What this Trial Is About

ACL injuries represent a major health and economic burden. The overall incidence of ACL injuries has increased and is likely to continue to increase, in part due to increased sports participation. In the acute post-surgical phase there is a period of physiologic recovery from the surgical injury and subsequent relative muscle disuse that is associated with atrophy loss of strength and anterior knee pain. Therefore, improvement of muscle function is a priority in the rehabilitation and reathletization process. To achieve significant muscle hypertrophy as well as a possible subsequent increase in strength, it is widely accepted that resistance exercises with relevant load (\~70% of the one repetition maximum - 1RM) are necessary; however, in patients undergoing anterior cruciate ligament reconstruction (ACL-R), exercises with high loads are considered unsafe in the early stages and could increase the risk of re-injury. BFR training is an established muscle training and rehabilitation technique in which the blood supply to and from the muscles involved in the exercise is restricted using an external device. Although the physiological mechanisms related to this intervention are not yet well understood, it is thought that in BFR training, despite the low level of mechanical tension, the main driver of myocellular hypertrophy could be metabolic stress that is realized by local accumulation of metabolites. Thus, it seems that hypertrophic adaptations can be induced with much lower exercise intensities using BFR. In fact, when combined with low-load resistance training (e.g., 20% 1RM), training with BFR has shown positive results in increasing muscle volume and strength after ACL-R in complete safety comparable to standard training without BFR. It has also already been demonstrated how incorporating the use of the hockey slideboard into the rehabilitation procedure following ACL-R gives benefits in terms of strength recovery of the extensor muscles of the operated limb with the same safety profiles as standard rehabilitation.

Effect of the Hockey Slideboard Training Combined With Blood Flow Restriction (BFR) in the Rehabilitation Following Anterior Cruciate Ligament Surgical Reconstruction (ACL-R)