Blood Flow Restriction – The Holy Grail for Accessory Work?

Blood flow restriction work makes you stronger than heavy training alone and is easy to recover from. Read up on the science of BFR and how to implement it.
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Image credit: http://bretcontreras.com/wp-content/uploads/bfr.jpg
Image credit: http://bretcontreras.com/wp-content/uploads/bfr.jpg

What you’re getting yourself into

3,900 words, 13-26 minute read time

Key Points

  1. Blood flow restriction (BFR) training involves cutting off venous blood flow out of a limb, but still allowing arterial blood flow into a limb, resulting in the best pump of your life.
  2. Because of the massive pump you get from BFR training, people assume it’s the bee’s knees for hypertrophy.  However, thus far, it doesn’t seem to cause any more growth than conventional, heavy training.
  3. The biggest benefit of BFR training actually seems to be notable increases in strength when it’s added to heavy training.  It causes a high degree of muscle activation (rivaling heavy lifting) and causes virtually no muscle damage, making it essentially “free” volume to help you get stronger without compromising recovery.
  4. There are a few more cool benefits, including enhancing recovery from training, and reducing atrophy when you’re injured.

Blood flow restriction (BFR) training, or occlusion training, is something that’s met with mixed reactions.  Some people are fully aboard the BFR bandwagon, and others think it’s just a gimmick.

To this point, the available evidence suggests that BFR training is quite effective as an adjuvant to conventional, heavy training … just not for the reasons most people think.

So first off, what is BFR training?

Essentially, you use a knee wrap or an elastic band to cut off venous blood flow in your arms or legs.  The blood pressure in your veins (which remove blood from the limb) is substantially lower than the blood pressure in your arteries (which bring blood to the limb), so you apply the wrap tight enough to keep blood from leaving the limb, while still allowing blood to enter the limb.

Most of the original studies used a special cuff to occlude venous blood flow, but using knee wraps or an elastic band works just as well.  From a scale of 0 (meaning no pressure at all) to 10 (meaning the pressure you’d expect form a tourniquet before getting a limb amputated), the pressure on your arms should feel like a 7, and the pressure on your legs should feel like an 8 or 9.  Apply the wrap or band as close to the top of the limb as possible – very close to the groin if occluding venous blood flow from the legs, and very close to the arm pit if occluding venous blood flow from the arms.

Use a light load.  It should be a weight you can get for 30-40 reps when you’re fresh (~20-30% of your 1rm is what’s used most often in the research).   Pump out as many reps as you can, rest for about 30 seconds, and pump out some more reps.  3-4 sets with short rest, totaling 60-100 reps is what’s done most often in the literature.  In some of the studies, the wraps are removed between sets, and in some, they’re left on between sets (bro-tip: it’s much more convenient to just leave them on between sets and admire all of your bulging blood vessels).

While you’re pumping out all of these reps, a ton of blood is driven into the limb, and very little of it can leave.  The result:  the best pump you’ve ever experienced.

When people try it for the first time, they assume that it must be god’s gift to hypertrophy training.  That’s what most people use it for – to get jacked.  However, it has other uses that go far beyond hypertrophy and, arguably, hypertrophy isn’t even the biggest benefit you can get from BFR.

But, before we get into the effects of BFR training, let’s backtrack a bit, and take a look at why and how it works.

The Mechanisms of BFR Training

There are six major mechanistic reasons why BFR training works for building muscle and strength.

  1. Metabolic Stress.  Identified as one of the three primary mechanisms of muscle hypertrophy (along with muscular tension and muscle damage), metabolic stress signals muscles to grow.  Constant BFR (leaving the wraps on between sets) works better that intermittent BFR (taking the wraps off between sets) for this purpose.  Intermittent BFR leads to greater metabolic stress than regular low-load training, and constant BFR leads to similar levels of metabolic stress as training at 65% of your 1rm without BFR – equal metabolic stress with much lower loads.
  2. Motor Unit Recruitment (one, two, three).  Regular low-load training potentially doesn’t recruit as many motor units as heavier training, even when training to failure.  I say “potentially” because you assess motor unit recruitment via EMG, and it’s very possible that as the first motor units recruited start to fatigue, they “drop out,” so that the EMG readings at failure would be lower than they would have been when training with heavier loads (which wouldn’t give motor units enough time to fatigue and “drop out”), even if motor unit recruitment throughout the entirety of the set was identical (more on that here).  Regardless, research shows that motor unit recruitment is substantially higher with low-load BFR training (specifically constant BFR) than with low-load training without BFR, and that motor unit recruitment is similar for low-load BFR training and heavier, conventional training without BFR.  This, as we’ll see later, is probably the biggest benefit of BFR training.
  3. Cellular Swelling.  Similar to metabolic stress, cell swelling has been identified as a mechanism that can cause hypertrophy.  Muscle thickness increases roughly 11.5-12% directly after a BFR workout, due to the increased fluid in the muscle, indicating (to use a scientific term) a buttload of cellular swelling.
  4. Modulating Hypertrophy Signalling Pathways and Gene Expression (one, two, three).  Key signaling pathways (like the mTOR pathway) and genes (like the myostatin gene) are affected to a greater degree by low-load BFR training than low-load training without BFR.  BFR training and heavier, conventional training affect them similarly, increasing protein synthesis and decreasing myostatin to similar degrees.  There’s also some data suggesting BFR increases the activity of heat shock proteins which may decrease catabolic signaling, but as far as I know, that’s only been observed in one rodent study thus far.
  5. Satellite cell proliferation and myonuclear addition.  If you remember from a previous article (I’m overhauling this one in the future because there are some things about it I’m not too pleased with as-is, but the mechanistic stuff about satellite cells and myonuclei is solid), addition of new myonuclei is an absolutely essential factor for long-term hypertrophy.  Muscles can grow until the muscle fibers hit their myonuclear domain limit without adding more myonuclei, but to continue growing, the addition of new myonuclei from satellite cells is crucial.  Low-load BFR training increases the satellite cell pool and causes myonuclear addition much more effectively than low-load training without BFR, and to a similar degree as heavier, conventional training.
  6. Growth Hormone Release.  It’s not clear whether acute elevations in ostensibly anabolic hormones affect muscle growth in any meaningful way, but the results of this study were eye-catching enough to at least give it a mention.  Low-load BFR training to failure caused an increase in growth hormone 290x higher than resting levels, and approximately 4x higher than low-load training to failure without BFR.

