Blood Flow Restriction Training: Less Stress, Equal Gains?

The Lay of the Land:

~2,900 words (10-15 minute reading time). Video synopsis available below (~7 minute viewing time) if you prefer to start there.

Take-away Points:

  • Blood flow restriction (BFR) training allows lifters to strategically reduce training stress by utilizing lighter loads while still achieving training effects somewhat comparable to what would be expected when doing more conventional resistance training.
  • Probably the biggest benefit of BFR training is that it allows lifters to get in extra work on a movement or body part without beating themselves too much.
  • BFR can also be valuable for training around injuries or training when you have limited access to weights.
  • All you need to get started are some manner of elastic bandages (e.g. ACE bandages), knee wraps, or similar elastic bands/wraps. 

Okay, guys.

This one might seem a bit wonky at first, so I’m gonna request right off the bat that you just suspend your disbelief for a moment and, well…

blood-flow-restriction-training

I say this because blood flow restriction training (henceforth referred to as BFR training) seems a little outlandish at first glance and is thus one of those topics that can often elicit the “WTF is this idiot talking about?” reflex upon its mention.

Many of you know by now that I mostly prefer to pick heavy things up and put them back down the conventional way, but if you’ll bear with me for a few minutes, I would like to posit how low intensity (as in lighter-weight) BFR training could be a useful supplement to the higher intensity training methods that we know and love.

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What is BFR training?

Before we dive into the applications, let’s take a quick look at the idea behind BFR training.

In a nutshell, BFR training involves low intensity (usually 20-30% of 1RM) resistance training performed while the blood vessels from either the arms or legs (depending on the muscle to be worked) are partially occluded by some manner of tourniquet (bear with me, bear with me). The goal here is not to restrict arterial supply of blood to the distal muscles, but rather to reduce venous return from them (of course, it is hard to really accomplish one without the other to some extent, venous return of blood is just achieved under less pressure than arterial delivery, thus it theoretically requires a bit less pressure to block).

This reduction in venous return from distal muscles (let’s say the biceps or triceps) can result in a pretty substantial pooling of blood (or, to put it scientifically, a mega-pump) within said muscles. As the muscles are worked in this condition, byproducts of energy metabolism such as lactic acid and carbon dioxide which would normally be partially cleared from the area and dispersed throughout the body via the vasculature instead become quite concentrated due to the reduced rate of clearance.

This buildup presents a potent stressor to the working muscle and nearby tissues and seems to act as a trigger for the expression of various growth factors in the area. For example, it has been shown that BFR training can induce increases in growth hormone production, S6K1 phosphorylation (a downstream marker of activity of the mTOR pathway oft-touted in discussions of protein synthesis), and cell swelling (this one isn’t such a surprise given the aforementioned mega-pump).

While these findings are interesting and probably at least partially explanatory of why BFR training could work, the most important thing for us to note is that several studies have demonstrated that low intensity BFR training can indeed produce significant hypertrophy in both trained and untrained individuals.

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You Want Me to Do What, Now?  

Okay, pause. Sounds kind of extreme, right? My knee-jerk reaction when I first encountered BFR training was that it sounded like a ridiculous idea, but the more I read and learned, the more I realized that it is indeed a viable approach to inducing hypertrophy and strength gains (more on this below)—not superior to more conventional (heavier) resistance training, mind you, but viable nonetheless. I have since used it to good effect in my own training.

So how does low intensity BFR training stack up against conventional, heavier resistance training?

While it is far from a perfect comparison, two meta analyses—one on conventional resistance training and one on low intensity BFR training—found similar effect sizes on muscle hypertrophy (and somewhat so on strength as well) between the two methods for subjects performing roughly the same number of sets (although volume is otherwise not perfectly accounted for between the two methods in this comparison).

These findings might seem surprising at first, but perhaps it will seem less bizarre if you consider the idea that BFR training is probably not so different than what bodybuilders have been doing for decades with “training for the pump” and time-under-tension training; we’ve essentially just found a way to provide a similar stimulus while further decreasing the load.

So, let’s consider our two methods here: low intensity BFR training and conventional resistance training. One lets us use heavy weights and feel like badasses. The other has us strapping up with bands and curling tiny pink dumbbells (okay, we’re probably not actually gonna go that light, but still). According to the research, both methods will give us comparable outcomes hypertrophy-wise, while the conventional training seems to take the cake for building strength.

