 The overall aim of this project is to investigate the healing processes of human tendon after suturing a ruptured Achilles tendon, and more specifically to determine the optimal loading pattern of the tendon during the rehabilitation period to ensure complete and good recovery of tendon structure and function. The investigators hypothesize that restricting early weight bearing and only allowing for passive stretching in the early phase of tendon healing will ensure better tissue regeneration and thereby prevent chronic tendon elongation and improve tendon tissue recovery and the clinical outcome. 