The surprising place Kate Hudson wears weights to strengthen her core

If you follow Kate Hudson on Instagram, you’ve probably noticed that the #girlboss loves Pilates. The actress behind Fabletics always seems to be upping the intensity, so much so that she grunts through the pain. And her latest workout addition is strengthening her core even more.

In a recent Instagram post, Hudson showed off her skills doing the “grasshopper” move on the Cadillac reformer. But because she loves a good challenge, the workout warrior added ankle weights to the already-tough exercise, which, according to her instructor, makes moves even more challenging for the lower body.

“Ankle weights are a great way to change things up and work your lower [body] more.” —Nicole Stuart, Hudson’s Pilates instructor

“Ankle weights are a great way to change things up and work your lower [body] more,” celebrity trainer Nicole Stuart told Self. And even though the weights aren’t a required feature of Pilates, “Kate just likes to throw them on sometimes to switch things up.”

So should you add them to your workouts, too? Trainer Amanda Shannon Verrengia said ankle weights can amp up lower-body or core workouts, but it’s best to skip them when it comes to cardio. “They’re great for leg lifts, V-ups, and bicycles because they force your core to work extra hard to keep your legs elevated,” Verrengia said. But using the extra weight during cardio exercises could “throw off your gait, interfere with your mechanics, and potentially cause injury in your back or hips. And when you’re jumping with the weights, you’re increasing the force of impact on your muscles, joints and ligaments, which over time can wear them down.”

If you do want to add ankle weights to your routine, it’s best to start small—and make sure you don’t go overboard. Verrengia recommends starting with a two-pound weight and working up from there. “People have a tendency to get overzealous with new workout tools, but strenuous, repetitive overuse of the same muscles can lead to injury,” she said.

And, while you may want to refrain from using ankle weights during every sweat sesh, if you incorporate them into your toning-focused workouts a few times a week, you’ll soon be giving Hudson a run for her Pilates hundreds.

Here’s how Kate Hudson gets her infrared sauna fix on the go. Also, this is the one diet she swears got rid of her acne.