The influence of load on tendons and tendinopathy:Studying Achilles and patellar tendons using UTC

Tendons are responsible for transmitting the forces produced by the muscle to the bones which results in movement. Loading the tendons is necessary to maintain the normal function and homeostasis. When a sufficient amount of load is applied to the tendon with a sufficient amount of rest between sessions, positive tendon adaptation is observed. However, when there is an imbalance between load and rest, tendons will respond negatively. For example, a negative response is the development of tendinopathy, a condition that causes pain and function impairment. Thus, the aim of this thesis was to investigate the influence of load on Achilles and patellar tendons with or without tendinopathy. To assess the tendon structure, a relatively new imaging technique was used, the ultrasound tissue characterization (UTC). Differently of the conventional imaging tools, the UTC objectively quantify (in percentage) the changes in tendon structure. The results of this thesis showed that in individuals without tendinopathy, the tendon structure reacted at the short term to the load (related to sports) performed. In patients with Achilles or patellar tendinopathy, after conservative treatment, it was observed an association between clinical and imaging examination (conventional ultrasound or magnetic resonance imaging) at the long-term follow-up. Using the UTC, there was an association between clinical examination and UTC outcomes at the short-term follow-up in patients diagnosed with Achilles tendinopathy. Generally, UTC imaging tool can be used in both tendons with and without tendinopathy to monitor the influence of load on tendon structure