I first discovered Blood Flow Restriction (BFR) Training back in 2013 when I was at University and was researching possible methods to increase the stimulation of Type 2b muscle fibres. However back then I didn’t really know what I was doing and it was very much trial and error and though they have great benefits, which I will discuss in this article, using them alone and without really having a structure I very quickly discarded them and forgot about them until I suffered a very serious knee injury in 2017.
I couldn’t walk and after an MRI scan, I had a bucket handle tear in my meniscus and rather than opt for surgery, I wanted to rehab the injury myself, as research now suggests it’s better in the long run to avoid a meniscectomy as the removal of the cartilage can cause degeneration in the joint and an early onset of osteoarthritis.
In the early stages of the injury I couldn’t bear load but I didn’t want to have to deal with significant muscle wastage so I did bike intervals with BFR bands around my upper thigh. Finally there are three zones to the meniscus, a white zone, with no blood flow, a red white zone with very little blood supply and a red zone which has access to blood, meaning this zone heals the fastest and most efficiently. I have no evidence but my theory was, if I could occlude the blood in my leg, this may influence the repair deeper in the meniscus and I was going to use the BFR bands to maintain as much muscle mass and fitness anyhow.
I believe it worked, the injury to a long time to repair because I kept doing sports that place a lot of stress on the knees but I maintained a decent amount of muscle mass through the first few stages and it was then I started researching the use of Blood Flow Restriction training and began using them with my athletes and that season had some of their best results and the 2 hamstring injuries that came about had a very fast turn around time.
Introduction and History
Blood Flow Restriction training is becoming more and more popular thanks to social media but this method was invented in Japan in 1966 and perfected through the 1970’s by Japanese Professor Dr. Yoshiaki Sato. BFR and the KAATSU method is the result of his life work and has had 100’s of studies published around his method https://www.kaatsu.com/index.cfm?Action=Research.Home
KAATSU is a Japanese word and trademarked term where KA (加) means “additional” and ATSU (圧) means “pressure”and uses the moderation of blood flow in the arms and legs in order to exercise effectively and efficiently. Limb blood flow is restricted via the occlusion cuff throughout the contraction cycle and rest period. This results in partial restriction of arterial inflow to muscle, but, most significantly restricts venous outflow from the muscle.
Dr. Yoshiaki Sato first discovered the idea of blood flow moderation training in a Buddhist ceremony where his legs went numb whilst kneeling on the floor. He could barely stand the pain any longer with his legs bent underneath him. Out of desperation, he began to massage his calves in an attempt to relieve the discomfort during the long ceremony. He realised that his blood circulation was blocked in his calves as he was sitting directly on his feet.
Over the next 7 years he tried and tested various methods and tools to restrict the blood flow to the limbs and by the age of 25, Sato developed the details of Kaatsu as it is currently practiced. At that time, he was a ski trip and fractured his ankle and damaged the ligaments around his knee. The injuries were diagnosed and the doctors told Sato that it would take 6 months to heal. With a plaster cast on, Sato rehabilitated himself with Kaatsu Bands applied to his upper leg.
He repeatedly applied Kaatsu pressure on and off while doing isometric exercises for 30 seconds on and a few seconds off three times per day. The results of his regimen shocked his doctor when his muscles did not atrophy and he fully recovered within 6 weeks.
Physiological Functions & Adaptations
During occlusion training the Type 1 and 2a fibres are starved of oxygen decreasing their work capacity. This increases a neural stimulation to other fibres of the same type that may be inactive and increases motor recruitment. That is to say when we actively contract the muscle we only every activate a percentage of it’s contained fibres. The percentage activated will vary from person to person but will never reach 100% of the muscle without external intervention from devices such as a Compex Muscle Stimulator which uses electrical impulses to stimulate 100% of motor units and in turn muscle fibres. By activating more fibers through occlusion training we are better able to train more of the muscle to the demands of our sports than we would likely be able to through standardized training alone. Once the Type 1 and 2a fibres are depleted and fatigued we recruit Type 2b fibres to continue the exercise in the absence of oxygen.
Muscle contractions under these conditions of restricted and impeded blood flow and congested vascular space, uses up intracellular phosphates energy stores and oxygen at a rate greater than the circulation can replenish them. Metabolic waste products accumulate. Homeostasis in the active muscle is lost. Consequently, as the tissue becomes more hypoxic and energy stores depleted, anaerobic glycolysis attempts to compensate by increasing its rate, which produces some ATP, but also produces a marked disturbance in muscle homeostasis, ultimately raising intracellular, interstitial and blood lactic acid concentrations. Hypoxia, acidosis, lactate ion per se, inorganic phosphate, AMP and many other local factors have been shown to turn on transcription and thus, protein synthesis in muscle cells. This is the so-called “local effect” of KAATSU that results in stimulation of muscle, tendon and vascular growth.
