It sounds too good to be true—get stronger and faster with shorter workouts. But science says that most recreational athletes are better off running or riding fewer miles and instead focusing on more intense efforts.
It’s called high-intensity interval training (HIIT), and its benefits have been outlined in an avalanche of scientific papers. A popular HIIT workout comes from researcher Izumi Tabata: Following a 10-minute warm-up, you alternate between 20 seconds of super-intense effort—as fast as you can go—and 10 seconds of rest, repeated for eight cycles. Including a cooldown, the whole workout takes just 20 minutes or so but is surprisingly effective.
Compared to those doing traditional endurance training, athletes doing HIIT not only showed an increase in their ability to do the intense efforts, they also demonstrated an increase in their aerobic endurance. This upends the age-old theory that endurance and power are separate energy systems in the body.