intermittent Recovery Test level 1 | sixteen semi-professional male soccer players | no significant change | no significant differences were shown | #3 |
Placebo | no change | total distance covered in Yo-Yo Intermittent Recovery Test level 1 | sixteen semi-professional male soccer players | no significant change | no significant differences were shown | #4 |
Beetroot juice and caffeine co-ingestion | no change | countermovement jump with arm swing performance | sixteen semi-professional male soccer players | no significant change | were not significantly different | #5 |
Caffeine alone | no change | countermovement jump with arm swing performance | sixteen semi-professional male soccer players | no significant change | were not significantly different | #6 |
Beetroot juice alone | no change | countermovement jump with arm swing performance | sixteen semi-professional male soccer players | no significant change | were not significantly different | #7 |
Placebo | no change | countermovement jump with arm swing performance | sixteen semi-professional male soccer players | no significant change | were not significantly different | #8 |
Beetroot juice and caffeine co-ingestion | no change | cognitive function | sixteen semi-professional male soccer players | no significant change | were not significantly different | #9 |
Caffeine alone | no change | cognitive function | sixteen semi-professional male soccer players | no significant change | were not significantly different | #10 |
Beetroot juice alone | no change | cognitive function | sixteen semi-professional male soccer players | no significant change | were not significantly different | #11 |
Placebo | no change | cognitive function | sixteen semi-professional male soccer players | no significant change | were not significantly different | #12 |
Beetroot juice and caffeine co-ingestion | no change | rate of perceived exertion during the Yo-Yo Intermittent Recovery Test level 1 | sixteen semi-professional male soccer players | no significant change | were not significantly different | #13 |
Caffeine alone | no change | rate of perceived exertion during the Yo-Yo Intermittent Recovery Test level 1 | sixteen semi-professional male soccer players | no significant change | were not significantly different | #14 |
Beetroot juice alone | no change | rate of perceived exertion during the Yo-Yo Intermittent Recovery Test level 1 | sixteen semi-professional male soccer players | no significant change | were not significantly different | #15 |
Placebo | no change | rate of perceived exertion during the Yo-Yo Intermittent Recovery Test level 1 | sixteen semi-professional male soccer players | no significant change | were not significantly different | #16 |
Caffeine alone | increase | average heart rate during the Yo-Yo Intermittent Recovery Test level 1 | sixteen semi-professional male soccer players | by 6 ± 9 beats/min | was higher | #17 |
Beetroot juice and caffeine co-ingestion | increase | gastrointestinal distress | sixteen semi-professional male soccer players | by 2.4 ± 3.6 a.u. | was greater | #18 |
BACKGROUND: 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. METHOD: 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. RESULTS: 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 < 0.05), and GI distress was greater in BJ + CAF compared to PL + PL (by 2.4 ± 3.6 a.u.; p < 0.05). CONCLUSION: These results suggest, neither acute co-ingestion of BJ + CAF nor BJ or CAF supplementation alone significantly affected team-sport-specific performance compared to the PL treatment.