The goal of this clinical trial is to gain insights into the effects of Blood Flow Restriction Exercise (BFRE) in patients with an acute Achilles tendon Rupture. The main questions it aims to answer are: Is BFRE an effective adjunct to usual care when compared with only usual care? When is the optimal timing for initiating BFRE: In the early treatment stage or at the later stage after hospital treatment? Participants will receive an intervention comprising 12 weeks of BFRE as an adjunct to usual care. * Either in the initial 1-12 weeks after Achilles tendon rupture, or * In the following 13-24 weeks after Achilles tendon rupture Researchers will compare the two groups at 13 weeks (3 months) to compare BFRE to usual care, and at 25 weeks (6 months) to compare the two time points for initiating BFRE (early vs. late).