June 2013: Jeremy Loenneke Q & Aby Matt Meinrod on June 23, 2013
MATT: Before we begin, Jeremy, tell everyone about your background, when and why you started training, and what exactly your area of expertise is.
JEREMY: I basically began training to get stronger for wrestling back in high school. I started looking through all of the muscle magazines for tips to get bigger and stronger and that’s how I came across the sport of bodybuilding. After digging a little deeper I came across the articles of Layne Norton and that’s really who turned me onto science and natural bodybuilding. I did my undergraduate work in Exercise Science at Southeast Missouri State University graduating with my bachelors in 2008. I met Layne and a lot of other influential people in my life while interning in Dr. Kim Huey’s muscle physiology laboratory at the University of Illinois. It was there that I developed a huge interest in blood flow restriction (BFR) training and the rest is pretty much history. I went back to Southeast Missouri State for my Masters in Nutrition and Exercise Science where I began research on developing a practical model of BFR with Dr. Joe Pujol. Following my Masters, I started working on my PhD at the University of Oklahoma in the Fall of 2010 under the mentorship of Dr. Mike Bemben. While at Oklahoma, I have also been lucky enough to collaborate a lot with Dr. Takashi Abe and Dr. Jacob Wilson who have both been huge positive influences in my life. Most of the work I have been a part of here has focused on a lot of the methodological questions of how to best apply BFR. My research interest boils down to how to make a muscle grow with my major emphasis being on how to make a muscle grow through the application of BFR by itself or in combination with exercise.
MATT: What exactly is blood flow restrictive training?
JEREMY: BFR training is simply restricting blood flow to a muscle and then exercising that muscle. It is very important that one understands that this is only a partial blood flow restriction and not complete arterial occlusion. The goal when applying the stimulus is to allow blood flow into the muscle (arterial) and completely restrict blood flow out of the muscle (venous). This causes blood to pool in the limb resulting in a swelling effect which may actually be mechanistically important for making a muscle grow. The benefit to training with BFR is that you are able to use a much lighter load (20-30% of max) and still see similar muscular benefits to that observed with higher load training (>70% of max). Some literature also suggests that BFR can increase muscle size and strength when combined with low intensity aerobic exercise, however, the magnitude of change is MUCH less than what you see with BFR in combination with low load resistance training.
MATT: I know this field is very new, but I always like to get simple opinions from experts on what they think is happening in certain cases. What do you think is causing the muscle growth? Do you believe it is the cell swelling itself from lactate accumulation, maybe proliferation of satellite cells, or something else?
Also, Jeremy from what you are seeing, do the changes appear to be sarcoplasmic or myofibrillar in nature?
JEREMY: Great question. I like to break up the benefits of BFR into three separate phases because it is clear that the mechanisms at work with resistance training in combination with BFR are not the same as BFR in combination with Aerobic exercise or BFR in the absence of exercise.
Phase 1 (BFR in the absence of exercise): I think a likely mechanism may be an acute increase in muscle cell swelling which may be playing an important role in the attenuation of muscle atrophy observed with short term BFR. This stimulus does not appear to be a big enough to actually increase muscle size but it certainly seems like it may slow down its loss. A lot more mechanistic work needs to be done in this Phase before we can be more certain.
Phase 2 (BFR in combination with low intensity aerobic exercise): I think acute muscle cell swelling is again playing some role. It may be that there are greater increases in intramuscular lactate during this phase which may augment the swelling response enough to result in an actual increase in muscle size. Like before, this phase needs a lot more work.
Phase 3 (BFR in combination with low load resistance training): Almost all the mechanistic work thus far has been completed in this Phase. Low load resistance exercise in combination with BFR has been shown to increase mixed muscle protein synthesis (likely myofibrillar more than anything). The increase in protein synthesis may occur through a metabolic stress induced increase in muscle fiber activation which is important because muscle fiber activation and protein synthesis appear to be related. Others have found decreases in myostatin and the atrogenes (related to protein breakdown) and a recent study found a rapid proliferation of satellite cells with this type of training. Whether the proliferation of satellite cells are important for muscle hypertrophy is debatable, but some evidence does suggest that they are important for long term changes in growth. We have also descriptively shown that short term changes in muscle cell swelling may be playing a prominent role in this Phase as well, but future research is needed to confirm this.
