The side lying clamshell exercise is one of the most prescribed exercises for people with weak glutes. Clamshells are a favourite exercise of most physical therapists and featured in nearly every group class as the best way to strengthen your gluteus medius muscle. While the clamshell is intended to have good activation of the gluteal muscles there are several problems this exercise that can create problems in the hip and pelvic region, and in some cases can even make the glutes weaker! In this article, I will explain how to use this exercise correctly and ensure you avoid the common mistakes many people make.

Why Is The Clamshell Exercise So Popular?

One of the main reasons people love this exercise so much is that it is so simple to do and requires no equipment other than a small resistance band. The skill level is very low and someone can learn this exercises instantly, although it can be completed poorly which I will explain shortly. It is usually very effective at producing a muscle fatigue in your butt once you complete about 15 reps although you need to use a small band around your knees as shown in the picture above. Without a band it does next to nothing. EMG studies have found good activation of both the gluteus medius and gluteus maximus muscles during the clamshell so this is usually enough for most people to feel confident using this as a “go-to” exercise for the glutes.

This low skill requirement, combined with the fact it targets the glute area quite well, makes it a safe option for a trainer or therapist to feel confident in prescribing it to someone as a corrective exercise for weak glutes. Most trainers and therapists will know that weak glutes contribute to creating many injuries like knee pain, back pain, hip related problems. Having exercises in your toolbox that you are confident people can do on their own is vital in finding a successful outcome for their problem. 

I myself have used this exercise for many years, and still do. However, I also recognize its limitations and the problems it can create if not used wisely and prescribed carefully. I learned this lesson the hard way several times when prescribing it to a person with hip and glute weakness in the belief it would help their condition, only to make things much worse. I have also seen several people become really good at this exercise and suffer no complications, but it did very little to help them with their existing problem.

Having a better understanding of how the hip really works is the secret to knowing whether to use this exercise or not. Hopefully by the end of this article you will know how to use this exercise more effectively. Firstly we need to explain what the glutes actually do.

What Do The Glutes Actually Do?

The Gluteus Medius is a hip extensor, abductor, and external rotator while it also stabilizes the pelvis in the frontal plane. There is three distinct heads of the gluteus medius muscle that perform a unique role as the body moves:

1. The posterior fibres - These fibres contract at early stance phase to lock the ball into the hip socket. The posterior fibres therefore essentially perform a stabilising or compressing function for the hip joint.
2. The middle/anterior fibres - These run in a vertical direction, help to initiate hip abduction, this is where the clam comes in which is then completed by a hip flexor muscle known as the TFL. The glutes work in tandem with TFL in stabilising the pelvis on the femur, to prevent the other side dropping down.
3. The anterior fibres - These allow the femur to internally rotate in relation to the hip joint at mid-to-end stance phase. This is essential for pelvic rotation, so that the opposite side leg can swing forward during gait. The anterior fibres perform this role with TFL.

What this means is that to truly strengthen the glutes you will need an exercise that performs ALL of these three key functions in order to restore optimal movement and strengthen correctly. The clamshell exercise while effective with hip abduction it ignores the other key functions the glute medius performs. People often wrongly assume if you make a muscle stronger it will automatically work better. If you think doing 3 sets of 20 reps of the clam is going to make your glutes work better when you walk or run you will be in for a big surprise.

The best exercise to effectively stabilize the hip, act as a hip rotator, and lock the head of the femur into the socket, creating a very tight and stable hip joint during gait are single leg stance exercises. More specifically the single leg deadlift or single leg squat. These single leg exercises not only strengthen the glutes more effectively but they prevent the ball and socket joint from rattling around during walking and running.

For more information on this make sure you read the article – Why the single leg squat is the best exercise for knee pain

You can also find a ton of ideas for glute strengthening in the FREE checklist below you can instantly download by clicking here.

Unfortunately, these movements are very difficult to learn and compensation can be a real problem so you will need to regress to easier exercises and work your way up. This is where the clamshell can be useful if it is used in this way. More on this shortly.

But…….. You need to be aware of potential problems it can cause.

