Personalized Blood Flow Restriction Training - Should My Practice Have It?

Recently I took a Personalized Blood Flow Restriction (PBFR) Training course with Owen’s Recovery Science. This is an oversimplified explanation of PBFR and its potential mechanisms but can serve as a basic introduction to those who may be looking into the tool for their clinic or would like to learn more about it.

Recommendations have been made over the years by various organizations (American College of Sports Medicine, National Association of Sports Medicine, etc.) on the benefits of heavy-load exercise in order to stimulate muscular hypertrophy and strength adaptations. These recommendations typically sit between lifting 65–75% of the 1-RM depending on the organization in order to elicit these adaptations. Similarly, in the field of rehabilitation it is widely known that diminished strength or muscle atrophy can lead to a multitude of disabilities, including osteoarthritis, and is a critical factor in rehabilitating post-operative, acute, and chronic musculoskeletal pain. Unfortunately, while some degree of strength and hypertrophy are attainable with low loads worked to failure, these improvements have been shown to be significantly less than those found with heavy-load training. Enter blood flow restriction training, which has been shown to increase hypertrophy with loads that are 30% of the 1-RM to levels that are comparable to heavy-load training.

Personalized Blood Flow Restriction training utilizes a tourniquet system that completely occludes venous outflow of either the upper or lower extremity while still allowing for partial arterial flow. While the exact mechanism of PBFR training is still currently unknown, the primary theory involves the hypoxic and ischemic state of the extremity. Studies have shown increased contraction of fast twitch muscle fibers when undergoing PBFR compared to standard low-load training. The use of the anaerobic pathway, secondary to the hypoxia, produces elevated levels of blood lactate which in turn increases the production of metabolites such as growth hormone, insulin-like growth factor, myogenic stem cells, and down regulates myostatin which all play a role in hypertrophy. Additionally, the muscle swelling that occurs in the extremity upregulates the production of MTORC1 (mammalian target of rapamycin complex 1) which stimulates the muscle protein synthesis pathways. Added protein synthesis may be a factor in helping to mitigate atrophy. Regardless of the mechanism, recent meta-analysis & systematic reviews have shown that when compared with low-load training, low-load BFR training is more effective and tolerable, and therefore a potential clinical rehabilitation tool.

Our post-operative patients, acute injuries, and the elderly all have one thing in common—muscular atrophy. This muscular atrophy may be due to the anabolic state of the extremity following a surgery/acute injury or just from age-related sarcopenia. Due to the ability to promote increased muscular hypertrophy and strength at low-loads, personalized blood flow restriction training may be an extremely valuable tool for the rehabilitation clinician. Some studies have even shown diminished atrophy with just the tourniquet effect on the extremity without even including exercise, which for a post-operative population can help significantly with recovery. When utilizing a tourniquet-based system on our patient population, it is important to understand the associated risks that come with those methods. Risk factors of PBFR that have been found in the research include temporary bruising at the site of the tourniquet (13%). Transient numbness of the extremity with the tourniquet after cessation of inflation occurred in 1.2% of the population. A dull pain or discomfort due to the tourniquet has also been reported in up to 9% of patients. Other rare side effects, which were all experienced less than 1% of the time, include lightheadedness, a temporary cold feeling of the extremity, venous thrombus, and pulmonary embolism. While further research may be needed into the exact mechanism by which PBFR works, due to the minimal risk/danger and the significant improvements in strength for our patients, this tool can be critical in our fight against muscle atrophy.

1. Fry, Christopher S et al. “Blood flow restriction exercise stimulates mTORC1 signaling and muscle protein synthesis in older men.” Journal of applied physiology vol. 108,5 (2010): 1199-209.
2. Hughes L, Paton B, Rosenblatt B, et al. “Blood flow restriction training in clinical musculoskeletal rehabilitation: a systematic review and meta-analysis.” Br J Sports Med (2017) 51:1003-1011.
3. Abe, T., Yasuda, T., Midorikawa, T., Sato, Y., Inoue, K., Koizumi, K., & Ishii, N. Skeletal muscle size and circulating IGF-1 are increased after two weeks of twice daily “KAATSU” resistance training. International Journal of KAATSU Training Research, (2005) 1: 6-12.