Shin splints can be inconvenient and painful. Here's what causes them.

Gym memberships usually skyrocket and many workout facilities often feel like they're overrun as each New Year begins. Many of us, either looking to lose a little holiday weight or pushing to get in shape as part of a New Year's resolution, find ourselves checking in at the local gym, or, when it's too full, put on our running shoes to exercise outside instead. 

As noble as our efforts may be, many of us often end up doing too much, too fast, and cause injury in the process. Among the most common sports-related injuries are shin splints. "Shin splints account for 10-15% of all running injuries and about 60% of lower leg pain syndromes," says Dr. Brent Lambson, a board-certified sports medicine physician at Revere Health Orthopedics in Utah.

Avoiding this injury begins with understanding what shin splints are and what causes them. 

What are shin splints?

The official medical term for the condition is medial tibial stress syndrome, or MTSS, but doctors know exactly what patients are talking about when they complain of shin splints. "Shin splints are a condition that causes pain over the front of your tibia or shinbone," says Dr. Matthew Anastasi, a sports medicine specialist at Mayo Clinic in Arizona. He says this pain can be experienced anywhere along the bone, "but is most commonly located in the bottom third."

The pain one feels occurs as the result of small tears or inflammation in the muscles, tissue, or tendons around the bone and often feels like "a persistent ache," says Lambson. Sometimes this pain lessens with rest, but other times additional treatment is needed. In addition to causing discomfort, shin splints can also be debilitating. Some people find that the condition limits everyday activities like getting around the home or office, and athletes can be especially inconvenienced as shin splints often require putting many of their physical activities completely on hold. 

What causes shin splints?

Shin splints are known as an overuse injury because they are usually related to the sudden or prolonged use of one's lower body. "One of the most common scenarios we see is when someone dramatically increases their level of exercise in a relatively short time frame, such as adding too much mileage to their running program," says Anastasi. He explains that one's calf muscle is made up of several muscles that attach along the shinbone, "and the dramatic increase in activity can cause inflammation and pain at these attachment sites." Matters are made worse when someone doesn't allow that pain or inflammation to heal, which can cause the condition and its symptoms to worsen. 

In addition to overexerting oneself physically, Anastasi says that a person's risk for shin splints also increases if they already have tight hamstrings, quads or calf muscles. "Flat feet can increase a person's risk as well," he adds. 

Dr. Naomi Brown, a pediatric sports medicine specialist at Children's Hospital of Philadelphia who specializes in sports injury prevention and overuse injuries, agrees that causes of shin splints vary and are often multifactorial. External factors she points to that can contribute include the use of inadequate footwear while exercising and the surface one is running on - harder surfaces like pavement or concrete tend to cause more issues than softer ones like a track, treadmill or compacted dirt such as on a hiking path. Running on an incline or decline can impact shin splints as well.

"Internal factors that can contribute to shin splints include biomechanics such as hip or core weakness or a lack of flexibility," Brown adds. She says a previous running injury or being overweight can also contribute to stress in the area and increase one's risk of getting shin splints. 

How do you know if you have shin splints?

While shin splints can become very painful, for many people it's a condition that builds over time. "If someone is merely walking, they may not necessarily notice any pain in their shin," explains Anastasi. "However, when they increase their activity in the form of jogging or running, they can start to develop or notice the pain."

Once the discomfort becomes unbearable, shin splints are usually diagnosed by one's healthcare provider after he or she conducts a physical examination and understands what physical activity may have contributed to or caused the condition. Having shin splints diagnosed is important, Lambson says, because "untreated shin splints can eventually lead to a stress fracture where the bone breaks and it may need surgery for complete healing."

Such measures can often be avoided, however, by catching the condition early and by resting your lower body between strenuous physical activity. "As with any exercise program," Anastasi says, "it's always important to listen to your body."

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