Mechanisms are cool and all, but what are the effects on strength and hypertrophy?

For starters, overall, low-intensity BFR training seems to be about as good for hypertrophy and strength as heavier conventional training.  Kreiger found an effect size of .35 for hypertrophy and an effect size of 0.8 for strength from multi-set conventional resistance training in his meta-analysis, and Loenneke found an effect size of .39 for hypertrophy and an effect size of .58 for strength from low-intensity BFR training in his.  However, it’s worth pointing out that the overall effect sizes for both hypertrophy and strength are depressed quite a bit in the low-intensity BFR training meta-analysis, since it included studies where the mode of exercise was incline treadmill walking with BFR.  When only looking at resistance training studies, the effect size was 1.08 for both strength and hypertrophy (though, obviously, with a smaller sample size).

When taking an aerial view, BFR training and conventional training have pretty similar effects.  The fact that you get similar hypertrophy from low-load BFR training isn’t overly surprising, in light of the fact that number of hard sets is the main determinant of hypertrophy, but the fact that the strength effects are similar is surprising, since generally training intensity (the percentage of your 1rm you’re training with) is an important determinant of strength gains.  More on that a bit later.

Low-load BFR leads to nearly identical muscle activation as much heavier training. Click To Tweet

It’s also worth pointing out that the BFR meta-analysis was just looking at studies that solely utilized BFR training, not BFR in addition to heavier, conventional training.  I’m going to assume that most people reading this article are also lifting heavy stuff, and aren’t planning to use low-load BFR training for the entirety of their training plan, with perhaps the exception of when you’re rehabbing an injury.  More on that later as well.

There are five studies worth digging into that had well-trained subjects and combined BFR training with heavy resistance training.

The first is a glorious study, because the muscle being trained was the biceps.  That also makes it the least relevant for people primarily concerned with getting strong, but I’m sure that if you look deep down into your soul, you’ll be able to admit to yourself that getting jacked arms is a worthy training goal, and that they are a great compliment to a huge squat or deadlift.

Just tell me with a straight face that you don't want to look like this.
Just tell me with a straight face that you don’t want to look like this.

The researchers split the subjects – college-aged men, with at least one year of lifting experience – into two groups.  One group did curls with BFR for 4 weeks (3 sets of 30 reps with 30% of their 1rm), followed by heavier curls for 4 weeks (3 sets of 15 with 60% of their 1rm).  The other group did heavier curls for 4 weeks, followed by curls with BFR for 4 weeks.

Both groups gained the same amount of muscle over the 8 weeks of the study.  They also gained the same amount of muscle during their BFR phase as their heavier training counterparts did; during the first four weeks, the people doing BFR curls gained as much muscle as the people doing conventional curls, and during the last 4 weeks when they changed training protocols, the people doing BFR curls (who did heavier curls for the first 4 weeks), again, gained the same amount of muscle as the people who did heavier curls (the people who did BFR curls for the first 4 weeks).

Low-load blood flow restriction training works about as well as heavier training for building muscle Click To Tweet
From Lowery et. Al (2013)
From Lowery et. Al (2013)

The next study is from Leubbers (2014).

Over the course of 7 weeks of offseason training for Division IAA football, he split the players into four groups:

  • One group just followed the standard high-intensity off-season training program for football.
  • One group did the same high-intensity training program, with additional sets of squat and bench with 20% of their 1rm (1 set of 30 and 2 sets of 20) without BFR.
  • One group did the same high-intensity training program, with additional sets of squat and bench with 20% of their 1rm utilizing BFR.
  • One group basically just did accessory work, along with the light squats and benches with BFR.

Over the course of the study, the athletes’ arms and legs got bigger, and their chests didn’t, but there were no significant differences in hypertrophy between the training protocols.

When looking at strength, however, the group doing high-intensity training combined with low-intensity BFR had the largest increases in the squat.  Their squats increased ~25kg over 7 weeks, vs. ~14kg for the group only doing high intensity training, and the group doing high intensity training plus low-load training without BFR.  The group doing high-intensity training combined with low-intensity BFR also had the largest increases on bench, but the difference wasn’t significant (~8.5kg vs. ~7kg for the other two groups doing high intensity training).

Also note that these were pretty strong dudes to begin with.  The average squat at the start of the study was around 200kg.

Screenshot 2015-10-21 04.17.53

It’s also interesting to note that it seems like the stimulus from the BFR training is what drove the larger strength increase.  My knee-jerk reaction was that the additional training volume was what made the difference, but the group doing the light squats without BFR, in spite of also having significantly higher training volume than the group only doing high-intensity training, gained the same amount of strength over the course of the study.

The next study by Yamanaka (2012) is very similar.

The researchers split the subjects (Division 1 football players) into two groups.  Both groups continued their normal off-season strength training program.  In addition to their normal high-intensity training, one group did one set of 30 reps, and 3 sets of 20 reps with 20% of their 1rm squat and bench with BFR, and the other group did the same sets and reps without BFR.

The group using BFR gained more strength in the squat and bench press than the group doing the same sets and reps with the same relative load without BFR.  In addition, the BFR group’s chest circumferences increased more (~3.1 cm vs. 1.5cm).

Screenshot 2015-10-21 04.59.12

The next study is by Cook (2013).

This study was performed on semi-pro rugby players.

