Traumatic injuries are usually the result of impact and collisions, and typically occur suddenly, so generally there's not much you can do to prevent them (although in most games or sports one of the aims of the rules is to reduce the risk of injury, so following the rules should make you safer).



But other injuries occur over time, and as a result of identifiable problems, and so are preventable in many cases.

The risk factors that lead to injury are usually classified as being extrinsic (outside the body) or intrinsic (personal to your body).

Typical extrinsic factors include:

* Excessive load on the body. The tissues of the body are capable of withstanding considerable stress: more than three times your weight can go through the body even when jogging slowly. But tissues that aren't accustomed to such forces won't have adapted to withstand them and are likely to be injured when they're applied. When deciding how often, how hard and for how long to exercise, you need to consider the impact on your muscles and joints. Build up gradually to avoid injury.

* Poor technique. A number of so-called 'overuse injuries' are related to sports or exercise technique. Indeed, some injuries are even popularly named after their sport (for instance, tennis elbow). Often it's the repetition of an action with faulty technique that results in excessive load on tissues and subsequent injury.

* Poor or inappropriate equipment, especially footwear and, in some sports, headgear. If your activity involves impact (things such as running and jumping) then wearing proper footwear that supports your feet and cushions your body from shock is vital. Your need for specialist footwear or - other sports equipment - may be determined in part by intrinsic factors such as 'over pronation'

* Failure to warm up and warm down. Many of the body's tissues (particularly muscle) respond better to loading when they're warm. The warming-up process should include whole body exercise that increases blood flow to muscles and makes them more responsive. At the end of every training session, you should also warm down, bringing your body back down to normal, usually through low intensity activity, followed by flexibility exercises.

Intrinsic injury risk factors include things such as the shape and structure of the major joints. For example, feet that 'pronate' (roll inwards) or have a weak arch often contribute to lower leg, shin and knee conditions in runners, as do 'knock knees' (genu valgus) or 'bow legs' (genu varus).

Other injury risk factors include:

* Leg length discrepancy

* Muscle weakness or imbalance

* Limited flexibility

* Joint laxity - not being able to control and stabilise joints throughout their full range of motion

* Being overweight - this increases the load on muscles, tendons, ligaments and joint structures during weight-bearing activities