Could performance be
controlled by the mind?

We are all familiar with the 'placebo effect' in medicine. A patient recovers because they believe in the healing power of a drug or therapy with no intrinsic therapeutic benefits.

A new study demonstrates that the mind can be just as powerful at influencing outcomes in sport. If athletes believe they are using a performance-enhancing drug, they may think their performance improves, and in some it can, even if they are actually taking a dummy drug.

Professor Ken Ho, Head of the Pituitary Research Unit at the Garvan Institute of Medical Research, presented his team's findings to The Endocrine Society's 90th Annual Meeting in San Francisco on 17 June.

"Athletes are doping with growth hormone to improve sporting performance without any evidence it actually improves performance," said lead author Jennifer Hansen, RN, a nurse researcher at Garvan.

"The study told us that athletes who were on the dummy drug, but who believed they were on growth hormone, thought their performance had improved and actually showed some improvement in all measures of performance. One test in particular, jump height or power, showed a significantly greater improvement among these incorrect guessers."

Sixty-four athletes participated in the study, 32 men and 32 women. For 8 weeks, half the group received growth hormone while the other half received an inactive substance (placebo). Neither the researchers nor the athletes knew which athlete was taking what. At the end of the treatment period, athletes had to guess whether they had been taking growth hormone or placebo, as well as rate their sporting performance on a self-assessment questionnaire. They were then tested on endurance, strength, power and sprint capacity, and actual performances were compared with self-assessments.

"The results so far suggest that the placebo effect may be responsible, at least in part, for the perceived athletic benefit of doping with growth hormone for some people."