Your glutes are a group of three muscles that form your buttocks: the gluteus maximus, gluteus medius, and gluteus minimus. Together, they make up one of the largest and most powerful muscle groups in your body, responsible for everything from standing upright to climbing stairs to keeping your pelvis level when you walk. Understanding what each muscle does helps explain why weak glutes can cause problems far beyond your backside.
The Three Muscles That Make Up Your Glutes
Each of the three gluteal muscles has a different size, position, and job. They’re layered on top of one another, with the largest on the outside and the smallest tucked deepest against the hip.
The gluteus maximus is the biggest of the three and the most visible. It’s the muscle that gives your buttocks their shape. It originates from the back of your pelvis, sacrum, and tailbone, then attaches to your thighbone and a thick band of tissue that runs down the outside of your leg. Its primary job is hip extension (pushing your leg behind you) and external rotation (turning your leg outward). You use it heavily when you stand up from a chair, walk uphill, or push off while running. MRI studies of recreational athletes show a median volume of about 770 cubic centimeters in men and 620 cubic centimeters in women, making it one of the largest single muscles in the human body.
The gluteus medius sits beneath and slightly above the maximus, fanning out along the outer surface of your pelvis and attaching to the bony bump on the side of your hip. It works primarily as a hip abductor, meaning it pulls your leg out to the side. The front portion also rotates the leg inward, while the back portion rotates it outward. Its most critical everyday role is stabilizing your pelvis when you’re standing on one leg, which happens with every single step you take.
The gluteus minimus is the smallest and deepest of the three, sitting directly under the medius. It attaches to the front of the same bony bump on the side of your hip and works alongside the medius to abduct the leg and stabilize the pelvis. At roughly 110 cubic centimeters in men and 85 in women, it’s a fraction of the maximus’s size, but it plays an outsized role in hip stability.
What Your Glutes Actually Do
The glutes do far more than power big movements. They act as the primary connection between your upper body and your legs, transferring force through the hip joint during virtually every weight-bearing activity. The maximus and medius together maintain alignment of both the hip and knee joints during walking, running, squatting, and jumping.
One of the most important things the glutes do is keep your pelvis level when you walk. Every time one foot lifts off the ground, your body is momentarily unsupported on that side, and the pelvis naturally wants to drop. The gluteus medius and minimus on the standing leg fire to prevent that drop. When these muscles are weak, the pelvis sags on the opposite side with every step, producing a characteristic lurching walk pattern called Trendelenburg gait.
The gluteus maximus also plays a key role in protecting your lower back. The sacroiliac joint, where your spine meets your pelvis, transfers the entire weight of your trunk into your lower body. The maximus contracts to lock this joint in place and prevent excessive movement. When it fails to do its job, the resulting instability puts extra pressure on the joints and discs of the lower spine, particularly at the L5-S1 level, which is the most common site of low back pain.
Why Glutes Weaken (and What That Feels Like)
Prolonged sitting is the most common reason glutes stop working properly. When you sit for hours, your hip flexors (the muscles on the front of your hip) shorten and tighten. Meanwhile, the glutes on the opposite side lengthen and become less efficient at activating. Over time, this creates a condition informally called “dead butt syndrome,” or gluteal amnesia, where the muscles essentially forget how to fire when you need them.
The consequences ripple outward. When your glutes aren’t pulling their weight, neighboring muscles pick up the slack. Your hamstrings may overwork during hip extension, your lower back muscles may compensate during lifting, and the small stabilizers around your knee may be overwhelmed during single-leg activities. This is why weak glutes are linked to knee pain, hip pain, lower back pain, and even ankle problems. The issue isn’t always in the place that hurts.
Exercises That Target the Glutes Most Effectively
Not all exercises activate the glutes equally. Electromyography (EMG) studies that measure muscle activation during various movements reveal some surprises. The standard bodyweight squat, often considered a go-to glute exercise, actually produces relatively low glute activation, around 10-13% of maximum capacity. Lunges aren’t much better at roughly 19-20%.
Exercises that isolate the glutes from other muscles rank significantly higher:
- Clamshells produce the highest preferential glute activation of any exercise tested, with about 44% maximus activation and 27% medius activation while keeping surrounding muscles relatively quiet.
- Single-leg bridges generate about 35% maximus and 31% medius activation, making them one of the best bodyweight options for both glute muscles at once.
- Quadruped hip extensions (on all fours, extending one leg behind you) activate 28-30% of both the maximus and medius, with even higher activation when the knee is bent.
- Side-lying hip abduction hits the medius hardest at about 44% activation, making it the single best isolation exercise for the side glute.
- Lateral band walks (sidesteps) produce about 30% medius and 27% maximus activation with minimal involvement from other hip muscles.
The key metric researchers use is the ratio of glute activation to activation of the tensor fascia lata, a small hip muscle on the front-side of the pelvis. Exercises where the glutes dominate this ratio are better for targeted strengthening. Clamshells score nearly double the next best exercise on this index, which is why physical therapists prescribe them so frequently.
Gluteal Tendon Problems
The glute muscles connect to bone through tendons, and these tendons can develop their own issues separate from the muscles. Gluteal tendinopathy is a condition where the tendon tissue gradually breaks down, causing chronic pain on the outside of the hip and deep in the buttock. It’s distinct from simple muscle soreness in that it doesn’t improve with rest. In fact, rest often makes it worse.
Early-stage tendon irritation (tendinitis) involves small micro-tears from repetitive movement and typically responds to rest and ice. But once the tendon has progressed to true tendinopathy, the tissue itself has deteriorated, and recovery requires targeted loading exercises over a longer timeline. The pain often disrupts sleep, since lying on the affected side compresses the irritated tendon against the hip bone.