- Blood flow restriction (BFR) training involves partially restricting arterial inflow and fully restricting venous outflow in the limb during rest or exercise. Doing this allows you to significantly enhance strength and muscle mass using as little as 20% of your single-rep max weight
- BFR training may be an ideal muscle-strengthening strategy for most people, but especially as an alternative for the elderly or injured, as it requires just a fraction of the weight you’d typically use in conventional resistance training
- BFR has the ability to prevent and treat sarcopenia like no other type of training. BFR training also improves your aerobic capacity and cardiovascular endurance. One of the simplest ways of doing this is to walk with the cuffs high on your thigh for 15 to 20 minutes
- BFR also improves osteoblast formation, or the formation of bone, and helps prevent further degradation of bone density, thus lowering your risk of osteoporosis
In this interview, Dr. Ed Le Cara, a chiropractor with a Ph.D. in sports medicine, shares his knowledge about blood flow restriction (BFR) training — a form of training that I believe is one of the greatest innovations in the last century. He’s also a certified athletic trainer and a strength and conditioning coach and one of the leading educators on BFR in the US.
“I combine all those backgrounds into the treatment plan and approach that I use with my patients,” Le Cara says. “One of the frustrations I’ve had — I’ve been in practice for about 20 years — was that very often patients would see me while they’re in pain, and once the pain is gone, give up on their previous exercise regimen.
But with my understanding of exercise and exercise physiology, I knew that once they were out of pain, they still had not gotten their body to the capacity they needed in order to meet the demands their sport or their life was imposing on them. Otherwise, they wouldn’t have gotten injured in the first place.
A lot of times it’s because they run out of insurance visits and that only got us through the point of where they’re decreasing in pain. Or they think that once they’re out of pain their injury is healed.
It was very frustrating for me to see people consistently injure themselves over and over again, and I wasn’t given enough time to really, truly increase their body’s capacity for the demand of sport, life or whatever they’re applying on it that was causing injury.
Then in about 2012, a good friend of mine, who at the time was the director of sports medicine at FC Dallas, said, ‘Hey. You’ve got to really check out this thing called BFR training.’ I had never heard of it … I looked at these different databases that I had access to.
I was overwhelmed with how much research was already out there. My previous experience with different types of modalities that I use in the clinic or different exercise appliances, there was not a lot of literature. Or we had to try to apply literature that was already existing towards what we were trying to do …
This was totally the opposite. Over 650 studies at the time had been done. It had been utilized for years, [it was] validated and reliable … It was almost too good to be true. To get strength or hypertrophy in four to six weeks was like, ‘There’s no way.’ Physiologically that was impossible. And to not be causing muscle damage associated with that? I was a very big skeptic to say the least when I started.”
What Is BFR?
BFR involves exercising your muscles while partially restricting arterial inflow and fully restricting venous outflow in either both proximal arms or legs.1 Venous flow restriction is achieved by using bands on the extremity being exercised.
By restricting the venous blood flow, you create a relatively hypoxic (low oxygen) environment in the exercising muscle, which in turn triggers a number of physiological benefits, including the production of hormones such as growth hormone and IGF-1, commonly referred to as “the fitness hormones.”2
It also increases vascular endothelial growth factor (VEGF), which acts as “fertilizer” for growing more blood vessels and improving their lining (endothelium). BFR, originally known as KAATSU training, was developed over 50 years ago by Dr. Yoshiaki Sato. Now 73 years old, Sato is still in excellent shape and a true testament to the value of this approach.
Between 1996 and 2015, Sato, along with exercise physiologist Naokata Ishii and Dr. Toshiaki Nakajima, a renowned cardiologist at the University of Tokyo Hospital, performed a variety of groundbreaking research, proving the benefits of KAATSU.
Much research on BFR has also been done in the U.S. in recent years, but it didn’t really catch on until 2010, when Steven Munatones from the KAATSU Global Company was granted permission by Sato to bring the technology to the U.S.
BFR — Low-Intensity Exercise With High-Intensity Rewards
BFR provides many benefits through a variety of mechanisms. As noted by Le Cara, you’re essentially tricking your brain and body into thinking that it’s doing high-intensity exercise, yet you’re doing low-intensity exercise. He explains:
“High-intensity resistance training is defined as somewhere between 65% and 90% of someone’s one rep max (1RM), depending on what resource you’re looking at. Low-intensity exercise is around 20% to 35% of your 1RM.
