Stress fractures are tiny cracks in a bone caused by the overuse and the repetition of movements during exercise
When your muscles are fatigued, they become unable to absorb additional shock during exercise and transfer the overload of stress to the bone. This constant process causes tiny “microcracks” in the bone.
Stress fractures are most common in the weight-bearing bones of your lower legs. They result from increasing the amount and intensity of activity or from an impact on unfamiliar surfaces. For example, a tennis player who changes from a soft to hard court may experience a stress fracture. Athletes participating in tennis, basketball, track and field, and gymnastics are most susceptible to stress fractures, especially if they are not resting enough between training sessions.
The most common signs and symptoms include swelling and pain that decrease with rest, and increase with activity. Also, there may be a spot that feels tender or painful when pressure is applied. A stress fracture is sometimes mistaken for a shin splint (an inflammation of the tibia or shin bone that commonly affects runners). However, stress fractures are more serious.