“Dead butt syndrome” sounds like something a physical therapist made up to get people off their couches. It also happens to be a real condition, with a real medical name, and if you sit at a desk for a living, there’s a reasonable chance you have it.

Gluteal amnesia, as it’s actually called, is the clinical term for what happens when the glute muscles weaken and stop firing correctly, according to Body & Soul. Physiotherapist Jimmy Goulis of Pollinate Health describes the glutes as the largest and most powerful muscles in the body, responsible for walking, running, climbing stairs, getting out of a chair, and maintaining balance. When they stop doing their job, other muscles are forced to compensate, and that’s when things start to go wrong.

“The brain loses its ability to recruit the glutes efficiently when we need them,” explains exercise scientist Amelia Phillips, co-founder of Vitality360.

The cause is simple enough. Prolonged sitting squashes the gluteal muscles, sciatic nerve, and blood vessels in the area. Over time, the muscles lose strength and endurance. The brain essentially forgets how to call on them. You might notice this as lower back pain during glute bridges, or quads that fatigue quickly during squats, while your glutes contribute almost nothing.

How to tell if your glutes have switched off

Phillips recommends two at-home checks. The single-leg bridge involves lying on your back, bending your knees, extending one leg, and driving through your planted heel to raise your hips off the floor. If the hips drop or the hamstrings immediately take over, the glutes are checked out. The second is a floor-to-standing test, no hands, no knees. Harder than it sounds for most people.

What Weak Glutes Actually Cost You

The consequences of weak glutes move through the whole body. Phillips links poor glute function to increased joint stress and identifies lower back, knee, and hip pain as predictable consequences. Goulis adds that the relationship is circular: pain makes glute activation harder, and weak glutes create more opportunities for pain.

The longevity connection also holds. Phillips links glute strength to mobility, fall prevention, and functional independence as people age. As Goulis puts it, glutes are what allow people to walk efficiently, climb stairs, and get out of chairs.

Here’s How to Fix Dead Butt Syndrome

Goulis recommends breaking up long stretches of sitting every 30 to 60 minutes, walking during phone calls, and taking the stairs when possible. At home, glute bridges, side-lying leg raises, and step-ups are good starting points. At the gym, hip thrusts, Romanian deadlifts, squats, and split squats do the rebuilding work.

Your butt isn’t actually dead. It’s just been sitting too long and has forgotten what it was meant to do.