When Clamshell Exercises Cause Problems

If you fail to assess the hip correctly you can run into some big problems with using this exercise. The hip flexor muscle tensor fascia latae (TFL) is often found to be dominant and hypertonic that will inhibit the glutes from firing. This means that many people who present with weak glutes and hip stability problems preferentially engage the TFL instead of stabilizing the hip using the Glut Medius. Since the TFL continues onto the Iliotibial Band (ITB), symptoms often present along the lateral leg when the TFL is hypertonic.

In addition to this you will often find the quadratus lumborum (QL) on the opposite side to be tight and strong as a compensatory reaction to the pelvis dropping on the weakened side. Both the TFL and QL over time will become stronger and tighter as they seek to provide a new form of stability to the pelvis. This over-activity must be addressed first before attempting to strengthen as they effectively inhibit the glutes from firing. They basically “steal” their work and this is when the clamshell exercise exacerbates this compensation by assisting the TFL in becoming even stronger.

You must attempt to weaken these areas first using stretching, foam rolling, and various mobility work as shown in the videos below.

You can read more about this in the articles below

• 10 best hip mobility drills
• How to correct lateral pelvic tilt
• Are tight hips the cause of your knee or back pain?

The other thing to consider is the technique being used. While this is a very low skill exercise it can be performed very poorly that can lead to poor activation of the glutes.

Three of the most common compensations are:

1) Rolling the Pelvis Backward. To find an easier way to lift the leg and avoid activating the gluteus medius you will see people try to use momentum and rock their lumbar spine and pelvis backward. This encourages other muscles to become more involved and leads to further weakness of the glutes.

​2) Lumbar Side Bending. This compensation is more common to females with larger hip bones. This is where muscles such as the obliques and QL be in a mechanical advantage to assist and attempt to compensate for the poor movement. To minimize lumbar compensation, always make sure the lumbar spine is positioned in neutral. Putting a pillow underneath the side of the obliques lying on the floor can be a way to overcome this.

3) Posterior tilt. This is a very common compensation as many people attempt to clench their butts hard to work them harder. While this sounds like a good idea it leads to chronic stiffness and “gripping” problems that eventually ruin hip alignment. You must maintain a neutral pelvic position throughout. A neutral pelvis and neutral lumbar spine requires a slight anterior pelvic tilt and many people attempt to strengthen the glutes by using a posterior tilt. This is even taught this way in Pilates with the pelvic curl exercise. Not only is this a disaster to the glute function but completely ruins the body’s ability to centrate the hip socket.

You can read more about this in the article – Why anterior pelvic tilt is so important for hip stability

When the Clamshell Exercise Is Useful

While there are many faults associated with the clamshell exercise it is not all doom and gloom. And it does not mean you it is a useless exercise for there are many people who will benefit from using it.

Firstly, this is a great way to teach someone “hip dissociation. This is where the person learns how to move their hip without any additional movement from the lumbar spine or body as we discussed earlier in compensatory mistakes. This is a very important lesson for a person with back pain to learn for it is common for them to use their core and lower back to sacrifice stability in order to move. If this exercise is taught well they can learn that they must tighten the core and ONLY move their hip in abduction.

Watch the video below of the technique I use to help someone learn how to do this.

Secondly, this can be a useful exercise to use in the early stages of rehabilitation when they are still developing skills with more advanced functional movement. You can build a base level of strength that will be useful later on, but most importantly they learn how to activate the glutes with hip abduction.

I also like to use several other variations to aid with hip centration which I will explain.

Clamshell Exercises Regressions

The two exercises shown below are variations I will often use with people suffering with extreme hip related problems. The Closed Clam which is featured on the left is an excellent exercise for a person with severe hip pain as it improves hip centration by activating several of the smaller muscles of the posterior region of the hip.

The Reverse Clam is one I use very rarely and this relates more to sporting athletes that require significant internal rotation of their hip. Sports like tennis, golf, and other throwing sports require the trailing leg on a throwing action to rotate inwards on the follow through. If there is a dysfunction in this motion it creates compensation into the lower back. Often this exercise is used in combination with the multi-direction lunge that uses this hip movement on the diagonal action.

