Blood Flow Restriction Training: What You Need to Know
Experts have proven over the years that in order to increase muscle size and strength you must lift greater than 70% of your one-repetition maximum (1RM) or lift until failure. Many of the patients that come into the clinic are unable to achieve these standards – sometimes due to pain, immobilization, deconditioning, surgical protocols, tissue healing timelines or a myriad of other factors. Heavier loads (>70% 1RM), essential when used at the correct stage of rehab, put increased stress on joints and bones that may not be tolerated at times. This is where blood flow restriction (BFR) can present a huge advantage in getting you back to do the activities you love. Blood flow restriction training is a rehabilitation device that will allow patients to reap the physiological and mechanical benefits of lifting heavy loads, but while performing the exercises at 20-30% of one-repetition maximum vs. 70% of one-repetition maximum. Not only can BFR improve muscle size and strength faster, but it can also improve aerobic capacity following injury or lack of activity. Aerobic capacity is a term used to describe how well your body is able to utilize oxygen and spend more time doing the activities you love.
BFR can be defined as the brief and intermittent occlusion of arterial and venous blood flow using a torniquet while at rest or exercise. Here at SPT, we use a cuff placed snuggly around either the upper arm or leg to reduce, but not completely stop blood flow. Now this may sound scary, but when applied and monitored by a medical professional here at SPT the risk and side effects will be managed carefully. The major benefit from this technique is you can exercise using significantly less weight and still achieve gains in muscle size and strength. It is widely accepted that it will generally take anywhere from 6-12 weeks for you to gain muscle size, but with the use of BFR muscle size can be gained in as little as 2-3 weeks!
How BFR Works
If you are a science nerd like me, the following explanation will interest you, but if not feel free to breeze past this section. There are a variety of hypothesis of why BFR works, but one of them can be explained this way. The brief and intermittent occlusion of blood flow causes a decrease in oxygen transport to the muscle. When this happens, your body decreases the activity of your slow twitch (type 1) fibers and increase the activity of the fast twitch (type II) fibers, which fatigue more quickly. There is then an increase in motor neuron recruitment that results in increased muscle recruitment. Lactate acid then increases causing a large spike in growth hormone (almost 2 times!), IGF-1, MTORCI and myostatin, which then leads to an increase in protein synthesis that causes an increase in muscle size. With an increase in motor neuron recruitment and muscle size you reach the ultimate goal of boosting muscle strength. There is also a proposed cellular swelling mechanism that will occur causing an increase in nutrient delivery to the muscle.
How BFR Can be Utilized in Physical Therapy
Often times in the early phases of rehabilitation heavier loads (>70% 1RM) are not appropriate in order to protect the healing tissue. Muscle size and strength decrease can result because of this and BFR can help fight back. BFR training can be done at 20-30% of one-repetition maximum that allows for protection of healing tissues, but also will allow for increase in muscle growth and strength maintenance. Pre-operative and post-operative ACL repair, total knee replacement and knee scope are all potential diagnosis where BFR would be beneficial.
BFR can also be useful in the fight against aging. Muscle mass decreases approximately 3-8% per decade after the age of 30 and this rate of decline is even higher after the age of 60 (Volpi, E, et al.). Loss of muscle mass and strength can directly lead to decreased levels in function and injuries in older adults. BFR can be deployed to help increase in muscle size, size and aerobic capacity for greater independence and ability to perform everyday tasks (Takashi A et al). It has also been shown to help improve pain levels (Bryk et al). This can be done using loaded exercise, cycling or walking in combination with BFR.
If you’re interested in learning more about how BFR works or if BFR can help you, give SPT a call or stop in for a free injury screen!
Volpi E, Nazemi R, Fujita S. Muscle tissue changes with aging. Curr Opin Clin Nutr Metab Care. 2004 Jul;7(4): 405-410
Takashi A et al. Effects of low-intensity walk training with restricted leg blood flow on muscle strength and aerobic capacity in order adults. J Geriatr Phys Ther. Jan-Mar 2010;33(1):34-40
Bryk F. F et al. Exercises with partial vascular occlusion in patients with knee osteoarthritis: a randomized clinical trial. Knee Surg Sports Traumatol Arthrosc. 2016 May;24(5):1580-6
Ohta H et al. Low-load resistance muscular training with moderate restriction of blood flow after anterior cruciate ligament reconstruction. Acta Orthop Scand. 2003 Feb;74(1):62-8
Pearson J S and Hussain R S. A review on the mechanisms of blood-flow restriction resistance training-induced muscle hypertrophy. Sports Med. 2015 Feb;45(2):187-200.