If you look, you can even see behind me some of the modalities that I use in my clinic. I’m using resistance tubing and resistance bands. I’m using dumbbells no heavier than about 20 pounds. I’m able to take these light weights, apply something to occlude the blood flow and allow patients’ bodies to think that they’re doing very high-intensity exercise when they’re not.
The advantage to this is that I don’t cause any damage to the tissue if I do it appropriately, whereas normal exercise and training at high intensity does. These patients cannot tolerate more damage to their tissue because they’re already injured.
We use the same exercises that we do in rehab, very light load, but we’re able to mimic high-intensity exercise, which, outside of the physiology that occurs, is really the game-changer. That’s what allows us to see quick adaptations.”
In the video, Le Cara demonstrates the basics of how the BFR cuff works.
“I have this cuff and I place it on my limb. Now, I inflate this cuff … to a certain percentage of what’s called my limb occlusion pressure (LOP). I’m reducing the amount of arterial flow into this arm, but I’m totally restricting any venous return.
What happens is that fluid that should be returning to my heart under normal circumstances is not. That means there is extra fluid hanging out down here that never gets back to my heart that can’t be involved in cardiac output. Cardiac output is the amount of blood that’s being pumped to the body.
The other part of that equation is the heartrate. Heartrate times stroke volume is equal to cardiac output. And so, if I reduce the stroke volume, my heartrate has to jump up in order to keep the same amount of blood flow going out to the working muscles.
That’s where, really, physiologically, we see the stress induced on the aerobic capacity system, and why these exercises raise your heartrate so rapidly and give you this sense of having to work very, very hard to do very light loads.”
Aerobic Improvements With BFR
Aside from helping you grow bigger muscles, BFR training also improves your aerobic capacity and cardiovascular endurance. One of the simplest ways of using BFR is to simply walk with the cuffs high on your thigh for 15 to 20 minutes. According to Le Cara, you can improve your aerobic capacity in as little as four or five weeks doing this.
“I had a patient who had experienced stroke. He could walk about four or five minutes at a time without feeling like he was going to fall, and had fallen a few times. Of course, we know that when we have this increased risk of falling, we have increased risk of fracture and further problems down the line.
He was asking for a way to be able to do two things: He wanted to be able to go quail hunting with his buddies … [and] he wanted to be able to take the dog out for a walk with his wife. That’s what he did every night of his life until this happened. It was really having a negative effect on him psychologically.”
Le Cara had the man walk on a treadmill with the cuffs on his legs for one minute holding on to the handles, and one minute unsupported. Over the course of four or five weeks, he was able to build up to where he could walk for 20 to 25 minutes without feeling like he was going to fall.
“That’s just one of many examples. But that was very profound because he was so limited in what he could do. He really needed something to help him translate from the rehab setting to life,” Le Cara says.
“When I put the cuffs around both legs and go for this walk, not only do I improve aerobic capacity, but [researchers] have also seen increased … hypertrophy of the thigh.
They’ve also seen increase in strength at the knee … If you can increase your strength with just walking for 15 minutes a couple times a week, then that’s also going to translate into a decrease in fall risk.
Things that have been measured, like the ‘sit to stand’ test, ‘timed up and go’ test … also improve. We’re seeing increases in strength and aerobic capacity at the same time with a very simple exercise like walking, which normally does not cause positive adaptation.”
BFR Improves Bone Density
Interestingly, BFR also improves bone density, thereby lowering your risk for osteoporosis. As explained by Le Cara, who is familiar with the medical literature on this, BFR improves osteoblast formation, or the formation of bone. It also helps prevent further degradation of bone density.
“There are many pathways associated with it, including capillarization and VEGF. But the primary thing I think helps the most is that when we inflate the cuff and we’ve got the swelling in to the limb, because the swelling is all around in all the tissue, you’ve got the bones surrounded, 360 degrees all around, [and] that creates a stress on the bone.
When we stress the bone, now the body has to respond by stimulating bone growth. So, I think Wolff’s Law comes into effect through that mechanism, in addition to the physiological adaptations that are occurring … It appears that hypoxia, or the decrease in oxygenation, also stimulates [bone growth].
There’s a stimulation of the vascular endothelial growth factor (VEGF) that occurs; numerous cascades that are happening. There’s something magical about creating an environment where there’s not enough oxygen and the body has to adapt due to that.”
