Blood Flow Restriction Therapy

Where We Are and Where We Are Going

Bryan G. Vopat, MD; Lisa M. Vopat, MD; Megan M. Bechtold, DPT; Kevin A. Hodge, MD


J Am Acad Orthop Surg. 2020;28(12):e493-e500. 

In This Article

Abstract and Introduction


Blood flow restriction therapy (BFRT) is an innovative training method for the development of muscle strength and hypertrophy in the athletic and clinical settings. Through the combination of venous occlusion and low-load resistance training, it induces muscle development through a number of proposed mechanisms including anaerobic metabolism, cellular swelling, and induction of type 2 muscle fibers. Muscle weakness and atrophy are prevalent among musculoskeletal rehabilitation patients, causing delayed return to functional activity. In traditional resistance training, muscle development requires exercise loads of 70% of one-repetition maximum (1RM), but the stress placed on connective tissues and joints can be detrimental to the elderly and rehabilitation patients. However, BFRT with loads of 20% to 40% of 1RM has been shown consistently in the literature to increase muscle strength, hypertrophy, and angiogenesis. The rate of adverse effects has not been found to be greater than that in traditional high-load resistance training, but its effects on the cardiovascular system have yet to be evaluated in long-term studies. Although further investigations are needed to determine the exact mechanism and optimal usage, current evidence is promising for the application of BFRT in athletes, rehabilitation patients, and the elderly patients.


Skeletal muscle is constantly adapting to its environment.[1] It responds to stress by stimulating muscle development, and it responds to disuse with atrophy.[2] The loss of muscle strength and size after musculoskeletal injuries and orthopaedic procedures is a well-known result of disuse and immobilization. Prevention of this detrimental effect has been associated with early return to athletic activities.[3] Traditional training routines generally use loads greater than 70% of one maximum repetition (1RM) to stimulate muscle development.[1,4] This may not be safe for all patients, especially those recovering from an injury where they are unable to tolerate high-load resistance due to the stress placed on the joints, soft tissues, and surgical sites. Therefore, there is utility in a low-load resistance routine that can still stimulate anabolic pathways.

Blood flow restriction therapy (BFRT) was originally developed in Japan in the late 1970s where it was termed KAATSU training.[5] This therapy combines metabolic and mechanical stress to stimulate muscle strength, hypertrophy, and angiogenesis. Metabolic stress occurs through vascular occlusion with the use of a tourniquet on the proximal upper or lower extremity. This occludes venous outflow while maintaining arterial inflow, creating a hypoxic environment, which drives anaerobic metabolism.[6] Mechanical stress occurs through low-load resistance exercise, with loads as low as 20% of 1RM.[7] This makes BFRT a useful tool in the rehabilitation of injured and postoperative patients as well as in the elderly patients, who often are unable to tolerate high-resistance training routines. Recently, it has gained popularity in athletic performance training, including many professional organizations, as an adjunct to traditional training routines to decrease musculoskeletal stress on the athlete.[1]

Although low-load resistance training alone has not been shown to promote muscle development, when combined with BFRT consistent positive effects have been reported. Hughes et al[8] recently published a meta-analysis investigating 20 studies and determined that low-load BFRT was more effective at increasing muscle strength compared with low-load training alone. However, low-load BFRT did not generate the same degree of strength gains compared with high-load resistance training. Therefore, the current focus is on its utility in the elderly and rehabilitation patients who are unable to tolerate high-load resistance training, as well as a supplement to traditional training routines in athletes. Given the current trend toward its increased use in these patient subsets, it is an important topic for an orthopaedic surgeon to understand.