Anabolic hormones such as testosterone and growth hormone couldbe beneficial for physical performance. The second to fourth digit ratio, suggested as a measurement of testosterone exposure during fetal life, has also been related to athletic ability. There is however a lack of knowledge on how the body`s own anabolic hormones and the digit ratio may affect muscle mass and physical performance in female elite athletes. In doping tests,the levelof steroid hormones, for example testosterone, is measured in urine. In men, genetic variations have been shown to affect the steroid hormone levels. However, it is not known if genetic variations and hormonal contraceptives affectthe steroid hormone levels in urine in female elite athletes. The purpose of this thesis was to study the body`s own anabolic hormones and the digit ratio in female Olympic athletes compared to untrained controls and to evaluate possible relationships with body composition and physical performance in the Olympic athletes. We also aimed to examineif genetic variations and hormonal contraceptives alter the steroid hormone levels in urine and if these hormone levels were different between athletes and controls. We found relatively higher levels of anabolic hormones and a lower digit ratio(higher exposure to testosterone during fetal life)in the female Olympic athletes. The anabolic hormones were associated with increased muscle mass, stronger bone tissue and better physical performance. A low digit ratio was related to steroid hormone levels in urine but not to hormone levels in blood. The steroid hormone levels in urine were lower in the athletes than the controls and both genetic variations and hormonal contraceptives affected these hormone levels. In conclusion,these findings reflect that the body`s own anabolic hormones are important for muscle mass and physical performance in female Olympic athletes. This knowledge is valuable for the ongoing discussion about hyperandrogenism in female athletes. Based on the digit ratio hormonal exposure during fetal life appearsto be associated withathletic performance. Furthermore, the associationbetween the digit ratio and levels of steroid hormones in urine can be related to how these steroid hormones are processed in the body. Both genetic variations and hormonal contraceptives resulted in differences in steroid hormone levels in urine. The higher levels of these hormones in untrained women compared to Olympic athletes can be a result of increased androgen excretions by alternative elimination routes in the athletes.
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