A sudden increase in intensity or frequency in activity level fatigues muscles too quickly to help shock absorption properly, forcing the tibia to absorb most of the impact. Lack of cushioning footwear, especially on hard surfaces, does not absorb transmitting forces while running or jumping. This stress is associated with the onset of shin splints. Muscle imbalance, including weak core muscles, inflexibility and tightness of lower leg muscles, including the gastrocnemius, soleus, and plantar muscles (commonly the flexor digitorum longus) can increase the possibility of shin splints. The pain associated with shin splints is caused from a disruption of Sharpey's fibres that connect the medial soleus fascia through the periosteum of the tibia where it inserts into the bone. With repetitive stress, the impact forces eccentrically fatigue the soleus and create repeated tibial bending or bowing, contributing to shin splints. The impact is made worse by running uphill, downhill, on uneven terrain, or on hard surfaces. Improper footwear, including worn-out shoes, can also contribute to shin splints. Diagnosis Shin splints are generally diagnosed from a history and physical examination. The important factors on history are the location of pain, what triggers the pain, and the absence of cramping or numbness. On physical examination, gentle pressure over the tibia will recreate the type of pain experienced. Generally more than a 5 cm length of tibia is involved. Swelling, redness, or poor pulses in addition to the symptoms of shin splints indicate a different underlying cause. Differential diagnosis Other potential causes include stress fractures, compartment syndrome, nerve entrapment, and popliteal artery entrapment syndrome. If the cause is unclear, medical imaging such as a bone scan or magnetic resonance imaging (MRI) may be performed. Bone scans and MRI can differentiate between stress fractures and shin splints. Treatment Treatments include rest, ice, and gradually returning to activity. Rest and ice help the tibia to recover from sudden, high levels of stress and reduce inflammation and pain levels. It is important to reduce significantly any pain or swelling before returning to activity. Strengthening exercises should be performed after pain has subsided, on calves, quadriceps and gluteals. Cross training (e.g., cycling, swimming, boxing) is recommended in order to maintain aerobic fitness. Individuals should return to activity gradually, beginning with a short and low intensity level. Over multiple weeks, they can slowly work up to normal activity level. It is important to decrease activity level if any