MATT: Who should consider using blood flow restrictive training? Since our audience is mostly bodybuilders how would you suggest they start BFR training?
JEREMY: I think BFR has a lot of benefit to bodybuilders, but I would never recommend somebody who is capable of lifting heavy weights to completely ditch that for low load exercise with BFR. I do think that adding it to your normal training program may be of benefit, especially during a deloading period or if you are rehabbing an injury. There are also those days in the gym where things just don’t feel “right”. I think in a situation like that, it makes sense to just train with a lower load in combination with BFR. You will be getting a sufficient stimulus for growth but you won’t be putting yourself at risk by lifting a load that you might not be able to safely lift that day. There is also some data to show that when an American football team added low load BFR training to the end of their normal high load workouts, they saw improvements in strength over what was observed with low load exercise without BFR.
I recommend using narrow (~7 cm wide) elastic knee wraps to practically apply BFR. Like I said earlier it should be tight enough to cause a fluid shift but not so tight that you are blocking arterial flow into the muscle. If you are in pain before you begin exercise, the wraps are way too tight. Data from the University of Tampa suggests that you should wrap with a perceived tightness of about 7 out of 10. The wraps should be applied at the top of the legs or the top of the arms (wrapped around side of arm, not over top of shoulder). You can do BFR with just about any lift; just make sure that the load is LOW (20-30% max). I recommend doing 3-4 sets of 15+ reps at a controlled pace of about 1-1.5 seconds up and 1-1.5 seconds down with 30 seconds of rest between each set. A lot of studies use the protocol of 30-15-15-15, so that may be something to shoot for. If you are unable to get even close to completing that many reps, then the wraps are too tight or the load is too high. In addition, the BFR should be left on throughout the exercise (including rest periods) bout and removed following the final set.
MATT: What kind of results have you noticed since your research has begun?
JEREMY: We theorized and developed the practical model of BFR (i.e. knee wraps) for research back in the summer of 2008. While at Southeast we did a lot of research on the acute response and found that the practical model responded similarly to what was observed with the more expensive BFR devices. However, acute data is one thing and is largely meaningless if it doesn’t translate over into real long term change (increase muscle mass and strength). Since then, an independent lab out of Middle Tennessee State found positive chronic change following the use of practical BFR and the University of Tampa also has some chronic data showing that the stimulus responds similarly to high load training.
MATT: Are there any negative drawbacks or precautions one should take note of before they start implementing this in their training?
JEREMY: I would be very cautious applying BFR if a person had a compromised vascular system or if they are at a high risk for thromboembolism. BFR has been safely applied to a variety of populations, but it is a stimulus that can be potentially dangerous if not completed correctly (i.e. cutting blood flow off completely or using it with too high of load/intensity). If you have never used BFR before, I would start with just one exercise and slowly transition it into your training until you get used to the stimulus.
MATT: Is BFR something that can be done year round or should there be scheduled breaks throughout the year?
JEREMY: I don’t see any reason why it can’t be done year round. Again, if you are capable of lifting heavy weight, I would use BFR in combination with low load/intensity exercise as a supplement to your heavy training not as a substitute.
MATT: Since training and nutrition tend to go hand-in-hand, are there any specific dietary suggestions that could enhance the results with BFR?
JEREMY: Not really anything specific other than what I recommend normally for people to consume. I recommend consuming optimal amounts of protein/carbs/fat every 4-5 hours throughout the day (~3-4 meals a day). Obviously those amounts are going to depend largely on the person’s current metabolism. If you do that throughout the day and train at some point between one of those meals, you should have an optimal environment for muscle growth.
Jeremy Loenneke is a PhD student in Exercise Physiology at the University of Oklahoma. He has previously earned a Master’s degree in Nutrition and Exercise Science from Southeast Missouri State University. He is also a competitive bodybuilder and powerlifter and proud member of Team Norton and the DRG. You can find him on twitter @jploenneke.