Tendon induce endothelial cell proliferation and migration, and VEGF mRNA has been shown to be expressed at the site of tendon injuries along with collagen I mRNA. Bone morphogenetic proteins (BMPs) are a subgroup of TGF-β superfamily that can induce bone and cartilage formation as well as tissue differentiation, and BMP-12 specifically has been shown to influence formation and differentiation of tendon tissue and to promote fibrogenesis. In animal models, extensive studies have been conducted to investigate the effects of mechanical strain in the form of activity level on tendon injury and healing. While stretching can disrupt healing during the initial
Achilles tendon the tendon but may involve the insertion, which is then known as enthesopathy. Though enthesopathy may be seen in the context of advancing age, it is also associated with arthritis such as gout and the seronegative spondyloarthitides. Achilles tendinosis is a known risk factor for calf muscle tears. Achilles tendon rupture is when the Achilles tendon breaks. Symptoms include the sudden onset of sharp pain in the heel. A snapping sound may be heard as the tendon breaks and walking becomes difficult. Rupture typically occurs as a result of a sudden bending up of the foot when the calf muscle