The common running injuries include shin splints, runners knee and tons more, but the sole cause of these injuries has nothing to do with you not being fit for running, the main cause of these injuries is your heel strike running style.
Is Heel Striking Bad For Your Achilles?
Heel strike running was found to be one of the biggest risk factors for Achilles injury because the hips and foot were found to be used too intensively to propel the body forward through each over-stride. This was found to shred the Achilles tendon as compared with forefoot running, which has a more protective effect on the tendon by eliminating an over-stride, driving higher step-rate and less risk of over-pronation.