[Marilyn]

Spin is indoor cycling. It's not just sitting on a bike though and peddling. The wheel on front is weighted, and there is a hand crank to increase and decrease resistance. An instructor leads a classroom of people on bikes in a 45 minute routine accompanied by some exhillerating music. You simulate climbing hills by increasing resistance. You run races cranking resistance on and off, alternating standing in the peddles and seated. You do jumps where you are seated for a certain number of spins, then standing for the same number of spins (usually 1, 2 or 4), and alternating several times. It's a pretty rigorous workout. The classes I attend usually include 40 to 45 minutes of spin, then we do floor exercises with weights, a big ball and such to work the abs, and strengthen the upper body. It's a great workout. Great cardio and burns lots of calories. It's easier on your knees than running. In fact, if you are doing it correctly, it doesn't stress any of your joints.