Research Corner: The Death of the Clamshell

Research has shown a clear link between glute muscle (your butt) weakness and ankle, knee, hip, and low back pain. There is also evidence that supports the connection between symptom severity and hip muscle weakness. However, there is significant variability in the effectiveness of hip strengthening programs when it comes to symptom reduction and quality of life. A recent systematic review highlights a few suggestions as to why these programs may have such varied effects: 1) the exercises used in rehab may not sufficiently activate the hip muscles enough to elicit strength and hypertrophy, and 2) these exercises may not effectively target specific segments of hip musculature.

What jumped out most to me in this review was the concrete evidence that the clamshell exercise is a waste of time. It has been a staple in rehab programs and Eric Prydz music videos for decades. TEN different studies with varying hip positions found that the clamshell provides low to moderate activation of glute med (some segments were reported to be as low as 3%). Over the years, the clamshell has slowly fallen out of the good graces of the rehab community but it still finds it way into rehab programs. If the clamshell is still in your toolbelt, here are some better options to get those glutes firing:

1) Hip hitch/pelvic drop variations have been shown to elicit high levels of all segments of glute med/min activity in healthy populations. This is a great exercise to work on the glutes' role as a multi-planar hip and pelvic stabilizer in weight bearing.

2) Rear foot elevated lunge, resisted standing hip abduction, lateral step ups, and resisted side steps are all excellent ways to work on different segments of the glutes in a weight bearing fashion. Working on the glutes in weight bearing keeps the exercise closer to daily function.

3) Not ready for standing exercise? Side lying hip abduction/internal rotation and single or double leg bridges are great options for working on glute strength on the floor.

As an evidence based profession, it's always important to revamp our techniques and stay on top of the latest research to continue to provide high quality care to our patients. I'll be using the research corner as an incentive to keep me on top of lit review and staying relevant in the always changing field of rehab science. Stay tuned for future posts and if you've got any topics you'd like to dive into, comment below!