Functional Progressions You Must Aspire To Using

When you progress to this stage is when you see the biggest impact with the clamshell. Integrating the hip abduction into functional movements teaches the body how to activate and maintain glute control in complex movement patterns. These exercises are far superior to isolating the gluteus medius for they teach the muscle how to interact with its synergistic partners DURING a movement. The clamshell is a great stepping stone to understanding how to do this.

One of the first exercises to use is the Crab Walk. This is when you teach the glutes to fire during a squat or bent over position. Technique is very important with this and there are several mistakes you need to be aware of. Watch the video below to see an explanation of what these are. The second video to the right features the Toe Touch Drill which is a basic stability exercise for improving single leg stance. This is not to be confused with strengthening as it is only preparing you for harder exercises to come. This is an excellent way to learn how to control the various factors that lead to gluteal weakness.

Once you have established control of this movement you can begin to apply this same method of thinking with lunges, and even single leg exercises. If you remember from earlier, the single leg exercises demand the highest level of glute strength.

These are called “iso-integration exercises” for they are attempting to isolate a weak muscle within an integrated movement. This is a very successful method to use with knee injuries where the person is unable to control the femur rolling inwards during single leg stance.

Watch the videos below to see how these work.

Do You Need More Help

To keep this article relatively short there is obviously a ton of information and additional exercises I have left out that I would use to help someone strengthen their glutes. If you currently suffer with hip, knee, or back problems you will find our online programs shown below a great resource that take you through all of the assessments and corrective exercises to get you back to full strength and out of pain.

Summary

There is no doubt the clamshell exercise can be a great addition to any strength training program, however you must ensure you do the following.

• Have adequate hip mobility first
• Use correct technique and avoid compensatory movement
• Intend to progress to functional movements

If you do these three things you will benefit from using the exercise. I would rarely use this with a person who can move well with functional exercises like deadlifts and single leg squats. The strength I gain from functional movement is always superior to isolated exercises and drills so I will maximise my time with these movements first and foremost. The only time I will see the use for the clam is as an exercise regression with a person suffering injury, or as an activation warm-up drill.

I hope this article gives you a greater understanding of this misunderstood exercise.

For more ideas and information on specific topics I may not have covered in detail be sure to check out our INDEX PAGE on the website that has over 300 of our best articles. These are all sorted into categories for quick reference so you can find what you are after more easily.

If you do need specific help with your exercise program please feel free to reach out to me for help and we can set you up with your individualised program.

About The Author

Nick Jack is owner of No Regrets Personal Training and has over 15 years’ experience as a qualified Personal Trainer, Level 2 Rehabilitation trainer, CHEK practitioner, and Level 2 Sports conditioning Coach. Based in Melbourne Australia he specialises in providing solutions to injury and health problems for people of all ages using the latest methods of assessing movement and corrective exercise.

References:

• Functional Anatomy of the Pelvis and the Sacroiliac Joint - By John Gibbons
• Muscle testing & function - By Kendall, McCreary, Provance, Rogers, Romani
• The Vital Glutes - By John Gibbons
• Movement - By Gray Cook
• Corrective Exercise Solutions - by Evan Osar
• Back Pain Mechanic - by Dr Stuart McGill
• Diagnosis & Treatment Of Movement Impairment Syndromes - By Shirley Sahrman
• Low Back Disorders - by Dr Stuart McGill
• Ultimate Back Fitness & Performance - by Dr Stuart McGill
• Core Stability - by Peak Performance
• Athletic Body in Balance - by Gray Cook
• Anatomy Trains - by Thomas Meyers
• Motor Learning and Performance - By Richard A Schmidt and Timothy D Lee
• Assessment & Treatment Of Muscle Imbalance - By Vladimir Janda
• How To Eat, Move & Be Healthy by Paul Chek
• Scientific Core Conditioning Correspondence Course - By Paul Chek
• Advanced Program Design - By Paul Chek
• Twist Conditioning Sports Strength - By Peter Twist
• Twist Conditioning Sports Movement - By Peter Twist