The human body changes over time: Certain muscles begin to lose their cells, bones diminish in density, and tissues no longer hold the same amount of water. No matter where you are in life, though, some workout moves prove perpetually beneficial for you and the muscles, bones, and joints you’ll call home from now until forever. When it comes to the best longevity exercise out there, physical therapist Joel Giffin, DPT, founder of Flex Physical Therapy, says one move—squats—are timeless.

“An exercise that’s good for all ages is a squat because there are infinite ways to modify, progress, change, and adjust it to accommodate the abilities of the individual,” says Dr. Giffin. “When done with optimal form, a squat is beneficial regardless of the level of difficulty because it is a functional exercise that represents a movement we need to do everyday: going from sitting to standing, or vice versa.” If you can do this movement easily, researchers believe it’s a really good indication of longevity.

That’s not all squats have going for them, though. “Additionally, squats activate the glutes. These muscles are relaxed and weakened when we are sitting, which most of us do way too much of. Squats strengthen the whole lower extremity, allow for the core to engage, and can be added to an upper-body workout at the same time,” says Dr. Giffin. Their peachy reputation holds true, yes—but the exercise has a lot more to offer as well.

As Dr. Giffin mentioned, however, the classic squat won’t be the best option for everyone. Some may experience knee or ankle pain when they stick with the hip’s width apart approach to the move. And if that sounds like you (or comes to sound like you in a decade or two), Dr. Giffin recommends grabbing onto a chair for assistance, bring your feet wide into a goblet squat to spare your lower back, or sitting back onto a box to limit your body’s range of motion. You could also add dumbbells or kettlebells to make the move harder—if you’re into that kind of thing.

The right way to do a squat: The physical therapist-approved longevity exercise

1. Stand with your feet about shoulder’s width apart.

2. Move downward like you are going to sit in a chair. Sit back into your glutes to allow them to lead the motion. Do not allow the knees to go in front of your toes.

3. Engage your glutes (along with your core). Think about the back of your legs working rather than the front of your legs.

4. Don’t let your hips go below knee level. “This should feel very comfortable—outside of some muscle burn—and pain-free,” says Dr. Giffin. “There should not be sharp, shooting, or achy pain.” You can move into a half or mini-squat if it’s not comfortable to go all the way down just yet.

5. On the way up push through the heels and work to activate the glutes.

6. Repetitions and sets will depend on your ability, but ost people can start with two sets of eight reps and work their way up.