How to Do the Reverse Clamshell for Well-Rounded Glute Strength

Reverse clamshells might sound like a corny dance move, but it's the ultimate exercise for maximizing the tiny but mighty muscle in your glutes: the gluteus medius.

Your gluteus medius is the small, deep muscle located on your outer glutes that plays a vital role in rotating your hip and moving your leg away from your body. Strengthening this muscle can help reduce your risk of injury and keep low back pain at bay.

• ​What is the reverse clamshell?​ It's a hip mobility and glute-strengthening exercise done while lying on your side with your legs and hips stacked and knees bent. It targets your gluteus medius as you rotate your top hip inward and lift your top foot and calf.
• ​What muscles do reverse clamshells work?​ Reverse clamshells train internal hip rotation, which happens when your thigh rotates toward your midline (the imaginary line that separates the two halves of your body). This motion primarily strengthens your gluteus medius.
• ​What's a clamshell vs. reverse clamshell?​ A traditional clamshell has the same starting position as a reverse clamshell, but you lift your top knee while your feet stay together.
• ​Who can do this exercise?​ This exercise is great for all fitness levels, but especially for those who want to build stronger glutes. Since it doesn't require equipment, you can do it anywhere.

The reverse clamshell exercise involves the internal rotation of your hip, meaning your thigh bone twists so the top of your leg rotates toward the center of your pelvis. This is the same motion your hips do when you walk, run and play sports, so it's important to strengthen this motion.

Painful internal hip rotation, morning stiffness, and hip pain are common symptoms associated with hip joint osteoarthritis, according to a 2013 article in ​Musculoskeletal Imaging​. By strengthening the muscles that support your hip joints — like your gluteus medius — you can help reduce pain and improve limited mobility associated with hip osteoarthritis, according to the Arthritis Foundation.

During some movements, when one hip can't internally rotate far enough for normal pelvis function, your other hip helps out by externally rotating, twisting your other thigh bone away from the center of your body.

Many other exercises that work on internal hip rotation make it difficult to isolate just one hip — potentially causing your other hip to externally rotate to help out, despite your best efforts.

But the reverse clamshell exercise immobilizes that other hip by planting it against the floor. In this position, you can only rotate the hip of your top leg, isolating the movement you're trying to train.

After just a few reps of this move, you'll feel your gluteus medius burning. Strengthening this muscle can help prevent low back pain. In an October 2019 review from ​BMC Musculoskeletal Disorders​, researchers found that people who have a weaker gluteus medius are more likely to have low back pain.

Your knee and ankle don't move during a reverse clamshell, so how can it protect you against injury in those joints? Sometimes, injuries occur in these areas when there's a weakness in ​another​ muscle or joint, and the joint that winds up getting hurt had to pick up the slack.

When your gluteus medius is weak, your knee may be more likely to collapse inward when you're moving side to side, a condition called "knee valgus." In this situation, your anterior cruciate ligament (ACL) — which stabilizes your knee joint — can tear. And weak hip muscles are also associated with lower limb injuries, according to a May 2012 review in ​Gait and Posture.​

As you lift your calf and foot, your hip doesn't need to have an extreme amount of internal rotation for the move to be effective. Having a smaller range of motion is very normal, so don't force your leg past what's comfortable.

When lying on your side, your thighs can be straight out in front of you, as if you were sitting in a chair. They can also be at a 45-degree angle to your torso, as in a quarter squat. Or they can be in line with your torso, with your shins pointed behind you.

Your hip can internally rotate in all of these positions, so pick the one that's most comfortable for you. As long as your knees are bent 90 degrees and your hips are stacked on top of each other, you can do the reverse clamshell exercise.

If you roll forward so your top thigh is slightly more forward than your bottom thigh, you may find it's easier to lift your foot. You'll also notice that your gluteus medius doesn't feel the exercise as much. Keep your thighs parallel to the floor and your hips perpendicular to it in the starting position to maximize your benefit.

This simple stretch can help improve internal rotation of the hip, Steven Head, owner of Head Strong Fitness and Performance, tells LIVESTRONG.com. It's a good alternative to the reverse clamshell exercise. Start here if the original move feels too intense for you right now.

The mini band adds resistance, making the move harder. But you may not need it! If you're able to feel the gluteus medius after a set without the band, you don't need the additional resistance.

Although his move doesn't train rotation of the hip, it's a great alternative to the reverse clamshell. It works your gluteus medius, and one of this muscle's main functions is to "abduct" the hip — to raise the leg out to the side.

With this reverse clamshell progression, you'll target your gluteus medius by moving your hip away from the middle of your body and extending your foot up. Although you won't be able to lift your foot and calf very high, you should feel this in the outer part of your glute.