Because high-intensity interval training (HIIT) can take just 15 to 20 minutes for a full session, it tends to be an efficient addition to a workout routine, especially if you usually do steady-state ...

Welcome to our Runner's World Club Sub-3:00 marathon plan, written by world-class coaches Tom Craggs and Robbie Britton. Here, we are offering non-members a free, two-week sample of our 16-week ...