Blood Flow Restriction Training (BFRT) provides a myriad of benefits for my strength and conditioning program athletes. I use BFRT during the progress of an athlete’s strength/body-building program in order to reduce load, thus allowing me to train them more effectively on a consistent basis. Without the aid of a BFRT program, training an athlete 4-5 days per week, with 2 days of rest, would risk overtraining as well as cause unnecessary muscle damage, leading to setbacks. BFRT allows for improvements in muscle strength, size and functional aerobic capacity in shorter amounts of time with less stress on the body than typical training .
BFRT is done by securing cuffs – similar to tourniquets – around the top portion of one’s upper or lower limbs. The cuffs restrict venous blood flow from the veins of the working muscles to the heart, and limits the amount of arterial blood flow to the limbs from the arteries, creating a cell-swelling effect of the muscle, or “pump” . The increased duration of low O2 results in an increase in muscle excitability, leading to fatigue. Fatigue then directly forces our nervous system to recruit the largest fast-twitch fibers available, which have the greatest capacity to grow [1, Page 44]. Once exercise is performed, the muscle begins to fatigue, then metabolites, such as lactate are released directly stimulating muscle growth and increased myosatellite cell proliferation . These satellite cells are typically only present during moderate to high rates of muscle damage associated with high intensity exercise. This is important because moderate to high rates of muscle damage does not occur with BFRT [1, Page 44].
With BFRT, there is a drop in blood flow due to venous occlusion. The reduction in blood flow results in a drop in stroke volume (SV). This drop in SV will lead to a rise in heart rate (HR) so as to maintain the amount of blood flow required in order to continue exercise. HR increase occurs autonomically in order to maintain cardiac output during exercise. As such, a two week on-ramp program is warranted before any exercise is performed [1, Page 51].
The first eight sessions, including the on-ramp program, are dedicated to discovering an athlete’s upper and lower body limb occlusion pressure (LOP) – or the minimum amount of pressure needed to stop blood flow. Once the athlete’s upper and lower LOPs are found, the measurements can then be considered as the athlete’s upper or lower body maximum pressure limit or baseline – which is similar to understanding an athlete’s 1RM (one-rep max). For example, during a BFRT strength training program, if we wanted to train an athlete with cuffs on their arms for x number of minutes, we would inflate the cuffs to 50% of their LOP, then begin low-intensity resistance training (i.e., LOP = 180mmHg, 50% LOP = 90mmHg).
Finding an athlete’s LOP takes roughly 5 minutes for each measurement, and the athlete should spend an additional 8-10 minutes becoming acclimated to wearing cuffs while lying down passively first, then by walking around. Immediately after discovering their LOP, have them lie down passively for 5 minutes, then begin walking around free-flow for an additional 3 minutes before taking the cuffs off [1, Page 57].
According to the BFRT Handbook, when beginning BFRT, cuff occlusion should be set independently for the arms and legs. Upper body occlusion should be set between 40-50% of the athlete’s LOP; the lower body should be set between 60-80% LOP. The athlete is to complete a standard workout of 4 sets of 30, 15, 15, 15 repetitions, while resting 30 seconds in between sets, and 5 minutes with the cuffs on afterward. If working with an athlete recovering from an injury or returning to exercise from a sedentary lifestyle, the program is scaled down to 4 sets of 20, 12, 12, 12 repetitions [1, Page 58]. The workout should last around 8 minutes, about 15-20 minutes in total, with respect to application time, taken to failure. Meanwhile, after the beginning of our session with BFRT, regular programming resumes with heavy-resistance training, and weight-lifting, meanwhile having the athlete finish the last 5 minutes of their training on a stationary bike or rower, wearing BFR cuffs at 20-35% LOP.
