There are a number of common causes of running injuries. For each of these, there are steps you can take to minimise the likelihood of injury.

Body tissues such as muscles are continuously stressed and repaired on a daily basis, as a result of both 'normal' functional activities and sport. An overuse injury often occurs when a specific tissue fails to repair in the time available, begins to breakdown initially at microscopic level and then over a period of time develops into a true injury. So, the first time you feel a soreness, a stiffness or a pain is not necessarily when it all began.

However, there are many health and other benefits associated with running. For most of us it is well worth 'managing' the injury risk as the benefits are so great. Being aware of the risks, ways in which injuries can be avoided and the steps that can be taken to treat them will contribute to effective management of injuries.

While guidance can be given, it is general in its nature, whereas individual complaints may need individual attention. If you do pick up an injury (including 'tightness' 'irritation' or 'niggle') that does not settle down after a day or so, you should closely monitor it and consult a practitioner who has expertise in sports injury if you are still experiencing pain after a week.

Causes of injury  1 Overloading due to constant repetition of the running action

This is probably the most significant factor in injury potential. The main difference between walking and running is that in walking there is always one foot on the ground whereas in running there is a phase where neither foot is in contact. This means that running is a series of "jumps" from one leg to the other and the stresses are so much greater.

You can minimise the risks by running on softer sufaces, ensuring your footwear is appropriate and cross training, for example by cycling, if possible.

2 Biomechanical factors related to the running action

The way you run, or your running 'style' is very relevant. We all know that some people look fantastic and others look dreadful. How you look does not always directly link with how 'stressful' your action is but there could be link. Knock-knees, bowed legs, 'flat feet' and 'arched' back could all affect your efficiency and therefore your injury risk.
Style can be difficult or even impossible to change so always consult a coach or a 'therapist' with experience of working with runners before you go about trying to change your style.

3 Lack of recovery
Running places stresses on the body. If given adequate time to recover these stresses will act as a stimulus causing the body to adapt in a positive manner making it fitter and stronger. However if adequate time is not allowed between training sessions then the body is not able to recover fully. This can result in minor damage to tissues not fully repairing and as a consequence of this they will be damaged further during subsequent training sessions. This is how overuse injuries are caused.

You should always ensure you are fully recovered from an injury before starting to exercise again.
  4 Inadequate nutrition

Hard training causes depletion of muscle's glycogen stores. Muscle glycogen is an essential fuel during strenuous exercise, the depletion of which causes fatigue and inhibits performance. Glycogen stores are replenished by eating plenty of carbohydrate in the form of bread, pasta, potatoes, rice and where appropriate, energy replacement drinks. If glycogen stores are not effectively replaced the next run will be started in a semi-depleted state, causing potential fatigue and therefore increased injury risk. The same may also be true of dehydration and fluid replacement after exercise.

Eating and drinking regimens should be considered as an integral part of a training programme at all times. 

5 Inappropriate training

We are all different and our body will respond differently to training stresses. Even runners of a similar standard should not assume that what appears good for someone else will definitely be good for them. Group training can be very beneficial but make sure that you plan your training specific to your needs when considering the type, duration, intensity and frequency of exercise. Training must involve appropriate progression for you, so that adaptation occurs with subsequent strength and fitness gains. Get this wrong and once again the potential for injury rises.

Speak to your coach, or re-assess your programme if you are worried about your training.

6 Inappropriate preparation
Having planned your training make sure you are fit and healthy enough to be able to complete it. Be honest with yourself if feeling tired or 'under the weather', consider whether you should do the planned session today or not. Some of the most successful athletes are not fearful of adapting their plans according to how they feel where appropriate.

Wear the appropriate footwear and clothing and chose the surface according to the aims of the training. Warm up and stretching should vary according to how you feel, what training you are doing, the climate etc. While general guidance can be given, there is not necessarily one correct way to prepare or to stretch. Each individual has to explore around the theme for them, seek appropriate advice and guidance and develop programmes which seem to be effective for them. Failure to adopt this approach can increase the injury risk factors once again.

7 Inadequate fitness

Sometimes, particularly in group training, it is easy to get dragged into doing sessions that are just that too intense or too quick for you. The potential for the beginning of an overstrain, overuse or inflammatory injury is very high in these circumstances. Always having a clear picture as to the aim of that training session should help to avoid this. There is no disgrace in doing less repetitions or starting ahead of some others to make sure that the session matches your needs as oppose to leaving you on the brink of overstrain. Be careful when resuming training following injury or illness. Often we convince ourselves that we are in shape to do a certain session when really we are not. The risk of injury is always looming around the corner if we push things too hard too early.

Beware of the Sunday long run. In 'normal' healthy circumstances it may be fine but if you are recovering from injury or illness and perhaps you have just run your first race on the Saturday, is it really a good idea to go and do that long run? Should you not have a couple of really easy days to replenish your glycogen stores and allow tissue adaptation to occur before you head off onto the longer run? Be wary of planning your running around how easy it is to do on that day as opposed to what would be best to do.

8 Postural and anatomical factors

Certain postures and anatomical factors can predispose an athlete to injury. For example, if you have a leg length discrepancy this could stress the back, the pelvis, hip, knee and shin etc. Bowed legs, knock knees and flat feet may put more stresses into certain areas when running than others. Sometimes things can be done to reduce these stresses so it may be worthwhile seeing a practitioner who has experience in running analyses for advice. Video and 'force plate' analysis (which can examine the way your foot moves during a running step) are now quite commonly available and could help to reduce the injury potential.
Postural re-education is also a possibility. This requires an evaluation by a skilled practitioner and a careful plan of action which will take time to complete. It is often very difficult to change posture quickly so be a little wary of the quick fix. 

9 Muscle imbalance and weakness

This overlaps with posture and anatomical factors in many cases. As a result of the stressful postures we adopt on a daily basis, in particular sitting, it is quite common to develop potential problems with the 'balance' of muscle activity. Many other things can influence this too, but if we are not using our muscles in a particularly co-coordinated and efficient manner, it is possible to develop some muscles which are overworked and therefore tight and other muscles which are under-worked and long. This will alter movement patterns and postural control which can increase the potential for injury.

A consultation with a practitioner who has expertise in movement and muscle balance would be necessary to explore the risks.

10 Prior injury

Often runners think they have fully recovered from an injury at the point at which it is no longer painful enough to stop them running. At this point tightness, weakness, imbalance and other effects of the injury still persist to create an imbalance that the runner takes with them back into their training. Failure to understand that rehabilitation often has to carry on for some considerable time past this point can leave a runner predisposed to a repeat or new injury.
  Understand that just because you do not feel any more pain from the injury that your body is still recovering and you may need to continue your rehabilitation treatment for some time after the injury has 'healed'.

11 Inappropriate footwear

There is no doubt that shoes appropriate to the running action, size of person and training surfaces are a critical factor in injury potential. Shoes should be assessed for signs of excessive wear regularly. Check for outer sole wear, breakdown of the mid-sole, distortion of the heel cup, breakdown or damage to the upper and for the resistance to distortion of the shoe (grasp the heel in one hand and the front of the shoe in the other and twist in opposite directions) as a comparison with when the shoe was new. Read Choosing running shoes and when in doubt seek the advice of a therapist with relevant experience or a good running shop.