This is a classic method for working the legs, glutes and hips, along with cardio events between resistance training.

Stand with your feet together and arms at your sides. Jump your feet apart while raising your arms overhead. Return to the starting position and repeat the movement continuously for 40 seconds.

Don’t try to hit your pace in the first minute, or even the first mile. “It’s okay to be a little bit off on the slow end,” Stachel says. In fact, with zone 3 work in general, he suggests erring on ...