Whether youre out of shape or very fit, spinning classes can help you keep your New Years resolutions. You ride a stationary bicycle in a group, with a leader who tells you what to do and plays lively music to set the tempo. Many health clubs and gyms offer these classes, and I recommend them to all of my patients. Spinning relatively safe because it is done with a smooth rotary motion that does not involve the muscle damaging road shock of running.

The pedals drive a chain that is attached to a heavy flywheel that spins smoothly as you pedal. The amount of work you do is determined by the resistance on your pedals, not by how fast you spin. You perform a lot of work when you spin slowly against great resistance, and do not do much work when you spin very fast against very little resistance. A brake is attached to the flywheel and you regulate the resistance on the pedals by turning the brake clockwise to increase the resistance, and counter-clockwise to decrease resistance.

Before you start real training, you need to do some background work. Start out by pedaling at a very slow rate with no resistance. Stop when your legs start to feel heavy or hurt. You may be able to go ten minutes on the first day, five on the second, and perhaps not be able to exercise on the third. Persist and eventually every healthy person should be able to work up be able to work up to a full 45-minute class.

Your instructor will have you warm up by spinning without any resistance until you start to break a sweat. Then you will turn up the resistance a little and spin the pedals until your thigh muscles start to burn. Then pedal easily with little or no resistance until you have recovered, usually about a minute or two. You will continue to alternate into the burn and out of the burn until your leg muscles start to stiffen, which is a signal that you are through for the day.

You need to experiment to learn how high you have to turn up the resistance. If you turn it up too high, you will burn out your muscles and not be able to finish the class. If you dont turn it up high enough, you will not achieve a high level of fitness, not feel sore the next day, and not gain the benefits of being in a high level of fitness. If you have worked out correctly, your thigh muscles will be sore on the next day. Then you have to pedal easily with little or no resistance for as many days as it takes for your muscles to feel fresh again. For most people, this will be one or two days. Then when your muscles are fresh again, youre ready for another hard workout.

Gabe Mirkin, M.D.

Dr. Gabe Mirkin has been a radio talk show host for 25 years and practicing physician for more than 40 years; he is board certified in Sports Medicine and three other specialties.

Dr. Mirkin's daily features on fitness have been heard on CBS Radio News stations since the 1970's. He has written 16 books including The Sportsmedicine Book, the best-selling book on the subject that has been translated into many languages. His latest book is The Healthy Heart Miracle, published by HarperCollins.

Dr. Mirkin is a graduate of Harvard University and Baylor University College of Medicine. A Boston native, Dr. Mirkin did his residency at the Massachusetts General Hospital. He has served as a Teaching Fellow at Johns Hopkins Medical School, Assistant Professor at the University of Maryland, and Associate Clinical Professor in Pediatrics at the Georgetown University School of Medicine. He has run more than forty marathons and is now a serious tandem bicycle rider with his wife, nutritionist Diana Mirkin.