It seems like a pretty clear choice here, right? So why did I bother bringing up BFR training in the first place?

It mostly comes back to that one factor: intensity.

bfr-blood-flow-restriction-training

Okay, they’re blue. Sue me. (Please don’t)

Reduce the Stress and Keep the Gains – Applications for BFR Training

I think that most people who have been in the strength game for at least a few years can attest that, even if you have managed to avoid major injury thus far, lifting heavy stuff can take its toll this way or that. Muscles can get tight, and joints can get achy. Of course, sometimes there are major underlying issues or imbalances causing these problems, and in those cases, they should be addressed appropriately, but sometimes, the problems are more minor and can be trained around (as opposed to trained through). At these times, low intensity techniques like BFR training that are still effective for inducing hypertrophy and strength gains can be pretty handy for getting work in without placing excessive stress on touchy joints or tissues.

In the case of minor to moderate muscle strains, I actually think that BFR training could be great for a rehab protocol. If you’ve ever heard of or tried Bill Starr’s rehab program for pulled muscles (in a nutshell, the program has you do a movement that involves using the pulled muscle with super light weight for 3 sets of 25 each day while gradually increasing the weight; pump work!), you’ll know that getting an injured muscle belly moving and full of blood can help a lot with expediting the healing process.

Utilizing BFR training on, say, a pulled hamstring while using a similar protocol would likely amplify the growth stimulus (as very low intensity resistance training tends to not elicit as much growth in the absence of BFR) and improve the effectiveness of rehab. Full disclosure: to my knowledge, this exact application of BFR training has not been well-explored; this is just me hypothesizing. 

What has been shown in a somewhat related vein is that daily sessions of BFR alone (just the occlusion itself without any resistance training) can reduce disuse-related muscle loss during periods of immobilization (administered via a cast in this particular experiment). So, whether it’s a minor injury or something that’s resulted in complete immobilization, BFR might be able to help you get back in peak condition sooner (as can things like active imagery, which you can read about in my guest post over at Strengtheory if you’re interested).

But I’m in Tip-top Shape

No issues or injuries? First off, congratulations on that, and secondly, BFR training definitely still has some great applications for you. I’ll propose two (or three).

First, BFR training could be used to provide a meaningful stimulus to specific muscles during periods of demanding, specialized training blocks that make training that muscle directly with conventional methods either overly time consuming or just too demanding in terms of total workload.

Let’s say someone is in a high frequency block where they are squatting and benching three times per week and deadlifting twice. If they are maintaining moderate to high intensity on most of these days, they might not have ample resources (time or recovery-wise) to throw in an appreciable amount of, say, arm work without impairing the rest of their training. With BFR training though, they could still provide a meaningful stimulus to ‘dem guns while only adding 5-10 minutes to a training session maybe twice a week and also while sparing the joints and nervous system from much additional battering.

The second option I’ll mention is utilizing BFR training for accessory work after you’ve performed your standard strength or hypertrophy work for the same muscle group/movement pattern. An example of this would be something like using BFR for triceps pushdowns following some close grip bench pressing (or even following some heavier bench work with low intensity BFR bench work). The idea here would be to provide a broader range of stimuli to the muscle, in this case beginning with more of an emphasis on mechanical stress and then transitioning to focusing more on inducing tissue swelling and energy metabolite buildup once you are somewhat fatigued from the heavier lifting.

This isn’t so different than what a lot of lifters (especially those following programs like Jim Wendler’s 5/3/1) do when they start a day with heavy work on a main movement and then move on to assistance/accessory work in slightly higher rep ranges, but applying BFR training as a finisher for an already worked muscle could be a good twist to help you fight stagnation—be it physical or mental.

A couple studies like this one have investigated the effects of adding low intensity BFR work in at the end of “conventional” strength training sessions. Interestingly, this study found that adding supplemental BFR training led to superior increases in average 1 rep max strength on the squat and bench (although the bench 1RM increase was not statistically significant) when compared to either the conventional strength training alone or the conventional training plus supplemental low intensity work without BFR.

