Fitness Myths

For years, we've been told that you have to stretch before working out. But this is just one of the many workout myths that may actually hinder your performance.

Dr. Sean Kenniff from CBS station WFOR-TV in Miami visits The Saturday Early Show to clear up some common misconceptions.

"In the medical field, we are constantly learning new things," Kenniff says, "And some of the things that we learn make obsolete our old ways of thinking. The problem is, not everyone hears about the latest drug for breast cancer, treatment for heart attacks, or best way to work out. And they sometimes base what they do on this old way of thinking, which can, in the end, do them more harm than good."

Here are some of the myths with Kenniff's explanations:

Stretching Improves Your Workout - Since we were kids in gym class, we've been told that you should always stretch before working out to improve your performance and reduce injuries. But this long-held belief is not true. A study done in Sweden a few years back found that stretching really holds no benefits for most activities. Other studies have shown that holding a stretch for 20 to 30 seconds before training may actually relax your muscles making it more likely that you get injured.

Cross Training Shoes Work For All Sports - There's a reason that shoe companies make sneakers specifically designed for long-distance runners, sprinters, and tennis players, and it's not just so they can make more money. It's because each type of shoe offers the best support for whatever activity you may be doing. If you occasionally play tennis, or basketball, or run, a cross trainer is probably okay. However, if you spend more than three days a week on a specific activity, you need to buy a shoe designed for that sport. Your feet will thank you.

Heat Makes You More Flexible - Bikram yoga is becoming very popular in the U.S. You may have heard about it. It's the form of yoga where you work out in a room that is kept at a temperature of more than 100 degrees Fahrenheit. The thinking is that the heat loosens you up and allows you to do moves you may not normally be able to do. The problem is, the heat doesn't make you as flexible as you may feel. This can cause people to overstretch their ligaments and tendons. So, in order to avoid these kinds of injuries, only stretch to the point where you feel slight discomfort, and never hold it for more than a minute.

High-Impact Exercises Hurt More Than They Help - Running and step classes are just two of the many high-impact exercises that are very popular. Unfortunately, some people mistakenly think that these exercises, which are a great way to burn a lot of calories in a relatively short amount of time, can harm the body. But if you are doing these exercises the proper way and using the right equipment, you can actually help your body by improving bone density and help stave off osteoporosis. Just remember that when you are doing these exercises, you should keep your knees slightly bent when your feet hit the ground.

If You're Not Perspiring, You're Not Exerting Yourself Enough - Some of us sweat a lot, some of us not very much at all. So you should never use the amount you perspire as an indication of how hard you are working out. When exercising, you should find it hard, but not impossible, to hold a conversation.