Thinking about taking up jogging?

To see if you're fit enough, stand on one leg for 30 seconds, and then the other. If you wobble a lot or fall over, your legs probably aren't strong enough. After all, when running you have your weight on one foot for 80% of the time.

Wondering if you're up to aerobics?

To check whether your heart can take it, find a bench and step up and down for three minutes. Immediately sit down and locate your pulse. Ten seconds after your last step, record your pulse for one minute. As a guide, if you count more than 107 (men) and 115 (women), you are not doing so well and should be careful before embarking on an overly ambitious exercise programme.

Are you strong enough?

Gauge your power with the vertical jump test. Face a wall with your arms extended fully above your head and mark where your fingers touch the wall. Then jump up as high as you can, recording the highest point. Subtract the standing height from the height jumped. If you can't manage more than 30cm (men) or 20cm (women), you've got some work to do.