Blood Flow Restriction Training
Blood Flow Restriction Training, commonly referred to as BFR training or BFR (may also be called occlusion training or Kaatsu training), involves the application of a specialized tourniquet cuff to the proximal portion of an exercising arm or leg to reduce arterial inflow and restrict venous outflow into the limb. Exercising in this manner allows the use of low intensity exercise to elicit positive adaptations in muscle size, strength, or endurance typically associated with much heavier loads or higher intensities. The pressure applied with BFR should be personalized to the individual’s Limb Occlusion Pressure or LOP (You’ll see us refer to this as Personalized Blood Flow Restriction or PBFR). A range of pressure looks like it can be effective and different pressures may be required for the arm (40-50% of LOP) and for the leg (60-80% of LOP). With BFR, resistance exercise or strength training performed with weight as light as 20-40% of an individual’s 1 repetition maximum can facilitate changes typically seen with lifting heavy weights, while endurance exercise can be prescribed for much shorter than typical durations and intensities less than 50% VO2max.
The application of BFR has great potential to improve exercise prescription in a rehabilitation setting (physical therapy, occupational therapy, athletic training, etc.) since it’s common to see patients that have exercise loading or intensity limitations due to injury, surgery, pain, or deconditioning. There may also be significant benefits in non-clinical populations with implementing BFR as a periodization tool or as a way to increase training frequency.
If you want to dive deeper into the available evidence on BFR, you can find some of the key papers on our Publications Page. You can also see a little more of our personal take on some of the BFR evidence or sub-topics by checking out our Blogs and Podcasts.
What are the best practices for applying Blood Flow Restriction?
“In many respects, the permutations of intensity and duration of exercise and the application of BFR are endless.” (Ferguson et al., 2021)
Based on the effects of blood flow restriction it's easy to see BFR as the magic bullet that makes all exercise effective, but you still have to hit a lot of the same targets or manage a lot of the same variables as exercise without blood flow restriction. Some of the variables that can and should be accounted for when prescribing Blood Flow Restricted exercise:
- Restriction Pressure: Percentage of Limb Occlusion Pressure (LOP = the minimum pressure needed to stop arterial blood flow in a limb)
- Pressure Application: Continuous or Intermittent (amount of blood flow to restrict)
- Rep / set scheme
- Load progression / regression
It’s important to keep in mind that while BFR is great for reducing the load needed to achieve fatigue and stimulate an anabolic effect, one must still achieve a session volume (weight x total reps performed) similar to that of heavy load training. And while the ability to lift light has inherent appeal, there is likely a floor beyond which you cannot continue to reduce load and expect equivalent outcomes.
Very low loads can be effectively used to improve tolerance and slow down the loss of muscle during the very acute phases of rehab (check out our blog on Anabolic Resistance or our podcast on preventing muscle atrophy for more on this). However, to achieve similar results to high load resistance training while using BFR, it looks like we need a training load of 20% 1RM or above and to use a relatively high pressure (60-80% LOP in the lower extremity or 50% LOP in the upper extremity) when at that 20% intensity. As the loading increases, the cuff pressure can likely come down. The individual’s strength should continuously be monitored and the training loads adjusted/progressed to reflect their change in strength. This can be accomplished by formally determining an individual’s maximal strength or multi-repetition max every 4 weeks and progressing their working weight after the individual is able to complete the prescribed sets and reps. If we can account for these within session targets of effort, load, and BFR cuff pressure, then we should see consistent effects from our use of BFR.
What patient populations can benefit from doing Blood Flow Restriction Training?
Almost any patient that is cleared to participate in exercise but can’t perform exercise at a high enough intensity to cause adaptation could benefit from Blood Flow Restriction Training.
- BFR After Anterior Cruciate Ligament Reconstruction
- Managing Muscle Strains: Get a deeper understanding of the balance between fibrosis and repair after a muscle injury and some of the potential benefits of blood flow restriction or hypoxia on muscle.
- BFR for the Older Individual: Low-intensity resistance exercise with blood flow restriction may add significant value for an older population that struggles to maintain muscle mass and for whom low load resistance training may not be enough.
- BFR and Pain: Low-load resistance training with blood flow restriction and low-intensity cycle training with restricted blood flow have the potential to cause an analgesic effect. This may be one of the more valuable clinical tools to manipulate.
Nothing about BFR is diagnosis specific and its application could be as variable as traditional exercise. It can be used as a strategy to make available exercises stressful enough to induce an adaptive response.
Is BFR Safe?
BFR has consistently demonstrated to be a safe modality in the literature. It has been performed on thousands of subjects in the peer-reviewed literature with little to no side effects.
One of the most common questions we get is, “Will BFR increase the likelihood of having blood clots or cause a DVT?”
Resistance exercise combined with blood-flow restriction and the application of passive BFR has never been shown to increase any variables involved in clot formation. Some additional information on the variables influencing clot formation (Virchow’s Triad) and our current understanding of what happens when we occlude or restrict blood flow can be found in our blogs on BFR and VTE and BFR and Thrombophilia. We also had the folks that wrote the guidelines for clinical practice on VTE on our podcast if you really want the deep dive on DVT and VTE.
Another common question is, “What are the effects of blood flow restricted exercise on blood pressure and heart rate?”
