Effect of caffeine on delayed-onset muscle soreness: a meta-analysis of RCT

Abstract Background There are multiple strategies that have been suggested to attenuate delayed-onset muscle soreness (DOMS). Caffeine has been shown to assist with blocking pain associated with DOMS. However, currently there is still controversy over the effects of caffeine use. Main body We conducted a meta-analysis to compare pain associated with muscle soreness by both the VAS and indirect markers by CK of caffeine and placebo after exercise. The meta-analysis was carried out in accordance with the PRISMA guidelines. Relevant studies from Medline and Scopus published up to May 20, 2021, were included, which resulted in a total of 477 and 132 studies being retrieved from Scopus and Medline, respectively. Seven studies met the inclusion criteria, and in these, there were 68 persons in the caffeine group and 74 persons in the placebo group. A visual analog score of muscle soreness was recorded pre-exercise, immediately post-exercise, and at one to four days post-exercise; the scores at these time points in the caffeine group as compared to those in the placebo group progressed from 0.00 (95% CI − 0.51, 0.50) to − 0.20 (− 1.09, 0.69), − 0.92 (− 2.20, 0.36), − 1.02 (− 1.86, − 0.19), 0.00 (− 0.36, 0.36), and 0.18 (− 0.56, 0.92), respectively. No statistically significant differences were noted for CK between the two groups at 24 h post-exercise. Short conclusion Our meta-analysis results indicate that caffeine supplements reduce delayed-onset muscle soreness when compared to a placebo 48 h after exercise. However, at 24 h post-exercise, caffeine can reduce DOMS only in people who worked on resistant exercise. The CK used in this meta-analysis did not show any differences. Trial registration : PROSPERO CRD42021260248. Level of evidence I.