They were split into two groups.  The first group trained for 3 weeks without BFR, then for 3 weeks with BFR, and the second group followed the opposite pattern.

They trained three times per week, doing 5 sets of 5 with 70% of their 1rm for squat, bench press, and pull-ups each day.  The cuffs to restrict blood flow were only applied to the legs (even for pull-ups and bench press) and were removed between sets.

During their time doing BFR training, the athletes added an average of 5.4kg to their bench, and 7.8kg to their squat.  During their time without BFR, the athletes added an average of 3.3kg to their bench, and 4.3kg to their squat.

Screenshot 2015-10-21 05.16.09

This study was interesting for a couple reasons.  For starters, even though the cuffs were only applied to the legs, even during upper body exercises, the BFR group still had a larger increase in bench strength, suggesting that BFR may have systemic effects in addition to the local effects in the muscles with restricted blood flow.  Additionally, they were using relatively high loads (70% of their max) – not the low loads typically used in BFR studies.

Blood flow restriction may have systemic effects in addition to local effects in muscles. Click To Tweet

Last but not least, we have one more study to look at.  It’s a Masters Thesis by O’halloran (2014).

His study also combined high intensity training and low-load BFR training.

  • One group trained exclusively with loads in excess of 70% of their 1rm and no BFR.
  • The other group did 38% of their training with loads in excess of 70% of their 1rm with no BFR, and 62% of their training with 30% of their 1rm and BFR, for one set of 30, and three sets of 15.

Training volume (total weight lifted) was roughly equated.

Over the course of the study, both groups’ bench press, leg press, biceps cross sectional area, and thigh circumferences increased, with no significant differences between groups.  These were already relatively strong guys on the outset as well – they were benching around 220-245lbs, and leg pressing around 800lbs.

So, on the whole, we can take a few things away from these five studies that combined conventional high-intensity training and low-load BFR training and pretty well-trained athletes.

  1. Low-load BFR training works about as well as heavier training for building muscle (Lowery’s study), though the effects of combining the two may not be additive for hypertrophy.  Leubbers’ study showed that adding BFR training to high-intensity training didn’t increase hypertrophy, but Yamanaka’s did.
  2. It appears that BFR training doesn’t just affect the muscles with venous blood flow occluded.  Both Yamanaka’s study (increased chest growth when the cuffs were applied to the arms) and Cook’s study (larger increases in bench press, even though only leg blood flow was restricted) demonstrated increases in either strength or hypertrophy in muscles other than those below where the cuffs were applied.
  3. The most notable effect seems to be an increase in strength.  Leubbers’ study showed a larger increase in the squat, Yamanaka’s study showed a larger increase in both squat and bench press, Cook’s study showed a larger increase in both squat and bench press, and O’halloran’s Thesis showed that substituting a sizable chunk of high-intensity training for low-load BFR led to the same increases in strength.

The effects on strength are the most surprising.  You’d expect (or at least, I’d expect) there to be a bigger difference in hypertrophy, but apparently the mega-pump lies to you.

When you think through it, though, it makes sense.  Plenty of things make muscle grow; tension, volume, metabolite accumulation, muscle damage, etc.  With low-load BFR, tension is lower, metabolite accumulation is high, but not any higher than conventional training for 10+ reps, and there’s very, very little muscle damage that takes place.  It gives you a solid growth stimulus, but nothing that you can’t also get from just picking up heavy stuff, and when you add it to a program that revolves around picking up heavy stuff, it doesn’t seem to offer any additional hypertrophy benefits.

However, strength is another beast entirely.  Strength is partially dependent on structural factors (how much muscle you have), and partially dependent on neural factors (how well you can activate those muscles).  Remember, low-load BFR causes roughly the same amount of muscle activation as much heavier, conventional training.

BFR training has proven to be pretty disappointing for people with the sole goal of building muscle, since notable increases in muscle growth on top of heavier training haven’t really manifested themselves (with the exception of additional chest growth in Yamanaka’s study).

However, low-load BFR training is basically the holy grail for strength athletes, at least as far as accessory work goes.

  1. When you add it to heavy training, it makes you stronger than heavy training alone.  It’s not just a matter of getting stronger from adding extra training volume because it beats out low-load training without BFR.
  2. It’s incredibly easy to recover from since it causes essentially no muscle damage.  (note: you may very well get sore the first couple of times you do it, simply due to novelty; this should go away pretty quickly, though)
  3. Because it also causes high muscle activation, it also aids in the neural side of strength development.  Its effects are very similar to heavy training, and O’halloran even showed that you can replace a hefty amount of heavy training with low-load BFRs and get the same increases in strength.
Blood flow restriction work makes you stronger than heavy training alone and is easy to recover from Click To Tweet

You can almost think of it as “free” volume.  You get all the upside of lifting heavy, but it’s way easier to recover from.  You can add low-load BFR to your current training program to get stronger, faster without compromising recovery.  Or, if you’re having issues with recovery, you can sub out some (not all) of your heavy training for low-load BFR and get the same strength increases without taxing your ability to recover to nearly the same degree.

Other Stuff Worth Noting

BFR without strength training speeds up recovery from training.  One study showed that 2 sets of 3 minutes of BFR for the legs immediately after a training session significantly sped up recovery and enhanced subsequent performance for power-related tests.

BFR can also decrease muscle atrophy when you’re injured, and speed up the recovery of strength when you can get back to training.  In one study, BFR (multiple sets of 5 minutes of occlusion, without exercise) significantly decreased muscle atrophy of the quads and hamstrings during the post-operative period following ACL reconstruction.  In another, low-load BFR training helped people get muscle and strength back faster than training without BFR during the reconditioning phase following ACL reconstruction.  Low-load BFR training can be a godsend to people dealing with or recovering from injuries.  BFR without training can keep you from losing as much muscle if you’re so jacked up you can’t do anything (of course, consult with a physical therapist first), and low-load BFR training can help you maintain muscle and strength if you have aches and pains you need to train around.  If you want to read more about how to progress from totally-jacked-up to picking-up-heavy-stuff-again, I’d strongly recommend this review.

