Knowledge Level: Intermediate
The purpose of training for most people, is to enhance performance. However, occasionally we may miss a few days, weeks or even months through injury, illness or other commitments. A common fear is that we will lose our fitness gains through missed training. This fundamental training principle is called reversibility, or the ‘use it or lose it’ principle.
Sometimes our fears of getting worse are unfounded, but inevitably we will get slower if we don't ride our bike regularly. Andy Kirkland, a British Cycling Level 3 Coach and Chartered Scientist explains why.
If we load our body sufficiently through training, physiological adaptations such as increased aerobic capacity, improved exercise efficiency and increased muscle strength will occur. The rate and magnitude of these adaptations are very individual with some of us responding to training better than others. Following similar principles, if we stop training, this adaptation reverses, and we will get slower as a result. How quickly this happens and by how much is dependent on our current training status and genetics.
The first changes we notice will happen as a result of hormones. To understand a bit more, think about a training ride or race that you have really suffered during. It is often not very pleasant at the time, but once you are showered and changed, you will quickly forget your suffering and will probably have an enhanced feeling of well-being. This is because the body ‘rewards’ us by releasing feel-good hormones, including opioids, catecholamines and dopamine.
However, we may suffer withdrawal symptoms when a session or two is missed, especially if we train most days. This is because we are not getting our rewarding hormone hit. Such feelings of deprivation can result in low mood, increased tension and fatigue. Similarly, if you have ever tapered for a big event, you may be familiar with these feelings, thinking you have lost all your fitness and adding to pre-race nerves. Fortunately, the majority of affects from missing a few days training are psychological rather than physical, and by simply recognising this, can make it easier to deal with.
After 3-4 days without training, physiological changes will occur. We will become slightly less efficient on the bike because we begin to rely more on carbohydrates rather than fat. When we hit the two week mark without training, blood volume decreases, reducing our ability to deliver and use oxygen (VO2max decreases). After a month or so, muscle physiology starts to change resulting in further decrements in performance. Luckily, this maladaptation process stabilises and further losses in fitness are slow.
To minimise the effects of detraining, it is important to maintain a healthy balanced diet, accounting for reductions in training load. Without our exercise ‘hormone hit’ it is easy to seek out other things that make us feel good, like eating unhealthy food, but this is best avoided. If illness or injury doesn’t prevent you from doing so, other forms of exercise such as running or swimming will minimise the detraining effect too. That is why it is important not to live a sedentary life style in the off-season.
Recognising that the effects of the odd missed training are psychological, may help stop you feeling so bad when you fail to pull your bib shorts on, for example when you are feeling overly fatigued, when the weather is miserable or during a taper. However, it is important that missing sessions does not become a habit and that, for the majority of the time, you train consistently and hit the targets that your training plan prescribes.