Gluteus maximus

The gluteus maximus is the largest of the gluteal muscles and the most superficial, which is why it gives the buttocks their shape (TeachMeAnatomy). It sits on the back of the pelvis with the gluteus medius and minimus, in a region that also carries major nerves and blood vessels into the leg (Elzanie & Borger, 2023).

Where is the gluteus maximus?

It starts on the back surface of the pelvis (the ilium), the sacrum and the coccyx. Its fibres slope across the buttock at about 45 degrees and attach to the iliotibial tract and to the gluteal tuberosity of the thigh bone. It is supplied by the inferior gluteal nerve (TeachMeAnatomy).

What does the gluteus maximus do?

It is the main extensor of the thigh: it straightens the hip, moving the thigh backwards, and it helps rotate the thigh outwards. It is used mainly when force is needed, such as running or climbing (TeachMeAnatomy). That matters for desk workers, because a day spent mostly sitting asks little of it.

Exercises that load hip extension recruit it strongly. A review of 16 studies found very high activation in step-ups, deadlifts, hip thrusts, lunges and squats (Neto et al., 2020). A body-weight version of hip extension, the glute bridge, has its own page.

What happens to the gluteus maximus when you sit?

It seems obvious that you sit on your glutes. The anatomy is more interesting. Standing up, the gluteus maximus covers the ischial tuberosities, the sit bones, but as the hip bends the muscle slides aside, and in sitting the bone takes weight more directly (Johnson & Varacallo, 2024).

An upright MRI study scanned 35 people sitting on foam, 29 of them full-time wheelchair users. The soft tissue under the sit bones was mostly fat, and most participants had little or no gluteus coverage over the bone, whatever group they were in (Sonenblum et al., 2020). So when you sit, much of your weight rests on bone and fat rather than on a cushion of muscle.

You may have heard of “dead butt syndrome” or “gluteal amnesia”, the idea that long sitting switches the glutes off. We could not find studies that have tested this in desk workers. What is better established is that sitting for long, unbroken stretches is worth breaking up for other reasons; see lower back pain from sitting.

Gluteus maximus and lower back pain

Weak glutes are often blamed for back pain, an idea that belongs to the wider muscle imbalance story. The trials give a mixed picture:

• A review of five trials with 309 people found that adding hip strengthening to usual back rehabilitation improved pain slightly, by 5.4 points on a 100-point scale, with moderate-quality evidence for pain and low-quality evidence for disability (de Jesus et al., 2020).
• In a trial of 80 people with non-specific low back pain, adding progressive hip strengthening to a motor control programme did not reduce pain or disability more than the motor control programme alone. Both groups improved (Kendall et al., 2015).

In 150 people with chronic low back pain, the side muscle, the gluteus medius, tested weaker than in people without pain (Cooper et al., 2016). Studies like that compare groups at one point in time, so they can’t show whether weakness led to the pain or the other way round.

When is buttock pain a reason to see a doctor?

Pain in the buttock that runs down the back of one leg, often with tingling, numbness or weakness, is more likely to be sciatica than a muscle problem. See a GP if it hasn’t improved after a few weeks, is getting worse or is stopping your normal activities. Go to A&E or call 999 if you have sciatica on both sides, severe or worsening weakness or numbness in both legs, numbness around your genitals or bottom, or changes in bladder or bowel control (NHS). The muscles at the back of the thigh, which share the hip-extending job, are covered under hamstrings.