For many people running is the most natural form of exercise imaginable. Yet despite the media focus on running mechanics and new generation footwear, high injury rates continue to frustrate recreational and elite runners alike. Matt Lancaster, Physiotherapist with Athletics Australia at the London 2012 Olympic Games and Director of ALLCARE Physiotherapy, Sandy Bay, Tasmania, considers the biological mechanisms which underpin our running robustness.
Nature’s great machine
The analogy between human movement and mechanical engineering is well worn, and no where more than when considering running.
We have levers, joined by hinges and balls in sockets. Our muscles produce force like pistons. They help us absorb impact and control and stabilise our frame. Tendons function as springs. Ligaments are guide ropes. We have an engine to drive us forward and a need to consume fuel to maintain momentum. And at the hub of this grand design is a mesmerising control system, coordinating our limbs and our core and our lungs and our heart to make sure our myriad components function as nature’s most advanced machine.
When our mechanics are good, we are smooth and efficient, our running is effortless and we never break down. Or so the mantra goes.
Actually, while how we run is undoubtedly important, mechanics alone do not provide the full picture, as many injured runners with apparently good technique and fantastic footwear will testify.
Putting the Bio into Biomechanics
All machines fatigue and deteriorate over time. For mechanical engineers, calculating when this will happen is probably not complicated. However, few machines grow stronger the more work they do, which is precisely what can happen to you. The more you run, the better your body is equipped to... run.
Whatever your level of running, changes in fitness are evident over time. This is the fundamental reason why people train. And while it is easy to associate this improvement with changes in your heart and lungs (the engine), adaptation is also occurring elsewhere in your body.
For instance, anyone who remembers the leg soreness they experienced the first few times they ran after a lengthy break will be familiar with the particular eccentric demand that running places on our muscles. Compared to concentric muscle activities such as cycling, eccentric muscle contractions are relatively low in their energy cost, and adaptations within our muscles contribute to the efficiency of increasing power output during running.
Running, and in particular sprinting is also associated with developing more efficient tendons, with increased elastic stiffness (think of a thicker, more effective rubber band). And the effect of ground impact means both recreational and elite runners develop higher bone density than cyclists and swimmers.
Beyond the mechanics of how we run, these specific biological changes, which occur in our tissues at the most fundamental, cellular level enhance our robustness to the stresses and strains of further training, are good for our health and lead to improvements in running performance.
So why do we still get injured?
Clearly our tissues need a sufficient training stimulus to adapt, and it makes sense that as we become fitter, over time that stimulus will need to increase. However, training errors can lead to a break down in our biological adaptive mechanisms as tissues become overly stressed.
Stressed tissues (such as bone, tendon or muscle) which are subjected to further excessive bouts of the same stress (because you wouldn’t listen to your body and REST!) can too easily become injured tissues. This is the basic mechanism for the majority of overuse running injuries, regardless of biomechanics, and leads to weeks and months of frustration for many runners.
Manipulating your body’s adaptive mechanisms, by carefully planning your training and reacting to how your body responds, is at the heart of successful and consistent training.
5 Tips to Injury Free Adaptation
- Progress training steadily, particularly after a break from running.
- Be patient and stick to a training plan that is appropriate for you.
- Let your key runs be challenging but not exhausting.
- You should be able to perform an easy run the following day.
- Allow sufficient time between key speed or hill sessions for your body to recover (2-3 days).
- Plan lower intensity weeks into your training cycle.
- Incorporate lower intensity recovery runs into your training week.
- Keep your heart rate around 60-70% of your maximum (0.6 x (220 – your age)).
- Listen to your body!
- Keep a diary and record levels of soreness and fatigue. If you are not recovering – REST!
There is no guaranteed way to avoid injury, but understanding that your body adapts to training at the most basic cellular level, and that excessive stress leads to a failure of this mechanism and potential injury, leads to smart training choices. Why not place the injury odds firmly on your side.
By Matt Lancaster (Athletics Australia Physiotherapist)