Effects of Low-intensity Strength Training With Concomitant Blood Flow Restriction on Pain Perception in Patients With Anterior Cruciate Ligament Surgery

After surgical treatment of a tear of the anterior cruciate ligament, physiotherapeutic exercises are done as standard therapy. This is to achieve a rapid improvement in pain and knee function. In this study, the Investigators examine how low-intensity strength training with simultaneous restriction of blood flow works and whether it is effective and well tolerated. For this purpose, a pressure cuff is applied to the leg during training. Participation in this study will last four weeks for each participant. The Investigators will invite participants for 11 study visits. One appointment will last about 30 minutes. If a participant decides to take part in the study, they will be randomly assigned to one of two groups. The participants will belong to either an experimental group or the control group. In the experimental group, the participants will be treated with the intervention method. The intervention method involves 4 weeks of low-intensity strength training with an additional pressure cuff on the leg, which should lead to improved adaptations to the muscle as well as a reduction in pain. In the control group, the participants will receive the same strength training only without the additional pressure cuff. The benefit is that in addition to the participants actual rehabilitation program, each participant will receive free training to build their muscles. This could contribute to an accelerated rehabilitation process and a faster build-up of strength as well as an improvement in pain. It is additionally possible that the participants will help future patients with their participation. The intervention method for strength training with simultaneous restriction of blood flow (Blood Flow Restriction Training) has been studied for some time. There is good evidence of improved muscle, tendon and pain adaptations in both healthy individuals and patients with ACL injury. Whether this training method also has an effect on pain perception will be investigated in this study.

Participants may experience side effects if they are treated with the intervention method (low-intensity strength training with simultaneous restriction of blood flow). The Investigators may not yet know all the risks and side effects of the intervention method. So far, the following risks and side effects are known:

* Temporay numbness * Muscle soreness * Pressure sensation