Vascular occlusion training

Blood flow restriction training abbreviated BFR training) or Occlusion Training is an exercise approach whereby resistance exercise or aerobic exercise is performed whilst a tourniquet is applied to proximal aspect of the muscle^[1].In this novel training method, limb blood flow is restricted via a 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^[2]. Given the light-load nature and strengthening capacity of BFR training, it can provide an effective clinical rehabilitation stimulus without the high levels of joint stress and cardiovascular risk associated with heavy-load training ^[3]

Application

Many practitioners are using a range of equipment as well as BFR protocols that do not match usage within published literature^[4]. The current approaches that focus on applying BFR during exercise consist of automatic pneumatic tourniquet systems or handheld manual blood pressure cuffs, and more recently elastic wraps, at a range of different pressures and durations. Research demonstrating the influence of thigh circumference and cuff width ^[5] on occlusion pressure has accentuated a likely need for an individualised approach to BFR, particularly with regard to the setting of the restriction pressure. More recently, a technique to calculate and prescribe the occlusive stimulus as a percentage of total limb occlusion pressure is just one example of efforts to account for the above factors and provide an individualised approach to prescribing BFR training that is relatively quick and inexpensive. While the relationship between BFR pressure and the underlying tissue compression during exercise is not yet fully understood, BFR training using 40%–80% of limb occlusion pressure is safe and effective when supervised by experienced practitioners ^[6] ; therefore, lower pressures may provide less risk without the need for higher pressure.

Adaptations

Historically, heavy exercise loads of approximately 70% of an individual's one repetition maximum (1RM) have been deemed necessary to elicit muscle hypertrophy and strength gains ^[7]. In recent years, research has demonstrated that augmentation of low-load resistance training with blood flow restriction (LL-BFR) to the active musculature can produce significant hypertrophy and strength gains ^[8][9], using loads as low as 30% 1RM ^[10]. BFR training has been found to yield hypertrophy responses comparable to that observed with heavy-load resistance training ^[11].

Risks

When using belts and lifting straps for tourniquet, the amount of pressure on the vasculature cannot be controlled and there are reports of rhabdomyolysis cases due to VOT.^[12] Sato himself risked his life in 1967 after uncontrolled sessions of VOT, leading him to focus more on control and adjustment of the pressure applied on the vasculature.

See also

• Kaatsu

References