PT Crab 🦀 Issue 142 - Butts

This week, we’re talking butts. For two reasons. One, I have glute max strain that’s a bit of a pain. And two, I’m working with a patient with a remarkably overdeveloped TFL and weak glute med and it’s really interesting. So let’s talk butts. Strengthening them preferentially, to be specific. How do you separate TFL from Glute med? Is what you learned about that correct? What about glute max? How do we bulk that up in a controlled manner? Read on for more.

Also, if you like butts, I highly recommend Butts. Technically called Butts: A Backstory, it’s a book by Heather Radke that looks into the cultural history of butts. And it’s amazing.

With that, let’s dive in!

Here are some Glute Max exercises

The Gist - We know the glute max is important for physiological balance, injury risk, and performance, so how do we strengthen it? This is an odd duck of a paper that just takes us through a bunch of exercise ideas for glute max. It’s actually quite interesting and I’ve tried out a few of the exercises myself, I like them a fair bit.

Because we get into those tough, let’s talk about what the glute max does. It’s got three functions, local and global stabilization and global mobilization. The local stabilization is based on its connections into the thoracolumbar fascia, SIJ, and lumbo-sacral areas to stabilize the spine and pelvis, and the connections to the IT band and femur bring about stabilization to the femoral head and knee joint. Globally, it stabilizes in all three planes since it has abduction, external rotation, and extension components. And I’m sure you understand the global mobilization part.

The paper argues that glute max becomes dysfunctional via lifestyle, postural, and other muscular factors. Lifestyle and posture-wise, there’s evidence that prolonged sitting reduces activity as does increased pelvic anterior rotation. Overactivity of hip flexors can lead to reciprocal inhibition while hamstrings can dominate hip extension motions, something called synergistic dominance.

To test strength, it’s recommended to perform MMT or isometric dynamometry in prone with the knee bent to 90 degrees to inhibit hamstrings. You can also assess via knee control and performance ability with movement-based tasks like squats, deadlifts, steppes and downs, landing, jumping, and changes of direction.

But let’s talk exercises.

Tell Me More - It’s hard to just write down exercises, but I’m going to anyway, so deal with it. Normally we use things like squats, deadlifts, step ups, lunges, SL RDLs, and lateral steppes to after the glutes. But if we do that, we have to do it right. For one, any exercise that you want to preferentially strengthen glute max should be done without anterior pelvic tilt and with the addition of an internal rotation or adduction moment to engage the glute’s ER and abduction forces. That includes things like therabands around the knees for squats, weight in the opposite hand for RDLs, overhead weight in the opposite hand for squats, addition of a knee adduction force for a split squat, and the like.

In the non weight-bearing area, it’s important to continue to bias exercises toward the glutes. For bridges, for example, increased knee bend decreases the hamstrings’ force in the movement. The hip thrust with barbell is a particularly good exercise for glute activation. Other things that work well are side planks with abduction, bird dogs, and bridges with an adduction force. For higher level folks, sprint training is good to improve glute force, but if they’re not properly recruiting it, they have a heightened risk of hamstring injury, so you need to engage the glute and adjust posture first.

And that’s all I’ve got. Check out the open access paper for good pictures and further detail as well.

Paper? Gots its.

What about Glute Med?

The Gist - A big focus of hip abductor training is often strengthening glute med without allowing TFL to take over. But to really do that, we need to know how effective each exercise is for activating this muscle while keeping TFL turned down. This piece used EMG analysis on twenty healthy volunteers aged 18-50 who performed 11 exercises: SL hip abduction, clamshells with resistance, bilateral bridge, unilateral bridge, hip extension with knee bent, hip extension with knee straight, forward lunge, squat, sidesteps with elastic resistance, hip hikes, and forward step ups.

After collecting data, they compared how much each muscle was recruited to perform the exercise. This paper has lots of data with math and numbers and all that crap and I’m going to skip it all because it boring. Instead, lets’ take about what the activation index is and what the results showed.

The activation index is a mathematical comparison of the amount of activation of each muscle to one another. Higher numbers indicate more glute activation and/or less TFL activation, since they’re based on each other. So if you’re looking to preferentially activate glutes, higher is better.

Let’s see how they did:

• Clamshell: 115
• Sidesteps: 64
• Unilateral bridge: 59
• Hip extension with extended knee: 50
• Hip extension with bent knee: 50
• Side-lying hip abduction: 38
• Step-up: 32
• Bilateral bridge: 32
• Squat: 28
• Hip hike: 28
• Lunge: 18

Tell Me More - The table above isn’t the whole story. Since the researches were looking at both glute med and max relative to TFL, some of these exercises did a good job activating just glute med but didn’t end up high on the list. For example, side-lying hip abduction highly preferentially activates glute med over TFL, but not glute max, so it ends up fairly low on the list. Similarly, squats didn’t cause much muscle activation in the glutes and even less in TFL. This is probably because they were unweighted squats and thus quite easy. This points to a real weakness in the study, I know. But if you stick with the top 5 or 6 exercises on the list, you will get the results you’re looking for.

Paper? Here. Open access cuz it’s old.

How to load glute med

The Gist - If you’re bringing someone back from injury to the glutes or if you are just going after weaknesses there, it’s good to have an order to apply them in and this big systematic review and meta-analysis attempts to come up with one. They stratify exercises based on type and percent of maximal voluntary isometric contraction they produce, splitting into four categories of low (0–20%), moderate (21–40%), high (41–60%) and very high (>61%). They looked at 20 studies that reported the outcomes of 33 exercises to come up with their organized list.

To cover this in brief, I’m going to pull things straight off the table at the end. If you want more detail, you’ll have to check out the paper. This is a nerdy, number filled one that’s not super exciting to break down, but the usable stuff is quite usable indeed.

Very highs included:

• Single leg squats
• Sidestepping with band
• Forward step ups
• Lateral step ups
• Side bridge
• Prone hip extension

For highs, we’ve got:

• Hip hikes
• Standing hip flexion/extension in both the stand and mobile legs
• Single leg wall squats
• Skater squats
• Single leg deadlifts
• Forward lunges
• Forward and sideways hops
• Side-lying hip abduction
• Unilateral supine bridge
• Standing hip abduction (WB limb)

Mediums include:

• Clamshells
• Single leg balance on unstable surface
• Sumo walks with band
• Sideways lunges
• Backward step ups
• Standing hip abduction (NWB limb)

And lows include:

• Double leg squat
• Double leg wall sit
• Single leg balance on stable surface
• Bilateral bridge

phew Big list, I know. But with it in hand, you can consider methods of grading up exercises to increase the challenge on glute med as you rehab someone. Prior to looking this over, I assumed that side-lying hip abduction was probably tougher on the glute than forward step ups. And I was wrong.

Paper? Here y’all gos.

As always, share the Crab far and wide. It’s through your telling others about it that we grow. Thanks! I don’t advertise at all, any subscriber growth is just you and you’re doing great.

Bye!