Abstract: Sedano, S, Marín, PJ, Cuadrado, G, and Redondo, JC. Concurrent training in elite male runners: The influence of strength versus muscular endurance training on performance outcomes. J Strength Cond Res 27(9): 2433–2443, 2013—Much recent attention has been given to the compatibility of combined aerobic and anaerobic training modalities. However, few of these studies have reported data related to well-trained runners, which is a potential limitation. Therefore, because of the limited evidence available for this population, the main aim was to determine which mode of concurrent strength-endurance training might be the most effective at improving running performance in highly trained runners. Eighteen well-trained male runners (age 23.7± 1.2 years) with a maximal oxygen consumption (V[Combining Dot Above]O2max) more than 65 ml·kg−1·min−1 were randomly assigned into 1 of the 3 groups: Endurance-only Group (n = 6), who continued their usual training, which included general strength training with Thera-band latex-free exercise bands and endurance training; Strength Group (SG; n = 6) who performed combined resistance and plyometric exercises and endurance training; Endurance-SG (ESG; n = 6) who performed endurance-strength training with loads of 40% and endurance training. The study comprised 12 weeks of training in which runners trained 8 times a week (6 endurance and 2 strength sessions) and 5 weeks of detraining. The subjects were tested on 3 different occasions (countermovement jump height, hopping test average height, 1 repetition maximum, running economy (RE), V[Combining Dot Above]O2max, maximal heart rate [HRmax], peak velocity (PV), rating of perceived exertion, and 3-km time trial were measured). Findings revealed significant time × group interaction effects for almost all tests (p < 0.05). We can conclude that concurrent training for both SG and ESG groups led to improved maximal strength, RE, and PV with no significant effects on the V[Combining Dot Above]O2 kinetics pattern. The SG group also seems to show improvements in 3-km time trial tests.