About this Research Topic
The manipulation of blood flow via the use of specialized blood pressure cuffs/tourniquets may be used to achieve specific outcomes for muscle, exercise, performance and function. This manipulation may be broadly captured by the techniques of a) blood flow restriction exercise, and b) ischemic pre-conditioning, and as such these form the basis/focus of this special research topic.
Blood flow restriction (BFR) exercise is a novel training technique used for increasing skeletal muscle mass and strength and is historically known as ‘Kaatsu’ training (a Japanese word meaning “added pressure”). This BFR technique restricts muscle blood flow through the application of an external pressure, typically using a pneumatic tourniquet/cuff system applied to the most proximal section of the upper or lower limbs. Inflation of the cuff produces a mechanical compression of the underlying tissues including both the venous and arterial vasculature, which likely effects a reduction in venous return while creating a tissue hypoxia distal to the cuff, with the magnitude of both these effects being modulated by the phase and intensity of any limb contractile activity or exercise. Importantly, the gains in skeletal muscle size and strength with BFR training have been typically demonstrated when using light exercise loads/intensities (e.g. 20-30% one repetition maximum; walking exercise), therefore, BFR has been examined during voluntary resistance and aerobic exercise, and also passively without exercise. More recent research has also examined the combination of BFR with non-traditional exercise modalities such as whole body vibration techniques and neuromuscular electrical stimulation. Despite a growing body of evidence in support of beneficial skeletal muscle outcomes as well as functional performance benefits in a range of populations, at present, there is no universal standard method for the application of BFR during exercise. Differences exist for cuff type and size, pressures used the method for determination of cuff pressure and the duration of BFR application. Its present uses include rehabilitation from injury and to improve aspects of athletic performance.
Ischemic preconditioning (IPC) is, by contrast, when a tourniquet/cuff is placed on either the arms or legs of participants prior to exercise performance, irrespective of the exercise modality. The application of an IPC protocol pre-activity may render skeletal muscle of athletes more resistant to fatigue due to similar muscular modifications demonstrated in a clinical setting. As such IPC is currently being assessed as to its validity as an ergogenic aid in both aerobic and anaerobic exercise performance. Furthermore, evidence exists around the use of IPC to assist with recovery from exercise/fatigue and adaptation to training.
The aims of this research topic are to shed more light on the transcriptional, vascular, hemodynamics, neuro-humoral, and systemic consequences of training with forms of blood flow manipulation. Appropriate article topics include, but are not limited to acute responses to aerobic or resistance training with BFR and/or ischemic preconditioning. Furthermore, “special interest” in manuscripts focused on chronic outcomes from long-term training with BFR are encouraged to further enhance our understanding of the field.
Keywords: Ischemic Preconditioning, Occlusion, Kaatsu
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