Specific guidelines that aim to facilitate the recovery of soccer players from the demands of training and a congested fixture schedule are lacking; especially in relation to evidence-based nutritional recommendations. The importance of repeated high level performance and injury avoidance while addressing the challenges of fixture scheduling, travel to away venues, and training commitments requires a strategic and practically feasible method of implementing specific nutritional strategies. Here we present evidence-based guidelines regarding nutritional recovery strategies within the context of soccer. An emphasis is placed on providing practically applicable guidelines for facilitation of recovery when multiple matches are played within a short period of time (i.e. 48 h). Following match-play, the restoration of liver and muscle glycogen stores (via consumption of ~1.2 g⋅kg−1⋅h−1 of carbohydrate) and augmentation of protein synthesis (via ~40 g of protein) should be prioritised in the first 20 min of recovery. Daily intakes of 6–10 g⋅kg−1 body mass of carbohydrate are recommended when limited time separates repeated matches while daily protein intakes of >1.5 g⋅kg−1 body mass should be targeted; possibly in the form of multiple smaller feedings (e.g., 6 × 20–40 g). At least 150% of the body mass lost during exercise should be consumed within 1 h and electrolytes added such that fluid losses are ameliorated. Strategic use of protein, leucine, creatine, polyphenols and omega-3 supplements could also offer practical means of enhancing post-match recovery.

Objectives. To determine the effects of consuming polyphenol-rich foods, juices and concentrates on recovery from exercise-induced muscle damage (EIMD). Method. Eligibility criteria. Randomised and quasi-randomised placebo-controlled trials with a parallel or cross-over design evaluating the effects of consuming polyphenol-rich foods, juices and concentrates on recovery from EIMD in humans. Eligible studies included at least one of the primary outcome measures: maximal isometric voluntary contraction; MIVC, delayed onset muscle soreness; DOMS, or countermovement jump; CMJ. Information sources. AMED, Cochrane Central Register of Controlled Trials, International Clinical Trials Registry Platform, PUBMED, SCOPUS (Elsevier), SPORTDiscus (EBSCO), and the UK Clinical Trials Gateway were searched from inception to September 2020. Risk of bias and quality of evidence. Risk of bias was assessed using Cochrane Risk of Bias 2 tool. Quality of the evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation framework. Synthesis of results. Random effects models were used to determine the effect of polyphenol supplementation on recovery from EIMD. Data are presented as standardised mean differences (SMD) with 95% confidence intervals (CI). Results. Included studies. Twenty-five studies were included; 15 had a parallel, and 10 had a cross-over design. A total of 527 participants (male: n = 425; female: n = 102) were included in the meta-analysis. Synthesis of results. Consumption of polyphenol-rich foods, juices and concentrates accelerated recovery of MIVC immediately post-exercise (SMD = 0.23, 95% CI 0.04, 0.42; p = 0.02; low-quality evidence), 24 h (SMD = 0.39, 95% CI 0.15, 0.62; p = 0.001; low-quality evidence), 48 h (SMD = 0.48, 95% CI 0.28, 0.67; p < 0.001; moderate-quality evidence), 72 h (SMD = 0.29, 95% CI 0.11, 0.46; p = 0.001; low-quality evidence) and 96 h post-exercise (SMD = 0.50, 95% CI 0.16, 0.83; p = 0.004; very low-quality evidence). DOMS was reduced at 24 h (SMD = −0.29, 95% CI −0.47, −0.11; p = 0.002; low-quality evidence), 48 h (SMD = −0.28, 95% CI −0.46, −0.09; p = 0.003; low-quality evidence) and 72 h post-exercise (SMD = −0.46, 95% CI −0.69, −0.24; p < 0.001; very low-quality evidence). CMJ height was greater immediately post-exercise (SMD = 0.27, 95% CI 0.01, 0.53; p = 0.04; low-quality evidence), at 24 h (SMD = 0.47, 95% CI 0.11, 0.83; p = 0.01; very low-quality evidence), 48 h (SMD = 0.58, 95% CI 0.24, 0.91; p < 0.001; very low-quality evidence) and 72 h post-exercise (SMD = 0.57, 95% CI 0.03, 1.10; p = 0.04; very low-quality evidence). Polyphenol supplementation did not alter creatine kinase, c-reactive protein, and interleukin−6 at any time points. At 72 h post-exercise, protein carbonyls (SMD = −0.64, 95% CI −1.14, −0.14; p = 0.01) were reduced. Discussion. Limitations of evidence. Risk of bias was high for 10 studies and moderate for 15. Sensitivity analyses excluding the high risk of bias studies reduced the SMDs for MIVC and DOMS, and for CMJ effects at 24 and 48 h were no longer statistically significant. Interpretation. Consuming polyphenol-rich foods, juices and concentrates accelerated recovery of muscle function while reducing muscle soreness in humans. Maximal benefit occurred 48–72 h post-exercise, however, the certainty of the evidence was moderate to very low. Supplementation could be useful when there is limited time between competitive events and impaired recovery could negatively impact performance.

