The expectations of life depend upon diligence; the mechanic that would perfect his work must first sharpen his tools. – Confucius
Take a moment to ponder the importance of tools; and not just tools, but the right tools. Consider the following scenarios: cutting a tomato without a sharp, serrated knife; swimming laps without fog-resistant goggles; roofing a house without a pneumatic nail gun… frustrated yet? Having the right tools is paramount to achieving success in any field, especially in the practice of physical therapy. In today’s ever-changing, evidence-based, efficiency driven, patient-outcome propelled world in which we practice, understanding, implementing, and mastering treatment techniques is a must. The toolbox of a physical therapist abounds with a plethora of options: appropriate therapeutic exercises,mobility/stability drills, joint mobilizations, soft tissue techniques, manipulations, PNF patterning, rhythmic stabilizations; however, as the research base expands, our knowledge deepens, and evidence-based practice is pushed, newer techniques emerge. Today’s post will examine one such technique and the research supporting its use.
What is Blood Flow Restriction (BFR) training?
The APTA defines blood flow restriction training as the “application of external pressure over the extremities where the applied pressure is sufficient to maintain arterial inflow while occluding venous outflow distal to the occlusion site” with the goal of “[enabling] patients to make greater strength gains while lifting lighter loads, thereby reducing the overall stress placed on the limb.”1
Originally developed in Japan in the 1960’s, BFR training was first adapted in the United States to aid the military with limb salvage for blast trauma victims attempting to avoid amputation. From this niche adaptation to more mainstream training and rehab approaches, BFR training continues to gain in popularity. But, with many fad therapies, does the science substantiate its perceived effectiveness?
What are the benefits?
The literature supports several benefits when implementing BFR into clinical practice:
- Increases lactate production resulting in recruitment of larger motor units.2 This allows for therapists to achieve significant strength gains using relatively low loads; i.e. 20% one-repetition maximum (1-RM) compared to 80% 1-RM. This is ideal for deconditioned or post-operative patient populations.
- Increases growth hormone synthesis and release, increasing collagen synthesis3. Potential benefits include assisting in tendon reorganization through eccentric loading in tendon dysfunction pathologies, namely lateral epicondylitis or Achilles tendinopathy.
- Decreases myostatin gene expression allowing a proliferation of myogenic stem cells resulting in muscle hypertrophy4. A study by Laurentino et al in 2012 measured myostatin levels between three groups: low-intensity resistance training (20% 1-RM); low-intensity resistance training + BFR (20% 1-RM+BFR); and high-intensity resistance training (80% 1-RM). After 8 weeks, there was a measureable decrease in myostatin in the BFR group and high-intensity group, highlighting the utility of BFR for strength and muscle hypertrophy without the risk of heavy loading protocols.
- Increase in osteoblastic activity promoting greater bone density/health5 This allows for treatment of stress fractures, scaphoid fractures, etc.… without the risk of injury during periods of restricted weight bearing.
- Improvement in aerobic capacity evidenced by greater VO2max and exercise time until exhaustion6. In a study conducted by Abe et al in 2010, an increase in aerobic capacity was exhibited by the BFR group compared to the control group in less time (15 minutes, 3x/week for the BFR group compared to 45 minutes, 3x/week for the control group).
Applications for BFR training are numerous and a new horizon is approaching to help all types of populations, from active military and veterans, elite athletes, post-operative patients, elderly, and even astronauts7. The foundational research is strong and continues to grow; however, a tool is only as effective as the master in whose hands it rests.
Contributing Author Credit: W. Evan Stringfellow, PT, DPT, CSCS, Cert. DN
Photography Credit: Jesper Aggergaard
- Yasuda T, Brechue WF, Fujita T, Shirakawa J, Sato Y, & Abe T. (2009). Muscle activation during low-intensity muscle contractions with restricted blood flow. J Sports Sci, 27 (5), 479-489.
- Takarada Y, Takazawa H, Sato Y, Takebayashi S, Tanaka Y, Ishii N. Effects of resistance exercise combined with moderate vascular occlusion on muscular function in humans. J Appl Physiol. 88: 2097–2106, 2000.
- Laurentino GC, Ugrinowitsch C, Roschel H, Aoki MS, Soares AG, Neves M, Tricoli V. (2012). Strength training with blood flow restriction diminishes myostatin gene expression. Med Sci Sports Exerc, 44 (3), 406-412.
- Beekley MD, Sato Y, Abe T. KAATSU-walk training increases serum bone specific alkaline phosphatase in young men. Int J KAATSU Training Res 2005;1: 77–81.
- Abe T, Fujita S, Nakajima T, Sakamaki M, Ozaki H, Ogasawara R, Ishii N. (2010). Effects of Low-Intensity Cycle Training with Restricted Leg Blood Flow on Thigh Muscle Volume and VO2MAX in Young Men. J Sports Sci Med, 9 (3), 452-458.
- Loenneke JP, Pujol TJ. KAATSU: Rationale for application in Astronauts. Hippokratia. 2010; 14,:224.