Aerobics:

Warm Up Before and Cool Down After
A good aerobics teacher will incorporate a warm-up and cool-down session into the class. Slow, gentle stretching before and after helps reduce your risk of injury and muscle soreness. It could be time  to dance on over to a different class if your teacher is big on bouncing but light on stretching.

Go at Your Own Pace
The beauty of exercising to music with a group and being led by a teacher is that you tend to work harder and longer than you would on your own. That's good -- but not if you overdo it. Bouncing and straining to keep up with the class can lead to injuries. Aerobics class is not a competition. Go at your own pace. Allow your strength and flexibility to build gradually.

Watch Your Form
Good form brings better results and fewer problems. Tuck in your pelvis a little so your lower back is elongated. This protects your lower back when standing. Make sure your knee is aligned over your ankle, and no farther forward, when doing a lunge. Don't do moves that require you to lock or hyperextend your knees or elbows. Remember to monitor your breathing.

Look Straight Ahead
Looking down at your feet can cause neck and/or back pain. Pain has no place in an aerobics class or any other fitness activity. You're overdoing it if you're feeling the burn.

Wear the Proper Shoes
Don't wear just any pair of athletic shoes to aerobics class. Running shoes and tennis shoes, for instance, don't provide the cushioning and support you need. Look for shoes that cushion the ball of the foot, with good arch support that minimizes pronation (inward rotation) of the foot. Some cross-training shoes work well, so shop around.

Don't Bounce on a Bad Floor
Dancing on concrete, hardwood or linoleum-covered floors is asking for trouble. They're too hard. Dancing on a floor with too much padding isn't good either, because it allows too much rotation and pronation of the legs and feet. Ask your aerobics teacher about the floor you're dancing on. You know you've got a problem if she or he ducks the question or makes excuses.