How to Do Clamshells (Form & Benefits)

When you think of glute exercises, the last one you may think of is the clamshell. What you also may not realize is it's a simple yet effective exercise that strengthens your glutes and hip abductors.  

Why is that important?

As we get older, adults typically spend more time sitting, which causes glutes to weaken and hip flexors to tighten.

The less mobility we have in our hips, the more force we start to take in the lower back. The back isn’t designed to bend all the time to make up for a lack of hip mobility, it is meant for stability and support.   

What is a Clamshell?

The name comes from the way you position your legs at the start of the exercise, stacked on top of each other hinging open like a clamshell. One of the best things about this exercise is that it can be completed with little to no equipment and can be done just about anytime, anywhere.

Plus, there are many variations and progressions that you can work your way up to, but for now, we'll focus on the base clamshell, break down what muscles it works, and the benefits of the exercise.

What Muscle Groups Do Clamshells Work?

Your glutes are made up of three muscles on each side of your body: the gluteus maximus, gluteus medius, and the gluteus minimus. 

The gluteus medius is the main abductor (movement away from the midline of the body) and external rotator of the hip.

The gluteus maximus extends the hip and assists with abduction and external rotation of the leg.

Lastly, the gluteus minimus serves as the primary internal rotator of the hip joint, which helps with abduction and inward rotation at the hip.  

The clamshell exercise targets and strengthens both the gluteus medius and the gluteus maximus. These glute muscles are in charge of not only hip stabilization but also of power and balance.

Building the strength in these muscle groups helps to protect the lower back and your knees. Strengthening and growing the glute medius also helps you run faster and lift heavier. 

Who Are Clamshell Exercises For?

Hip strengthening exercises are especially important for runners or anyone who plays sports where running is involved, such as soccer or tennis.

Pretty much anyone that spends a lot of time sitting and/or not participating in weight training can benefit from this hip-strengthening exercise because they’re more likely to be prone to injuries stemming from weak hips.

So if you’re someone who struggles with feet, ankle, or knee pain chances are it originates in the hips.

Runners especially can benefit from clamshells because inadequate hip stabilization can be the underlying cause of many running injuries. To prevent such injuries, exercises such as the clamshell can create a balance between the thighs, glutes, and pelvic floor. Not to mention, this exercise feels great on tight hips.

Test Your Glutes And Hip Flexors

Even if you do not suffer from lower back, knee, or hip pain that doesn’t mean you should neglect working clamshells into your regiment. Luckily, there are some simple exercises you can use to test whether you need to focus more on your glutes. These tests can be done at home or in the gym at any time.  

Single-Leg Glute Bridges

The biggest factor to keep in mind while doing these is if your hip bone on the side with your lifted leg is sagging below the other side. If this happens, then you need to focus on strengthening your glutes. This test is better suited for non-athletes and people who are recovering from injuries. 

1. Lie on your back with your knees bent.

2. Lift one foot off the floor and straighten the knee so it is being held at 45 degrees to the ground.

3. Place your hands on your hips and keep elbows off the floor.

4. Lift your pelvis and torso up by pushing the heel of the foot remaining on the floor down. The only points of contact to the floor should be your shoulder blades, head, and foot on the floor.

5. The goal of this exercise is to try to keep your pelvis (hip bones) level.

6. Always make sure to switch sides and repeat.

Pistol Squats

Pistol squats are more suited for more advanced athletes and people with strong and stable lower body strength.

The biggest test is the inability to do the exercise without putting your balancing foot down or allowing the knee of the working leg to collapse during the test. You should also be able to maintain your balance without holding onto anything.

If you struggle to do these things while doing a pistol squat, don’t worry, clamshells can help to build your glutes. In fact, this is such a great exercise that we recommend working these into your fitness regiment even if you can do these without much trouble. 

1. Stand in front of a standard height dining chair or a workout box on its shortest side.

2. Lift one knee up to about 90 degrees of hip flexion with the slightly knee bent. This leg is meant to help with balance and shouldn’t touch the floor again until after the set is complete.

3. Perform a single leg squat until your buttocks touch the surface of the chair.

4. Do not sit down at the bottom, you should be keeping the tension on the muscles and focusing on keeping your balance. 

5. As soon as you make contact with the chair slowly stand back up keeping your opposite leg lifted off the ground until you're back at the starting position.

6. Make sure to switch sides and repeat.  

How to Perform the Clamshell Exercise

During the exercise, it's easy to rock your torso or top hip back behind you to help make it easier to raise your knee. Try to avoid doing that as it takes the good stress off of your glutes, core, and hips. If you do this, then you won't get as many of the muscle-strengthening benefits.

