THINK OF TRAINING as digging a hole in the ground. The more you train, the more you dig. When we recover from training, the hole refills itself and the subsequent muscle growth is the neat mound of earth on top of the hole. The fitter we get, the quicker the hole refills. The less fit we are, well, the harder the hole is to dig in the first place and longer the hole takes to refill.

When we train, and train, and train, and train some more we dig deeper and deeper and deeper until we dig deeper than the body can recover from. Eventually we reach a point where we cannot dig any deeper and the hole cannot refill, let alone form a mound on top.

Over-training is a complex mix of the physical and psychological, and both are inextricably linked. An inability to train any more can leave an athlete depressed if targets are not being met. The response is to try harder, but instead of improving, the athlete only gets worse, hastening the downward spiral. The symptoms of overtraining are, first and foremost;

1. Tiredness

Where once you could go through a wall, now it’s a struggle to get out of bed. Where once you took two stairs at a time, now you need a handrail. Where once you could train twice a day, now you barely complete a session every two days. You are wrecked, all day. While many other factors influence how you feel – such as the stresses of work and personal life – it’s important to realise what tiredness really is.

2. Mood swings

This is related to the above and comes about through a lack of sleep. Eight hours sleep is required if you’re in heavy training, even more is better again, says Irish international marathon runner, Sergiu Ciobanu “they say eight but if you can get 10, even better. Sleep is more important than anything you can do in the gym or on the road.” Listen to your body and observe how little things irritate you. This is a sure sign you need to take the foot off the gas for a week.

3. Poor performance

This is the biggest physical indicator of whether you’re overtrained or not. You used to be able to hold a plank for two minutes but now you can’t do one minute, you could bench 120 kilos eight times but now five is a chore? A well-planned exercise programme should see you hit those numbers and progress week after week after week. Not regress. A rest week every 3-4 weeks is absolutely key to improvement.

4. Elevated heart rate

This is a brilliant way to tell you what you might be refusing to believe. You’re knackered, so listen to your heart. Every morning take your pulse for 15 seconds and multiply it by four (so as to get your resting heart rate). Write this number down on a piece of paper and observe how it fluctuates over the course of two months. As you get fitter your resting heart rate drops naturally as your heart has been trained to work more efficiently. Of course, there are many reasons for a high resting heart rate – such as dehydration, a lack of sleep, alcohol in the system, stress – but if taken over a long period you’ll get an idea of what’s normal. Anything above normal for a prolonged time (of a few days) is proof you’re overtrained, or you’ve stopped training altogether. Notice how a period of rest will see your heart rate drop back down again.

5. Lack of motivation