When most people think about their glutes, it’s the maximus—the meatiest muscle—that gets all the attention. After all, it’s the one that powers your squat and deadlift, motors a sprint, and (yes) fills out a pair of jeans. 

But the glute medius, the main muscle along your outer hip, shouldn’t be ignored.

“Practically speaking, the gluteus medius is most important for stabilizing the pelvis and femur,” says Rachel Straub, M.S., C.S.C.S., exercise physiologist and author of Weight Training Without Injury: Over 350 Step-by-Step Pictures Including What Not to Do! “Weakness in this muscle is a primary cause of pelvic drop and inward movement of the femur during weight-bearing movements, such as walking, running, and jumping.”

In other words, weak glute meds can cause your knees to collapse and your lower back to twist unnaturally when you run, which can lead to ailments and injuries ranging from knee pain, shin splints, and joint overuse because your stability is diminished.  

To prevent and correct glute medius weakness, Straub recommends incorporating these three moves.

3 exercises to strengthen your gluteus medius:

1. Clam shells

This tried-and-true beginner move is a great warmup exercise for leg day. Grab a mini-band or tie a loose, flat resistance band (like the ones used in PT) into a loop that's about a foot across. Wrap the band around both legs just above your knees. Lie on your side, knees bent. With your heels touching, open your top knee against the band. Hold for at least 10 seconds, then return to the start. Do 8–12 reps. Rest. Complete on the other side. Perform 3 total sets.

2. Side steps
Using the same band from clam shells, stand and place it around both legs, just above your thighs. Come into a quarter squat and begin stepping to one side, allowing the trailing leg to step in but not fully. You want to keep some tension in the band. Take up to 10 steps to one side, then switch directions. “Aim for 3 sets at least three days a week, resting in between days as needed,” says Straub.

3. Side step-downs 
This more advanced move requires a lot of control. Stand off to the side of a step or box, so one leg is free/dangling. Step down with the free leg, doing a single-leg squat with the supporting leg. Aim to tap the heel of the free foot to the floor. Watch that your bending knee stays perfectly square. The higher the box, the harder this move is; so you may find you need to hold on to something at first for control. Do 8–12 reps on each side. Perform 3 sets per side.