While this study reported that changes in muscle thickness were not significantly different between BFR and non-BFR training groups, another very similar study did report an increase in average chest girth (as well as one measurement of arm size) for their BFR group that was significantly greater than that of their non-BFR group. While this trend didn’t hold consistently true to a statistically significant level for all of their measures of leg and arm girth, I wouldn’t be too surprised if there was something to the idea.

It’s important to point out that we know pretty well that instead simply adding more conventional weight training would lead to further improvements in strength and hypertrophy. However, this strategy comes with the clear issue that there is a limit to the amount of work you can continue to add before you start beating your body up too much (which seems to be much less of an issue with low intensity BFR training and thus a big part of the reason we should care about this).

At this point, there seems to be something of a positive trend, but I think we may need more evidence before we can say conclusively that supplementing conventional training sessions with BFR training of the same muscle/movement pattern can produce greater hypertrophy than a comparable amount of conventional training of the muscle/movement could in a given session.

The last application I’ll briefly mention is that BFR training could be a good option for times when you are unable to gain access to free weights for whatever reason and want to add a new twist to body weight work such as push-ups, pull-ups, air squats, etc. I haven’t toyed with this myself personally, so I can’t speak to it from a place of experience, but I think that the logic behind using BFR this way would be fairly sound.

In short, the research tells us that:

  1. Low intensity BFR training alone for a muscle group can lead to both hypertrophy and strength gains.
  2. Following heavier, conventional resistance training of a muscle/movement pattern with low intensity BFR training for that same muscle/movement pattern can further improve the development of strength and (maybe) hypertrophy.

While I’m only an individual, I can say that I have had good success with applying BFR training at the end of my own training sessions, so I would wholeheartedly recommend trying it out yourself.   

What You’ll Need to Get Started

Assuming I didn’t lose you way back at the “resistance training performed while the blood vessels to either the arms or legs are partially occluded by some manner of tourniquet” part (or just at the words, “blow flow restriction training” in the title), let’s finally get to exactly what you’ll need to implement BFR training into your own workouts.

For starters, occlusion is going to be administered at either the arms (wrapping as close to the shoulder/armpit as possible) or the legs (wrapping as close to the groin as possible). The legs or the arms. That’s it!

In most of the aforementioned studies investigating BFR training, blood pressure cuffs were used for the occlusion so that they could monitor the exact pressure exerted on the limb being wrapped (most of these studies shot for a pressure of ~100 mm Hg). We, however, don’t necessarily need sphygmomanometers (such a fun word) to make this work. Instead, any kind of knee wrap, compression wrap, or elastic bandage will do.

Full-width wraps can be used for the legs, but for the arms, most wraps are a bit too wide to fit well, so I’d recommend cutting a wrap in half lengthwise to make two thinner cuffs. This may seem like a dangerous disregard for the established procedure, but even Jeremy Loenneke, one of the foremost researchers on BFR training, is a proponent of using wraps this way for the occlusion effect. His (paraphrased) recommendation is to wrap with a tightness of 7 out of 10 on a scale where 0 equals no pressure and 10 feels like you’re preparing for an amputation.

The point here is that the wrapping itself should be firm, but not painful. They may be a little uncomfortable, but if the wraps are causing you significant pain (or making your limbs go numb, etc.) before you begin your exercise , they are probably too tight. Now, once you are mid-exercise, some pain can be expected due to the radical pump and metabolite buildup, but it should be a “feelin’ the burn” kind of pain (since picking up BFR training, I have come to appreciate the phrase, “skin-tearing pump,” in a whole new way) as opposed to the kind of pain that tells you something might really be wrong. If something feels wrong or there is severe pain, either loosen your wraps or just call it a day. Also, make sure you apply the wraps such that you are able to easily remove them yourself (or make sure you have a friend on hand).

In short, practice caution. From everything we know so far, BFR training is safe, but that’s never stopped the population from having a few individuals who manage to hurt themselves and go on to throw everyone else in a panic about it. A review of the available literature assessed the potential health concerns associated with BFR training and basically found that most of the effects in terms of things like oxidative stress and cardiovascular changes were very similar to those normally observed in response to conventional resistance training. The review also pointed out that BFR training has not been shown to have any negative effect on nerve conduction velocity and that it causes only minimal muscle damage (which goes hand-in-hand with my earlier point about BFR training allowing you to get work in without adding as much stress and recuperative load on the body).

