Blood Flow Restriction (BFR) Training in Physical Therapy: The Ultimate Guide to Using BFR Training to your Advantage
What is Blood Flow Restriction Training?
Blood flow restriction (BFR) training has been around for over 50 years. It involves restricting arterial blood flow into the arm or leg while simultaneously fully occluding venous return of the blood flow. This increases the oxygen demand of muscles during exercise and traps certain byproducts in the exercising muscles.
BFR training allows for someone to improve muscle strength and size while training at lower intensities. Research points to using 20-40% 1RM loads with 50-80% occlusion for the best benefits. Exercising with loads in the 20-40% 1RM range would normally not be enough for strength and hypertrophy gains. Improvements with low-intensity training with BFR use are statistically similar exercising at higher intensities (70-80% 1RM) but without the compressive and shear forces on joints, ligaments, and cartilage. High intensity training does still seem to be superior to low-intensity training with BFR, however there are many circumstances that could limit someone’s ability to train at high loads, such as injury, surgery, osteoarthritis, etc.
Who should use BFR training?
BFR training is safe for the overwhelming majority of people looking to improve their performance or recover from an injury. That being said, it may not be the best for everyone.
There are certain precautions and contraindications to using this modality. I will not go into detail on that today as it’s more complex than a short list, but you will want to discuss potential contraindications with a qualified BFR provider before starting a training regimen.
I love the use of BFR in post-operative physical therapy. It has the ability to limit atrophy of muscles and reduce pain in the early stages, build strength without overloading surgical repairs, and ease the transition to return to high-intensity training.
BFR also can be used to allow lifters to train at lower loads to prevent injuries to connective tissues while still maintaining or improving muscular strength. Along the same lines, it can provide variability to a training program.
What are the Benefits of a BFR Training Program?
1- Improves muscle strength and size
Making gains in muscle size and strength are typically done by training at higher intensities, such as 70+% of your 1-RM. These gains can be made with BFR training at 20-40% of your 1-RM. It’s all about your net protein (amount of protein synthesis minus your protein breakdown). Some other factors that play a role in increasing muscle strength and size are significant increases in gene expression like mTOR1c (protein synthesis), increases in hormones like Growth Hormone (GH) and Insulin Like Growth Factor 1 (IGF-1) all of which signal the body to grow muscle and recover faster. Additionally, there is a down regulation, or blocking, of the Myostatin gene. This is important because the less Myostatin the more muscle growth you will have.
2- Improves endurance
BFR training can help improve your VO2 max via lactate production. Increased lactate production increases cognitive ability, increases motor recruitment, and increases the number and efficacy of your body’s mitochondria. Increased mitochondria means increased oxygen consumption and increased energy production. This all happens in relatively short bouts of BFR training and means that muscular endurance is improved in less time than with traditional endurance or interval training.
3- Activates more muscle fibers
With low-intensity training, the muscle environment remains in an aerobic state, meaning that it is using oxygen. When you apply BFR cuffs during low-intensity training, it creates an environment that is lacking oxygen (similar to high-intensity training). This is important because it causes you to fatigue your slow-twitch muscle fibers and activate your fast-twitch muscle fibers to perform the movement. Without releasing the cuffs, the environment will remain anaerobic and you will continue to recruit more and more muscle fibers that you otherwise would not have used. This leads to more muscle growth, strength, and power!
4- Quicker workouts
For endurance athletes looking to get in a strength training session or for anyone looking to workout at submaximal loads for long durations to get a “pump” or for hypertrophy, it can take a long time to get through a workout. BFR training allows you to workout at submaximal loads, but speeds up the fatigue process to get the same results in a faster session.
5-Improves athletic performance
Athletes of all types, shapes, and sizes can benefit from BFR. The ability to increase in-season training volume without increasing the demand for recovery allows the athlete to maintain higher levels of strength and muscle size throughout the season without jeopardizing game-time performance. In fact, the ability to maintain higher levels of strength and size may actually help increase in-season performance. If it is good enough for elite athletes and the military special forces, it is good enough for you!
6- Increases HGH levels
Human growth hormone (HGH) increases by up to 300% with the use of BFR training. Increased HGH leads to increased insulin growth factor-1 (IGF-1). When combined with higher testosterone levels, this stimulates muscle growth. BFR training can help with testosterone replacement therapies. This is more natural than using supplements.
7- Avoids muscle atrophy and weakening after surgery
BFR training helps you recover faster after surgery. This is my favorite utilization of this modality because the impact is that much greater! Typically after surgery, you will deal with pain, swelling, stiffness, and weakness. After a knee surgery (i.e. ACL reconstruction, total knee replacement, arthroscopy, etc.), your quads will have difficulty activating and you will be on precautions to avoid lifting and squatting. When all of this happens, you lose a lot of muscle size and strength. For the reasons in #1, you can use BFR training with low-impact, low-intensity exercises to fight off muscle wasting.
