The clamshell is the ultimate multitasking move. A classic in most Pilates practices, the exercise can help strengthen your glutes, correct your alignment, stabilize your hips and pelvis, and relieve pain in your hips, back, and knees. It’s so effective, in fact, that The Journal of Orthopaedic and Sports Physical Therapy calls the exercise one of the best moves for preventing injury and finding hip strength.

That said, the move can feel confusing (and a little bit awkward and silly) to do correctly, and as a result, you never really know if you’re reaping its full benefits. Today, trainer, Brian Spencer, is going to teach you that with the right form, the Pilates clamshell can solve all of your alignment woes.

The Pilates clamshell involves lying on your side while hinging your legs open and closed, mimicking the movement an actual clam makes underwater. This motion builds strength in key areas of the lower body, helping to improve stability in these spots. “When our pelvis and low back are in check, most of the rest of us is in check,” says Spencer. This is because by strengthening the large muscle groups in your lower body, you are minimizing the strain and tension that other functional movements and exercises inflict on your lower back or thoracic spine. Because it forces you to maintain control while you open and close, it’s great for anyone with tight hips, but especially for runners.

As far as the move itself goes, the Pilates clamshell is just what it sounds like. To do it, all you have to do is lie on your side with your knees stacked and bent at a 45-degree angle. Then, rest your head on your lower arm while using your other arm to stabilize your hips with your hand. Engage your core and then, with your feet still touching, raise your upper knee as high as it can go while still keeping your hips stacked, and return to close.

Of course, proper form is important both to prevent injury and reap the benefits of the move. In this episode of The Right Way, Spencer breaks down the 3 most common mistakes people make when doing the Pilates clamshell. Then, he demos how to do the move properly. Press play on the video above for everything you need to know. .

Oh hi! You look like someone who loves free workouts, discounts for cutting-edge wellness brands, and exclusive Well+Good content. Sign up for Well+, our online community of wellness insiders, and unlock your rewards instantly.