Human growth hormone can make the difference between finishing first in a sprint race and finishing last, a world- first study of the performance-enhancing effects of the banned injections has shown.
"This is the first time anyone has demonstrated that growth hormone has a positive effect on performance," Ken Ho from Sydney's Garvan Institute of Medical Research said. "The advantage comes not with greater power or strength but the provision of energy required for muscle to perform at the start of a burst of activity."
Difference between first and last place
The study, showing daily injections boosting sprint capacity in men and women, was funded by the World Anti-Doping Agency (WADA).
"We found the enhancement in sprint capacity would correlate to a 0.4-second improvement over 10 seconds in a 100m dash," Ho said. "This improvement could turn the last-place finisher in the Olympic finals into a gold medal winner."
Hormone treats growth disorder
Growth hormone, produced naturally by the pituitary gland, is used legitimately to treat growth disorders in children.
WADA suspects illegal use over decades because tests to detect doping have only been available since 2004.
"It's widely believed that it's quite extensively abused," Ho said. "And if you take a hormone which is identical to what the body makes, it becomes very difficult to detect it."
Ho said the surprise in the study was that growth hormone did not increase muscle mass or improve strength, power or endurance.
In February, English rugby league player Terry Newton became the first athlete to be punished for taking growth hormone.
Given that growth hormone would only have improved his speed at the beginning of a match, Newton may not have drawn any benefit from cheating. - (Sapa, May 2010)