Indeed, that “magic” was recently elucidated further with the award of the 2019 Nobel Prize in Physiology or Medicine3 for the discovery of how cells sense and adapt to the availability of oxygen, which involves responses in VEGF, hypoxia-inducible factor 1-alpha (HIF1A) and erythropoietin. In essence, by creating a hypoxic (low oxygen) environment, your body thinks you’re doing high-intensity exercise, and responds accordingly.
Wide Rigid Cuffs Versus KAATSU
While KAATSU specifies the use of narrow elastic occlusion bands, Le Cara has developed his own take on the technique using rigid, nonflexible wider bands, which is actually listed as a Class 1 medical device (blood occlusion device) in the U.S. He explains why he decided to veer from Sato’s already established parameters:
“When I’m experimenting with different modalities and I’m unsure of them, my first tendency is to go to the literature. What is the literature suggesting? What has been studied? What hasn’t been studied? When I went there, there was really a hodgepodge of different types of modalities being used to occlude blood flow.
Nothing was sticking out to me … There really wasn’t a resource … except for very expensive modalities [and], frankly, until I’m confident that something works, I am hesitant to spend the money.”
This is understandable, considering the original KAATSU equipment was rather large and had a price tag around $16,000. (However, as of October 2019 they have a unit that sells for only $8004 and is the one I personally use every day and endorse. Unfortunately, Le Cara has never worked with the KAATSU system, but has used numerous elastic and thinner bands.
“What I first did was based on the recommendation of my buddy who … had mentioned a certain type of band, and so I ordered those and started using them. What I first noticed was that exercise didn’t seem to be that hard. I was actually using the cuffs on all four limbs. It still wasn’t that hard …
When we have these cuffs [on] … it creates these little spaces in the cuff, and then the accumulation of metabolites distal to the cuff or closer to my hand can still escape. It wasn’t truly occluding arterial flow, so it wasn’t creating a hypoxic environment.
Now, my veins were sticking out like crazy. What we know is that because the veins are closer to the surface or more superficial, they’re much easier to occlude. The deeper pressure is what’s needed in order to get to the arterial flow to really create that hypoxic environment that we have already said is very beneficial.
Some of the other literature that came out [showed] that if we use a very narrow band, less than 5 centimeters, then it requires much higher pressures in order to occlude the arterial flow.
I wanted to use something that was wider so I didn’t need so much pressure, especially if I was going to use this with my compromised patients or people who maybe had … contraindications.
I wanted something that was as safe as possible. So, we developed something that was wider, that had that full diaphragm — the bladder that gets inflated with air …
When you have the little segmented bladder, when you inflate it, you really can’t find true LOP. I was never able to quantify with my patients what a safe and effective pressure was. We were using something called ‘arbitrary pressures or guessing what pressures we needed to use. With my patients’ safety, I don’t guess.
Realistically, I was what I like to call ‘undercooking’ people, not using enough pressure to occlude. I wasn’t getting the benefit I really wanted to see. We needed something wider.
We needed something that had that full diaphragm or bladder that could be inflated and that I could measure LOP using a Doppler to know exactly what each individual’s LOP was … [even] in different positions, like standing, sitting or lying down, depending on what position of exercise I was putting somebody in.”
The Case for Wide, Rigid Cuffs
So, to summarize, the reason Le Cara recommends using a wider rigid inflatable cuff instead of a narrower, flexible inflatable cuff, is because it traps and accumulates metabolites more effectively at lower pressures, thus reducing risk to damage beneath the cuff.
When using a flexible cuff, the muscle contraction will force the blood to return back to your heart. Even though the return flow is initially restricted, it doesn’t remain restricted once you do the contraction.
However, there are three concerns when using wide rigid cuff systems. The first is that wider cuffs will tend to limit movement during exercise. The second is that there appears to be an attenuated response to BFR benefits to the muscle and tissues under the cuff.5
Finally, although BFR improves hypertension in the long-term, there is a greater risk of eliciting an acute hypertensive response, especially in those who already have hypertension or the elderly that already have compromised vascular resilience.6 For these reasons it is likely wiser to choose narrow elastic bands like the KAATSU in these populations.
As with the KAATSU system, you would place the wide cuff proximal to the bicep, distal to the deltoid. With the wider band, the correct placement is essentially as close as you can to the armpit, right below the deltoid tubercle (the insertion point of the deltoid). On your leg, the cuff would go right below the greater trochanter; in other words, as high up on the leg, near your groin, as you can.
