Performance and Submaximal Adaptations to Additional Speed-Endurance Training vs. Continuous Moderate-Intensity Aerobic Training in Male Endurance Athletes

We examined performance and submaximal adaptations to additional treadmill-based speed-endurance training (SET) vs. continuous moderate-intensity aerobic training (MIT) twice / week. Twenty-two male endurance athletes were tested before and after 10-week SET (6-12 x 30-s sprints separated by 3-min rest intervals) and MIT (20-40 min continuous running at similar to 70% maximal oxygen uptake [(V)over dotO(2max)]. The SET group attained greater acute heart rate (HR) and blood lactate responses than the MIT group (d = 0.86-0.91). The SET group improved performance in a time-to-exhaustion trial, V02., and lactate threshold (d = 0.50-0.73), whereas no training-induced changes were observed in the MIT group. Additionally, the SET group reduced oxygen uptake, mean HR and improved running economy (d = 0.53-0.86) during running at 10 and 12 km.h(-1). Additional SET imposes greater physiological demands than MIT resulting in superior performance adaptations and reduced energy cost in endurance athletes.