Keep in mind, I’m not recommending low-load BFR as the sole focus of your training plan.  You should still be picking up heavy stuff (of course, since you’re reading Strengtheory, I doubt I have to tell you that).  One study showed that low-load BFR doesn’t affect tendons to the same degree heavy training does.

Interestingly, it seems that the additive increase in strength only applies to well-trained athletes.  One study on untrained folks found that adding low-intensity BFR training to heavier training didn’t increase strength gains.  It could be that untrained people are already getting all the strength benefits they could possibly get just from picking up heavy stuff, but that more well-trained people have that capacity for greater increases in strength that don’t manifest themselves because further increases in heavy training would compromise their ability to recover (since their training is already inherently more stressful).  That seems plausible enough to me.

People get leery of BFR because cutting off blood flow just seems like it would be dangerous.  However, rates of adverse effects are exceptionally low, even in diseased and at-risk populations.  You can completely cut off blood flow to a limb for over an hour without any long-term risks, and with BFR training, you’re still allowing arterial blood flow, so you could likely occlude venous blood flow for even longer (though I wouldn’t recommend it).

The thinner the device for cutting off venous blood flow, the better off you are.  With thicker wraps, you run a greater risk of cutting off arterial blood flow.  I generally use the resistance bands you can find in most gyms that some middle-aged women use for biceps curls.  I get weird looks when I raid the BodyPump room in the middle of a class, but #yolo.  Knee wraps can do the job as well, but bands are a better option if they’re available to you.

Bro-tip:  BFR work seems to work best, in my experience, when added in for a 4-8 week block, then replaced with more conventional accessory work for the next 4-8 week block.

Implementation

  1. Pick up heavy stuff as you generally would.  You don’t need to really change your program to add low-load BFR since it’s exceptionally easy to recover from.
  2. After your heavy sets, do 3-4 sets of 15-40 reps with 20-30% of your max with BFR, resting about 30 seconds between sets.  Whether you leave the wraps on between sets or take them off is up to you, but leaving them on seems to be better for muscle activation, and they’re annoying to take off and put back on between sets anyways.  This works really well for squat and bench (or you could do leg press and DB press after your squat and bench work, if you prefer).  Whether it helps the deadlift or not hasn’t been examined in the literature, and anecdotally, it doesn’t seem to help out your hammies as much as your quads.
  3. Though not required, I’d strongly recommend you also bust out a sweet superset or five for your arms.  Who cares if science says it won’t make your arms grow any faster than regular curls and triceps extensions?  You get the same hypertrophy effect, but you get it by way of stupidly awesome pumps, which is a benefit in and of itself.

Alternately, if you’re having issues recovering from your training, you can sub out one or two heavy sets for 2-3 sets of low-load BFR.  This is particularly useful for short stints when you know beforehand that recovery will be compromised (if you know you have a deadline coming up that’ll stress you out and decrease how much you can sleep, or something of that sort).

If this is a subject that interests you, I’d strongly recommend you check out these three reviews as well (one, two, three).

This was a snippet from the Second Edition of the Art and Science of Lifting that I’m working along on right now.  If you already have the First Edition, the Second Edition will be free for you when it comes out!


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90 thoughts on “Blood Flow Restriction – The Holy Grail for Accessory Work?”

  1. Hi Greg,

    What are your thoughts on occlusion training for those in a caloric deficit? I feel as though it’d be a great way to add ascessories and volume in without too much additional stress.

  2. Hey Greg, nice write-up! I have noticed a lack of a reliable summary of BFR, and I’m glad to see you filling that void! I did have a couple questions though:
    How many reps can you to perform to failure with 20% of your 1rm? I assume it’s alot higher than 30.
    If the answer is more than 30, could the studies not taking the low-load no BFR sets to failure have skewed the results a bit?

    Also just wanted to say, I am a bit disappointed to see no mention of myo-reps here :(. Anecdotally, I’ve used myo-reps for both my biceps and back 4x a week, and have noticed the reps I can perform steadily increase(with almost no fatigue) and have noticed a bit of a size increase (even though I was on a piss-poor bulk, 9.5bf% forever a skinny kid).
    On myo-reps, a question I’ve always wanted to ask is how they compare to “normal” sets. I’ve seen Borge Fagerli recommend people use between 15-30rm for myo reps (though I believe I’ve read he himself goes as high as 35-50), and in your article “grow like a new lifter”, you stated hypertrophy is about the same for 5-30rm. So with myo-reps your essentially doing a 1st set of 15-30(which should have as much hypertrophy as 5-30), and then doing sets of 3-5 until failure, always staying near failure. Does this have the same effect of taking multiple sets to or near failure? Or is there no clean way of comparing the effect to “normal” sets and reps?

    1. “How many reps can you to perform to failure with 20% of your 1rm? I assume it’s alot higher than 30.
      If the answer is more than 30, could the studies not taking the low-load no BFR sets to failure have skewed the results a bit?”

      I recommend people to just go to failure to sort of fool-proof it (http://www.strengtheory.com/training-to-failure-or-just-training-to-fail/). Some of the studies are done to failure, and some are done with defined set/rep schemes (30/20/20/20 and 30/15/15/15 are pretty popular). I *believe* there’s some data showing that, at least for one set, people can do the same amount of reps before failure with and without BFR (it came up in my searching but it didn’t make the final cut of the article, and now my search skills are failing me), so I’m not sure how much that would affect it, but that’s definitely a good point. In the meta, low-load training without BFR produced much less hypertrophy than I’d expect, based on the results of the low-load training to failure studies I’ve seen.

