The researchers first measured physical fitness and the ability to pull a weight, jump, and sprint on a bicycle. They then assigned half of the group at random to receive either growth hormone or salt water injections for 8 weeks. At the same time, they assigned half of the men at random to also receive testosterone or salt water injections. They measured physical performance at the end of the 8-week period and again at 14 weeks after the athletes had stopped receiving the drug or salt water injections.