Is Blood Flow Restriction Training for Real or Just Another Fitness Fad?
For almost 20 years I have been helping people overcome pain with manual therapy and using exercise to help them improve functional capacity. I have found it very easy to perform manipulation, tooling, needling, taping (among other modalities) to help alleviate pain. But as a clinician I have the responsibility to include active therapy (exercise) whenever possible. My belief is manual therapy is the bridge to help people be more active and exercise more. The difficult part for me has been the exercise prescription component. Even as a strength and conditioning coach and athletic trainer, I had difficulty knowing ‘how much’ and ‘how often’ to get tissue adaptation (stronger and/or bigger) yet not aggravate the injured tissue.
In about 2012 I had an epiphany, what I was calling ‘strengthening’ really wasn’t. Body weight exercises, small dumbbells and resistance tubing was not enough load to cause strength and size changes.
The American College of Sports Medicine (ACSM) has stated muscular strength and hypertrophy can be achieved through moderate to high intensities of resistance exercise that utilize 8-10 upper and lower body exercises. These exercises should target major muscle group’s 2-3 times per week at a training intensity of more than 65% of the subject’s one-repetition maximum (Donnelly 2009). I definitely wasn’t getting this type of load with the light resistance I was using.
The problem is many people (injured, elderly, compromised) can’t tolerate these high loads due to pain, low tissue capacity, weight-bearing or load precautions. Some people can’t tolerate the effort and fatigue associated with moderate to high exercise intensities. Sadly, true strength and hypertrophy training had to wait until the tissue could tolerate higher weights or in most cases never happened.
Previous injury is a major risk factor for future injury and never getting one’s capacity back to pre—injury status is a huge component.
I also thought, how long does it really take for true strength and hypertrophy changes take to occur? Literature suggests consistent training at high loads for 12-16 weeks is what it takes for the body to adapt and get bigger and stronger (Garber 2011, Patrella 2008).
Being a cash based practice, I usually wouldn’t have someone with me that long. For those that are not cashed based, most insurance companies in the US will not pay for someone to go thru pain reduction (1-4 weeks) then 16 weeks of progressive resistance training. My best option was to refer my patients out once they had pain reduction and full range of motion to a gym or CrossFit box and attempt co-management with their coach and hope they didn’t reinjure themselves.
In about 2014 my own original research on lumbar multifidus morphology and function demonstrated increased size and strength doesn’t always matter. Sometimes motor control is the bigger issue. With all this conflict regarding true strength and hypertrophy circling in my head, I decided to change the focus of my exercise prescription and become a corrective exercise ninja.
Corrective exercise was great! I could help people improve mobility and learned how to do magic tricks like getting people to touch their toes who hadn’t in years!!
All valuable techniques but my inner strength coach wanted to increase the patient’s capacity to tolerate the demands they were placing on their body.
If I could increase the patients’ capacity, they could continue to do the activities they love to do. If I couldn’t, then the demands were higher than capacity and injuries would continue.
“Avoiding injury is simple…keep your functional capacity above the demands you ask of your body”
Many people stop running, lifting or CrossFitting because they keep injuring themselves. What if we thought of increasing capacity instead? People could stay active and healthy and do what they want to do.
In 2013 my friend, Skylar Richards of FC Dallas told me to check out Blood Flow Restriction Training (BFRT). Not knowing a thing about it, I did what all nerds do…went to PubMed. I was overwhelmed with the amount of literature available supporting the safety and efficacy of BFRT. I wanted to read as much as I could to understand the mechanisms, indications and most importantly, the contraindications to using a modality that tricks the brain and body into thinking one is performing high intensity exercise (65-90% 1RM) yet only using low intensity loads (20-35% 1RM).
I quickly went to the internet and tried to find the best product to purchase and started using the technology on myself. I loved the affect but found there wasn’t any resources to help me integrate BFR into my practice. My mission over the last three years has become to educate others on the safety, efficacy and evidence based protocols to use blood flow restriction training in a safe and effective way.
BFRT is the brief and intermittent occlusion of arterial and venous blood flow using a tourniquet while at rest or exercising. Using this technique, you can exercise using low loads (20-30% 1RM) and still achieve significant gains in muscle size and strength (Slysz 2011). In addition, instead of these changes taking up to 16 weeks, literature suggests changes start in as little as 2 weeks while only having to train 2-3 times per week (Slysz 2011).
This scenario is perfect for the rehabilitation setting where we normally need a couple of weeks to get pain levels down using manual therapy and modalities, then we can start implementing strengthening programs to improve capacity of the injured tissue and the person as a whole.
BFRT for Strength & Hypertrophy
We once thought for muscle hypertrophy to occur we needed to induce enough mechanical stimulus to cause muscle damage. The body would then respond by healing the tissue causing adaptation over time. If we provided enough stimuli in a frequent enough manner for a long enough duration, strength and hypertrophy would occur.
Mechanical stimuli is the external load placed on the tissue: what we now know (thanks to BFR studies) is adaption is more complicated than just damaging and repairing tissue. We now know muscle hypertrophy can also be attained if working at lower loads (30-50% of 1RM) until failure. Working until failure also causes damage to the tissue and requires repair. Working at high intensities or working low loads to failure is not an option for those that have tissue injuries. So what else can we do to stimulate strength and growth changes?