      I’m really not 100% sure what I think about myoreps. Mechanistically, they’re solid, and they haven’t been directly studied in the literature yet, but thus far, protocols using similar protocols (drop sets, cluster sets, etc.) aren’t looking too promising.

      1. GREG, COULD YOU ELABORATE MORE ON THINGS LIKE DROP SETS NOT LOOKING TOO PROMISING? I was assuming that both drop set and myo reps (or rest pause) would hit the full spectrum fibers in a few sets and equal the efficacy of more straight sets. Hmmm

  3. Hi Greg. Great article I love your stuff. Quick question. How do you wrap with old lady resistance bands? I tried with wrist wraps and I think they are a little too short. Can’t picture using resistance bands. Thanks! Fan from. Thailand.

  4. I disregarded BFR as just another trend that would come and go. I’m so glad you wrote this article. I completely respect and trust your opinion. IMO, as a natural lifter to build muscle you need volume and heavy training, the problem is recovering, this should help. I need to give this a try. Thank you.

  5. Interesting stuff.

    Could you comment on the implications this may have for grip strength? I’m thinking of two scenarios: either training a movement which happens to improve grip strength as a secondary effect (e.g. pronated curls), or training a movement for the explicit purposes of increasing grip (e.g. static holds).

    Would BFR have any practical applications for the latter scenario, any reasonable expectation of grip strength improvement via the former scenario, or will it largely leave grip strength unaffected in any case?

    1. yep! It can help grip strength. Incidentally, that’s actually what was used to test strength in a lot of the original research (early 2000s and prior). I didn’t include those studies in the article because I figured they’d be less relevant to most of the readers, and most of them were done on untrained people, but BFR for static grip work does seem to improve grip strength more than regular grip work does (though the same mechanisms)

  6. Awesome reading. I just got one question. How do you use resistance bands for occlusion training? I cant think of any way to tighten a band around my limbs so they do not loose up during a set. Keep up the good wirk and greetings from germany

    1. Just pull them tight and poke a loop through (as if you were getting blood drawn). As long as the loop is big enough, it won’t come loose, and then you can pull the free end of the loop to remove the bands easily after the set.

  7. Great article!
    I had dismissed BFR as more a gimmick than a useful tool especially looking at results from meta analysis, I wasn’t doing high volume at the time so recovery wasn’t an issue.
    Now I have greatly increased squat and bench volume being able to train my back without cutting into recovery as well as not significantly increasing total training time sounds really good.

  8. I thoroughly enjoyed this article and you did a great job with it. I have tried occlusion training with a few different muscle groups and the only muscle group I use it consistently with now is my calve training. I alternate between occlusion and more traditional training and get 2 to 3 training sessions in a week.

    I can honestly say I have seen visible results. I believe it can be attributed to the added muscle activation as you wrote about in your article. I have a naturally tight Achilles tendon, soleus, and hamstrings so getting my gastrocs to do any “work” I think has been the problem in my calf development. Adding in the occlusion and getting the “huge pump” in my gastrocs has helped resolve this problem.

  9. Do you think low load BFR would help heal golfers elbow faster? I was working through this nagging pain but it’s not going away so I took a week off. It doesn’t seem to be helping. I was doing so well too…

    1. That’s a question to ask a physical therapist. Now, if you just want to rest it until it starts feeling better, using some BFR can help you maintain strength while you rest it (either doing BFR without exercise, or training with low enough weights that they don’t bother your elbow), but in terms of actively rehabbing your elbow, that’s outside my realm of expertise.

  10. So would doing BFR instead of (or in addition to) low intensity/volume during a deload be a good idea for miantaining/improving strength, or do you think it needs to be preceded by some heavy work to have any benefit?

  11. Hey Greg,
    Great article, seems to be really well supported.

    Quick question relating to implementation of BFR… Do you have any more pointers for ensuring you have the correct tightness? Having never had a limb tourniqueted for amputation, your scale of 0-10 doesn’t give me much reference…. Should it hurt? What kind of sensations should be present when you have it right but arn’t overdoing it?

    1. The best indicator is a massive pump. If it’s not too uncomfortable and you don’t get a great pump, then it’s probably too loose. If it’s really uncomfortable and you don’t get a great pump, it’s probably too tight (this may be accompanied by a bit of numbness as well).

  12. A good way to get people to make sure they haven’t occluded arterial flow is to make them check for radial and dorsalis pedis pulses. It wouldn’t be too hard for people to pick up the pulses once they get the hang of it.

  13. Very good. I was a client of Jay Schroeder of Ultra-Fit in the 90’s and into the 2,000’s.
    He stated that his “ISO EXTREMES” did several things that were somewhat contrary
    to what a local muscular endurance method is supposed to do. One is to cut off blood supply.
    Now if i am not mistaken he said that would not allow the slow twitch fiber to get the “fuel” they
    needed and it would result over time to a proliferation of fast twitch fiber (fibers changing their function
    and behavior not actually turning into another fiber type).
    Brandon

    1. That smells fishy to me. In humans, in response to just about any type of training, the only major fiber shift you see is from IIx to IIa. Not letting fibers get enough fuel is actually what causes the shift toward more oxidative characteristics (they develop characteristics to get more out of the fuel available to them).

    2. Hey Brandon, Any chance I could pick your brain about the loaded stretching/iso extremes you did with Jay Schoeder?I have congenital limb deficiency, and I’m hoping this may help with developing my arm. Thanks!

  14. I’m probably wrong here, but is there a possibility that your cns gets underrecovered due to high neural activation if you use this “free volume” to expand your workout?

    1. Potentially, but I’d doubt it. Central fatigue from training is largely caused by inflammation resulting from the training process (largely due to muscle damage) – at least, that’s the current hypothesis I find most convincing. You can read more about that here: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.457.7252&rep=rep1&type=pdf

      With little to no muscle damage from BFR training, I doubt it would contribute to central fatigue very much, if at all.