The majority of the exposure around BFR training has been in the ‘fitness’ / bodybuilding world due to it’s ability to increase muscle mass but these benefits can also crossover to the older population.
One study found that Muscle size and arterial stiffness after blood flow-restricted low-intensity resistance training in older adults as significant gains were found in a group of healthy adults 61-84 years old.
Researchers observed an 8% increase in MRI cross-sectional area, a 34% increase in leg press strength (1-RM), an 18% improvement in squat volume exercise, and it has been widely documented that leg and grip strength are great indicators for longevity.
One study from 2000, explored what was happening as a result of KAATSU/ BFR training and found that muscle cross-sectional area and isokinetic strength increased with the experimental group while doing KAATSU and working only with light weights.
But, what really got the attention of researchers was how plasma lactate concentrations were higher in the KAATSU group working with light weights (higher than the KAATSU group working with heavier weights at 80% 1-RM.) Take a look at figure-4 from the study: ‘I would assume this would be due to length of the sets and total time under tension being greater in the lighter load’.
This implies that not only can you increase hormonal responses to metabolic stress with KAATSU, but you may see more of an effect using very light weights versus the heavier weights/resistance. This study really kick-started the global KAATSU movement.
Performance Benefits – Anaerobic Running & 100m Sprint
This study was actually made aware to me by one of old ex athletes (credit to Will Kennedy), we had just been doing a block of high volume BFR step ups in the gym and he had found that these bands could be used for our aerobic tempo sessions, our submaximal conditioning sessions to not only improve the athletes ability to recover between reps and improve contact stiffness but coupled with the BFR bands, we could directly influence 100m sprint times.
Behringer et al. 2016 found that Low-Intensity Sprint Training With Blood Flow Restriction Improves 100-m Dash. The results showed a greater increase of the rectus femoris muscle thickness (a muscle well developed in elite sprinters) and a higher rate of force development and a significant reduction 100m times in the BFR group.
If you’re interested in reading this study in more detail please follow this link. https://pubmed.ncbi.nlm.nih.gov/27941491/
Performance Benefits – Aerobic Running and VO2 Max
As for aerobic running and VO2 Max improvements, which is not my area of expertise, I did come across a study with BFR training VO2 Max and 1.5 mile performance times and I appreciate to many endurance athletes, that isn’t very far.
Interestingly this was measured after participants (well trained males) performed BFR walking and the results showed significant improvements in VO2Max, decreased 1.5mile run times and increases in muscle mass in the thigh.
Having walked up mountains with BFR bands in the past, I can confirm it makes it a lot harder and do believe regular work with the bands could see the benefits for endurance athletes.
You can find the study and abstract below.
In fact research from (Abe et al., 2006) on BFR and (AE) Aerobic Exercise that has shown the training effects to take place within 6 weeks of training and that the intensities used during BFR-AE are generally low in nature (45% heart rate reserve or 40% VO2 max).
Safety and Concerns
Wrapping the limbs and performing exercises can seem alarming to many who haven’t looked into the research and for many years I’ve had to support the safety of using tourniquets for exercise and I appreciate seeing veins bulging from the muscles might looking worrying, however I always evaluate the risk to reward ratio and following KAATSU protocol there is a near perfect safety record in patients that were arguable some of the most vulnerable patients in the hospital.
If you still have any doubts, please see the following 32 studies.
