Jumping rope should be done on surfaces that have some give to avoid joint injury. Home exercise machines can be adapted to any fitness level and can be used day or night. For burning calories, the treadmill has been ranked best, followed by stair climbers, the rowing machine, cross country ski machine, and stationary bicycle. Recently, elliptical trainers have been gaining popularity and, according to one study, are even better than treadmills for elevating heart rate and increasing calorie and oxygen consumption. Stationary bikes and stair climbers condition leg muscles.
Stationary bikes are fairly economical and easy to use safely.
The pedals should turn smoothly, the seat height should adjust easily, and the bike's computer should be able to adjust intensity. Stair machines offer very intense, low-impact workouts, which a recent study showed to be as effective as running with less chance of injury. Rowing and cross-country ski machines exercise both the upper and lower body. Cheaper models of exercise machines tend to be flimsy and hard to adjust, but many sturdy, moderately priced machines are available. The higher-end models may utilize computers to record calories burned, speed, and mileage.