Leg strength Step classes work the quads, hamstrings, glutes and calves. A study in the journal Medicine and Science in Sports and Exercise found that 12 weeks of step aerobics increased lower body power by 11-14%.
Cardiovascular fitness Research has found that step burns about 9.6 calories a minute. Regular classes can also reduce blood pressure, raise "good" (HDL) cholesterol and improve aerobic capacity.
Healthy bones A study from California State University found that, in women who did step aerobics three times a week for six months, the bone density of the spine, hips and thigh bones increased by up to 3.3%.
Balance and coordination Straightforward stepping may not take much coordination, but the choreographed movements are often more demanding. Some moves involve balancing on one leg.
Cellulite Although some experts believe that a combination of strength training and cardio helps to combat cellulite, there's no hard evidence that step, or any other lower-body activity, targets it specifically.
Leg strength Rebounding - exercise on a mini-trampoline - involves jumping and jogging, double- and single-legged, which enhances strength without the associated stress on joints caused by higher-impact exercise
Cardiovascular fitness Rebounding is a match for stepping in the calorie-burning stakes. Research from the University of New Mexico, claims it uses about nine calories a minute, comparable to exercising on a treadmill.
Healthy bones NASA prescribes rebounding as the ideal exercise for astronauts to prevent a loss of bone mass, owing to the absence of gravity in space, and help them recover from space flight.
Balance and coordination Research suggests that rebounding may improve "kinaesthetic awareness" - your sense of where you are in space. This is very important in preserving balance and preventing falls later in life.
Cellulite The American Institute of Reboundology claims that it has a positive effect on the body's lymphatic system. Lymph flow increases by as much as 15 times, improving circulation, skin tone and detoxification.