Congress Looks Into Science of HGH Test for NFL Nearly two full seasons since signing a labor deal that paved the way for HGH testing in the NFL, the league and the players' union still haven't agreed to implement anything. The NFL Players Association won't concede the validity of a test that's used by Olympic sports and Major League Baseball, and the sides haven't been able to jointly pick an expert to help resolve that impasse. So now Congress steps in. The House Oversight and Government Reform Committee is holding a hearing Wednesday to take a look at the science behind tests for human growth hormone, a substance that is hard to detect and believed to be used by athletes for a variety of benefits, whether real or only perceived - including increasing speed and improving vision.