Distance running injuries: Eliminate these training errors and reduce your chances of getting hurt.

It is well accepted that one major cause of distance running injuries are training errors committed by the athlete concerned. In one study, James and colleagues (1978) were expecting to show that anatomical and biomechanical factors were the most likely causes of running injuries. However, contrary to their hypothesis, they found that some 60 per cent of the running injuries in their survey were due to training errors. Other researchers such as Brody (1980) and Clement and colleagues (1981) confirm that training errors are a highly significant, if not the most common cause of running injuries.

If you commit a training error, it doesn't mean that you are doing the wrong type of training. Instead, training errors are generally associated with high volumes or intensities of training, or any rapid changes in training. This may mean that you are doing the right type of training but just too much of it, or too much training too soon. For example, two common training errors athletes commit are periods of high mileage without easy days in between, and sudden major increases in mileage.

Understanding why training errors cause injury becomes obvious when you think about what happens to your body when you train. During a training run the bones, joints and muscles in the legs and low back are stressed and this causes damage. Thus a recovery period must follow the training. During the recovery, the damage is repaired. In time, regular training combined with adequate rest results in what is called 'supercompensation'.

With supercompensation, the body responds to the stress by growing stronger. This happens to all the bones, ligaments, tendons and muscles. Once stronger, the bones and joints can handle greater stress, absorb more shock, and the muscles can act more efficiently. However, if you continue with high mileage training day after day, there is never sufficient recovery. In time, instead of growing stronger, your body becomes permanently weakened and an injury will result.

The same is true if you suddenly hike up your mileage. Your body is not currently conditioned for the higher levels of stress and so injury results. The bones, ligaments, tendons and muscles are only ever as strong as their current training level. They cannot suddenly develop extra strength as an immediate response to training increases. Supercompensation is a long-term progressive adaptation, not a short-term acute reaction.

Coaches and athletes are well aware that they have to get a positive training effect in muscular strength, anaerobic metabolism and aerobic metabolism. What they too often forget is that positive training effects must also occur in bones, ligaments and tendons if the athlete is to train injury-free.

Avoiding these two common training errors - prolonged high mileage and sudden mileage increases - is a major priority for any athlete. The first step in ironing out these errors is careful planning of training. Athletes must never train on a willy-nilly, do-what-they-feel-like basis They should always plan every element of their training, including rest days. Then they must ensure that the plan is followed, avoiding extra training just because things happen to be going well.

Many athletes make the mistake of planning their high-quality running sessions, but make up the 'steady runs' element of their training as they go along. This is wrong. For each month, you should plan your training in every detail. Any planned increases in mileage should never be greater than 10 per cent a week. A full rest day is recommended once a week or every other week. Easy days are recommended every three days.

Slow and steady does it
The crucial underlying principle in correct planning is for slow and steady progression. The starting point is to work out what level of mileage you can currently train at without becoming injured. Then you must plan a slow progression over a period of months up to the mileage level you would like to be training at. As well as being the correct practice for injury prevention, this long, slow progression of training is also the key to improved performance. Common sense says that an athlete who attempts an 80-miles-a-week regime but regularly takes weeks off through injury will not be as fit as the athlete who starts on 40 miles a week, slowly builds up 60 and continues injury-free.

Prolonged high mileage and sudden increases in mileage are not the only kinds of training errors. In fact, just about any rapid change in any aspect of training could be classed as a training error and likely to cause injury.

A sudden addition of high-intensity training is another common training error. This could be the situation when, say, you have spent months on steady mileage training and then decide to include fast anaerobic interval sessions. Again, the same principle applies. The body has not yet been trained to cope with running at a fast pace, with the higher muscle forces and impact forces that result from increased speed. The muscles tire quickly and so extra strain is placed on the bones and joints. Result: injury.

Again, slow and planned progressions are the way to avoid this training error. A good way to start with higher intensity sessions is with a fartlek workout once a week (this involves including fast sessions in your run when you feel like it, taking easy sections for recovery). After a few weeks of fartlek runs you can then add an interval session at 3K pace. For example, start with an 8-10 x 400m with 60 secs recovery, building up to 25 x 400m. Once used to this pace, you can attempt faster paced sessions to train the anaerobic system.

Another example of a training error is a sudden change in running surface. Hard surfaces, such as roads, require high impact forces to be absorbed. Obviously you must be able to cope with this. However, at the same time hard surfaces are true and do not dampen the propulsive forces. Conversely, soft, off-road terrains attenuate impact forces, thus lessening the need to absorb shock, but dampen the propulsive forces. This means you may have to change your neuromuscular coordination to adapt.

If you train regularly on hard surfaces and then switch to training on soft surfaces, or you do a one-off cross-country race, problems may occur due to the different stress on the muscles. And vice versa: if you regularly train on soft terrain and then switch to hard surfaces, you will suffer because you cannot cope with the high impact forces.

Artificial surfaces also have unique properties that you must be used to coping with. If athletes are to train or race on different surfaces then they must plan in advance the switch in surface and build up the training on the new surface slowly.

Compounding the problem
The worst kind of training errors are compound rapid changes. The classic compound change that runners make is to spend all winter doing steady running on the road in trainers and then switch to fast training on the track, in spikes, for the summer season. Here there are three variables that have suddenly been changes: the intensity of the running sessions, the surface and the shoe. With spikes there is lower heel lift and less support. This means there is greater dorsi flexion and potentially more pronation. This will place greater stress on the muscles in the lower leg.

This change in biomechanics caused by the shoes, along with the higher impact forces from the fast speeds and different muscle recruitment required for the spongy nature of the track is often too much for the athlete and injury will result. However, if you include some speed training on the track, in spikes, throughout the whole training year, you will drastically reduce injury risks in the spring when you want to increases intensities for track racing. As long as you are used to, and can cope with, a variety of surfaces or shoes then that is fine. Remember, it is rapid changes that have to be eliminated, not necessarily variety.

The training errors I've mentioned are typical of those committed by distance runners. But not just by them. Coaches and athletes of all events and sports must realise that prolonged high-intensity training, prolonged high volumes of training or any kind of rapid change in any aspect of training should be seen as a training error. This is a vital principle to understand. It should be followed in any training programme or potential improvement will only be curtailed by injury.

Clearly, then, it is very important for injury prevention to avoid training errors. With careful planning and slow progressions, athletes should be able to avoid the kinds of errors I've discussed.

But a word of warning: because elite performance requires high mileage and high-intensity training, athletes are still at risk simply from hard training. Some may be able to withstand it; others may need to reduce their training to remain injury-free. Only then will they reap the benefits of uninterrupted training. To underline the point, here is a telling comment from Derek Clayton, the former world-class marathon runner:

'If I had my competitive career to run over again, I would change some of my attitudes to injuries. I would show them more respect. Because, after all, injuries weren't some unknown barrier I was trying to break through. Injuries were simply my body telling me that something wrong was happening'.