HIstorically, the term 'tendinitis' was used in order to describe the chronic pain which was associates with a tendon overuse problem. Nowadays, this opinion has changed. The absence of inflammatory cells in biopsies indicates a non-inflammatory degenerative process. Moreover, it has bene hyupothesized in a theoretical model that this degenerative process is a continuum that has three stages: reactive tendinopathy, tendon disreapir and degenerative tendinopathy. This model now requires scientific and clinical evaluation. Therefore, being able to assess, detect and define the true stage of these tendon injuries is the cornerstone for further research. Ultrasound is commonly used to interrogate these tendons when symptoms develop. Symptomatology has been shown to correlate with various sonographic abnormalities. However, the 'normal' sonographic appearance of these tendons in high-demand athletes is not well established. A number of abnormalities have been common, even in asymptomatic individuals. Consequently, the purpose of the present study is 1) to investigate whether the rpesence of certain tendon structures in asymptomatic athletes can predict the development of future tendon problems and, once the athlete suffers from an overuse injury, 2) to define which characteristics of tendon integrity can predict good outcome for conservative management. Furthermore, during rehabilition, exercise levels should be based to the stage of tendon integrity.