Kayla Itsines says *this* is the most common mistake people make during HIIT

Having spent many a gym sesh in the last few years sweating through Kayla Itsines’ BBG workouts, I would estimate that I have done upwards of 5,000 squats. And there’s a reason why the move—in its various iterations—is featured so heavily in her routines: Because it really, really works. Those seemingly simple up-and-down motions will make you feel the burn in your quads and thighs, and leave you with a seriously perky peach. But according to Itsines, though squats are one of the most common moves in any workout, they’re also one of the easiest to do incorrectly, which you may not even realize while you’re doing them.

“The biggest mistake that women make when they’re squatting is that their knees will fall in,” says Itsines. “Women get pain in their hips and don’t even realize that the right leg might be coming in.” So, when you wake up the next day, that’s why you might wonder what you’ve done to your left leg to make it more sore. The easiest fix? Add a resistance band into the mix.

She suggests placing a small resistance band around your thighs in order to keep your knees pointing in the right direction.  “What you’ll do is push against the band, so it focuses more on your glutes, and you’re engaging your muscles more,” she explains. “If you’re looking to engage or warm up your muscles, a resistance band is a great thing to add in. With this addition, you’re getting even resistance, so you’re focusing on those muscles rather than just doing a squat, and you’ll feel it in the right place.”

Squats aren’t the only move that Itsines likes to integrate resistance bands into. In fact, she says, you can actually replace your weights with them when you’re on the go. “You can do a bicep curl, a back row, some postural work—you can actually do a whole workout with a resistance band,” she says. So if you’ve ever taken an impromptu day off because you didn’t have weights on hand (which, I’m going to be honest, I do literally all of the time), consider that no longer a valid reason to skip your sweat sesh… even if there are dozens of squats on the menu.

Squatting the wrong way can wreak havoc on your knees, so here’s how to avoid knee pain when squatting. And this is how Kayla Itsines has tweaked her workouts now that she’s pregnant (hint: there are far fewer burpies involved).