The exercise will engage, activate, stabilize and strengthen the muscles behind you, from your foot all the way up to your upper back and forearms.

“This activation will realign your body and create more stability,” says noted musculoskeletal therapist Phil Wharton, co-author of The Whartons’ Strength Book: Lower Body. “And you will generate more power, allowing you to kick in to that extra gear.”

At the start, you contract the trapezius and quadriceps muscles. On the way back up, you contract the trunk, glutes, hamstrings, ankles, calves and quadriceps. Wharton cautions that this exercise can place considerable stress loads on the sacral, lumbar and cervical spine. It can also irritate the hamstring, so don’t push it.

Beginners should attempt two sets of 10 to 12 reps per leg the first time they are trying it as a good benchmark.

Here’s a demonstration, done by Olympian Nick Symmonds (Photos: Scott Draper/Competitor)