Running for fitness or competition might seem like a simple activity, but up to half of all runners can get some sort of injury each year. That injury might be minor and they run through it until it gets better or it may be serious enough for them to have to stop running. The most common reason for these injuries is that they simply over did it. They run too much before the body has been given a chance to adapt or get used to the distances being run. Every time that a load is applied to the body it is important to give it a rest before applying another load by going for another run. If too much load is applied before recovery from a previous training session, any damage get exacerbated and this may progress into an injury. Rest is just as important as the training runs and that is how fitness and strength is increased and is also how injury is avoided.
In addition to the too much too soon scenario, biomechanics also plays a role. This is the way that we run and different runners do it differently. Different running techniques can load different tissues in a different way and load some tissues too much, so that when running that might be enough to cause an injury. For example, conditions like medial tibial stress syndrome (shin splints) can occur when the width between the foot placement when running is too narrow. Those with this condition may benefit from running with a wider base of gait. Another common biomechanical problem is runners is tight calf muscles. When running this causes the arch of the foot to collapse or overpronate and can result in a a range of conditions like plantar fasciitis to runners knee. These people will benefit the most from a calf muscle stretching program. The treatment of running injuries will depend on the cause and should be directed at the cause, whether its biomechanics to training load issues.