Australasian Science: Australia's authority on science since 1938

Lift Less, Gain More

The belief that lifting heavy weights is necessary to build muscles is being challenged by evidence that resistance training at low loads with blood flow restriction (BFR) can increase muscle size and strength.

“BFR, also known as Kaatsu training, involves performing exercise with a restrictive cuff placed around the exercising limbs,” said Mr Charlie Davids of The University of Queensland’s School of Human Movement and Nutrition Sciences. “This reduces the amount of blood and oxygen delivered to the exercising muscles, leading to an accumulation of metabolic by-products, such as lactate, causing some parts of the muscle to fatigue quickly while others compensate.”

Davids said that BFR has potential implications for the injured and elderly, who “often possess musculoskeletal conditions that limit their ability to achieve significant gains in muscle size and strength with normal resistance exercise. The low loads typically used with BFR mean that the muscles and joints are subjected to lower levels of stress, which may accelerate the recovery from musculoskeletal injury, or allow elderly people to combat the natural decline in muscle mass that occurs with ageing.”

Davids said that BFR was also showing promise for healthy individuals and athletes. “The reduced training stress may mean a greater number of training sessions can be performed in shorter periods,” he said. “Training sessions could potentially be increased to twice daily, which has been demonstrated to produce marked increases in muscle size in as short as 2 weeks.”

Davids is investigating the responses of healthy individuals to BFR training in an effort to translate the practice to clinical domains. “There is a lack of consensus among scientists, practitioners and coaches as to how this novel exercise method can be adapted to cater for the goals and health considerations of various populations,” he said. “We want to address this gap by assisting with the formulation of evidence-based guidelines for BFR resistance exercise.”