A big bee in my bonnet has always been the idea of asymmetry being the enemy of the runner. So with this in mind I just wanted to bring up the subject of ‘camber’ and how it can really upset your body and result in injury.
A camber is ‘a convexity in a road surface’, i.e. the centre of the road is higher than the sides. Lots of runners always run on one particular side of the road. This means that one leg will be hitting the road higher than the other. Over time this could lead to imbalances in the muscles of the foot, leg and pelvis, even leading to one leg being functionally shorter than the other. This can be the source of a whole host of running injuries, including ITB syndrome, plantar fasciitis, runners knee, hip and back pain.
So, as a rule of thumb it is best to vary the camber you are running on. This also relates to running on pavements (sidewalks), as they often slope (in the opposite direction to the road camber in many cases, so that water flows into the gutter).