  15. Hey Greg, enjoyed the article.

    Looking at some of the studies on well trained athletes, could it be that the gains from BFR are at least somewhat a result of it being a novel stimulus?

    1. That’s a really good question. I wonder, though, how novel your body actually perceives it as being. I haven’t seen anything that suggests any of your body’s responses (from muscle activation to gene expression to signalling pathways to absolute amounts of metabolite accumulation to effects on satellite cells) differ between low load BFR and heavier conventional training. The only difference may be the magnitude of the acute GH spike, but I’m really not sure how important that is. I guess it’s just a question of whether, for novelty effects, it matters if it’s different outside your body, or different inside your body (and if there are differences inside your body that we don’t know about yet that could make it a novel stimulus in both regards).

      Short answer: I’m really not sure. But ultimately that wouldn’t change the picture all that much. It would just mean that it would be more useful cyclically (alternating blocks you included it in, instead of keeping it in your training permanently) than permanently.

  16. Do you think there are any real benefits of doing BFR with typical hypertrophy volume/intensity levels? I was just curious since almost all of the sources you listed and I’ve seen online use BFR with loads less than 50%.

  17. Sounds good Greg – thanks for the insight.

    One last question – how would you suggest applying the “30% of 1RM for sets of ~30 reps” to static grip training?

    I currently train static barbell holds for three sets of 30 seconds each. Is it as simple as tying bands off on the forearm side of the elbow and training the same weight x 30 seconds x 3 sets as before, or would you suggest something different?

  18. Hey Greg,

    Great article as always. But I’m curious how to apply BFR to benching. Where do you put the bands. I can’t think of a way to restrict the blood flow to the pecs.

    1. Still around the upper arm. That’s what Leubbers and Yamanaka did. Either the systemic effects make a difference, or the chest just ends up doing more work as the triceps fatigue.

  19. Greg,

    Would you recommend a higher frequency for this type of training due to the faster/easier recovery? For instance if someone wanted to increase arm size, specifically to strengthen their bench press (or leg size for squat), would you recommend training arms(legs) in this fashion 2-3 times a week? Or perhaps one standard heavy day and then another day of just BFR training, maybe even full body training just an extra day per week using only BFR? Any help would be greatly appreciated.

  20. Hey Greg!

    Currently 8 month post knee sugery with bursa/bursitis condition in the knee. Had a major infection in the left knee. My rehab has been with a knee specialist( physical therapist). To this day my knee is still very “unstable” in terms of how it feels and is capable of from day to day. I used to powerlift, but i cant see that happen soon.

    Can i incorporate BFR for hypertrophy? Sorry if you already used answered in the article.

  21. Hey Greg!
    First, I need to tell you that your articles are fucking great and you just need to keep them coming.

    Are there any risks when it comes to BFR? I’m specifically thinking about the insane blood pressure that must occur within the restricted limb. Any reason to believe that it could potentially damage the vascular or lymphatic system in any way? Seeing as how things that produce an effect always have a side effect.

    1. The blood pressure likely wouldn’t be an issue. Blood pressure gets INSANELY high with regular lifting (and the valsalva maneuver) anyways. Like, systolic pressure going 300+. If you have a pre-existing vascular disease, that’s no good, but the BP increases you get from BFR training aren’t going to be as high as the BP spike you get from squatting or DLing a 1rm.

  22. Hey Greg! I’m quite interested in trying some BFR training for these great gains the research talks about, but my worry is blood clots. Even though it’s only for a couple minutes, could this possibly be an issue? I’m almost 21 years old, and am pretty active with lifting and being a track a field thrower, so I don’t think I should worry about blood clots, but I’m just wondering if there is a risk of it.

    1. Out of 12,000+ people, the rate of venous thrombosis (blood clots in your veins) was 0.055%, or about in 1 in 4,500 from the injury data I linked. Also, keep in mind, the majority of those people were elderly, and were using BFR because they couldn’t safely train with heavy loads (and then some young people rehabbing injuries as well).

      The rate of venous thrombosis in America is 1-2 per 1000 – http://www.cdc.gov/ncbddd/dvt/data.html. No idea about rates in Japan where the injury data came from, though.

      In other words, the rate of venous thrombosis among the people for whom we have injury data is actually lower than it is in the American population as a whole, so it’s probably not something you need to worry about.

  23. A little late to the party here, but I was wondering about the study showing increased recovery and power performance after BFR. I couldn’t seem to get the study to come up but do you think some of the strength increase shown could simply be a result of the participants being better recovered, and therefore better able to display their strength? Perhaps better recovery from session to session allowed for higher quality work (bar speed?) during the study period, or maybe simply doing one BFR session at the end of the study was enough to give a small dissipation of fatigue and allow greater performance? I doubt that it’s the whole picture and question what the performance difference was in the recovery study was.

    1. “do you think some of the strength increase shown could simply be a result of the participants being better recovered, and therefore better able to display their strength?”

      Yep, that was the whole point of it. I may have explained that poorly, though.

  24. Do you think a “similar” effect can come from more sets and very short rest periods? Similar to what Gironda preached with his 8x8s and 10-20 sec rest periods?

  25. GREG, #1- Some of the studies: Div 1 football, and semipro rugby players? I get what they are trying to do here, as in apply the studies to already thoroughly trained dudes . . . to get away from any noob effect slanting the study. But then again, because of the their sport (type and level), these guys are the ones who DO respond to just about ANY kind of training (endowed genetics, almost freaks, etc). They are NOT your average joe strength training dudes by any stretch. (Oh, almost forgot: and drugs; hardly policed at all in college sports, esp. off-season I’d imagine)

    #2- Do you think HIIT type training would provide the same TYPE OF effects as BFR . .i.e. pump training. Prowler pushes are a mother f’er on the legs . . .massive burn, pump, bloodflow, flush, etc. Same thing w/ Rower HIIT workout, my back is swole afterwards.

