How great is your injury risk?

Why do runners get injured? Is it just bad luck or are there some runners more at risk than others?

The risk factors can be divided into two 'camps': intrinsic and extrinsic.

Examples of extrinsic risks are

• The surface that you run on. Are you pounding the pavements on a regular basis or are you able to do some or all of your training on the grass?
• The terrain that you run on. If the terrain is particularly uneven and rough, are you agile and strong enough to be able to cope with it?
• Footwear. Are your running shoes supporting your foot type and gait and is the cushioning at a good level to absorb impact?
• Fatigue. When you become fatigued you run less efficiently and so can put extra stress and strain on muscles, tendons, ligaments and joints.
• Inadequate recovery. Training causes injury to the body but, if the load is right, this damage should only be at micro levels. During recovery the body heals itself and makes itself stronger. If you don't allow this to happen and you train hard before the mending has taken place you break the body down even further.

Examples of intrinsic risks are

• Age. As we get older our bodies change. Wear and tear builds up in the joints. Connective tissue becomes less elastic, and lubricating fluids decline, making us more injury-prone.
• Sex. Research suggests that women are more prone to injury than their male counterparts. The research has mostly looked at knee injuries amongst team sport players but there are suggestions that female runners suffer more anterior knee pain than male runners and that women are more at risk of injury as a result of hormone fluctuations during the menstrual cycle.
• Previous injury. Injury can compromise the stablilising muscles around the joints and this can make you more prone to injury in the future, especially if you haven't had a robust rehabilitation programme.
• Conditioning. If you are new to running you may not be conditioned sufficiently to maintain a good running technique during your training session. It is essential that you build your training load carefully and sensibly so that your strength builds in tandem with your running fitness and you can cope with the training programme that you have selected.
• Biomechanics. Some find running easier than others and this could be down to your biomechanics. Biomechanics can be changed, especially if the problem is due to lack of strength in a muscle, tightness in a muscle or lack of flexibility around a joint, for example, but sometimes biomechanics can't be changed if, for example, the issue is anatomical alignment.
• Posture and Movement skills. These relate to the biomechanics that you can improve. By working on your balance, co-ordination, running drills, flexibility, and core strength you can improve your posture and movement skills.
• Foot type. There are various foot types: neutral, hyperpronated (tends to overpronate when running), subpronated (tends to underpronate during running), feet with high arches and feet with low arches. Those with a neutral foot type are at less risk of injury. Studies have found that certain foot types make a runner more susceptible to certain injuries.
• Weight. Those who are at either end of the spectrum are more at risk of injury than the average runner. If you are very heavy you will experience greater impact through your body every time your foot strikes the ground. The force that goes through your body, when you run, is approximately twice your body weight. If you run 20 miles per week you make approximately 1,000,000 foot contacts per year. If you weigh 75kg that is 75,000,000kg of impact going up each leg every year so you need to be pretty robust to withstand that! At the other end of the scale, if you are very light you probably won't be strong enough to withstand long-term training before breaking down.

In order to stay injury free you need to assess your injury risk and determine how much training you are able to do in relation to it. On the table below, if you take the y axis as the injury risk and the x axis as the training load, you can see that, for example, a runner with poor biomechanics who trains hard is in danger of becoming injured whereas a runner with efficient running technique, has a neutral foot and who trains on safe surfaces but doesn't train hard will only make small improvements and may not be as good as they could be. The trick is to minimise your injury risks as much as possible and then train as hard as is sensible for a long and enjoyable running life!

Injury risk v training load

High risk, low load = SOME IMPROVEMENT, SOME DANGER	High risk, high load = DANGER
Low risk, low load = MINIMAL IMPROVEMENT	Low risk, high load = OPTIMAL IMPROVEMENT