(Guest Post by Daniel E. Newmire, Ph.D. Candidate, CSCS, CISSN)

Blood Flow Resistance Training Blood flow resistance training (BFR), known as occlusion training by some; however originally named KAATSU. KAATSU was founded, assessed, and generalized to public in 70’s- 80’s by Yoshiaki Sato of Japan and later brought to the US (11). BFR, for the most part, has been readily utilized in conjunction with resistance exercise or training (RET) for numerous populations for the promotion of skeletal muscle mass and strength. BFR is employed byusing flexible pressurized cuffs that are bilaterally placed proximal to elbow (below your shoulders) or knee flexors/extensors (below your hips) to mechanically compress and restrict blood flow to and more so, venous release in the exercised muscle group during resistance training (RET). This protocol results in pooling of blood, cell swelling, mechanical stimulation (commonly associated with RET), accumulation of metabolites (lactic acid, NO2, etc.) that may increase and promote muscle growth (10).

Figure 1: A prominent authority in BFR; Dr. Jeremy Loenneke’s research has highlighted many of the benefits and limitations of this protocol for use in differing populations.

Figure 1: A prominent authority in BFR; Dr. Jeremy Loenneke’s research has highlighted many of the benefits and limitations of this protocol for use in differing populations.

Additionally, the BFR protocol may influence the actions of muscle satellite cells by increasing their number that result in nucleus additions in the exercised muscle fibers that regulate muscle protein synthesis (MPS). Lastly, BFR has also shown decrease myostatin (MSTN) gene expression similar to normal higher intensity RET (5, 9). Within the last several years BFR has gained much traction and popularity in the fitness and gym industry as well as some success in the rehabilitation and aging population settings and lastly has also leaked into the athletic performance market as a technique as an additive exercise protocol. However, with the popularity of a newer additive training protocol should come the knowledge of the benefits and limitations of its usage which originates from those who continue to assess its effect on different outcomes. Some fitness “enthusiasts” via coaches, gym members, personal trainers, and competitors who may or may not be a qualified authority or without the proper background of BFR training; either promote or discount the usage without detailed and credible information to give to interested persons to make a choice of adding to their training regiment.

Practical Blood Flow Restriction Usage in Gym Settings During resistance exercise, neuronal motor units and therefore its interconnected muscle fibers are recruited in a sequential manner known as the ‘size principle.’ Smaller motor units stimulate type I fiber is recruited

Figure 2: Human muscle fibers and the spectrum actions and metabolism (3)

(Figure 2: slow, smaller, slow twitch, endurance related) first followed by larger motor units of type IIa, typeIIax, and type IIx (Figure 2: fast, larger, more anaerobic, more force, power related). Higher intensity exercise or activity will recruit larger motor neurons and larger, quicker fiber types. Type II fibers have the greatest capacity for growth and therefore should be targeted. Generically, for muscle hypertrophy, it is prescribed that one should train at an intensity of >67% of 1RM, for 7-13 repetitions (1). However, it has been observed that in conjunction with BFR, low-load intensities of 30-50% of 1RM are used with increases in muscle hypertrophy. So simplicity, if one bicep barbell curls 100lbs for 1 repetition with both arms; with BFR only 30-50lbs would be required to see muscle gains. A typical BFR protocol is 30 repetitions followed by 3 sets x 15 repetitions with 30–60 s of rest between each set. If that goal amount of repetitions is not being reached at the prescribed load set to 20–30% of their 1RM, then more than likely the wraps have been applied too tight (6).

In respect to BFR implementation, it is typically achieved by slightly restricting blood flow to the working muscle, though more so congesting blood in the muscle and surrounding tissues with the application of external pressure via a tourniquet, lab-based pressurized cuff, or elastic banding predominantly used for knee and elbow stability. Being that most gym patrons do not carry a blood pressure cuff nor an automated version in their gym bag to measure specific pressure applications to follow appropriate guidelines of BFR, the question is how do I know how much pressure to apply with my knee wraps? Optimal pressure application is shown to be effective at low as 50 mmHg and up to 100 mmHg because it is a sufficient constriction to restrict venous blood flow, which causes pooling of blood in the local venous system and a possible congestion in the capillary beds. Typically, >75% of the blood volume resides in the veins; they are the known as the major capacitance vessels. “Venous capacitance is defined as the relative amount of blood volume that can be held in the peripheral veins at a given point in time” (4, 7). An average, healthy human blood pressure is ~120/80 mmHg.

Figure 3: Dr. Jeremy Loenneke showing a knee extension resistance exercise with practical application of knee wraps for BFR training (7).

