Sydney, May 5 (Inditop.com) A growth hormone showed a 0.4 second improvement in a 10-second sprint in tests, enough to turn a last-place Olympic athlete in an event – running or swimming – into a gold medal winner.
The study justifies growth hormone being a banned substance, even though evidence of its performance enhancing effect has been very poor until now. Growth hormone, produced naturally in the body, is important for growth and metabolism.
Injectable growth hormone is available for people who have growth hormone deficiency. Many athletes use the drug because they believe that it bulks up their muscles and improves their physical performance (growth hormone “doping”).
Until this study, no scientific research had been undertaken to show that growth hormone improves physical performance.
Researchers at the Garvan Institute of Medical Research demonstrated that growth hormone increases an athlete’s ability to sprint on a bicycle, but has no effects on fitness, weight lifting or jumping.
The effect on sprint capacity nearly doubled in men who received testosterone injections in addition to growth hormone supplementation.
The study looked at 103 healthy recreational athletes, aged 18 to 40 years, who had engaged in regular athletic training for at least a year.
It was double-blind and placebo-controlled, meaning that neither the investigators nor the participants knew who was receiving the drug or dummy injections (salt water).
Ken Ho, endocrinologist, professor and head of pituitary research at Garvan, undertook the project with Udo Meinhardt and Anne Nelson, as members of a larger team. “Those athletes given growth hormone improved their sprint capacity by four to five percent,” said Ho.
“Growth hormone recipients did not increase their muscle mass. They did, however, retain body fluid and experienced swelling and joint pain, unlike those who received salt water injections.”
“In conclusion, growth hormone increases athletic sprinting when given alone or in combination with testosterone,” said Ho, according to a Garvan release.
“This is the first demonstration of improvement in a selective aspect of physical performance with growth hormone. We believe that this effect may bring a competitive advantage to athletes engaging in sprint events.”
This work was funded by the World Anti-Doping Agency.
Their findings were published in the Annals of Internal Medicine.