    1. >because of the their sport (type and level), these guys are the ones who DO respond to just about ANY kind of training

      It’s not that they responded to training; it’s that they responded BETTER to a particular style of training.

      >Do you think HIIT type training would provide the same TYPE OF effects as BFR . .i.e. pump training.

      Perhaps, but not to the same degree

  26. Hi Greg,

    Have you looked into any of the studies where aerobic capacity and VO2max were tracked? One was a study involving low intensity intervals on a bike using 30% Ppeak while a different study had participants ride at 40% VO2max for 15 minutes.

    Chris

    1. I have, and I’m not sure what to make of them. Apparently low intensity cardio with BFR can improve VO2 quite a bit for sedentary old people, and there was actually one study where it improved VO2 in collegiate basketball players, which was very unexpected. tbh, that still doesn’t make sense to me, though, and as far as I know there’s only been one study in healthy young people.

  27. Christopher Knight

    What if someone on a 5 or 6 month cut did BFR training exclusively for the entire period? It seems from your article that they should not only maintain their current muscle mass (and increase a bit, i’m sure) but be completely fresh and ready for muscle damage galore in the bulk to follow, right?

  28. Hi Greg,

    First off just wanted to thank you for these awesome articles. Really upped my training knowledge game ever since I started reading your articles.

    I was wondering, is it normal that your biceps feel like they are going to cramp up when doing BFR? When the third of fourth set comes around I get a feeling that’s very reminiscent of a muscle cramping up, especially when I focus on the concentric contraction. A word of note: I don’t push it to the point where the muscle actually fully cramps up, but I do get muscle spasms (or at least feels like it). It’s not fatigue what stops me from continuing my sets, but the feeling of upcoming cramps. The next day my biceps feel very sore, especially the most proximal part of the muscle belly of the long head (but it doesn’t feel like typical DOMS) and when I supinate my forearm and isometrically contract my biceps they wil also cramp (not for long though).

    BFR is supposed to be very low taxing on the muscles. But cramps + high muscle activation + lengthening every rep seems pretty taxing to me?

    Daniël

    1. How long have you been doing it? I get pretty sore from my first session or two, but progressively less sore the longer I do BFR work. Also, there’s a chance that you’re just getting the band/wrap too tight, so your muscles feel like they’re cramping from hypoxia since no oxygenated blood can get to them.

      1. This was the first session. Soreness in it self doesn’t worry me. But I am a little bit hesitant to try again. Mainly because it feels different then normal around the muscle-tendon area (little bit like a strain, although that differentiation is hard to make) and because of the spasms/cramps. Didn’t experience any tingling so I doubt it would be from hypoxia (skin did change a bit though but not blue or pale, more reddish). But I will check my pulse and capillary refill to be sure next time.

  29. Hey Greg,

    I know some new research is showing that shorter rest periods are inferior to longer rest periods. Do you know why this would be considering the metabolic stress/cell swelling would be higher in the shorter rest periods? Also since all sets were taken to failure wouldn’t the decrease in load or even total reps between groups not matter?

    I know the main logic is that shorter rest periods mean a little less volume. But I figured since both groups were taking all sets to failure this wouldn’t matter.

    I thought potentially that metabolic stress/cell swelling would be good, but then maybe needs to be cleared out otherwise you might get an endurance effect, so shorter rest periods would be inferior, but that wouldn’t make sense because then you would expect BFR then to have this same issue/ But BFR compared to regular training you get equal growth, even though in theory the rest periods are short/ not even considered a full rest period since the muscle is not exactly free to relax.

    1. Those are lots of good questions without good answers (at least I don’t have any). I think you’re onto something here “I thought potentially that metabolic stress/cell swelling would be good, but then maybe needs to be cleared out otherwise you might get an endurance effect, so shorter rest periods would be inferior,” though. That’s my thought as well, though I’m not totally sure it makes sense in light of some of the concurrent training literature (“endurance” stimuli through a long ROM without repeated impact – like cycling – don’t seem to blunt muscle growth to a meaningful degree, even if it comes right before lifting). With BFR, it may just be that it’s different enough compared to “normal” training that it doesn’t matter that you’re not clearing the metabolites. I’m really not sure, though.

  30. Hi Greg,

    Thanks for posting this article, your site has been a great resource for me. I read this article a while ago but am now looking to introduce BFR into my strength training.

    I saw your recommendation is to include a few sets after your heavy work and I assume this is the method the studies used when combining heavy work and BFR?

    I was considering including the BFR work in my morning training sessions though. I currently do two-a-days, with the morning session primarily consisting of mobility work and very light accessory work (band pullaparts, BW lunges etc.) just to hit the areas that i’d normally miss in my heavy sessions, so a few sets of light squats and bench with BFR wouldnt be too overtaxing for that time in the morning.

    My initial thought was just to give it a go and see but thought i’d just ask the question to see if you’re aware of anything that suggests it’s a definite no no?

    Thanks

    Chris

    1. “I saw your recommendation is to include a few sets after your heavy work and I assume this is the method the studies used when combining heavy work and BFR?”

      Yep!

      “I was considering including the BFR work in my morning training sessions though. I currently do two-a-days, with the morning session primarily consisting of mobility work and very light accessory work (band pullaparts, BW lunges etc.) just to hit the areas that i’d normally miss in my heavy sessions, so a few sets of light squats and bench with BFR wouldnt be too overtaxing for that time in the morning.

      My initial thought was just to give it a go and see but thought i’d just ask the question to see if you’re aware of anything that suggests it’s a definite no no?”

      Is the morning session the same muscles/movements as the afternoon session? If so, I probably wouldn’t recommend the BFR work in the morning. However, if it’s different stuff (i.e. BFR bench in the morning and squats in the afternoon), that would probably work fine.