If the applied BFR constriction is set to greater or equal to the systolic pressure of 120 mmHg, arterial blood flow into musculature will be severely restricted or seized and create a possible hypoxic environment and in turn, defeat the purpose of BFR (flow in is > flow out of musculature/surrounding tissues). The wraps need to be applied tight enough (pre-exercise) to cause a “visual fluid shift”. Equating to a visually assessed “muscle swelling” you may similarly see immediately post-exercise with or without BFR. As stated before; the wraps should not be so tight that arterial flow is restricted entirely (6).

Limitations of Blood Flow Restriction Protocol

It is important to understand the benefits and limitations of training styles and how they may be incorporated into a person’s training regiment, while also understanding it may not serve any greater purpose when compared to traditional training methods. BFR has been observed in numerous populations and conditions such as: elderly, rehabilitation from injury, as well as patients with cardiovascular disease (CVD) and diagnosed with idiopathic inflammatory myopathy, and lastly it has been used in highly trained athletes during injury rehabilitation and additive to normal training protocol (6, 8, 12). While there may be a greater concern for those who have been diagnosed with CVD or an injury; in general, for athletes or gym patrons the concern becomes what is optimal for muscle size and strength gains. It has been shown that BFR does indeed influence an increase in muscle crosssectional area (CSA) and appropriate strength gains; however, for athletes, BFR should be used as “supplementary protocol” in addition to their current primary training cycle. Lowload BFR exercise does not provide the same neural stimulus compared to traditional highload resistance exercise. In athletes with extensive strength training experience and backgrounds; optimal muscular adaptations may require traditional high-load RET as a primary regiment with additive low-load BFR training (12). Lastly, there is newer conflicting evidence that observed low-load RET to failure (20-50% 1RM) has shown similar vascular adaptations, satellite cell proliferation, muscle size and strength gains when compared to BFR (2, 9, 13, 14). Leading to question if BFR or occlusion training is the stimulus to drive greater adaptations to RET or is it low-load RET to failure?


1. Baechle TR, Earle RW. Essentials of strength training and conditioning. Human kinetics; 2008.

2. Fahs CA, Rossow LM, Thiebaud RS et al. Vascular adaptations to low-load resistance training with and without blood flow restriction. European journal of applied physiology. 2014;114(4):715-24.

3. Gundersen K. Excitation-transcription coupling in skeletal muscle: the molecular pathways of exercise. Biological Reviews. 2011;86(3):564-600.

4. Krishnan US, Taneja I, Gewitz M, Young R, Stewart J. Peripheral vascular adaptation and orthostatic tolerance in Fontan physiology. Circulation. 2009;120(18):1775-83.

5. Laurentino GC, Ugrinowitsch C, Roschel H et al. Strength training with blood flow restriction diminishes myostatin gene expression. Med Sci Sports Exerc. 2012;44(3):406-12.


7. Loenneke JP, Pujol TJ. The use of occlusion training to produce muscle hypertrophy. Strength & Conditioning Journal. 2009;31(3):77-84.

8. Madarame H, Kurano M, Fukumura K, Fukuda T, Nakajima T. Haemostatic and inflammatory responses to blood flow-restricted exercise in patients with ischaemic heart disease: a pilot study. Clinical physiology and functional imaging. 2013;33(1):11-7.

9. Nielsen JL, Aagaard P, Bech RD et al. Proliferation of myogenic stem cells in human skeletal muscle in response to low-load resistance training with blood flow restriction. The Journal of physiology. 2012;590(17):4351-61.

10. Pearson SJ, Hussain SR. A review on the mechanisms of blood-flow restriction resistance training-induced muscle hypertrophy. Sports Med. 2015;45(2):187-200.

11. Sato Y. The history and future of KAATSU training. International Journal of KAATSU Training Research. 2005;1(1):1-5.

12. Scott BR, Loenneke JP, Slattery KM, Dascombe BJ. Blood flow restricted exercise for athletes: A review of available evidence. Journal of Science and Medicine in Sport. 2015.

13. Wernbom M, Apro W, Paulsen G, Nilsen TS, Blomstrand E, Raastad T. Acute low-load resistance exercise with and without blood flow restriction increased protein signalling and number of satellite cells in human skeletal muscle. European journal of applied physiology. 2013;113(12):2953-65.

14. Yasuda T, Fukumura K, Iida H, Nakajima T. Effect of low-load resistance exercise with and without blood flow restriction to volitional fatigue on muscle swelling. European journal of applied physiology. 2015;115(5):919-26.

Request more information

Request Information Now!