Do practise running lightly and quietly. Pounding and foot-slapping are a sign that something is wrong with your technique - you are wasting energy and jarring your whole system.

Don't allow your head to bob or roll à la Paula Radcliffe. The head weighs about 10lbs, so a nodding movement is going to place a tremendous load on the rest of the body, creating tension in the shoulders and putting pressure on the spine. Focusing your gaze 20 to 30 metres ahead helps.

Do vary the speed of your runs. Research published in the Journal of Applied Physiology last year found that six minutes of short, flat-out sprints gave similar results to long, slow runs that required several hours of training a week.

Don't avoid hills, however tempting. Running repetitions up hills (fast up, slow down) is the outdoor equivalent of strength training. And it seems so much easier when you return to flat ground.

Do lengthen your stride. Ideally, a long-distance runner should take 170-190 strides per minute. If you take many more than that, you are probably not running efficiently.

Don't allow your wrists to flap around. A common mistake is to assume that flopping your hands means a relaxed style - in fact it creates tension, as the shoulders tighten to pick up the slack.

The best exercise? The hamstring stretch. Generally, sports scientists agree that it is more beneficial to stretch after a run (warm up beforehand with a gentle jog). Although it's important to stretch all major muscles, the hamstrings need particular attention. Stand in front of a low desk or dining chair (just above knee height) and extend one leg to place on the surface. Put your hands on your hips and keep the raised foot relaxed. Reach forward from the hips, keeping your pelvis straight and the knee of the raised leg straight and the supporting leg slightly flexed. Hold for several seconds. Repeat on the other side.