Aerobics, especially high impact, is a tough form of exercise to the lower extremity. To avoid injuries to the feet, knees and hips you should be in shape enough to workout at a high level, use proper equipment, have a suitable floor surface and carefully choosen shoes.

The forces generated during aerobic movements can be up to six times that of gravity directed at each bone of the foot. Aerobic shoes must first and foremust have good shock absorption and be well cushioned.

Aerobic moves often involve side to side or lateral movements for an extended period of time. If your foot has the tendency to supinate or pronate (turn outside or inside) it's important to see a podiatrist who may recommend controlling the side to side movement by using special inserts.

Because of the lateral movements, shoes must have a well formed arch that corrects for these forces and a thick upper leather to provide stability to the front of the foot. Shoes should also have a firm toe box that is high enough to prevent pain in the toe and nail areas.

Simple sneakers or tennis shoes you may have hanging around your closet probably will not be sufficient. The major shoe companies have developed both aerobic and cross training shoes that will meet the necessary safety enhancing criteria. These shoes provide the needed arch support, cushioning and side to side support which will allow safer turning and twisting.

Running shoes are also not a good candidate for aerobic footwear. Runners primarily move straight ahead so their shoes aren't made for lateral support. They also often have an outside flair that puts you at a greater risk for injury.

The best time to try on aerobics shoes is in the afternoon when you feet have had time to swell a bit. They should fit snug but not tight. Wear the same socks (athletic socks of acrylic blend) you are going to exercise in. Once you've found the right shoe, tie them doubly and securely. This helps prevent tripping accidents.

The pair of shoes you choose for aerobic classes is a very important determinate in how many and what kind of injuries you could sustain. It is imperative duting those high impact or interval classes to have properly supported shoes. Low impact also does a lot of side to side movements so don't think you can get by with your old closet sneakers in these classes either.

Dr. Lanny Schaffer is an Exercise Physiologist and The President of The International Fitness Academy. For more savvy fitness and safety information go to http://www.aerobics-exercise-coach.com