To prevent losing out on all of those gains, think about keeping the side of your top hip facing the ceiling the entire time you do this exercise. You can place your top hand on your hip to remind yourself of this cue, make sure that your hand doesn’t move. 

If you continue to struggle with your torso rocking or your top hip falling back behind we recommend that you try shortening the range of motion until you get more flexible and stronger.

Hip Clamshell Exercise Progression

You can progress your way to the clamshell by taking it slow and working up to it in order to avoid pain or inefficiency. This can be especially beneficial for beginners or those rehabbing from a past injury. 

Once you've worked your way through the progressions and feel confident, it's time to perform the clamshell. 

How to Do the Clamshell Exercise: 

1. Start by laying on either side and make sure your hips are stacked on top of each other. This can be performed either on an exercise mat or the floor. 

2. Stretch your right arm out along the mat. This helps to support your head and keep your body stable throughout the movement. Make sure to keep your neck neutral to avoid unnecessary strain.

3. Bend your knees to 45-degree angles and stack your top leg on top of the bottom leg. 

4. Pull your belly button towards your spine as you engage your core. This helps to stabilize your spine and pelvis. 

5. Use your top hand for control. You can place it on the ground in front of you or we recommend putting it on top of your side.

5. Keep your hips, pelvis, and upper body stationary throughout the entire movement.

6. Your feet will also remain together as you lift your top knee as high as you can without losing form. So it is an external rotation of the top femur. Your bottom leg should stay firmly on the floor.

7. Pause at the top of the movement and focus on squeezing your glute muscles. To make sure you can stay focused while you’re working out, make sure to check out CHARGED-AF.

8. Return your left knee to the starting position on top of your right.

9. Make sure to work both sides of your body, you wouldn’t want to develop imbalances. 

The Best Ways to Mix Up Clamshells

When you’re first starting off with clamshells, we recommend that you start with just your body as resistance, especially if you’re using this movement as part of your warm-up routine or as a physical therapy movement. 

As you get stronger and your hip flexors loosen up you might want to consider adding resistance or modifying the movement.

By adding resistance to the movement, you can work your glutes, core, and lower back muscles even more.

A great way to challenge yourself with clamshells is by adding a lighter resistance band. To get the most out of using a resistance band make sure to place the band around both legs, just above the knees. The band should not go around your knees, as this is a great way to injure yourself.

As you get stronger and more comfortable with bands, you can work your way up to more heavy-duty resistant bands and start incorporating this into your workout routine.

How Often Should You Do Clamshell Exercise?

Based on what you’re trying to accomplish, how often you need to do clamshells will vary. For example, whenever physical therapists are putting together exercise programs, they typically prescribe different sets and reps based on the outcome they are trying to achieve, whereas a powerlifter will need to do different sets and reps if they are trying to build strong glutes.

To make things easier here is a short guide to figuring out how often you should be doing clamshells: 

To Improve Your Activation/Coordination 

If you’re someone who is having a hard time getting those glutes to contract at all, or your hips are incredibly stiff, start with 5 sets of 15-20 reps with no extra resistance.

Make sure each repetition is done slowly with a focus on your glutes contracting.

You can do this once a day, every day of the week. 

To Build Strength

To build strength, start off by doing 4-5 sets of 6-10 reps with a resistance band that makes the last few repetitions a real challenge to do. The goal is to challenge yourself without trying to cheat the exercise without cheating.

You don’t have to do this as often as someone trying to work on their coordination so you can do this once every other day.

To Build Endurance 

Distance runners and athletes participating in longer duration sports can benefit from clamshells because inadequate hip stabilization can be the underlying cause of many endurance athletes' injuries.

To help prevent that, do 3-4 sets for as many reps as possible (with proper form) without stopping or cheating. Take adequate rest between sets, resting for 60-90 seconds between sets should be sufficient.

You can use clamshells like this once or even twice per day, five days per week. We recommend working it in towards the end of your workout routine.

To Build Strength And Endurance

You would think the best way to build up your strength and endurance is to just combine both of the sections above. Unfortunately, that isn’t the case.

If you were to do that, you could be risking injury because you may be overworking the area.

Instead, we recommend doing two sets of 6-10 reps with a resistance band and then following that up with two sets for as many reps as possible without a band.

Do that once per day, 4-5 times a week and you’ll be seeing results in no time.  

Clamshell Closing Thoughts  

There's nothing wrong with strengthening the glutes with Romanian deadlifts or hip thrusts, but the clamshell is a beneficial way to isolate this muscle group, strengthen and add flexibility to the hips, reduce back pain, and add some variety to your workout. So make sure to give them a try, your glutes will thank you later.