Effectiveness of maximum, explosive and combined strength training on endurance runners performance indicators: a systematic review and meta-analysis

Objective: This study aimed to analyze the effect of practicing maximum strength (MAX), explosive strength (EXP), or both combined (COMB) on seven runners’ performance indicators: vertical jump (VJ), one-repetition maximum squat (1RM), peak velocity/peak running speed (PV), lactate threshold (LT), middle-distance time trial (TT), maximum oxygen consumption (VO2max), and running economy (RE). Methods: A systematic review (Scopus, Web of Science, Sports Discuss, PubMed) with meta-analysis was conducted following PRISMA standards. Inclusion criteria (PICOS) were: Recreational or well-trained athletes aged 18-45 performing concurrent training for at least five weeks. The search terms used were related to different types of strength/endurance and participants’ age and sports modality. Twenty manuscripts were selected, and quality assessed with PEDro. Results: MAX training is more effective than EXP and COMB in improving VJ, 1RM, and PV, while COMB is more effective than MAX and EXP to enhance TT. MAX is more effective than EXP in improving LT. Concurrent workouts do not provide additional benefits to VO2max. It is unknown which strength modality (MAX, EXP, or COMB) is more effective in improving RE. Conclusion: Concurrent training is more effective than single-mode endurance training for enhancing specific performance variables in adult endurance runners. Middle- and long-distance runners may consider incorporating MAX training to target specific goals (i.e., improving VJ, 1RM, LT, PV) while utilizing COMB training to enhance TT. Certain variables may benefit from EXP. New randomized controlled trials are required to confirm these findings. Keywords: endurance, running, concurrent training, maximum strength, explosive strength