EFFECTS OF A CONCURRENT STRENGTH AND ENDURANCE TRAINING ON RUNNING PERFORMANCE AND RUNNING ECONOMY IN RECREATIONAL MARATHON RUNNERS

Ferrauti, A, Bergermann, M, and Fernandez-Fernandez, J. Effects of a concurrent strength and endurance training on running performance and running economy in recreational marathon runners. J Strength Cond Res 24(10): 2770-2778, 2010-The purpose of this study was to investigate the effects of a concurrent strength and endurance training program on running performance and running economy of middle-aged runners during their marathon preparation. Twenty-two (8 women and 14 men) recreational runners (mean +/- SD: age 40.0 +/- 11.7 years; body mass index 22.6 +/- 2.1 kg.m(-2)) were separated into 2 groups (n = 11; combined endurance running and strength training program [ES]: 9 men, 2 women and endurance running [E]: 7 men, and 4 women). Both completed an 8-week intervention period that consisted of either endurance training (E: 276 +/- 108 minute running per week) or a combined endurance and strength training program (ES: 240 +/- 121-minute running plus 2 strength training sessions per week [120 minutes]). Strength training was focused on trunk (strength endurance program) and leg muscles (high-intensity program). Before and after the intervention, subjects completed an incremental treadmill run and maximal isometric strength tests. The initial values for (V) over dotO(2)peak (ES: 52.0 +/- 6.1 vs. E: 51.1 +/- 7.5 ml.kg(-1).min(-1)) and anaerobic threshold (ES: 3.5 +/- 0.4 vs. E: 3.4 +/- 0.5 m.s(-1)) were identical in both groups. A significant time x intervention effect was found for maximal isometric force of knee extension (ES: from 4.6 +/- 1.4 to 6.2 +/- 1.0 N.kg(-1), p < 0.01), whereas no changes in body mass occurred. No significant differences between the groups and no significant interaction (time x intervention) were found for (V) over dotO(2) (absolute and relative to (V) over dotO(2)peak) at defined marathon running velocities (2.4 and 2.8 m.s(-1)) and submaximal blood lactate thresholds (2.0, 3.0, and 4.0 mmol.L-1). Stride length and stride frequency also remained unchanged. The results suggest no benefits of an 8-week concurrent strength training for running economy and coordination of recreational marathon runners despite a clear improvement in leg strength, maybe because of an insufficient sample size or a short intervention period.