Calorie burning

Step machine: This is no slacker in the calorie burning stakes. A 63kg (10 stone) woman can burn 572 calories in an hour. If possible, use your arms rather than holding the handles - or at least don't slouch. 4/5

Elliptical trainer: Unlike the step machine, this targets the upper and lower body equally. More calories are burned on the elliptical trainer than on the treadmill or stationary cycle. 5/5

Healthy joints

SM: It sometimes gets a bad press with regard to knees, but research on injured athletes shows that the use of a step machine as an alternative to cycling for knee rehabilitation has no harmful effect. 3/5

ET: While there is some impact in stepping, there is almost none in elliptical training, as the feet stay in contact with the pads throughout the movement. The use of the upper body also keeps joints mobile. 4/5

Aerobic fitness

SM:Great for cardiovascular fitness. One California State University study found that runners who only stepped for nine weeks improved their performance as much as those who continued to run. 5/5

ET: An excellent aerobic workout. Research shows that 12 weeks of training, three days a week, improves oxygen uptake by an average of 2.7ml/kg/min (average uptake for a woman is 38ml/kg/min). 5/5

Toned bottom

SM:When used with good technique, the step machine is fantastic for firming your buttocks and working your hip extensors hard. The deeper your steps, the greater the butt-firming effect. 5/5

ET:The elliptical trainer works the thighs, hips and bottom, but some research suggests there is less emphasis on the bottom muscles and more emphasis on the front of the thighs. 5/5

Beginner-friendly

Requires less coordination, as the upper body is fixed while the legs move. There is some impact on the joints, especially the knees, so it may not be the best choice for the very overweight. 4/5

Research shows that for the same work rate, the level of "perceived exertion" is higher on the elliptical trainer - in other words, you feel as if you are working harder, but you're not. Could be off-putting. 3/5