By Tanner Garrity Tricks of the trade tend to sweep through the Olympic Village like wildfire. You might remember the cupping craze from the Rio Olympics, when swimmers started showing up the pool with dark purple circles all over their backs. Or reports from earlier that year that high-profile athletes were adopting blood-flow restriction (BFR), a strength-training hack that involves placing an inflated “performance tourniquet” around one’s arms and legs. Olympians even seem to copy each other in matters outside the field of competition — over 1,000 athletes and coaches apparently brought bur…