Piacentini, MF, De Ioannon, G, Comotto, S, Spedicato, A, Vernillo, G, and La Torre, A. Concurrent strength and endurance training effects on running economy in master endurance runners. J Strength Cond Res 27(8): 2295–2303, 2013—Running economy (RE) has been seen to improve with concurrent strength and endurance training in young and elite endurance athletes. The purpose of this study was to evaluate the effects of 2 different strength training protocols on RE and strength parameters in a group of regularly training master marathon runners. Sixteen participants were randomly assigned to a maximal strength training program (MST; n = 6; 44.2 ± 3.9 years), a resistance training (n = 5; 44.8 ± 4.4 years), and a control group (n = 5; 43.2 ± 7.9 years). Before and after the experimental period, resting metabolic rate, body composition, 1 repetition maximum (1RM), squat jump, countermovement jump, and RE were evaluated. The MST group showed significant increases (p < 0.05) in 1RM (+16.34%) and RE (+6.17 %) at marathon pace. No differences emerged for the other groups (p > 0.05). Anthropometric data were unchanged after the training intervention (p > 0.05). Taken together, the results of this preliminary study indicate that master endurance athletes seem to benefit from concurrent strength and endurance training because the rate of force development may be crucial for RE improvement, one of the major determinants of endurance performance.