Placing a tourniquet on a limb and occluding a percentage of arterial inflow and venous outflow induces a metabolic stress. Performing BFRT creates a hypoxic environment in the limb due to decreased oxygen supply (less arterial flow equals less oxygen). Since the resistance is low and we do not perform the exercises to failure, no muscle damage occurs. The brain thinks it is performing high intensity exercise because why else would their be a hypoxic environment, so the brain responds with the natural repair response.
Natural repair responses include stimulation of growth hormone, insulin growth factor, protein synthesis, and myosatellite (stem) cells. The body is able to make new tissue without having to repair any damage. The result is faster strength and size gains with low load.
BFRT can be used with the same protocols that one is currently using in a rehabilitation setting. Light resistance but simply adding a medical grade tourniquet. Techniques can be used pre-surgically to prepare for a limb for surgery, immediately after surgery or an injury, during the normal phases of rehab, and even in performance and recovery.
There is evidence to support that performing BFRT with low-load resistance training (20-50% 1RM) can lead to gains in muscle size and strength (Slyz 2016, Ozaki 2011). Evidence also suggests BFRT can improve bone health (Hughes 2017), improve cardiovascular health including VO2 max, and can even improve muscle activation, perfusion, and endurance following surgeries such as ACL reconstruction (Zargi 2018).
Is BFRT Safe?
Most of the early research in BFRT was focused on safety due to the concerns of potential blood clots, muscle damage, cardiovascular stress, and tourniquet risk.
There are ways to reduce the risk associated with using BFRT: those ways would include properly screening the patients for pre-existing risks, using a tourniquet that is wide ( > 5cm), using individual limb occlusion pressures, keeping tourniquet inflation less than 20 minutes, and not taking the exercise to failure.
Most people I work with are most concerned about thromboembolism but with proper use and screening BFRT poses little risk (Clark 2010).
As a rule of thumb, if the person is cleared for high intensity exercise, are older than 15 and not pregnant, they can perform BFRT.
BFRT is a technique that is quickly gaining popularity in the rehabilitation and sports performance world. Improving patient and client outcomes in a safe and effective manner should be the paramount of all rehabilitation and sports performance environments.
In my opinion, BFRT should be in every rehabilitation center and sports performance facility. I will continue my quest to help people learn and understand this modality in a safe and effective way. Ultimately the more professionals who learn how to implement BFRT, the more individuals will be able to be healthy and active.
Ed Le Cara is a full time clinician at his multi-disciplinary clinic, Body Lounge Park Cities in Dallas (TX) where he uses manual therapy and BFR with most patients. In addition, he teaches others how to improve their evidence based patient treatment with an emphasis on progressive resistance exercise. To learn more about Ed, please follow him on his social channels: Instagram (edlecara), Twitter (edlecara), Facebook (Ed Le Cara, PhD); or go to his website, www.edlecara.com where he offers an online BFR course and certification and evidence based cuffs or you can contact him to teach a course at your facility.
Donnelly JE, Blair SN, Jakicic JM, Manore MM, Rankin JW, Smith BK; American College of Sports Medicine. American College of Sports Medicine Position Stand. Appropriate physical activity intervention strategies for weight loss and prevention of weight regain for adults. Med Sci Sports Exerc. 2009;41:459-471.
Slysz J, Stultz J, Burr JF. The efficacy of blood flow restricted exercise: a systematic review and meta-analysis. J Sci Med Sport. 2016;19(8):669–75. doi: 10.1016/j.jsams.2015.09.005.
Ozaki H, Loenneke JP, Buckner SL, et al. Muscle growth across a variety of exercise modalities and intensities: contributions of mechanical and metabolic stimuli. Med Hypotheses. 2016;88:22–6.
Garber CE, et al. American College of Sports Medicine position stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise. Med Sci Sports Exerc.2011 Jul;43(7):1334-59. doi: 10.1249/MSS.0b013e318213fefb.
Hughes L, Paton B, Rosenblatt B, et al. Blood flow restriction training in clinical musculoskeletal rehabilitation: a systematic review and meta-analysis. Br J Sports Med 2017:bjsports-2016-097071
Ozaki H, Sakamaki M, Yasuda T, et al. Increases in thigh muscle volume and strength by walk training with leg blood flow reduction in older participants. J Gerontol 56 2011b;66:275–263.
Žargi T,Drobnič M, Stražar K, Kacin A.Short-Term Preconditioning With Blood Flow Restricted Exercise Preserves Quadriceps Muscle Endurance in Patients After Anterior Cruciate Ligament Reconstruction. Front Physiol. 2018 Aug 24;9:1150. doi: 10.3389/fphys.2018.01150
Bond CW, Hackney KJ, Brown SL, Noonan BC. Blood Flow Restriction Resistance Exercise as a Rehabilitation Modality Following Orthopaedic Surgery: A Review of Venous Thromboembolism Risk. J Orthop Sports Phys Ther.2019 Jan;49(1):17-27. doi: 10.2519/jospt.2019.8375
Clark BC, Manini TM, Hoffman RL, Williams PS, Guiler MK, Knutson MJ, McGlynn ML, Kushnick MR (2010) Relative safety of 4 weeks of blood flow-restricted resistance exercise in young, healthy adults. Scand J Med Sci Sports. doi: 10.1111/j.1600-0838.2010.01100
Petrella JK, Kim JS, Mayhew DL, Cross JM & Bamman MM (2008). Potent myofiber hypertrophy during resistance training in humans is associated with satellite cell-mediated myonuclear addition: a cluster analysis. J Appl Physiol 104, 1736–1742.
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