Q: I have been running for many years without injury. Recently however, I have had a series of injuries including sore knees, shin splints and even some heel pain. Why am I getting injured so much now and not before?
A: Injuries are multi-factorial and particular to each individual. The multiple factors contributing to musculoskeletal overuse injuries include (1) training errors, (2) abnormal biomechanics, (3) incorrect equipment, (4) flexibility and muscle strength, and (5) underlying injury or disease. These are not listed in a particular order. That is, training errors are no more or less important than incorrect equipment or muscle flexibility. Your recent series of injuries is most likely related to a recent change in one or more of these 5 factors.
When a runner makes a training error, this usually means they made a sudden increase in running distance, intensity or speed. Intensity can relate to running speed, but doing more hill work for example, will also increase running intensity. Another common training error relates to being consistent, not skipping runs and trying to make up your weekly mileage on the next run. Adhering to a well-structured running program usually controls the training errors quite well.
Abnormal biomechanics can also lead to overuse injuries. The "big" one is over-pronation of the foot, but this alone usually does not cause injuries. Many people run with over-pronated feet without injury, mainly because they were the correct shoes, have good flexibility and train consistently. Abnormal biomechanics becomes more of a problem when trying to recover from an injury, or when you make training errors or wear the wrong shoes. Abnormal biomechanics can also be improved with the correct footwear and in some cases, shoe inserts such as orthotics. This brings us to incorrect equipment. Equipment equals shoes in running. Simply, the correct shoe for your foot and lower limb biomechanics and structure can reduce the risk of injuries. The wrong shoe can increase the risk.
Perhaps one of the more important factors listed, is the influence that muscle flexibility has on overuse injuries. Most of us don't stretch consistently or even correctly. Tight muscles, particularly in the calves and thighs can lead to foot, ankle and knee injuries. Finally, some overuse injuries can be related to underlying disease processes or injuries. Ligament damage in the knees for example, can alter stresses on the knee and lead to running-related overuse injuries.
Dr. Nick Brown
Dr. Brown is a postdoctoral researcher in the Department of Biomedical Engineering at The University of Texas.
