Surely there is no such thing. The harder you train the better you perform. Your body needs regular and intense exercise and if you are feeling a bit tired then all you need is a good hard run to put you back on your feet again. Not necessarily so.

Runners are generally perfectionists, capable of pushing themselves to their limits, and usually totally incapable of knowing when to slow down or even stop.

Overtraining is a very real entity. Find out how to recognise and prevent it.

When do you know you are overtraining?

Fatigue is recognised as part and parcel of effective training. How do you distinguish between this and the fraction more which indicates overtraining?

If you are training hard and begin feeling generally fatigued, but your performance is stable or still improving, then you are not overtraining. If, however, your performance starts to drop off then your fatigue is probably one of the first signs of overtraining.

How do you monitor this effectively and not just assume that your performance is dropping because you are not training hard enough?

Tim Noakes in 'The Law of Running', suggests that performance during time trials will be a good indication. Are you having to run harder to achieve the same times? If you are, you are probably training too much.

Of course many people fail to pick this up and continue training, usually even harder, and go on to develop what Bruce Fordyce calls the "plods".

Symptoms of this are sore muscles, heavy legs, sluggishness and a general feeling of fatigue and malaise. If you are sensible enough to rest completely for 24 to 48 hours then the "plods" should disappear completely.

If you do not then you will crash into the full blown overtraining syndrome, with persistent muscle soreness, loss of interest in training, an increase in resting heart rate and changes in sleeping patterns. Once all this has happened then recovery will take six to eight weeks, during which time it is impossible to train or race effectively.

Other signs of severe overtraining can include diarrhoea, persistent weight loss, swollen lymph glands, increased susceptibility to infection, loss of menstruation in women, inability to concentrate and loss of libido.

Other factors which will contribute to overtraining are poor nutrition, lack of sleep, drug or excessive alcohol use, work pressures, emotional conflict and a monotonous training routine.

How can you prevent overtraining?

The key to preventing overtraining is to recognise it early and prevent yourself from getting anywhere near the severe overtraining syndrome described above. If you answer "yes" to three or more of the following questions then it is time to reduce your training:

• Does your normally comfortable pace leave you short of breath?
• Do your legs feel "heavy" for longer than usual after a hard work out or race?
• Do you find it especially hard to climb steps?
• Do you dread the thought of training?
• Do you find it particularly hard to get out of bed in the morning?
• Do you have a persistent lack of appetite?
• Are you more susceptible to colds, headaches and other infections?
• Is your heart rate five to ten minutes higher than usual?
• Is your heart rate during exercise higher than usual?

Tim Noakes's advice is to start running again only when you want to and then only slowly. However, he points out that overtraining in most runners is a chronic, relapsing condition so for prevention, some insight is required by the runner.

Once the full blown, severe overtraining syndrome has developed then it is necessary to rest for anything between 6 and 8 weeks.

Even early overtraining which shows itself in the form of a cold or other infection 7 to 14 days before a standard marathon or ultramarathon will slow the runner between 5 and 20 and 45 to 60 minutes in each respective race.

Continuing to train when overtrained will only prolong the eventual rest period. Better to rest early and for a shorter time.

Listen to your body and remember that we all have genetically determined limits to our performance. More is definitely not always better.

(Source: The Lore of Running. Third Edition, Oxford University Press. 1992. Tim Noakes.)