How to Build Muscle Mass Fast with Kaatsu Training

Douglas Robb at HealthHabits posted the other day about the Occlusion/Kaatsu training method, which is popular in Japan. While not necessarily useful to me, I found it a very interesting read.

Kaatsu Training
Kaatsu Training / Occlusion Training

What Kaatsu Training Does

Kaatsu training looks like it can increase muscle hypertrophy significantly more than regular resistance training over an extremely short period of time. In fact the results of the studies show that 2 weeks of Kaatsu training increases muscle mass to a higher degree than 5 weeks of regular resistance training.

The Definition of Occlusion

In medical terms, occlusion is the act of occluding or the state of being occluded; a shutting off or obstruction of something; a blocking of the central passage of one reflex by the passage of another.

Kaatsu training applies occlusion by restricting blood flow to target muscle groups, also called Blood Flow Restriction, or BFR.

So, What is Kaatsu Training?

Kaatsu training involves applying a tourniquet or a tight wrap to the proximal portion of the target limb in order to fully or partially restrict blood flow for the duration of a low intensity exercise session.

The guidelines of Kaatsu training are as follows:

  • Intensity is 20% of 1 rep max.
  • Training frequency is twice a day, 6 days per week.
  • The minimum duration of Kaatsu training is 2 weeks, for a total of 24 sessions in 14 days.
  • At least 4 hours between sessions.
  • Occlusion is maintained throughout the entire exercise session.

Why Kaatsu Training Works

The theory is that the metabolic buildup within the restricted muscles elicits a number of physiological changes including a significant rise in growth hormone, which is actually higher than that observed with higher intensity exercise. Isn’t that interesting?

The Studies

Several studies were performed using both the Kaatsu method and regular resistance training. The results of those experiments are shown in the table below.

Table 1: Training studies on the effects of high-intensity resistance training and low-intensity BFR training on skeletal muscle size and strength

Please see a more detailed version of this table in the PDF document linked at the bottom of this post.

(Journal, Year)
No. of Subj. Intensity
(reps x sets)
Weeks /
% Change
% Change
High-intensity Resistance Training
Akima et al. (MSSE, 1999) 7 Max
5 x 10
4/5 2 / 9 2.8 0.31
Seynnes et al. (JAP, 2006) 7 Max
7 x 4
2/3 5 / 13 5.0 0.36
Tesch et al. (Acta, 2004) 10 Max
7 x 4
2/3 5 / 13 6.0 0.50
Bell et al. (JSMPF, 1992) 16 Max
20 x 3
4 5 / 20 5.3 0.27
Wilkinson et al. (EJAP, 2006) 10 80-90%
6-10 x 3-4
3 8 / 24 5.4 0.23
Jones et al. (JP, 1987) 12 80%
6 x 4
3 12 / 36 5.0 0.14
Ahtiainen et al. (EJAP, 2003) 16 10RM
all-out x 5
2 21 / 42 4.7 0.11
Low-intensity BFR Training (training frequency: twice per day)
Abe et al. (IJKTR, 2005) 8 20%
30&15 x 3
12 2 / 24 7.7 0.32
T. Fujita et al. 8 20%
30&15 x 3
12 1 / 12 3.0
0.25 (MV)
0.29 (CSA)

Key: M-size, muscle size; CSA, cross-sectional area; MV, muscle volume.


  • Traditional resistance training performed 2-3 times per week causes muscle hypertrophy in about 5 weeks after roughly 10-15 training sessions.
  • After the completion of the Kaatsu training study by T. Fujita et al. (see Table 1) with both a Blood Flow Restricted (BFR) group and a control group, significant muscle hypertrophy was observed only in the BFR group as the CSA and MV both increased.
  • The resulting hypertrophic potential per session is similar to traditional high-intensity training.
  • 1-RM strength in the BFR group increased slightly due to increased muscle mass, although relative strength (1-RM/CSA) stayed the same.
  • Muscle damage normally associated with resistance training was not apparent in either group, as measured by blood levels of creatine kinase, myoglobin, and interleukin-6.
  • BFR training did not produce any signs of blood clotting.
  • Changes in muscle mass following 7-days (12 sessions) of low-intensity resistance training using BFR resulted in effects comparable to that of several weeks of high-intensity resistance training.
  • Changes in muscle mass following 14-days (24 sessions) of low-intensity resistance training using BFR resulted in effects greater than those seen after several weeks of high-intensity resistance training.
  • Kaatsu training produces changes in strength that are inferior to a resistance training program designed to maximize strength gains.

Should You Use Kaatsu Training?

I am almost tempted to say “Yes” based on the results of these studies, but in reality I know better. There are much better ways to train if you are a healthy person.

For bodybuilders, Kaatsu training appears to be an effective way to increase muscle mass… or you could just do 20 rep sets of breathing squats.

For powerlifters, the increased muscle mass could then be trained to maximize density and strength in program consisting of 2-3 weeks of Kaatsu training followed by 8-12 weeks of powerlifting. Don’t tell Louie Simmons that you are considering this though.

For Olympic lifters or sport-specific athletes, I don’t think Kaatsu training has much to offer you. Your best bet is to train for speed/strength and specific functionality. The increased muscle mass would probably be more of a hindrance.

For novice or intermediate athletes who really only exercise for fun or to stay healthy, Kaatsu training probably doesn’t have a place in your workout routine unless you want to worry about wearing really tight wraps or tourniquets while you exercise.

Additionally, occlusion training might be suitable for the following sub-sets of athletes:

  • athletes who are unable to sustain high loads due to joint pain
  • postoperative patients
  • cardiac rehabilitation
  • athletes who are unloading
  • astronauts


Read more about the T. Fujita et al. study here: Increased muscle volume and strength following six days of low-intensity resistance training with restricted muscle blood flow

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12 Responses to “How to Build Muscle Mass Fast with Kaatsu Training”

  1. Kaatsu is not suitable for individuals afflicted with arterial hardening,a condition brought on by sedentary living and muscle wasting, resulting in loss of the protein elasticin in arterial walls, hence loss of flexibility or elasticity. Such persons are more prone to strokes, hence increasing blood pressure to abnormal levels doing kaatsu runs a real risk.
    Arterial hardening can be rehabilitated by means of interval training since a combination of aerobic and anaerobic protocols work.

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