If her incredible dance moves and those abs-tastic mirror selfies are any indication, Jennifer Lopez is in really, really good shape—and proud of it. So when the world gets a peek at the exercises she actually does to put her muscles to work, we listen up. Celebrity trainer David Kirsch posted a video of the singer and actress doing platypus walks during a training session, and she crushes the lower-body exercise with exactly the focus you’d expect.
Wearing a shirt that says “but first, the gym” (because J.Lo’s got that dedication), Lopez is shown taking a few steps forward while holding a deep plié squat, then taking a few steps back, per Kirsch’s instructions. And while she looks strong with every step, the exercise is definitely no cake walk.
“Platypus walks work your entire body, but primarily fire up your legs and glutes,” says Sarah Otey, C.P.T. an NYC-based trainer and instructor at Barry’s Bootcamp. The challenge comes from actually doing the exercise with good form—your knees should be turned outward (instead of forward) with your knees stacked on top of your ankles. This is more difficult moving forward than moving backward, says Otey, because you have to fight against the urge to let your knees go forward.
“They require a lot of external rotation at the hip, activating all of your glute muscles,” says Otey. Done correctly, you should feel them in your butt, the backs of your legs, and your quads for a total lower-body burn, she says.
Here’s Lopez crushing them like a champ—to the tune of Justin Timberlake’s “Senorita,” no less:
They may be challenging even for a mega-star like Lopez, but platypus walks are actually an incredibly accessible exercise—there’s zero equipment required, it’s low-impact, and you don’t need a ton of space.
To try it yourself, do 40 seconds of platypus walks as quickly as you can, taking a few steps forward then a few steps back. Moving fast like J.Lo gets your heart rate up, says Otey—just make sure you can keep your form on point. You can include them in a cardio circuit, as part of a warm-up, or work them into a set of strength exercises.
Watch Kirsch, who’s also worked with celebs like Kate Upton and Heidi Klum, demo the exercise as well:
Note how Kirsch’s knees are turned out in this old-school throwback to his first fitness video (the move’s obviously been a favorite of his for a long time).
Even though we already knew that Lopez could take a mean pre-workout selfie, now we have official confirmation that she’s a beast in the gym, too—as if there was any doubt.
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