The “standard” protocol that has been used in a lot of the BFR training research involves doing 4 sets with 20-30% of your 1RM for the exercise as follows: 30 reps, 15 reps, 15 reps, 15 reps. Rest periods are normally kept short (30-60 seconds), and the occlusive wraps can be kept on for the duration of all 4 sets. Of course, you can play with variations of this general scheme (e.g. doing more sets, more reps, super sets, etc.) as much as you like.

I personally like doing antagonist supersets (e.g. a biceps curl variation superset with a triceps extension variation, with wraps applied at the arms, OR leg presses superset with single-leg Romanian deadlifts, with wraps applied at the legs). Another great option is following up your main work for the day (let’s say it was the bench press) with additional sets of the same movement using BFR and less weight (again, 20-30% of your 1RM is a good place to start). The exercise choices and possibilities for implementation are quite vast,  just remember to keep the weight light, enjoy your pump, and relish the burn (if you’re a masochist).

Summary

To wrap up, BFR training can be a valuable tool to add to your training toolbox to serve multiple functions, including:

  1. A standalone method for quickly working a body part that you otherwise don’t have resources or time to devote to without drastically impacting performance elsewhere
  2. Working around mild joint pains, preserving muscle tissue during long periods of immobilization/inactivity, etc.
  3. Adding an additional stimulus for strength and (maybe) hypertrophy following conventional resistance training of the same muscle/movement pattern
  4. Upping the ante with body weight exercises when you don’t have access to weights
  5. Rehabbing strained muscle bellies

In short, BFR training won’t necessarily give you magical gains, but it may just be the closest thing to that ‘one weird trick’ that we’re going to find anytime soon, and it can be quite useful to a lifter when logically implemented. I hope BFR training will serve you well for those of you who decide to try it!

As always, thanks for reading! If you have questions about using BFR in your own training (or even if you’re just wondering whether I’ve finally gone and lost my marbles), please let me have ’em in the comments below or on Facebook, etc. 

Also, please share the work if you’ve enjoyed it! Thanks, guys!

 

References

Krieger, James W. “Single Vs. Multiple Sets of Resistance Exercise for Muscle Hypertrophy: A Meta-Analysis.” The Journal of Strength & Conditioning Research 24, no. 4 (2010): 1150-1159.

Kubota, Atsushi, Keishoku Sakuraba, Sadao Koh, Yuji Ogura, and Yoshifumi Tamura. “Blood Flow Restriction by Low Compressive Force Prevents Disuse Muscular Weakness.” Journal of Science and Medicine in Sport 14.2 (2011): 95-99.

Loenneke, Jeremy P, Jacob M Wilson, Pedro J Marín, Michael C Zourdos and Michael G Bemben. “Low Intensity Blood Flow Restriction Training: A Meta-Analysis.” European journal of applied physiology 112, no. 5 (2012): 1849-1859.

Loenneke, JP, GJ Wilson and JM Wilson. “A Mechanistic Approach to Blood Flow Occlusion.” Int J Sports Med 31, no. 1 (2010): 1-4.

Loenneke, JP, JM Wilson, GJ Wilson, TJ Pujol and MG Bemben. “Potential Safety Issues with Blood Flow Restriction Training.” Scandinavian journal of medicine & science in sports 21, no. 4 (2011): 510-518.

Luebbers, Paul E., et al. “The effects of a 7-week practical blood flow restriction program on well-trained collegiate athletes.” The Journal of Strength & Conditioning Research 28.8 (2014): 2270-2280.

Yamanaka, Tetsuo, Richard S. Farley, and Jennifer L. Caputo. “Occlusion training increases muscular strength in division IA football players.” The Journal of Strength & Conditioning Research 26.9 (2012): 2523-2529.

Yasuda, Tomohiro, Riki Ogasawara, Mikako Sakamaki, Hayao Ozaki, Yoshiaki Sato and Takashi Abe. “Combined Effects of Low-Intensity Blood Flow Restriction Training and High-Intensity Resistance Training on Muscle Strength and Size.” European journal of applied physiology 111, no. 10 (2011): 2525-2533.

 

 

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