Thor Chris Hemsworth, the actor who played Thor, told the world his secret to body building. His muscular arms were vividly displayed in the movie. He used Blood Flow Restriction (BFR) Bands to grow muscle during his workouts. BFR Bands are gaining wider acceptable in the sporting world. Professional sports teams and USA Olympic teams have been using them for muscle growth and rehabilitation after an injury. Physical therapists are using it for their patients because they do not require weights. BFR B3 Bands reduce blood flow to the muscle during exercise and result in quicker muscle fatigue and the production of natural human growth hormone. Consistent use of BFR B3 Bands will deliver equal or better results with other weight lifting exercises. And they reduce workout time by about 1/2.