Blood flow restriction, also known as BFR, can sound pretty intimidating at first. I’ve had many patients ask, “You’re going to do what to my leg?!”  

Blood flow restriction has numerous benefits for increasing both strength and hypertrophy of muscle in a LOW LOAD environment. To gain strength, the American College of Sports Medicine suggests performing exercises at 80-90% of 1 rep max for 3-4 sets at 6-8 reps per set. Hypertrophy is the increase in muscle fiber size that usually accompanies an increase in muscle strength. Oftentimes, patients recovering from an injury or a surgery are unable to tolerate heavy strength training to get these strength gains and hypertrophy.

So… WHAT exactly is it? Exactly what it sounds like. BFR is the restriction of blood flow both to and from a muscle. The restriction of blood flow is achieved by inflating a tourniquet around an extremity and occluding blood flow at a specific pressure, known as “limb occlusion pressure.” By restricting blood flow, numerous cellular reactions occur. These cellular reactions are what lead to both strength and hypertrophy in a LOW LOAD ENVIRONMENT. 

WHY? BFR has been shown in multiple studies to: 

1. Enhance muscle hypertrophy
2. Increase muscle strength 
3. Improve aerobic capacity 
4. Prevent muscle wasting or atrophy 
5. Decrease pain with training 

HOW? There are many theories, but the big idea is that: 

BFR creates a low oxygen environment which leads to increased muscle fiber recruitment and metabolic stress causing the release of lactate and hydrogen ions which gives that muscle burn that occurs with heavy strength training. Essentially, by restricting blood flow, you are teaching your muscles to do MORE with LESS. 

The increase in metabolic stress leads to 4 major metabolic mechanisms:

1. New capillary growth or “angioneogenesis” 
2. Promotion of Vascular Endothelial Growth Factor (VEGF), which improves bone structure, healing rate, and muscle strength
3. Increase in growth hormone
4. Increased proliferation of myogenic stem cells, which are the stem cells that typically respond to heavy loading and are associated with protein synthesis

IMPORTANT NOTE: all of these happen with regular heavy exercise!! BUT—BFR allows all of these mechanisms to take place without lifting heavy. Perfect to kick start post-operative and post-injury recovery! 

BFR has been proven through multiple research studies to be a safe and innovative modality to increase strength and hypertrophy, without requiring the need for super heavy lifting or loading. 

So… who wants to restrict some blood flow? 

References: 

1. Reinhold, M., Lorenz, D. BFR: The Science, Safety, and Efficacy of Blood Flow Restriction Training. Mikereinold.com 
2. Owens, J. Blood Flow Restriction Rehabilitation. www.owensrecoveryscience.com