Shin splints, or medial tibial stress syndrome, refers to a non-specific cause for pain along the shinbone that occurs due to cumulative stress on the connective tissues attaching lower leg muscles to the bone. Shin splints often develop in runners or other athletes who engage in sports that pound on the lower legs. Although not a serious condition, shin splints can cause pain severe enough to curtail normal activity.
Over-use
The larger, more anterior bone of the lower leg, called the tibia attaches to the muscles controlling foot movement through tendons, ligaments and a type of connective tissue called fascia. Simple over-use of the lower leg muscles or repeated pounding of the feet on a hard surface can stress the connective tissues until they begin to pull away from the tibia, causing the pain and swelling of shin splints. The National Institute of Arthritis and Musculoskeletal and Skin Diseases says that shin splints primarily occur in runners, particularly those new to the sport who might not know their bodies' limits.
Unforgiving Surfaces
Running or vigorous walking uphill or downhill changes the angle of the ankle relative to the tibia and places unusual stress on the muscles and connective tissues of the lower leg. Similarly, exercise over uneven surfaces stresses the lower leg and over time can lead to shin splints. Exercise on hard surfaces, like tennis or basketball courts, also places extra pressure on the lower leg and can cause or worsen shin splints.
Improper Shoes
Shoes that fit poorly, fail to provide adequate support for ankles and arches, or old shoes that wear unevenly transmit stress to the tibia and can contribute to the development of shin splints. The Mayo Clinic recommends that runners replace their running shoes every 350 to 500 miles.
Structural Problems
People with flat feet or fallen arches tend to roll their feet inward, a motion called pronation. Like running in worn shoes or on an uneven surface, pronation causes an imbalance that stresses the muscles and connective tissue in the lower leg. Similarly, people with an imbalance in the strength of the calf muscles vs. shin muscles can develop shin splints.
Improper Warm-up
Improper preparation for exercise can contribute to shin splints, says the National Institute of Arthritis and Musculoskeletal and Skin Diseases. Stretching before exercising lengthens muscles and connections so they are less likely to tear and warming-up gradually before vigorous exercise gets the blood flowing to the muscles, which can help prevent injuries including shin splints. Athletes at risk for shin splints can consider additional measures like taping around the lower leg for added support or wearing leg warmers or sweatpants to retain body heat.
