Various measures of muscle strength have been shown to improve in response to BFR-RE interventions, including dynamic isotonic ( Burgomaster et al., 2003 Moore et al., 2004), isometric ( Takarada et al., 2000a Moore et al., 2004) and isokinetic strength ( Takarada et al., 2000c, 2004 Burgomaster et al., 2003 Moore et al., 2004), as well as rate of force development/explosive strength capacity ( Nielsen et al., 2017b). In recent years, a number of systematic reviews and meta-analyses have demonstrated BFR-RE to effectively increase skeletal muscle strength and/or hypertrophy in healthy young ( Loenneke et al., 2012d Slysz et al., 2016 Lixandrão et al., 2018) and older ( Centner et al., 2018a Lixandrão et al., 2018) populations, as well as load compromised populations in need of rehabilitation ( Hughes et al., 2017). Increases in muscle hypertrophy and strength with BFR-RE are extensively documented. For a more detailed understanding of the mechanisms of BFR exercise we refer readers to the following review articles ( Wernbom et al., 2008 Pearson and Hussain, 2015). It is envisaged that this will facilitate practitioners to be more informed and clearer in deciding the reasons why they should apply BFR, how they should apply BFR as well as understanding the safety issues associated with this BFR training. Therefore, the aim of this review is to provide a current, research informed guide to BFR from a group of world leading experts in the field. For example, there was a wide range of pressures applied by practitioners that resulted in unintended consequences such as a large incidence of numbness following BFR.
BLOOD IN BLOOD OUT CLOTHING HOW TO
(2017) suggests that practitioners are unclear on how to use and apply BFR in line with current research informed standards. This is positive, however, evidence from Patterson et al.
Whilst the number of research groups and studies investigating BFR have grown, so too has the number of practitioners using this mode of training ( Patterson et al., 2017).
In addition to this, when muscular contractions are performed under conditions of BFR, there is an increase in intramuscular pressure beneath the cuff ( Kacin et al., 2015), which further disturbs blood flow. The level of blood pooling may be influenced by the amount of pressure applied.
Furthermore, the diminution of venous blood flow results in blood pooling within the capillaries of the occluded limbs, often reflected by visible erythema. Compression of the vasculature proximal to the skeletal muscle results in inadequate oxygen supply (hypoxia) within the muscle tissue ( Manini and Clark, 2009 Larkin et al., 2012). When the cuff is inflated, there is gradual mechanical compression of the vasculature underneath the cuff, resulting in partial restriction of arterial blood flow to structures distal to the cuff, but which more severely affects venous outflow from under the cuff that is proposed to also impede venous return.
The technique of BFR in the muscle using a pneumatic tourniquet system involves applying an external pressure, typically using a tourniquet cuff, to the most proximal region of the upper and/or lower limbs. Yoshiaki Sato in Japan, where it was known as “kaatsu training,” meaning “training with added pressure.” Kaatsu training is now performed all over the world and is more commonly referred to as “BFR training" and achieved using a pneumatic tourniquet system ( Wernbom et al., 2008 Loenneke et al., 2012d). Performing exercise with reduced blood flow achieved by restriction of the vasculature proximal to the muscle dates back to Dr. Blood flow restriction (BFR) is a training method partially restricting arterial inflow and fully restricting venous outflow in working musculature during exercise ( Scott et al., 2015).