8- Aids recovery from tendon injury
As we talked about earlier, BFR training can increase HGH levels by up to 300%. HGH helps with muscle and tendon healing. Also, tendon rehab can be challenging due to the high levels of pain typically experienced during exercise. Research shows us that BFR training can mitigate the pain response in tendons during exercise while at the same time allowing you to build up strength and tissue resilience
Pain Relief with Blood Flow Restriction (BFR) Training
Blood flow restriction (BFR) training can be very beneficial in rehabilitation from an injury. While you are unable to tolerate heavier loads, you can use BFR training with bodyweight or 20-40% 1RM to achieve similar results as heavy (> 70% 1RM) loads. You can also use BFR training to enhance cardiovascular adaptations to exercise, including improved VO2 max. BFR training also provides analgesic (pain relieving) effects. I’m going to summarize a study published in 2018 on pain relief in the knees of active men from the use of BFR training.
The study in 2018 was testing if BFR training could induce pain relief in 30 participants with anterior knee pain. The participants performed a shallow single leg squat, a deep single leg squat, and a step-down from 20 cm. The participants then had to rate their pain on a scale of 0-10.
The participants then performed 4 sets of seated knee extensions (low load training) with 80% occlusion (normal level of occlusion for BFR training in the legs). The leg extensions were performed at a tempo of 2 seconds concentric and 2 seconds eccentric with the use of the metronome to keep the exercise standard across the participants. The first set was performed to failure, followed by three sets of 15 repetitions with a 30-second break between sets.
After doing this simple BFR exercise that lasted only a few minutes, the participants repeated their testing by performing a shallow single leg squat, a deep single leg squat, and a step-down from 20 cm. They had to then report pain again on the same 0-10 scale. The median reduction in pain after performing one BFR exercise was 60%. This decrease in pain lasted for “at least 45 minutes.”
While this study only commented on the pain relief lasting for 45 minutes, it may last longer with the use of more individualized programming and performing more than 1 exercise. Possibly even more important is that you can use this time of reduced pain to train movements that may otherwise be painful, such as squats or jumping, to address any faults in technique as well as prepare to return to these exercises pain-free. You can also use this time to load up some weight to make more significant changes. A quote from the study, “The clinical implications are that low-load BFR exercise may be used to reduce pain and provide a window of opportunity for clinicians to optimally load otherwise painful tissues and joints.”
Here is a link to the article. The full text is unavailable for readers to view without a subscription, but you can review the abstract.
How Does BFR Training Speed Up Recovery After Surgery?
Muscle breakdown, aka atrophy, happens incredibly fast after surgery or injury. When you’re injured or you’re not allowed to put any weight through one of your limbs or tolerate any load, in as little as two weeks that limb goes into a state of anabolic resistance and protein synthesis shuts down. This leads to a 30% loss of muscle mass in that limb!
This is a huge problem and will slow down your recovery significantly. BFR training in the early stages of post-op PT can help combat that muscle loss! Low intensity exercises with body weight or light weights that are safe for your healing tissues combined with BFR training can get you the same improvements in muscle size and strength as lifting at 70%+ of your 1-RM. Some people have even seen their surgical leg grow larger than their non-surgical leg within 3 months after ACL reconstruction surgery.
By limiting muscle atrophy and weakness early in post-operative recovery, we can limit complications after surgery and return to full activity faster. Many physical therapists and orthopedic surgeons have criteria for athletes to return to full activity in their sport. These criteria typically include a relative strength of 90% or greater of your non-surgical limb as well as other functional testing. Using BFR to limit muscle loss and improve strength faster will absolutely help you meet the criteria to return to your sport faster.
On top of these obvious benefits of using BFR to speed up your recovery after surgery, some other side benefits of this technique include reduced pain, reduced swelling, and improved range of motion. These benefits are mostly linked to improvements in cell perfusion and hormone levels seen with BFR usage.
If you have the option to get better faster, why wouldn’t you take advantage of it? There are some precautions and contraindications associated with BFR training, however if you are cleared for surgery (full occlusion with a tourniquet) then you will have met the requirements to perform BFR training (partial occlusion).
BFR training is a serious modality and should be treated as such. You want to use cuffs with adjustable pressures based off of your specific limb occlusion pressure (pressure needed to fully occlude blood flow). There are safety and efficacy concerns when the pressure is not monitored, such as when using wraps or straps. The pressure can be adjusted manually or automatically. Our system will auto-regulate your pressure throughout the workout to maintain the appropriate occlusion percentage as your muscle swells. You should work with a professional trained in proper usage of BFR.
For your reading pleasure, here’s an article from the Journal of Arthroscopy from 2 very accomplished and respected orthopedic surgeons supporting the use of BFR training after surgery: https://www.arthroscopyjournal.org/issue/S0749-8063(18)X0008-5
