The Effect of Strength Training on Endurance Performance Determinants in Middle- and Long-Distance Endurance Athletes: An Umbrella Review of Systematic Reviews and Meta-Analysis.

Abstract: Ramos-Campo, DJ, Andreu Caravaca, L, Clemente-Suárez, VJ, and Rubio-Arias, JÁ. The effect of strength training on endurance performance determinants in middle- and long-distance endurance athletes: An umbrella review of systematic reviews and meta-analysis. J Strength Cond Res 39(4): 492-506, 2025-Strength training is used to enhance endurance performance in middle- and long-distance endurance athletes. However, likely due to heterogeneity and the variety of training methodologies used, not all studies have found improvements in endurance performance with the incorporation of strength training. We aimed to review the available systematic reviews and meta-analytical evidence examining the effects of strength training on endurance performance factors in endurance-trained athletes. An umbrella review was conducted. Strength training programs were categorized into (a) maximal-strength training (>80% 1-Repetition Maximum [1RM]), (b) explosive-strength training (<80% 1RM), and (c) reactive-strength training (plyometric training). Male and/or female middle-to long-distance endurance-trained athletes were included. Variables analyzed were maximum oxygen uptake (V̇o2max), endurance performance, maximal aerobic speed or power, work and running economy, energy cost, and aerobic and anaerobic lactate thresholds. Seventeen systematic reviews were included in this umbrella review (12 with meta-analyses). Moderate to large effects were observed in all studies for running economy. Four meta-analyses examined the impact of strength training on V̇o2max, and none observed significant changes. Regarding endurance performance, 3 studies analyzed the impact of plyometric training and found small effects, except for 1 study, which found a large effect when compared with a control group. The risk-of-bias assessment revealed that most studies had low or critically low confidence levels, with issues in comprehensive literature searches, exclusion justifications, and handling publication bias. This umbrella review reveals that strength training improves endurance performance and running economy and helps maintain V̇o2max in middle- and long-distance endurance athletes. The review supports the general benefits of integrating strength training into endurance training programs.