Tart cherry juice (TC) and pomegranate juice (POM) have been demonstrated to reduce symptoms of exercise-induced muscle damage (EIMD), but their effectiveness has not been compared. This randomized, double-blind, parallel study compared the effects of TC and POM on markers of EIMD. Thirty-six non-resistance trained men (age 24.0 (Interquartile Range (IQR) 22.0, 33.0) years, body mass index (BMI) 25.6 ± 4.0 kg·m⁻²) were randomly allocated to consume 2 × 250 mL of: TC, POM, or an energy-matched fruit-flavored placebo drink twice daily for nine days. On day 5, participants undertook eccentric exercise of the elbow flexors of their non-dominant arm. Pre-exercise, immediately post-exercise, and at 24 h, 48 h, 72 h and 96 h post-exercise, maximal isometric voluntary contraction (MIVC), delayed onset muscle soreness (DOMS), creatine kinase (CK), and range of motion (ROM) were measured. The exercise protocol induced significant decreases in MIVC (p < 0.001; max decrease of 26.8%, 24 h post-exercise) and ROM (p = 0.001; max decrease of 6.8%, 72 h post-exercise) and significant increases in CK (p = 0.03; max increase 1385 U·L⁻¹, 96 h post-exercise) and DOMS (p < 0.001; max increase of 26.9 mm, 48 h post-exercise). However, there were no statistically significant differences between treatment groups (main effect of group p > 0.05 or group x time interaction p > 0.05). These data suggest that in non-resistance trained men, neither TC nor POM enhance recovery from high-force eccentric exercise of the elbow flexors.

The purpose of this study was to determine whether caffeinated gum influenced performance in a battery of soccer-specific tests used in the assessment of performance in soccer players. In a double-blind, randomized, crossover design, 10 male university-standard soccer players (age: 19 ± 1 years, stature: 1.80 ± 0.10 m, body mass: 75.5 ± 4.8 kg) masticated a caffeinated (200 mg; caffeine) or control (0 mg; placebo) gum on two separate occasions. After a standardized warm-up, gum was chewed for 5 min and subsequently expectorated 5 min before players performed a maximal countermovement jump, a 20-m sprint test, and the Yo-Yo Intermittent Recovery Test Level 1. Performance on 20-m sprints was not different between trials (caffeine: 3.2 ± 0.3 s, placebo: 3.1 ± 0.3 s; p = .567; small effect size: d = 0.33), but caffeine did allow players to cover 2.0% more distance during Yo-Yo Intermittent Recovery Test Level 1 (caffeine: 1,754 ± 156 m, placebo: 1,719 ± 139 m; p = .016; small effect size: d = 0.24) and increase maximal countermovement jump height by 2.2% (caffeine: 47.1 ± 3.4 cm, placebo: 46.1 ± 3.2 cm; p = .008; small effect size: d = 0.30). Performance on selected physical tests (Yo-Yo Intermittent Recovery Test Level 1 and countermovement jump) was improved by the chewing of caffeinated gum in the immediate period before testing in university-standard soccer players, but the sizes of such effects were small. Such findings may have implications for the recommendations made to soccer players about to engage with subsequent exercise performance.

Emerging evidence indicates that fruits rich in polyphenols may attenuate exercise-induced muscle damage and associated markers of inflammation and soreness. This study was conducted to determine whether bilberry juice (BJ), which is particularly rich in polyphenols, reduces markers of muscle damage in runners completing a half marathon. A total of 21 recreationally trained runners (age 30.9 ± 10.4 y; mass 71.6 ± 11.0 kg; M = 16; F = 5) were recruited to a single blind, randomised, placebo-controlled, parallel study. Participants were block randomised to consume 2 × 200 ml of BJ or energy-matched control drink (PLA) for 5 d before the Sheffield Half Marathon, on race day, and for 2 days post-race. Measurements of delayed onset muscle soreness (DOMS), muscle damage (creatine kinase; CK) and inflammation (c-reactive protein; CRP) were taken at baseline, pre-race, post-race, 24 h post-race and 48 h post-race. The effect of treatment on outcome measures was analysed using magnitude-based inferences based on data from 19 participants; 2 participants were excluded from the analyses because they did not provide samples for all time points. The half marathon caused elevations in DOMS, CRP and CK. BJ had a possibly harmful effect on DOMS from pre-race to immediately post-race (11.6%, 90% CI ± 14.7%), a likely harmful effect on CRP from pre-race to 24 h post-race (mean difference ES 0.56, 90% CI ± 0.72) and a possibly harmful effect on CRP from pre-race to 48 h post-race (ES 0.12, 90% CI ± 0.69). At other time points, the differences between the BJ and PLA groups in DOMS and CRP were unclear, possibly trivial or likely trivial. Differences in the changes in CK between BJ and PLA were unclear at every time point other than from baseline to pre-race, where BJ had a possibly harmful effect on reducing muscle damage (ES 0.23, 90% CI ± 0.57). Despite being a rich source of antioxidant and anti-inflammatory phytochemicals, BJ evoked small to moderate increases in exercise-induced DOMS and CRP. Further larger studies are required to confirm these unexpected preliminary results.