Running injuries, part 1 – Why do we get injured? The evidence
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Being a runner myself the last thing I want is to stop running through injury. Running has so many positive effects, in addition to the obvious on physical health. An injury can have a knock-on effect on all aspects of well-being. Obviously, an injury from a direct fall, a twist of the ankle, is easy to explain, there is a direct cause and effect. But what about those injuries, the majority of running injuries, that just develop? The dreaded plantar fasciitis, the stubborn ITB syndrome to name a couple, these can hinder performance for weeks, if not months. What causes these types of injury? Surely if we have a greater insight into why these develop, prevention could be more possible.
Lots of well-meaning advice is often offered, ‘it’s your trainers’, ‘you shouldn’t run on grass’, ‘you shouldn’t run on the road’. Professionals can also give conflicting advice causing confusion and frustration. The problem is, we have very limited research/evidence to support a lot of our well-reasoned theories. There is a limited amount of research that exists to support strength, flexibility and alignment to be the cause of an injury and the research we do have is generally of low quality. That is not to say that these factors should not be assessed to formulate a diagnosis and treatment plan but a single finding should not be given too much weight as the cause of injury, it is more likely to be a combination of many factors.
One area that does show some promising results is the strength of the adductor (inner thigh) muscles. Adductor strength may be a predictive factor for injury. An interesting study done in 2010 showed that adductor strength was reduced prior to injury. Strength was assessed at different stages and was found to be reduced just before injury occurred, compared to the original strength level. This suggests that keeping the adductors strong may play a role in injury prevention, although this has not been investigated.
Research suggests that errors in our training are likely to contribute heavily towards injury and therefore understanding these could help in injury prevention. An error might be a sudden change in the amount we put on our body (the load) or training when the body’s ability to run is lowered (the capacity). If we put too much load or if we change the load we are putting onto our body, for example suddenly increasing our distance or speed, our body’s capacity needs to be able to cope with this change. Equally, the load/training might not need to change but injury might still occur. In this case there might have been a change in the body’s capacity to take the normal training program. For example, a period of illness will reduce the ability to run at the same load, through reduction of fitness, strength, endurance etc.
Psycho-social factors are a well researched contributing factor for the development of injury. Stress has a well-documented effect on our immune system, lowering our capacity to withstand the load of running and in turn can play a role in injury. Sleep plays an important role in the recovery from a training session. Sleep deprivation, from a waking child for example, or from stress, will hinder the recovery and therefore reduce our body’s capacity to withstand the load during the next run.
Let us consider an example; a 32-year-old male who is an experienced runner runs up to a max of 10km in training sessions. He is in good medical health. He wants to complete a ½ marathon in 2 months time. He has a young child who has just started to wake again in the night. He is also coming up to a deadline at work and is working long hours to get the work submitted. He therefore can only run at the weekends so thinks, to make the most of it, he will increase the distance of his next run to 15km. He previously had a niggle in his knee after running but this was completely manageable, otherwise, he has been running comfortably and feels like he is getting stronger. Today on his run, after 13km his knee caused him to stop :(
Here we see that capacity has reduced through stress and lack of sleep. The error in training is pushing the distance too quickly. Normally this might have been fine but with the reduced capacity of the body to withstand the extra load, the niggle in the knee is now a bigger problem.
Injury is likely to be multifactorial, there is seldom a single risk factor. A 2017 study found exactly this and named training load increase, training intensity increase and decreased sleep to be the biggest risk factors. It is sensible to conclude that at a time of sleep deprivation, for whatever reason, training load needs to be carefully managed and not increased suddenly.
Through better understanding of the contributing factors of an injury, a better, more rounded approach to successful rehab can take place. In turn, recovery will be quicker.