One of the known and consistent effects of blood flow restricted exercise is an increase in hemodynamics (blood pressure and heart rate). The amount of change appears to be relative to the amount of mechanical compression of the vasculature (number of limbs being restricted and the amount or percentage of restriction pressure), the exercise intensity, and the duration under occlusion or restriction. For patients who have hypertension or other cardiovascular concerns, we recommend you explore exercise without BFR first to understand their tolerance and establish a baseline. If you decide to incorporate BFR, you may limit some of the hemodynamic response by training at a lower intensity, using a lower percentage of occlusion, or utilizing intermittent blood flow restriction. More details can be found in our blog on hemodynamics or in our podcast with Jamie Burr, PhD.
If you want even more information, you can read some of the safety studies and review papers on our Publications Page.
Can Blood Flow Restriction enhance athletic performance?
This has become a hot topic of discussion within blood flow restriction and ischemic preconditioning (IPC)/passive BFR. Here are a few ways that the available research suggests BFR might improve performance or at least be useful as part of a training program:
- Periodization of Exercise
- A few research studies have performed alternating weeks of heavy load and low load exercise with blood flow restriction. The results have been similar at the end of the training program, suggesting that BFR may provide an opportunity to load heavy less often while still getting the same effect.
- Addition of Exercise Volume
- Low-load blood flow restriction might also be a way to add a little more training volume to the end of a high intensity or heavy load training session. This might be a strategy to get past a plateau in training.
- Ischemic Preconditioning for Performance
- IPC or passive BFR has been shown in some instances to improve performance, especially in endurance based tasks. The most common improvement has been increased time to exhaustion.
- Ischemic Preconditioning for Recovery
- IPC or passive BFR has also been shown to improve some metrics of recovery, mainly decreasing delayed onset muscle soreness (DOMS) and reducing time needed to recover baseline strength. IPC in most of the examples in research is a post conditioning as opposed to preconditioning application.
Is BFR within my scope of practice as a Physical Therapist or Athletic Trainer?
Physical therapists have an existing firm foundation in anatomy, physiology, therapeutic exercise, and the cardiorespiratory system, as well as clinical reasoning, which are the components of the safe application of blood flow restriction training.
Physical therapist education provides PTs with the requisite knowledge (muscular and vascular anatomy, and physiology and exercise physiology), as well as skills (therapeutic exercise prescription, monitoring of physiological vital signs and blood flow) to perform and monitor this type of therapeutic exercise. BFRT is part of the professional scope of practice for physical therapists.
Link to APTA: What to Know About Blood Flow Restriction Training
Similarly, the Board of Certification put out some information through an Approved Provider update on whether Athletic Trainers are appropriate to perform BFR. “ATs are healthcare professionals and fall under the scope of clinicians qualified to learn and perform BFR.” They also went on to say “Advanced continuing education through the Board of Certification is currently utilized to ensure ATs are taught the efficacy and safety of BFR and proper medical tourniquet applications.”
Is Education required prior to using BFR in a clinic setting?
There are no strict requirements around education prior to prescribing BFR in a clinical setting. Since BFR fits within the scope of practice of PTs and ATs, it's up to the clinician to decide whether they're competent in implementing BFR. The additional guidance from APTA is that "each PT should consider his or her personal scope of practice before engaging in BFRT."
If you’d like to attend a course to enhance your understanding of BFR and how to apply it, you can find a list of our available Personalized BFR courses on the course page.
Why choose Delfi when there are cheaper options?
We commonly get asked about how the Delfi device compares to others in the market.
Delfi has a proven track record of medical device manufacturing over the last 30 years making industry-standard surgical grade tourniquets.
Delfi has a proven track record of innovation and quality in the area of tourniquet design and manufacturing.
Delfi revolutionized tourniquet systems in 1980 with the invention of the microprocessor.
The Delfi microprocessor is credited with markedly reducing the incidence of nerve injury from surgical tourniquet application.
The Delfi PTS possesses patented limb occlusion pressure (LOP) detection technology.
The accuracy of Delfi's LOP technology has been researched and validated against a trained doppler ultrasound technician. (https://link.springer.com/article/10.1007%2Fs40846-016-0173-5)
The Delfi system has research validation demonstrating it applies consistent pressure throughout the exercise (https://onlinelibrary.wiley.com/doi/10.1111/sms.13092).
The Delfi PTS for BFR is the most objective and safe way to perform and personalize BFR. Ultimately it is the responsibility of the clinician to decide what device to use for BFR. We prefer the objectivity of the Delfi device as it ensures a uniform application regardless of individual patient characteristics. Additionally, this objectivity allows a clinician to substantiate their choice in a BFR device.
The Delfi PTS for BFR is the trusted BFR system used by the Department of Defense, the largest healthcare systems, US Olympic teams and professional and collegiate sports. In fact, the Delfi PTS for BFR is the only BFR device available on professional sports workers compensation in every league.
If you’d like to calculate the number of patient visits needed to pay off a device or the ROI on a device, you can visit the ROI calculator page on our website.
For more information on Delfi and the Delfi PTS, including certificates of use, visit: http://www.delfimedical.com/personalized-bfr/
If you’re looking for more information on choosing an appropriate cuff or making a decision on the best tool to restrict blood flow, we have a blog that goes into the variables you may want to consider.
Who can purchase a Delfi PTS for BFR System from you?
At this time, only licensed medical healthcare providers that have completed an Owens Recovery Science, INC PBFR certification training may purchase a Delfi PTS for PBFR system.
This includes the following providers: Medical Doctors, Physical Therapists, Athletic Trainers, Chiropractors and Occupational Therapists.
If you’ve already gone through our course and would like to purchase Delfi, follow this link to our Purchase Page!