Compiled with the help of Dr Nanette Mutrie at the University of Glasgow and Rob Shannon, visiting lecturer in Health Behaviour Change at City University
If you are not someone who jumps at the chance of a 10-mile run at six o'clock in the morning, you will probably know what it is to lack motivation to exercise. But before you embark on another punishing, temporary and fruitless campaign, make sure you are properly armed. Here's how.

1 Look in detail at why you have failed before. Write down what happened and how you would overcome it this time. For example, if you gave up because of boredom, you could make a contingency plan beforehand of what you will change to on the day when you can't face your routine.

2 Be clear about your goal. Make it realistic and something you will be able to maintain. This may be a good time to consult an expert, if you feel the need, who will be able to tell you exactly what you should do to get what you want. An example of a good goal is to lose two inches from the waist or be able to run two miles after a month. An example of a bad goal is "to get rid of my disgusting thighs".

3 Find someone supportive to talk to about it - preferably someone who exercises and can goad you into going when you'd rather watch the telly. People who live in a social group where exercising is normal behaviour are far more likely to take up and maintain exercise than the person whose family and friends laugh with derision at the very mention of the word "trainers". The exception to this common sheep-like behaviour is the individual who responds to reverse psychology - the more they are told they can't do it, the more they are determined to do it.You should identify which group you fall into.

4 Examine motivation in the rest of your life. Yes, you have some. "People who really have no motivation," says Dr Mutrie, "are mentally ill." How does it work? What keeps you going at work? How do you clean the house? What keeps you brushing your teeth? Why do you go to the pub? The answer is probably a combination of pleasure, routine, ambition and fear of the alternative. If you can get exercise into all of these categories too, you are onto a winner.

5 Don't go mad at the beginning. The pounds 100 leotard and the 10-year gym membership may seem a good incentive but should anything go wrong you will be less inclined to start again next time. Build up a steady programme. Pushing yourself too hard at the beginning will not only put you at risk of injury but will also probably be most unpleasant and leave you thinking that exercise is something that you haven't done properly if you are not half dead. This is not a promising way to carry on.

6 Find an exercise that is right for you. If you hate running, don't. If you can't bear chlorine, don't go swimming. Despite what school taught you, exercise doesn't have to be unpleasant. You can get fitter to a certain extent by incorporating it into daily life - walking part of the way to work or going cycling at weekends.

7 Start thinking of exercise as part of life rather than a punishment. As Get Shorty recently put it so aptly, attitude plays a part. If you believe it will be boring and a struggle, it probably will be. If you look forward to the buzz and the end of your back pain you are likely to be more tempted.

8 Someone who was sporty at school is much more likely to be physically active now. Understand this and, if your school memories are a grim combination of humiliation and frozen fingers, give yourself a little emotional support. Chastising yourself for slip-ups doesn't help. Realise that there is a major self-perception shift needed to emerge from the unsporty blobby caterpillar to the lean and luscious butterfly. Reward yourself with new clothes or enoyable evenings out just for doing exercise. Don't wait to change shape before you start rewarding yourself.

9 Once you have successfully started exercising you don't always have to think about it. People for whom exercise is a way of life don't spend half a day beforehand thinking, "I must go, but I don't want to". They don't think about it until the time comes. The dread is very often worse than the activity.

10 Learn to be active in small ways too. Walking up stairs and escalators seems a small and unnecessary change. But walking up two flights of stairs a day was found by the American Journal of Psychiatry to account for six pounds of weight loss per year in the average male body. Just doing little things like this will also make exercise less of a shock to the system when you do go.