Ive been running for about 15 minutes out of my 30 minutes on the treadmill and my knees have been hurting since last week. My ankle feels kind of sore too. Am I doing something wrong to make my knees hurt or is it just something I need to get used too. Im only 22 and I just dont get why it feels like I have old lady knees.

I'm not a doctor or anything, so this should be taken with a grain of salt!

Treadmills are a high-impact aerobic activity. The hard surface puts a lot of stress on your weight-bearing joints (i.e., ankles, knees, hips). If you're not used to working out on one, it could just be that this is too much for your body. When I first started on the treadmill, I was always in pain. It wasn't until I lost some weight that the reduction in joint stress enabled me to stay on for longer amounts of time. (I went from 20 minutes walking to a solid 60 minutes of jogging/walking).

Also, remember that the more excess weight you carry, the more stress you put on your joints just in regular activities. You may want to consider a lower impact activity like a stationary bike or elliptical.

There is also a possibility that you're stomping your heel against the treadmill when you step, and you can try focusing on rolling from your heel to the ball of your foot -- a little less stress AND it works the calves and butt harder!!

Some info regarding knee injuries.

Additionally if you haven't gotten fitted for a pair of running shoes, then that may also be a cause for your pain. If you already own a pair, then it may be time to replace them.

If you haven't been fitted for a running shoe:
Runner's World list of specialty running stores in the U.S. and Canada

There's a lot more to a perfect fit than finding the right size.

I know you don't want to hear this, but I would slow down or stop exercising for a few days in order to rest your legs. And yes it sucks, but running on an injury will likely make it worse and lengthen your recovery time. If it makes you feel any better, I have to take a week or two off from running in order to heal a pulled muscle.

It's also possible that you are running too fast on the treadmill or that you added extra minutes before your body was ready. I would try running at the lowest speed you can for awhile. For example, I can run at 4.6 on the treadmill (14-20 minutes max), but my posture suffers since it is a bit too fast. As a consequence, I injured myself.

However I can more comfortably run at a 4.4 or 4.5 pace without hunching over. I wear a HRM during my workout and the intensity hasn't decreased with the speed. However don't use my speed as a guideline because everyone is different and you may be faster or slower than I am.

FWIW, I started on the treadmill 25 pounds ago and the only times I have been injured was due to the shoes wearing out and pushing myself too hard and overdoing it. Overcoming the Overdoing It Demon has been a struggle for me.

I agree with the other posts so far. And I strongly suggest you take it easy for a while, maybe try a different activity, and when you do use the treadmill to take the intensity/length of time down a bit. I injured my foot running on a treadmill last winter and it was painful when I walked for several months. I was too heavy for the amount of impact. It sucked. I'm being much more careful this time around. Don't learn the hard way! Good luck.

I wear knee support when I run because I have chondromalacia patella. The support keeps the knee in line. I, too, started out slowly and built up speed and time. I iced my knees after running as well plus built up my quads to take the pressure off my knees. While you may not have the same knee problem, I think building up quad strength is useful for anyone.

Hope your knees feel better soon!