A new study, just released from a group of researchers in Australia found that, contrary to past studies, GH use did increase one aspect of athletic competition: sprint speed. What's humorous about this particular study is that other researchers from the same Australian research group released another study about two years ago, in which they concluded that any benefits that accrue in athletes after using GH likely are due to the placebo effect, since one group of athletes used were told they were getting actual GH (but weren't), and other group just received a placebo, yet both groups made the same level of gains and athletic improvement. Apparently, the Aussie researchers have changed their tune, and now found that GH does in fact, increase sprint speed. But there are several caveats to consider with this study.
For one, the dosage of GH was 2 units a day, provided via subcutaneous injection. The study subjects consisted of 63 men and 33 women, ages 18 to 40, all of whom were described as "recreational athletes." This means that none were competitive athletes, which as discussed above would have been considered unethical. Not to mention that the study was sponsored by the World Anti-doping Agency (WADA). Ostensibly, the reason for the sponsorship was to prove that GH was useless for athletes, and thus hopefully discourage athletic use of GH. But it didn't quite turn out that way. Half the men in the study injected GH or a saline solution placebo for 8 weeks. Some of the men also injected themselves with testosterone in addition to the GH, at a dose of 250 milligrams weekly. The women in the study either self-injected GH, or a placebo.
After eight weeks, those using GH increased their sprint speed--as measured on a stationary bike--by 4 percent over their baseline or speed at the start of the study. Those who also used testosterone showed an 8 percent improvement in sprint speed. No other measures, such as endurance, strength, or jump height improved. In relation to body composition, GH reduced fat mass, and increased lean body mass, which was found to be not muscle, but extracellular water. This water retention was likely related to the reported side effects of swelling in two-thirds of the GH users, and joint pain reported by 47 percent. Another 28 percent said that they felt burning or tingling sensations in their skin.
The lead author of the study told news agencies that the "enhancement of sprint capacity would correlate to a 0.4 second improvement over 10 seconds in a 100-meter dash. This improvement could turn the last place finisher in the Olympic finals into a gold medal winner." Then, perhaps thinking about the WADA funding of the study, he added that since the subjects were recreational and not competitive athletes, it would be hard to translate this into real world athletic improvement.He also noted that the doses of GH used in the study, 2 units a day, are considerably less than what is used by many competitive athletes. As a yardstick, many pro bodybuilders inject themselves with 4-8 units or more of GH daily, along with large doses of various anabolic steroids and other drugs. I would also add that extrapolating sprint speed on a stationary cycle may not precisely duplicate competitive level sprinting on a track. The study authors also mentioned that 6 weeks after the study and GH/testosterone use had ended, the sprint speed returned to base levels, suggesting that the effect was due to the drug usage. This must have been an embarrassment to WADA, who paid for the study in the hopes that the findings would all be negative. Another interesting aspect of the study to consider is that the sprint gains doubled when testosterone was added to GH usage. This underscores the empirical findings of athletes that GH always works best when combined with testosterone or anabolic steroids.
Meinhardt U, et al. The effects of growth hormone on body composition and physical performance in recreational athletes: a randomized trial. Ann Inter Med 2010;152:568-77.
