This class uses minitrampolines and music to get hearts racing. With less strain on joints than cycling or running, it's safe for all fitness levels. A new generation of gym classes uses treadmills, rowing machines, stationary bikes, and stair climbers in a group setting. An instructor plays music and narrates your way through imaginary scenery, or motivates you to pump harder by doing sprints and running up and down short hills in sync with classmates. In trekking classes, marathon runners jog alongside beginners.
Instructors say the courses level the playing field.
You may be more inspired to get up at the crack of dawn to work out or exercise after work if you know others are waiting for you. You can take an early morning running class through Washington, D.C.'s Rock Creek Park or walk the busy boulevards of New York City with a gang from your gym. Wear good-quality shoes since outdoor surfaces can be less forgiving than gym floors. The class runs for six months preceding the New York marathon. Not thin, but better read Exercise is boring.