- Kaatsu Training: Application to Metabolic Syndrome
- Effects of Exercise and Anti-Aging
- Effect of KAATSU training on a patient with benign fasciculation syndrome
- A case of dementia presenting remarkable improvement in activities of daily living through KAATSU training
- Effects of low-intensity, elastic band resistance exercise combined with blood flow restriction on muscle activation
- Muscle hypertrophy following blood flow-restricted low force isometric electrical stimulation in rat tibialis anterior: Role for muscle hypoxia
- Hemodynamic and autonomic nervous responses to the restriction of femoral blood flow by KAATSU
- Can KAATSU be used for an orthostatic stress in astronauts?: A case study
- Repetitive Restriction of Muscle Blood Flow Enhances mTOR Signaling Pathways in a Rat Model
- Resistance exercise combined with KAATSU during simulated weightlessness
- Effects of Low-Load, Elastic Band Resistance Training Combined With Blood Flow Restriction on Muscle Size and Arterial Stiffness in Older Adults
- Key considerations when conducting KAATSU training
- Pentraxin3 and high-sensitive C-reactive protein are independent inflammatory markers released during high-intensity exercise
- KAATSU training as a new effective exercise therapy in a case of femoral medial condyle osteonecrosis
- Ischemic Circulatory Physiology, Kaatsu Training
- Use and safety of KAATSU training: Results of a national survey in 2016
- Effects of Low-Intensity KAATSU Resistance Training on Skeletal Muscle Size and Muscle Strength/Endurance Capacity in Patients with Ischemic Heart Diseases
- Low-intensity KAATSU resistance exercises using an elastic band enhance muscle activation in patients with cardiovascular diseases
- Increases in Thigh Muscle Volume and Strength by Walk Training With Leg Blood Flow Reduction in Older Participants
- Effect of knee extension exercise with KAATSU on forehead cutaneous blood flow in healthy young and middle-aged women
- Electromyographic responses of arm and chest muscle during bench press exercise with and without KAATSU
- Effects of KAATSU training on haemostasis in healthy subjects
- Effects of Walking With Blood Flow Restriction on Limb Venous Compliance in Elderly Subjects
- KAATSU training® in a case of patients with periventricular leukomalacia(PVL)
- Hemodynamic responses to simulated weightlessness of 24-h head-down bed rest and KAATSU blood flow restriction
- Effect of Low-Load Resistance Exercise With and Without Blood Flow Restriction to Volitional Fatigue on Muscle Swelling
- Hemodynamic and Hormonal Responses to a Short-Term Low-Intensity Resistance Exercise With the Reduction of Muscle Blood Flow
- Effect of KAATSU training on thigh muscle size and safety for a patient with knee meniscectomy over 3 years
- The effects of low-intensity KAATSU resistance exercise on intracellular neutrophil PTX3 and MPO
- Hemodynamic and neurohumoral responses to the restriction of femoral blood flow by KAATSU in healthy subjects
- Combination of KAATSU training® and BCAA intake for a patient after aortic valve replacement surgery: A case study
- Electromyographic responses of arm and chest muscle during bench press exercise with and without KAATSU
KAATSU training has even been shown to help those suffered with heart attacks and strokes as it can help with high blood pressure and metabolic syndrome. : Kaatsu Application to Metabolic Syndrome.
This is positive, however, evidence from Patterson et al. (2017) suggests that practitioners are unclear on how to use and apply BFR in line with current research informed standards.
Inflatable cuffs are commonly used in studies to precisely control the applied pressure for BFR. However, the high costs and limited accessibility, as in case of the original equipment (KAATSU Master; Sato Sports Plaza Ltd., Tokyo, Japan) , provides a significant access barrier to athletes interested in this type of training. Fortunately, recently published studies reported that elastic knee wraps provide a practical alternative for using BFR outside of laboratory settings and these wraps enable a venous pooling without an arterial occlusion.
With the growth of BFR bands in the Strength & Conditioning industry, it is very easy to find wide BFR tourniquets on Amazon at an affordable price.
When applying the bands, the most common measurement for applying pressure is for the athlete to tighten them to a perceived scale of discomfort of 7/10. 10 being uncomfortable and too tight.
I always follow the method from the studies I am wishing to recreate the desired effects from and for more guidelines on how to use BFR I recommend the KAATSU user manual.
What is recommended :
- KAATSU Clients should never exceed a 15-minute maximum KAATSU session on arms and a 20-minute maximum KAATSU session on legs
- There should never be any occlusion; KAATSU Clients should always have pink or beefy red palms on arms and flushedlegs.
- Do KAATSU 3-4 times per week for Injured Individuals
- Do not lift heavy weights when doing KAATSU (Recommended 30-40% maximum)
- Release the KAATSU Bands if you feel something is not right. If you feel lightheaded or if you have an unusual pain on one side or the other, stop and continue on another day
- Do 3-5 different exercises during KAATSU Training (e.g., hand grips, arm curls, tricep extensions). Each exercise should comprise 3 sets of 20-30 repetitions (or until you reach failure), with 20 seconds rest between sets.
If you follow these guidelines and match your training to the methods in the study you wish to recreate in your training you will safely reap the rewards of the BFR / KAATSU training methods.