PTQ Issue 1.2 | Page 4

FEATURE ARTICLE PRACTICAL BLOOD FLOW RESTRICTION TRAINING JEREMY LOENNEKE, PHD, ROBERT THIEBAUD, PHD, AND TAKASHI ABE, PHD B lood flow restriction (BFR) alone or in combination with low-load/intensity exercise has been shown to produce favorable changes in skeletal muscle (8). BFR is applied to the proximal part of the arms or legs with the intent to restrict arterial blood flow into the muscle while occluding venous outflow (5). In the absence of exercise, repeated cycles of BFR may attenuate atrophy and declines in strength. In addition, low-intensity aerobic exercise in combination with BFR produces small changes in muscle size and strength over those observed with exercise alone. However, the magnitude of change in muscle size and strength is largest when done in conjunction with low-load resistance training, which produces results similar to those observed with high-load resistance training (5). Low-load resistance training should be considered 20 – 30% one repetition maximum (1RM). The favorable muscular effects of BFR do n ot appear to be localized distal to the BFR stimulus as increases in size and strength have been observed in muscles not directly under BFR (e.g., pectoralis major) (1). Until recently, all of the research on BFR was completed using specialized devices that allowed for strict regulation of pressure. In 2009, a practical model of BFR was proposed that involved the use of elastic wraps (6). The purpose of this article is to discuss the available research behind this practical model. devices, recent research lends support to the efficacy of practical BFR from elastic wraps. To illustrate, low-load resistance exercise in combination with BFR increased muscular strength over those observed with the group completing the same exercises without BFR (17). In addition, the application of practical BFR with low-load training resulted in similar changes in muscle size as traditional high-load training (11). Furthermore, a recent case review provided evidence that practical BFR may be an effective stimulus for rehabilitating a knee injury (10). More research is needed but preliminary results appear to support practical BFR. BENEFITS OF BLOOD FLOW RESTRICTION Exercise in combination with BFR has been shown to result in favorable chronic adaptations across a variety of populations, including the elderly, highly trained athletes, those recovering from injuries (e.g., ACL, osteochondral fracture), as well as patients diagnosed with idiopathic inflammatory myopathy (2,3,4,10,13,14). While most research has been completed using specialized SAFETY OF BLOOD FLOW RESTRICTIONS One important point to note is the safety of BFR. Frequently, the blood pressure, blood coagulation, and muscle damage responses are cited as concerns for using BFR in combination with exercise. However, the application of BFR appears to offer no greater risk than regular high-load resistance training when the stimulus is used appropriately. 4 MECHANISMS Currently, the proposed mechanisms of the BFR-induced muscle hypertrophy include acute muscle cell swelling, increased fiber type recruitment from metabolic accumulation, decreased myostatin, decreased atrogenes, and the proliferation of satellite cells (5). Some of these have also been shown to occur with the practical model of BFR (5). The application of elastic wraps has been shown to increase acute muscle cell swelling, increase metabolic accumulation, and increase muscle fiber recruitment (16). It stands to reason that the other proposed mechanisms may also occur with practical BFR, but more research is needed at this time. PTQ 1.2 | NSCA.COM