Introduction

Have you heard of blood flow restriction training (BFRT)? A technique becoming more well-known in the strength training world, BFRT combines low intensity training with blood flow occlusion to produce physiological strength gains similar to that of higher intensity resistance training. Our team recently was certified in BFRT and are now implementing it with clients. Curious if it’s right for you? We cover the background, indications, and evidence behind BFRT below.

What is it? 

Blood Flow Restriction Training has been around since the 1960’s, where it was started by Yoshiaki Sato in Japan. He would experiment with various tubes and tourniquets to determine their effects on his physical training. The real benefit of these trials came when Sato injured himself while skiing, leaving him with a fractured ankle and injured knee ligaments. He was told by medical doctors that he would not recover for 6 months. However, while in a cast, Sato applied bands to his legs three times per day with varying pressure while exercising. By preventing muscle atrophy, he was able to recover in a mere 6 weeks.

Sato worked to develop KAATSU training up until 1982. Modern BFRT has been adapted from Sato’s early work. It was not until 2011 that BFTR began to be used in the United States by the military. Through experimentation, they developed protocols to aid in limb strengthening for prosthetics. The scope of BFTR has expanded to professional athletics, hospitals, universities, and clinics around the world to help individuals prepare and recover from surgery, minimize disuse atrophy, increase aerobic capacity, and enhance muscle strength.

Who and what can it help? 

BFRT is a mode to emphasize strength gains with a significant reduction in how much stress is placed on joints. It is a great way to accelerate recovery and prevent atrophy in individuals who are post-operative, injured, or have issues with joint loading. Blood flow restriction has been shown to stimulate muscle hypertrophy (muscle growth) through a response to metabolic stress and the tension that the cuff holds (mechanical tension). A low intensity is required to get the desired effects and can help improve one’s cardiovascular capacity, pain attenuation, and increase muscle size and strength. 

There is an identified need early in rehabilitation after injuries and surgeries to use light loads to prevent injury to the healing tissue, but also recruit motor units, prevent atrophy and potentially improve strength in a safe manner. BFRT may be a great way to assist individuals who will be undergoing surgery, but whose physicians want them to strength train ahead of the procedure. Blood flow restriction training can be helpful directly after acute injuries, with chronic injuries where individuals require less loads onto their joints, older individuals, preoperative, and postoperative individuals.

Evidence

So what does the current research indicate regarding BFRT? How does it work? Research has shown that a reduction in the blood flow to the muscles and decreased venous return creates a swelling effect. This activates the protein mtor, beginning a cascade of events to create an energy change from using the aerobic system to anaerobic system. This allows for recruitment of larger, faster twitch muscle fibers (type 2 fibers), which have the largest ability for growth. This is how low-level exercise can result in increased muscle size without performing higher intensity exercise and lifting.

Research has also shown that one can improve their cardiovascular fitness as a result of BFRT. With BFRT, there is a drop in blood flow due to a restriction in how much blood returns towards the heart, and therefore reduces the total amount of stroke volume. Our bodies will sense this decrease in total stroke volume, but will increase in heart rate in order to maintain the proper amount of blood flow to still exercise. This allows our heart to train with less stress and in less time than would be typically required. 

A 2017 study investigated high intensity training in comparison to blood flow restriction with low intensity training, and solely low intensity training. All groups had a positive effect on decreasing pain overall. However, the blood flow restriction groups with low intensity exercise and the high intensity exercise groups were the only two groups which demonstrated a statistically significant change in strength and in muscle size (cross sectional area measured). 

Research has been diving into the effect of BFR in a variety of populations. Ozaki et. al.  found that blood flow restriction training combined with a walking program demonstrated improvements in both muscle volume and strengin in older women between the ages of 57-73, suggesting a potential to decrease muscle atrophy and actually increase muscle size and strength. 

How are we using it in the rehab and fitness setting? 

There are a variety of patients and scenarios where blood flow restriction training can be beneficial. Due to the effect on muscle size, strength, pain levels, and cardiovascular fitness without putting excessive loads on joints, BFRT has a high potential in the rehabilitation setting. Research continues to emerge regarding the benefits of pre-operative use of BFRT and how preventing muscle atrophy prior to surgery can be beneficial in the long term. BFRT may be an appropriate training method for those who are non-weight-bearing or have been immobilized in a boot or cast. BFRT can also be used in individuals focusing more on training and wellness, with the ability to get desired muscle hypertrophy effects more efficiently with less overall load. 

Post-operative 

Due to the plethora of positive effects detailed above, BFRT is highly beneficial for individuals undergoing post-operative rehabilitation. Muscle atrophy secondary to disuse or weight-bearing precautions can delay healing and a swift return to athletic activity. If a patient is prohibited from higher levels of strengthening secondary to a post-operative protocol, BFRT allows for safe training within guidelines. However, the evidence currently does not detail a specific protocol that has proven effective in post-operative patients regarding pressure, duration, intervals, and specific exercises. Further research is recommended prior to recommending it for post-operative care. It is also worth noting that several operations have healing consequences such as open wounds, swelling, or clot risk that deem patients ineligible for BFRT.

Contraindications 

Despite the plethora of therapeutic and training benefits BFRT touts, there is a lengthy list of contraindications to this mode of therapy. If you are a healthcare provider hoping to implement this technique with clients, it is crucial to screen individuals. If you yourself are interested in trying BFRT, be mindful of the following conditions that are deemed unsafe:

• Circulatory issues or clot risk (DVT)
• Heart disease/insufficiency
• Severe, uncontrolled hypertension
• Diabetes
• Sickle cell Anemia
• Varicose Veins
• Pregnancy
• Less than 12 years of age
• Open wound or incision
• Infection 
• Cancer
• Lymphedema
• Significant edema or swelling

*Note: this is a preliminary list and other conditions may necessitate physician approval or be deemed precautions

Conclusion

Blood Flow Restriction training continues to emerge with new research. While more longitudinal studies are required to continue to learn more about BFR, it is shown to be an excellent resource to utilize for appropriate populations with a significant amount of research supporting the benefits discussed above. 

Curious if blood flow restriction training may be right for you? Reach out to us today for a free 15-minute discovery call. We can answer any questions you may have regarding this technique and whether implementing BFRT into your training or rehab is worthwhile.