Investigating Low-load Resistance Training With Blood Flow Restriction
The KAATSU training method, now better known as blood flow restriction (BFR) training was created in 1966 by Japanese sports scientist and bodybuilder Yoshiaki Sato. This technique is characterized by restricting muscle blood flow by applying an external pressure, typically using a tourniquet/cuff system applied to the proximal section of the upper or lower limbs.
The cuff pressure produces mechanical compression of the underlying tissues, including the venous and arterial vasculature, which causes a reduction in venous return by creating tissue hypoxia. This generates important physiological mechanisms for the improvement of musculoskeletal functions.
This form of intervention can be applied either in isolation (without training) or with aerobic or strength exercises. In this direction, the strength or resistance exercise of low-load (20-30% of 1RM) combined with BFR increased because it was a method that emerged as a possible alternative to high-load exercises (≥65% of 1RM). Thus, this training method has been effective for increases in muscle strength, muscle hypertrophy, localized muscular resistance, isometric strength, functional capacity and has been shown to be safe in relation to hemodynamics.
However, one of the major concerns in the application of this form of intervention is changes in hemodynamics. To clarify this, a study by Neto et al. (2017) systematically reviewed the available scientific evidence on the changes promoted by low load resistance exercise combined with BFR on hemodynamic measures in young individuals. These authors verified that the results are divergent when compared to low load protocols with BFR versus high load. Scientific evidence shows that continuous BFR (maintenance of pressure between sets) after a low load resistive exercise session appear to elevate hemodynamic measures when compared to low load protocols without BFR. Although, there appear to be significant increases in blood pressure between the protocols of a high load when compared to protocols of low load.
In addition, the hemodynamic changes promoted by low-load resistance exercise with BFR do not seem to differ between ages and body segments (upper or lower), but appear to be influenced by cuff width and are higher with continuous BFR when compared to intermittent (between series).
Thus, these changes are within the normal range, making this method safe and feasible for special populations, such as the elderly, heart disease, and others. Since it promotes increases in strength and hypertrophy using low loads, but without adversely affecting hemodynamic measures.
The study, Effects of resistance training with blood flow restriction on haemodynamics: a systematic review was recently published in the journal Clinical Physiology and Functional Imaging.