Over 800 clinical research studies published within the past 10 years showing evidence of BFRT’s ability to utilize low-intensity resistance at sub-maximal levels, establishing that BFRT effectively tricks the brain and body into thinking one is performing high intensity exercise . The need for practical BFRT use, or wrapping the limbs using ‘perceived pressure’ (such as “voodoo bands” or tourniquets) as a round-about measurement is no longer necessary or ideal, especially when it comes to utilizing both BFRT and high-intensity training (HIT). Notably, HIT and BFRT have similar yield in their persistence to affect the body and create change. To compare, as seen in the Kadi et al study (2004), BFRT training groups saw 30-50% increase in muscle fiber area within the first 4-8 weeks during and post training, while HIT training groups performed near-maximal effort (65%-90% 1RM), and saw 15-20% increase in muscle fiber area following a 12-16 week training period . This shows that hypertrophy gains can be achieved at BFRT’s very low loads of 20-35% of an athlete’s 1RM versus conventional training using heavier loads of 75% or more.
BFRT causes very little to no muscle damage when programmed correctly, utilizing high repetitions (15-30 reps) at sub-maximal low-intensity (20-35% 1RM), and usually taken to failure . One concern with BFRT is if restricting blood flow may increase the risk of blood clots. Multiple studies determined that BFRT does not increase clot risk; in fact, it releases numerous anti-coagulation factors similarly associated with heavy resistance training . The data from these studies suggest that cuff or tourniquet deflation is related to release of these anti-clotting factors, concluding that an acute bout of these types of exercises enhances fibrinolytic potential (anti-clotting factors), without elevating the thrombolytic potential (increasing the risk of blood clots) .
Another consideration is the potential of damage to the heart and blood vessels using BFRT. This is best addressed when comparing the amount of stress on the body from HIT, traditional resistance training, and low-intensity BFRT. While restricting blood flow may cause damage to veins and ultimately impair long-term blood flow, during BFRT exercise, there is increased vasodilation and blood flow over time compared to traditional resistance training (50-65% 1RM) alone . It is clear that HIT exercise results in much greater changes in blood pressure, heart rate, and cardiac output than low-intensity BFRT. MacDougall and his colleagues found that with heavy resistance training (80-100% 1RM), blood pressure had been shown to more than double, in some cases as high as 480/350mmHg during lifting, and 255/190mmHg during bicep curls, causing heart rates to frequently reach maximal levels . Compared to low-intensity BFRT, studies show an increase in blood pressure and heart rate by only 11-13 percent, with limb pressures ranging only between 50-230 mmHg  . A study even found improvements of 14% in capillarity vs no changes in work-matched control groups seen with heavy-resistance training .
An immediate concern for the safety in utilizing BFRT is the placement of the cuffs or tourniquets. As mentioned above, the cuffs should be wrapped around the top portion of one’s limbs, making sure the cuff does not overlap more than an inch. BFRT exercise can lead to numbness and tingling in the wrapped limb if wrapped too tight. However, a study published in the Scandinavian Journal of Medicine & Science in Sports saw no change in nerve conduction velocity (speed of transmission of nerve impulse) following four weeks of BFRT . Therefore, if the cuffs are placed correctly and are not too tight, then it is completely safe and does not cause local nerve compression. It is also important to note that the cuffs used in my programming – Smart Cuffs – are unique in their application when compared to other tourniquets and BFRT devices in that they provide an objective measurement of arterial & venous blood flow occlusion from the working muscle, making it safer to use while progressing with any aged athletes. These cuffs are 1 of the 2 only available FDA listed medical tourniquets on the market that take into account user safety through design and education [1, Page 74].
Given the wide body of research on BFTR, there is ample evidence that a BFRT program can be utilized most efficiently alongside or within most strength/weight-lifting training programs so as to maximize improvements to muscle strength, size, and functional aerobic capacity in shorter amounts of time with less stress on the body than typical training. Ultimately, Blood Flow Restriction Training propels me insurmountably as a health professional. It has allowed me to not only learn in more detail the relationship between our body, cells and how they are related to physical exercise/stress on the body, but as well has helped me evolve and have a greater understanding of the relationship & communication I need to have as a personal trainer with physical therapists and other health professionals also working towards the same goal of helping others.
**If you are interested in trying Blood Flow Restriction Training, or if you are looking to set up a Lean Muscle Mass / Strength Training program using BFR, please contact our Front Desk @ ANY Location!
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