Supplementary Table S1. Full Search Strategies for the Other Databases and Trial Registries Database Full search strategy Embase ('exercise'/exp OR 'training'/exp OR 'strength training': ti,ab OR 'resistance training': ti,ab OR plyometric*: ti,ab OR sprint*: ti,ab OR speed:ti,ab OR endurance:ti,ab) AND ('soccer'/exp OR soccer:ti,ab OR 'association football': ti,ab OR 'soccer player*': ti,ab OR 'football player*': ti,ab) Cochrane Library ([mh exercise] OR [mh "resistance training"] OR [mh sports] OR [mh soccer] OR exercise:ti,ab,kw OR training:ti,ab,kw OR "strength training":ti,ab,kw OR "resistance training":ti,ab,kw OR plyometric*:ti,ab,kw OR sprint*:ti,ab,kw OR speed:ti,ab,kw OR endurance:ti,ab,kw) AND ([mh soccer] OR soccer:ti,ab,kw OR "association football":ti,ab,kw OR "soccer player*":ti,ab,kw OR "football player*":ti,ab,kw) Web of Science Core Collection TS= ((exercise OR training OR "strength training" OR "resistance training" OR plyometric* OR sprint* OR speed OR endurance) AND (soccer OR "association football" OR "soccer player*" OR "football player*")) SPORTDiscus TX ((exercise OR training OR "strength training" OR "resistance training" OR plyometric* OR sprint* OR speed OR endurance) AND (soccer OR "association football" OR "soccer player*" OR "football player*")) ClinicalTrials.gov (soccer OR "association football" OR "soccer player" OR "football player") AND (exercise OR training OR "strength training" OR "resistance training" OR plyometric OR sprint OR speed OR endurance) WHO ICTRP (soccer OR "association football" OR "soccer player" OR "football player") AND (exercise OR training OR "strength training" OR "resistance training" OR plyometric OR sprint OR speed OR endurance) No study-design filter was applied in some databases and trial registries to maximize search sensitivity; randomized controlled trials were subsequently identified during screening according to the predefined eligibility criteria.