The nitty gritty science behind BFR Training

Proposed physiological mechanisms include:

1. The recruitment of larger fast-twitch (type II) motor units occurring secondary to the hypoxic state created by the tourniquet. In the absence of oxygen, ATP (energy) production changes from the aerobic (Krebs cycle) to anaerobic (Cori cycle). Recruiting more fast-twitch muscle fibers is advantageous as they have the greatest capacity to grow.

2. As muscle utilizes the anaerobic pathway during resistance training, the metabolic accumulation (e.g. lactate) within the muscle may be a trigger for hypertrophic changes. Systemic response from this metabolic accumulation includes significant increases in substances such as growth hormone, insulin like growth factor, myogenic stem cells, and down regulation of substance such as myostatin which results in muscle growth.

3. The muscle pump effect seen after BFR training may also play a role in hypertrophy gains. BFR training produces muscle swelling and plasma volume fluid shift. The muscle swelling appears to play a role in augmenting muscle size by activation of the protein synthesis pathway via MTORC1 (Rapamycin complex 1).