If your New Year's Resolution is to get in shape, pick an activity that you can enjoy and do safely for the rest of your life. Sixty-five percent of people who start an exercise program drop out in the first six weeks, often because of injuries.

Jogging and running are high-injury sports because your feet hit the ground with a force greater than twice your body weight. This force can injure muscles, joints and bones. Pedaling and swimming are safer because you pedal in a smooth rotary motion and when you swim, the buoyancy of the water dampens forces on your muscles.

The safest and most comfortable way to pedal is on a recumbent stationary bicycle. On a conventional bike, the pedals are below you, so you perch on a narrow seat and put pressure on the nerves in your crotch. When you pedal a recumbent bike, your legs are above your pelvis, so you can sit in a chair that does not pinch nerves. You lean against the seat