Medial Tibial Stress Syndrome (MTSS), commonly known as shin splints, is a frequent source of pain for runners, military recruits, and active individuals who engage in repetitive, high-impact activities. This overuse injury causes discomfort along the inner border of the shin bone, the tibia. Many people turn to calcium, a widely recognized supplement for promoting bone health, to address this pain. This article investigates the scientific validity of using calcium specifically to treat or prevent this lower leg complaint.
Understanding Shin Splints
Shin splints are not a structural break of the bone but an inflammatory condition where the muscles, tendons, and connective tissue repeatedly tug on the periosteum, the membrane covering the tibia. This constant pulling and strain results in microtrauma and subsequent inflammation along the inner edge of the bone. The pain is typically diffuse, spreading across a broader area of the shin, rather than being localized to a single, pinpoint spot.
The primary causes of MTSS are related to training errors, particularly a sudden or rapid increase in the duration or intensity of physical activity. Other factors contribute to the condition, including running in worn-out or improper footwear. Underlying biomechanical issues, such as excessive foot pronation or muscle weakness, can also lead to poor shock absorption and place undue stress on the tibia.
Calcium’s Essential Role in the Body
Calcium is the most abundant mineral in the human body, with 99% of it stored within the skeleton. It acts as the primary component that provides structural rigidity and strength to bone tissue, directly influencing bone mineral density. The body is in a constant state of bone remodeling, where old bone is resorbed and new bone is formed, a process that requires a continuous supply of calcium.
Beyond its mechanical function in bone, calcium plays an important role in several non-skeletal physiological processes. The mineral is indispensable for the proper transmission of nerve signals throughout the nervous system. Furthermore, it is required for the initiation and regulation of muscle contraction, enabling the fibers to slide past each other and generate movement.
Calcium and Prevention of Stress Injuries
While calcium is foundational to skeletal health, its role in preventing shin splints is indirect and often confused with its impact on a more serious injury. Adequate calcium intake, often paired with sufficient Vitamin D for absorption, is necessary for maintaining bone density and resilience. This nutritional support is primarily protective against stress fractures, which are tiny structural cracks within the bone itself.
Stress fractures represent a progression of bone microtrauma, whereas MTSS is characterized by inflammation and soft tissue irritation. Therefore, ensuring bone health through calcium intake is a preventative measure against a structural break, but it is not a direct treatment for the soft tissue inflammation that defines shin splints. Studies involving athletes have shown that while adequate calcium intake, sometimes exceeding 1,500 mg daily, can reduce the incidence of stress fractures, supplementation beyond a certain level does not necessarily prevent MTSS. Low calcium status increases the risk of a bone stress injury, but it does not treat the inflamed periosteum associated with shin splints.
Effective Management Strategies
Since calcium is not a targeted treatment for MTSS, effective management focuses on addressing the mechanical and muscular imbalances that cause the inflammation. The initial intervention is activity modification, which involves reducing or temporarily pausing the high-impact activity that causes the pain. Applying ice to the tender area for 15 to 20 minutes several times a day can help reduce localized inflammation and dull the pain.
Physical therapy is recommended and centers on strengthening the muscles of the lower leg, particularly the calf and anterior compartment muscles, to improve shock absorption. Stretching exercises targeting the calf muscles, such as the soleus and gastrocnemius, can also alleviate the traction forces on the tibia. Finally, ensuring proper footwear or utilizing custom orthotics to correct underlying biomechanical issues helps to distribute impact forces more evenly across the foot and lower leg.