BFR Provides Full Body Benefits
Interestingly, BFR doesn’t just benefit the limb being occluded. The chemical cascade that occurs as a result of the restricted blood flow provides body-wide benefits. Benefits occur both distal and proximal to the cuff, i.e., on both sides. You also get crossover effects, so while you might be working your right shoulder, your left will also benefit.
“We use this in rehab a lot when [one] shoulder has been immobilized,” Le Cara says. “I have a patient who I’ll go see as a home visit tonight. She just had surgery last week … She’s not moving this arm.
But I can do things over here that’ll get the crossover effect. I can do things with her legs. She can walk with the cuffs on … She can do things for other extremities to try to maintain her muscle mass and maintain that capacity as an entity …
Within 10 days of disuse, we can lose about 30% of our muscle mass … We start losing aerobic capacity at about Day 7 and we start losing strength and size right around that Day 10. So, if I tell somebody to take four or six weeks off, they’re way in a hole.”
Risk Factors and Contraindications
BFR is a fitness modality that really everyone can benefit from. The elderly, especially, need to consider it, as it’s one of the most effective ways to prevent sarcopenia or age-related muscle loss. Once you lose muscle mass, your risk of developing complications from everyday activities skyrockets.
Again, one of the reasons why BFR is so well-suited for the elderly is because you use such light weights. You don’t even need to use any. According to Le Cara, research has shown it takes three sessions of BFR for your body to start adapting.
In Le Cara’s clinic, the first visit typically involves establishing the patient’s LOP bilaterally while sitting, lying and standing, and taking down a thorough medical history to make sure there are no contraindications.
While very safe when done properly, there are risks when using a rigid cuff system like the Smart Cuff System, the two primary ones being a hypertensive crisis that could contribute to a stroke or heart attack, and blood clots, which could be lethal. Factors that place you at increased risk include:
1.Recent blood stasis — Situations in which you’ve had blood occluded, such as during surgery. Most people who have just had surgery in the orthopedic setting are at a slight increased risk for clotting.
Another situation that can raise your risk is after long travel. If you’ve sat on a plane for a day, it’s best to wait a few days to normalize, as blood stasis and pooling can put you at increased risk for a blood clot. Being bedridden for a period of time is another scenario that would apply here.
2.Blood vessel damage — A crush injury on a limb would be a risk factor, for example, or a venous graft. Poor circulation can also increase risk, necessitating lighter pressure to start.
3.Cardiovascular risk factors — If you have heart problems, has your physician cleared you for high-intensity exercise? “If they’re cleared for high-intensity exercise, cardiovascularly, they are cleared for BFR,” Le Cara says.
For patients with high blood pressure, he recommends keeping exercises to nonweight-bearing, single-joint exercises. “If I do a squat with somebody, like an air squat, compared to somebody doing a long-arch quad exercise or a quad extension off the edge of a table, there’s going to be a big difference in what cardiovascular stress is occurring. I will keep that in mind when I’m dosing or choosing which exercises to do,” he says.
Next, Le Cara will evaluate the tourniquet risk itself, to determine whether there’s any risk involved with the occlusion apparatus that might damage a blood vessel. Examples might include bunching of clothing underneath the cuff, or the cuff width being too narrow, requiring higher pressure.
“I’m really concerned mostly about people who are showing signs of poor circulation,” he says. “In those cases, I would keep the number of exercises lower, like maybe one or two to start and see how they tolerate them. I’ll also make sure that I’m only using the amount of pressure necessary for the occlusion required that is both safe and effective.”
The Benefits of Cellular Swelling
Oftentimes, Le Cara will perform a cellular swelling protocol on the first visit, which is where the cuffs are inflated to a point where arterial flow is slowed to a trickle with no venous return. In this case, there’s no exercise involved. This creates extracellular swelling, which pushes fluid into the muscle cell.
Your body basically translates the cellular swelling as a signal that the cells are about to die, so a signal is sent to regenerate the cells through protein synthesis. “It’s a way to get people ready for the exercise or future exercise dosages,” he says, “yet, I’m still seeing benefit with that.”
The second visit typically involves performing one or two single isolated exercises. So, if you’re rehabbing a bicep, you might start by doing four sets of a bicep curl, the first set being 30 repetitions and the second, third and fourth sets being 15 reps each, with 30 seconds of rest in between, using a weight that is about 20% of your one-rep max.
