Stress Fractures in Sport (ICL 5)

Stress fractures arise from the inability of bone to tolerate repeated mechanical loading and are characterized by damage to the bone’s micro-architecture. Repeated mechanical loading can cause an uncoupling of osteoblast bone formation and osteoclast bone resorption [1]. This can lead to bone loss and subsequent micro-damage that can result in localized bone weakening, resulting in stress fracture development. The etiology of stress fractures is multifactorial. The rate of occurrence depends on the bone composition, vascular supply, surrounding muscle attachments, systemic factors, and type of athletic activity. From a biomechanical standpoint, stress fractures may be the result of muscle fatigue, which leads to the transmission of excessive forces to the underlying bone. Muscles may also contribute to stress injuries by concentrating forces across a localized area of bone, thus causing mechanical insults that exceed the stress-bearing capacity of the bone (Table 5.1) [2, 3].