Whether you're a novice runner or a seasoned veteran, shin pain and bruising can rear its ugly head from time to time, interfering with your training and competition schedules. However, shin pain caused by running is not inevitable. If you have bruises on your shin, it's probably shin splints, which can be caused by your footwear, foot strike or foot type.
Pain and Bruising of the Shin
Impact stress from running normally affects the tibia, the large bone at the front of the shin that absorbs repetitive motion forces as your foot strikes the ground. Muscle fatigue leads to greater force applied to the fascia, the tissue that fuses the tibialis muscle to the bone, causing pain and inflammation within it, and eventually leading to bone stress and even stress fractures.
Visible bruising is indicative of bleeding and inflammation, a condition the American Academy of Orthopedic Surgeons calls chronic compartment syndrome. Shin pain can be treated and avoided with corrections in running mechanics and the use of proper protective footwear.
The way your foot strikes the ground and then pushes off can influence the amount of stress placed on the shin during running. If you strike with your heel and roll through, you may be overstriding, leading to the poor distribution of body weight during impact.
If you strike with the toe or ball of your foot, you absorb less impact with your calf and Achilles tendon, shifting the brunt of impact to your shin. Striking with the mid-foot shifts shock absorption to the large muscles of the calf and away from the shin. Foot strike is typically a habit that can be corrected with training.
Your foot type can influence how shock is distributed when you land. Runners with high, inflexible arches tend to experience more impact stress on the tibia, while those with flat feet tend to experience greater muscle fatigue when pushing off, gradually leading to stress on the fascia. Both extremes can predispose you to shin pain and bruising, though it can be helped with proper footwear.
To determine your foot type, do the "wet test." Stand on a wet towel, then step onto a colored piece of paper. Examine the imprint of your foot. If it is broad and triangular, you have a flat foot. If the imprint is slightly curved on the inside, you have a normal or neutral foot, and if your imprint is C-shaped, you have a high arch.
It's vital that you're properly fitted for running shoes, ensuring that you're wearing the right shoe for your foot type. Individuals with high arches, men weighing over 200 pounds and women weighing more than 150 pounds may require a stability shoe with a rigid midsole that provides good arch support. Flat-footed individuals whose feet tend to roll inward, or pronate when running, will do better with a motion control shoe. While highly cushioned shoes offer more shock absorption, they are generally less supportive of high arches and flat feet.