The speed at which you raise and lower the weight should be quite slow. Le Cara recommends two seconds up and two seconds down. This will help create metabolite accumulation in the muscle and an acidic environment that triggers the recruitment of more motor units. The slow pace is also what creates muscle fatigue.
“We know when we take exercise to failure, there is more damage to the tissue. I want to get the tissue tired. I want to create metabolite accumulation. I want to recruit Type 2 muscle fibers. But I don’t want to cause more damage, especially in the rehab setting, because that tissue is already damaged. I don’t want to cause more damage.
After that, I might go to a second exercise. In this case, typically if it was a bicep, I would pretty much bet that most of the muscle fibers are exhausted. They’re fatigued. So, there’s no reason to hit that exercise group again. I would then go to probably a tricep exercise and I would do tricep in
that same manner: 30-15-15-15-15, and then deflate.”
Sample Workout Protocol
If you’re injured, you’d certainly be wise to find a BFR trainer like Le Cara to guide you. But for the general public, this is really something you’ll want to learn to do on your own, for life. Le Cara describes what a typical home regimen might look like:
“I never do cuffs on all four limbs simultaneously. The reason is that I think you reduce stroke volume so drastically that you’re going to faint and feel sick. Primarily, I do cuffs on both upper or both lower extremities …
I don’t think you need more than about four, maybe five exercises a day, because by the time you’re done with five exercises, you’re done. You’ve totally fatigued all your motor units; you’re psychologically tired. You don’t need to do more than that.
My personal opinion is that if you can lift 65% (or more) of your 1RM … do it. And use BFR as a supplemental [exercise]. For example, I might feel like my upper body is not as strong as I would like, or my calf is not as big as I would like …
I [would then] do my normal exercise, and two or three times a week, I would do what I call a complementary BFR session — one or two exercises to the area that you want to focus on, but I would do it after you’re already done with your [regular strength training] exercise.
You only need to do it two or three times a week because [that] … has been shown to be as effective for strength and hypertrophy as five time a week … If you can’t lift that type of a load [65% of your 1RM], you should be doing BFR five days a week …
If I’m not doing high-intensity [conventional strength training] exercise, then what I do is alternate. I’ll do upper body one day and lower body another day.
I’ll do aerobic on my lower body days … I walk for 15 [minutes] and then do three or four exercises for my lower extremities, with the thinking that the more dynamic exercises you do, you’re going to get this fatigue factor going …
I’m looking at 45 to 60 minutes of exercise. I’m going to be really tired. I’m going to get an aerobic training effect. I’m going to get an isolated and integrated body approach. I’m going to get a pain reduction. I’m going to get my brain stimulated.”
Toward the end of the interview, Le Cara also discusses how to optimize your muscle growth once you’re used to the system and are ready to take it to the next level. One key take-home from that section is that the higher the pressure used, the better the results.
This is likely due to the highly hypoxic environment created. That said, as a general rule, you don’t want to exceed 50% LOP in the upper extremity and 80% LOP in the lower. The primary variable that will influence your ability to “bulk up” is the weight used.
Starting at 20% of your 1RM, Le Cara suggests increasing the weight you use by 5% every two weeks, until you get to 35% of your 1RM. As a general rule, your rate of perceived exertion should be around 8 out of 10 after you’ve completed the 75 reps (30+15+15+15). If the exertion feels too light, add more weight. If too hard, lower it.
Again, one of the biggest benefits of BFR outside of rehab is the prevention of sarcopenia. I’m particularly motivated because both my parents developed sarcopenia and likely passed away sooner than they would have, were it not for their frailty.
I will be sharing some exciting and important details not discussed in this interview next month, just in time for the New Year. It has taken me over six months to research and compile the additional information and training videos. I hope you will make it a part of your New Year resolution.
Every assisted care facility needs to provide BFR training. Most have exercise therapists, and they really need to understand and embrace this modality. It’s such a simple way to improve people’s quality of life. Once you lose the ability to stand up from sitting in a chair, it’s a rapid decline to death.
There’s an enormous body of science backing its use. All that’s really needed is for people to learn it. You can find information about Smart Cuffs certification courses on SmartToolsPlus.com.
In 2020, Smart Cuffs will be offering more than 250 live trainings across the world. “I have a really great cadre of instructors who are really passionate about the subject. We are going to be spanning the globe, spreading the word,” Le Cara says.
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