You’re not alone. Pilates instructor Norah Myers says getting a hamstring cramp during glute bridges is a maddeningly common problem.

“They do the bridge and instantly they get a hamstring cramp,” Myers says of her students. “I see it on their face, I see it in their body. Instantaneously, they come down from the bridge, they hold their leg, they’re like, ‘Ah, my hamstring!’”

It doesn’t have to be this way, people! There’s a simple fix you can make to avoid the dreaded hamstring cramp during glute bridges.

First of all, why is this even happening?

The glute bridge is, obviously, supposed to work your glutes. But if they’re not ready to work, your hamstring might activate all of a sudden to help stabilize you. The cramp is your nervous system trying to activate more muscle fibers.

“Muscle shaking and cramping happens when muscles that aren’t meant to be doing a particular exercise have to come in and compensate for muscles that aren’t engaging enough in that exercise,” Myers says.

So what can you do about it?

Myers’ advice to her clients—and the best way to prevent hamstring cramps during glute bridges—is to get your butt muscles firing before you actually lift your hips.

“If your hamstrings are cramping or shaking when you do a bridge, that means you’re not kicking in your glutes enough,” Myers says. “Really squeeze the glutes before you lift up.”

Squeezing (or activating) your muscles is important to get the most out of every exercise, not just glute moves. By making sure your biceps are working during a curl, or your core is engaged during a plank, for instance, you’ll ensure that you’re using the muscles you’re intending to work, and not relegating the stress of a movement to your joints or another body part (such as a swaying lower back). When it comes to building muscle, the mind-body connection is powerful.

Try this full-body activation workout to work on engaging your muscles.