This Is the Hardest Lower Ab-Strengthening Move You’ve Never Heard Of

You can do all the planks, Pilates workouts, and sit-ups in the world and never once fully activate your lower abs. In core exercises, it’s much easier to hit your upper abs, obliques, and back muscles than it is to burn out your lower abs, which happen to be the most elusivecore muscles of your body. But one trainer’s tapping a very specific crunch for lower abs that will specifically hit just the right spot… and hit it hard.

“Your lower ab muscles are for sure the hardest muscles to target in your core work,” says Javi Perez, a Miami and New York City-based fitness trainer (whose Instagram Live workouts are always a good, sweaty time, BTW). “They’re the hardest to access because our hip flexors often take over.” Even when working through lower ab-specific moves, he points out that it’s easy to do them incorrectly because “that area of our body is relatively weaker than, say, your hip flexors.” So it takes precision in form to really activate them.

Perez’s go-to lower ab exercise to hit the area? “I call it out as a ‘tap, tap, tap,’ or ‘three taps out, three taps in,'” he says of his signature move. To do it, you’re in a regular crunch position with your back on your mat, feet flat on the floor, and knees bent. You crunch up with your hands behind your head and stay in that position as you jump your heels out away from your butt. You’re jumping both feet out at the same time and tapping your heel on the ground, three hops out, then hopping them three times back in to the starting position.

“It’s important when you lift your legs to keep your knees in front of you, and just do a little lift off of the ground as you tap out and tap in,” says Perez. You can keep your hands behind your head and shoulders off of the ground, or you can modify it with either your head down or your arms down by your side for extra support.

“This exercise is a really easy way to activate your lower abs, even if you have never done a concentrated lower ab exercise,” says Perez of the tap-tap-tap crunch. “The challenge with this move is to keep your knees in front of you and allow your knees to travel forward and back with just your feet.” And yes: There are variations on this move so that you can burn out your lower abs even more.

“I do it in various crunch positions, sometimes with the knees pointed up, sometimes pointing out like in a butterfly position, and sometimes with the legs extended forward, tapping out to both sides simultaneously in a V and then tapping the legs back in,” he says. Just one minute of this lower ab move will have you feeling the core-quaking goodness.