Achilles tendon injuries are common especially in individuals who are physically active. There are two distinct types of Achilles tendon injuries; the painful overuse injury with a slow onset (tendinopathy) and the acute complete rupture which rarely is preceded with pain or symptoms. For both injuries mechanical loading of the tendon through exercise is a key component for successful treatment. However, understanding how to individualize the treatment for your patient can be a challenge. This Masterclass aims to give an overview on how injury and exercise affects the tendon in general and the Achilles tendon specifically. The lecture series will also cover specific topics such as how to design and implement an exercise rehabilitation protocol for patients with Achilles tendinopathy from initial injury to return to sport based on the current evidence. Finally, it will describe how to design a rehabilitation program for patients with an Achilles tendon rupture and provide for an in-depth understanding in the obstacles to full recovery after a rupture.