Shin splints are defined as pain at the front, inside area of the shin bone. This pain can hinder your performance and force you to cut back on your mileage. Overtraining on an inclined treadmill can tire your muscles, but is not the only cause of shin pain. Running surface and improper footwear can also play a role. Consult a physician about your symptoms and to receive treatment and prevention strategies.
Running's Impact
The shock of your feet hitting the ground is transferred to your musculoskeletal system. While running, your feet absorb up to two times your body weight with each step you take, even on a treadmill. Muscles and soft tissue, like cartilage and the plantar fascia that makes the arch of your foot, absorb the majority of your weight, minimizing stress placed on bones. Tired muscles, however, cannot maintain structural form, often allowing more impact to reach your bones. Over time, shin splints and even stress fractures can develop. Muscle overuse can also lead to an inflamed periosteum, which is the sheath that covers the shin bone, causing shin pain.
Treadmill Inclines and Muscle Fatigue
Increasing the stress on your leg muscles through an intense or long treadmill workout can lead to muscle tightness, especially at high ramp inclines. The greater the incline, the greater the load on your calf muscles, which must work harder to push your foot off the treadmill. Increasing the incline too frequently or too severely can tire your calf muscles, causing them to tighten. Running for extended periods at an incline can also fatigue these muscles. In addition to increasing your injury risk of muscle strain, tight calf muscles can pull on the shin muscle --- the tibialis anterior --- and the shin bone's periosteum. These forces can eventually lead to shin splints or other injuries.
Running Surface
The surface you run on has a direct impact on your body, and may play a role in your shin pain. Hard surfaces like concrete and asphalt are unforgiving, placing the greatest amount of stress on your shin bones. In regards to impact, treadmills rank slightly better than asphalt, but are still not as easy on the joints as running on a synthetic track, wood chips or grass. Though these surfaces come with their share of injury risk --- uneven surfaces leave you vulnerable to twisted ankles --- stepping off the treadmill once or twice a week can lessen running's impact on your body.
Foot Strikes and Footwear
The way your foot strikes the treadmill dictates what type of footwear you need. Both overpronation and oversupination can lead to shin splints. The arches of your feet flatten excessively during overpronation, increasing the stress on joints and bones. Oversupinating feet maintain too much of an arch, putting excess pressure on the outside of your foot and decreasing the proper absorption of impact. Orthotic insoles and shoes with supportive arches can correct flat feet. Flexible shoes with more cushioning can minimize the damage of oversupination.
Treatment and Prevention
Rest, ice and doctor-recommended anti-inflammatory medications can help alleviate shin splint discomfort. Stretching your calf muscles frequently can also reduce muscle tightness, which stresses the shin bone. Vary the incline on your treadmill, reducing it if your muscles feel fatigued or shin pain develops. Avoid landing heavily on the treadmill. Instead, take smaller, quicker strides, landing with a bent knee. Cross-training in a low-impact activity, according to MayoClinic.com, reduces the stress on your joints. Try adding biking or swimming to your weekly workout routine.
