Spinning is an intense aerobic exercise involving a room full of people on stationary bikes, music and the motivating words of an instructor.

During the class you vary your pace - sometimes pedaling as fast as you can, other times cranking up the tension and pedaling slowly from a standing position. This helps you to focus inwardly and work on your mind as well as your body.

These programs aim to simulate an outdoor bike ride, complete with sprints and hills. But you won't have to worry about any close encounters with harried hounds or testy truckers.

• Spinning burns serious calories.
  
  
• It works your heart and builds butt and thigh muscles.
  
  
• It doesn't involve a lot of coordination, so it's easier to concentrate on your form than in some other types of aerobic classes.
  
  
• You can finish a class, regardless of your fitness level, simply by adjusting your pace or the tension knob on the bike.
  
  
• Spinning offers an alternative to bicyclists when the weather is foul.
  
  
• It's more interesting than just using a stationary bike by yourself.
  

• Spinning doesn't work all leg muscles equally. Without some cross training, you may develop muscle imbalances that lead to injury.
  
  
• Serious Spinning enthusiasts have to watch out for overuse injuries in their knees, hips and lower backs.
  
  
• Rather than adjusting the intensity of their workout, some participants get carried away and go beyond their abilities to keep up with the class.
  
  
• Wouldn't you rather be cycling outside?