      1. Thanks Greg!

        The morning session is very generic, full body, but very light and lots of mobility. The evening sessions are more specific, Heavy Squat/Bench/Deadlift then Speed Days. I’ll try including the BFR exercises on days when i’m not doing the same Heavy exercises. So like you said, I’ll do BFR Bench on Squat days and vice-versa etc. I’ll report back with how it goes.

        Thanks again

        Chris

  31. As a potentially stupid question, would it be possible to achieve the same effects from bfr training to all body parts by wearing compression clothing? Or would the compression required be too much to realistically have for a shirt/pants? The way you describe it, if you got a compression shirt a size too small it might work, but do you personally think it would still be beneficial because most compression articles of clothing would seem to restrict blood flow overall rather than forcing more into a limb.

  32. I see this in your sample programs on Bench 2x Int. is it meant only for bicep curls, or for the tricep/ chest fly work as well?

  33. Hi Greg,
    Great article! Really enjoyed the read. I am currently into my second Bulgarian method (my first one gave me the biggest front squat strength gains ever btw, thx for that!), with no assistance exercises for quads and doing some relatively light hip thrusts twice a week. Could it be beneficial (strength-wise) doing dome BFR squats at a light load after the daily max set? Usually I am pretty careful with any assistance exercises while doing the Bulgarian method, but it looks like BFR training is easy to recover from.

    Another question: do you apply BFR to your own training?

    King regards,
    Timo

  34. Greg,

    Great article and I really value your concise commentary on the studies in a way that’s accessible to a wide audience. The Bro-tips are solid as well; oftentimes we tend to lose sight of the value in how a program ‘feels’ to someone which is incredibly important and oftentimes neglected in the evidence-based community.

    BFR is a great tool, and I’ve also seen success in incorporating it into higher frequency protocols for ‘light days’ (for reasons you’ve mentioned in the article) and as a flexible form of periodization on days you’re not “on” or when traveling and limited by equipment (easier to pack wraps than weight plates).

    Also +1 to performing it in a deficit as mentioned above. People are generally wrecked after their heavy work and BFR helps tremendously there when work capacity starts to wane. Plus, cutting time vascularity, man.

    Really, it’s a very versatile and useful tool and looking forward to continued study being done on the subject – particularly with regards to the systemic effects and so forth.

    Keep up the great work,

    -JM

  35. I have no Idea if its actually worth asking questions on a four year old post, but considering I’m quite unsure where else to adress it, I’m just gonna go ahead and ask here:

    In your “Implementation” segment you give us a good protocol on how to capitalize on some of this “free volume” that bfr offers. You say to lift heavy things as normal, then do some sets with bfr. This raises some questions regarding the optimal frequency of this protocol: if you bench 3x a week for instance, is there a point to doing som bfr bench sets after your conventional bench sets all of those 3 days? and lets say you where doing something very high frequency like your “Bulgarian” system with 5-7 days a week, would it be beneficial to do your bfr protocol for squat and bench (if those were your Bulgarian lifts) after every session (all 5-7?)

    Secondary if your normal session looks like this:
    -Heavy Bench training
    -Bench accessories (Triceps extensions, flies or whatever)

    Should one implement the BFR protocol like A or B? :

    A
    -Heavy bench
    -BFR bench
    -Accesories

    B
    -Heavy bench
    -Accesories
    -BFR bench

    Huge fan of all your work, big thanks for all you do for the lifting community!

    1. There was actually a really cool study recently that gives an idea for frequency that I think would be worth trying: https://www.ncbi.nlm.nih.gov/pubmed/30188363

      Pick maybe three muscle groups you want to focus on. Do BFR work for one of them every training day for two weeks straight, and don’t do any BFR for the other two. After two weeks, move on to the second muscle group, and stop doing BFR work for the first. After two more weeks, move on to the third muscle group, and don’t do any BFR work for the first two. Then repeat the process.

  36. Hi Greg!
    Do you remember where the study of the perceived tightness comes from? It’s a very subjective metric, and I wish I had something more concrete to pin it on. Concretely, my arms turn pretty purple (but I’m also the palest dude in the world) – and depending on what article you read, that’s either fine, or a huge no-no.
    Did you come across any other sources for some objective metrics that you can use? I’ve tried measuring capillary refill on my palm by pressing down, and that seems fine, and there’s also a pulse, so I assume I’m not cutting off the arteries.

    1. I personally think pulse + extreme pump are your best indicators. If you can still feel a pulse in your wrist or ankle, you haven’t cut off arterial flow, and if you get a bigger-than-normal pump, you’ve cut off enough venous flow.

      This is the study: https://www.ncbi.nlm.nih.gov/pubmed/23446173; I believe the recommendation for going a bit tighter on the legs was from a follow-up interview.

  37. Hi Greg,
    It was mentioned in MASS that blood flow restriction work could be effective because of a novelty effect. Could it be that 20 rep squats could also be effective for a short period atleast for someone who has never trained above 12 reps, because of a similar novelty effect?
    Also, im incorporating bulgarian split squats in my program for the first time but i heard they can be dangerous if i lose my balance. Is there any way to make this exercise safer?

    1. “Could it be that 20 rep squats could also be effective for a short period atleast for someone who has never trained above 12 reps, because of a similar novelty effect?”

      Possibly. I see 20 as on the line, somewhat (is 20 THAT different from 12?). In that paper on PLers, I believe the first BFR set was either 30 or 40 reps. I don’t think BFR was necessarily the magic in that study (moreso the huge difference in loading), but I think there’s a chance that a weight you can only do for 20 MAY still be a bit too heavy for it to be novel enough.

      “im incorporating bulgarian split squats in my program for the first time but i heard they can be dangerous if i lose my balance.”

      If you’re using a barbell and holding it on your traps, possibly. If you’re using DBs, you can just drop them. Or if you’re using a barbell, you could just use a front rack position so you can throw the bar in front of you.

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