Active Voice: KAATSU Training An Emerging Research Area & New ACSM Interest Group
By Alan Mikesky, Ph.D., FACSM and Michael Bemben, Ph.D., FACSM
Alan Mikesky, Ph.D., FACSM is professor and director of the Human Performance & Biomechanics Laboratory in the Department of Physical Education at Indiana University-Purdue University Indianapolis. His research interests in applying resistance training to various clinical populations led him to Japan, where he was taught by the founder of KAATSU training. Michael Bemben, Ph.D., FACSM is C.B. Hudson Presidential Professor in the Department of Health & Exercise Science at the University of Oklahoma in Norman. His research area is neuromuscular function in aging, with particular emphasis on exercise training, adaptive mechanisms and outcomes relative to muscle mass, strength and balance. Drs. Mikesky and Bemben co-chair the ACSM KAATSU special interest group, and they have conducted funded research and published articles regarding the physiologic and performance effects of KAATSU training.
In the last decade, there has been a large increase in the number of conference presentations and peer-reviewed publications reporting the effects of combining resistance training with muscle blood flow restriction. Many of the studies have been conducted in Japan where this type of training is known as “KAATSU” (the Japanese word for pressure). KAATSU is the addition of pressure via pneumatic limb cuffs that restrict, not occlude, blood flow to the exercising muscles. Because of the growing interest and potential applications of KAATSU, we want to introduce it by addressing several commonly asked questions.
What’s different about KAATSU?
Besides wearing the pneumatic cuffs that restrict blood flow while exercising, KAATSU training is different than traditional resistance training, as more repetitions are performed with lighter resistances. Typical resistance training involves performing 1-3 sets of 8-10 repetitions with loads that exceed 60 percent of maximal muscle strength. KAATSU involves three sets of 15 or more repetitions using loads that range from 10-50 percent of maximal strength. It is the lighter loads that make KAATSU a potentially viable option for certain clinical applications.
Is KAATSU training dangerous?
While there is no definitive answer to this question as of yet, it appears that when used as recommended and under the supervision of a trained professional, KAATSU training presents a low risk. Japanese researchers surveyed 195 medical/training facilities representing use by 13,000 people (45.4% male, 54.6% female). Ages ranged from under 20 years (17.8%) to over 70 years (14.6%). The most frequently reported side effect (~13%) was the appearance of small red spots, resulting from subcutaneous capillary bursts, which disappeared after a few days. The risk for more serious conditions, such as venous blood clots, severe muscle breakdown and worsening of ischemic heart disease was minimal (i.e. <0.02%). Numbness and cold feelings due to compression of peripheral nerves was also reported, but they were temporary and subsided after the release of the restrictive pressure.
Is KAATSU an effective resistance training mode?
To date, published KAATSU studies support its effectiveness at increasing muscle size and strength in untrained adult populations. The results have been comparable to subjects involved in traditional high-intensity training and greater than in subjects performing low-intensity training without blood flow restriction (see recent research review by Manini & Clark). There have also been reports of improved bone markers that suggest KAATSU could reduce the incidence of bone loss due to aging, injury or zero gravity. Increases in growth hormone and other anabolic hormones have also been reported in response to KAATSU. However, KAATSU research is in its infancy. Little is known about the underlying physiology of KAATSU or the body’s acute responses and chronic adaptations to it. Likewise, further insight into KAATSU training variables such as frequency, intensity and volume of training is needed. In short, numerous publications in respected journals indicate that KAATSU and its potential benefits are deserving of further scientific inquiry.
How can I learn more about KAATSU training?
In 2009, a KAATSU special interest group was formed within ACSM. The goal was to establish a network of exercise science professionals interested in KAATSU, to foster their interaction and to provide a means of quickly disseminating important KAATSU-related information. If you are interested in becoming part of the KAATSU special interest group, please contact Dr. Mikesky at firstname.lastname@example.org, and we’ll add you to our growing list.