I have a running joke with a couple colleagues that doing quick strength and stability assessment is trying to find the biggest slacker among our major stabilizing muscle groups. And when it comes to lumbar pain, the gluteals seem to win the prize.
The buttock muscle is a very large muscle group comprised of three major superficial muscles and a couple of smaller deep muscles that are involved more so in guiding movement. They are supposed to fire first and foremost doing a variety of trunk activities including forward flexion, which is when a lot of injuries to the lumbar disc seem to happen. In doing so, the gluteal muscles bear the the load and prevent the smaller lumbar muscles from being overloaded. I do recall from my days of doing dissection anatomy how surprisingly thick they were even in older cadavers, while the lumbar paraspinal muscles were comparatively so thin. As such, the gluteal muscles are really engineered to bear the brunt of the muscular stabilization process.
When gluteal muscles fail to engage properly and sufficiently, the lumbar paraspinal muscles and associated lateral groups like the QL have to take over. Two things will happen: first, they are not engineered to bear that kind of load and can easily get into an acute or repetitive injury cycle. Second, they tend to create distortion pattern in the lateral curve with hyperextension, chronically loading the lumbar facets. It's a loot lose situation.
The reason gluteal amnesia is so problematic and so prevalent is because muscles tend to down regulate their normal activity and firing pattern when exposed to prolonged pressure. Such as sitting on your butt the majority of the time. It's a scourge of the modern lifestyle that is probably driving the majority of the gluteal amnesia problem, much more so than direct injuries. The average American spends more of their wake up time sitting at home, work, in their vehicle, than they do ever being up around and moving. There are a few different ways to test for the firing pattern of the gluteal muscles, including the prone swimmers test, bridging, and standing squatting. It's usually pretty obvious. Treating gluteal amnesia involves a combination of trying to decreasing the amount of sitting time, changing the sitting posture to center the lumbar spine over the pelvis rather than posterior to it, which tends to increase pressure over the buttock muscles, frequently engaging gluteal in a variety of functional activities such as squeezing your butt muscles every time you get up and down from a chair, and more structured exercise routines such as bridges and squats.
