Make sure feet are hip-width apart, and tilt your hips slightly forward so your glutes are squeezing. From there, you can either bring your hands back to your chest and call that one rep (do 10 total) or simply hold the position. It may sound easy, but think of it like a standing plank. "A lot of times it's hard for people to feel their core engaging in a plank," says Woll. "This is a good way to start to get those core muscles firing. Do a plank after this and you'll understand how it works." In a plank, you're also supporting all of your body weight, she says -- Woll only put five pounds on this cable.