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Thoughts on Blood Flow Restriction

New devices and modalities seem to make their way into the physical therapy world with fanfare. As clinicians we want to do the best for our patients and sometimes the amount of treatment options can be overwhelming to wade through. Modalities, devices, and treatment options can be marketed quite aggressively, and this leaves the PT to sift through the data and testimonials to decode if it is a tool they would like to integrate into their practice or one that they can leave behind. If you have read through a lot of medical literature it can be frustrating to see the amount of treatments that have little to no effect on their own. It can be rare that a significant body of research exists in support of actual positive changes from a specific intervention. So, when something is presented that has clear evidence to support its benefits for patients it is very exciting and should challenge us to integrate it in our practice! I think that exercising under blood flow restriction is likely going to be the most beneficial “new” clinical treatment modality to become widespread in the lifespan of my clinical practice. I say new in quotations because there was experimentation with this starting in the late 1960/early 1970s by Dr. Yoshiaki Sato, but it has taken several years to become more widespread.

The research shows clear physiological improvements from exercises at 15-30% 1 RM under blood flow restriction. These improvements include: increase in aerobic capacity and VO2 max, higher level motor unit recruitment, increase in strength and force development, increase in hypertrophy, decrease in myostatin, increase in growth hormone as well as other benefits.  There are varying protocols, but generally, exercising with blood flow restricted should occur at least 2x/week for several weeks. There is also an importance placed on dosage. High repetitions to failure should be used with short rest periods in between sets. I usually use the 4 set scheme of 30 reps followed by 3 sets of 15. If the patient can reach these reps without failure the load should be increased.

When I first was trained in Blood Flow Restriction therapy it was not very widespread in Michigan. I traveled out to Colorado to train under Owen’s Recovery Science who uses the Delfi unit (the most expensive- but very high quality - option I am aware of for blood flow restriction therapy). In the last few years I have seen several companies begin to offer training courses (including on-line options) as well as growth in the actual tourniquet options.   More and more clinics are utilizing blood flow restriction now as well.

Each cuff or tourniquet is not created equal. As a medical professional I think that being objective in the pressure we are using is of utmost importance. Our commitment to safety limits the field of options in some sense as to which device you should use to occlude blood flow. I think it is important that no matter what cuff you are using you first find the limb occlusion pressure so that the prescription for exercise is personalized, specific, safe, and at a level that allows the gains mentioned earlier. There are machines that will calculate the limb occlusion pressure for you. Some of these are Smart Cuffs 3.0 and 4.0, the Delfi unit, and AirBands.  When automatic calculation is not an option, you can use a Doppler at the distal limb while inflating a cuff to find the limb occlusion pressure. The limb occlusion pressure is the starting point to determine the level of occlusion used while performing exercise. Wider cuffs require less pressure so they tend to be more comfortable. I also like a cuff that inflates evenly throughout. There are some cuffs that only inflate a portion of the cuff or have pockets of inflation. The Delfi unit probably has the most comfortable cuff on the market, but if you do not want to spend that much money, there are also other good options like Smart Cuffs. There are some machines that also auto regulate during an exercise to maintain a pressure close to the set pressure. Muscle contraction places more pressure against the cuff so the auto regulate mode tries to accommodate for this, which can make it more comfortable. The Delfi unit and Smart Cuffs 3.0 both have this option. There are models that have the pump built into the cuff for wireless use as well (AirBands and Smart cuffs 4.0).

The population I primarily work with are athletes, including several post-op diagnoses. There are specific benefits to lifting heavy, however, when an athlete is physically not able to do that safely, blood flow restriction therapy is a great option. The cuff restricts blood flow at a certain percentage and in this oxygen depleted environment the body switches over to Type II muscle fiber work, lactate builds up in the muscles and growth hormone production increases which are likely part of the mechanism leading to muscle hypertrophy and strength gains. The athletic population is not the only population that will see benefit from blood flow restriction therapy. The older or aging population can see great benefits from exercising under blood flow restriction as well. However, extra care needs to be taken with precautions/contraindications in this population. Research has shown that a walking program combined with blood flow restriction can increase strength and function as tested in the Timed up and Go.

There are some people who just do not tolerate the pressure well, but for the most part patients tolerate this okay. It is not a comfortable experience though! It is good to remind patients that it is normal to see the leg turning purple and feeling very tired. Warning signs would be nerve pain under the cuff or distal to the cuff as we want to make sure we are not causing damage to any nerves.

Ultimately, if you work with the orthopedic population I think this is an important tool to have in your tool bag. The amount of positive research should make this not a question of if you integrate it into your practice but how and when and what equipment, always first taking into account your patient’s safety.

Dr. VanZegeren is the Director of the Sports Academy at The Center for Physical Rehabilitation in Grand Rapids. She was certified in Blood Flow Restriction Therapy through Owens Recovery Science and has been using BFR since 2018. Rebekah earned her Doctorate in Physical Therapy from GVSU. She has participated as a volunteer medical provider at the Olympic Training Center in Colorado Springs as well as with the AVP.



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