ORAL CONTRACEPTIVE USE EVENS OUT THE EFFECTS OF TRAINING OVER A MENSTRUAL CYCLE
Sung, E., Han, A., Hinrichs, T., & Platen, P. (June 2, 2010). Endurance training and menstrual cycle: Effects of follicular and luteal phase-based training in subjects with oral contraception. Presentation 1566 at the 2010 Annual Meeting of the American College of Sports Medicine, Baltimore, Maryland; June 2-5.
"Monophasic oral contraceptives (OC) contain fixed doses of estrogen and progestogen which are taken for 21 days, followed by seven days without any hormone intake, leading to more or less constant concentrations of blood estradiol and progesterone) during the first 21 days. The regulation of other interacting hormones like IGF-1, testosterone and DHEA-S, all of them possible anabolic hormones on the level of the muscular cell during endurance training, is not clear so far in OC users."
This study investigated possible different effects of "quasi follicular phase-based" versus "quasi luteal phase-based" endurance training on endurance capacity in healthy women (N = 14) using oral contraceptives. Ss completed endurance training on a bicycle ergometer for each leg for three menstrual cycles (12 weeks). Ss trained one leg mainly in the follicular phase and the other in the luteal phase. Blood samples were taken on 11th day of the menstrual cycle in the follicular phase and on 25th day of menstrual cycle in the luteal phase to analyze values of estradiol, progesterone, total testosterone, free testosterone, IGF-1, and DHEA-S. Prior to and after training, a incremental bicycle ergometer test was conducted for each single leg for the determination of lactate concentrations, heart rates, maximal power, and maximal oxygen uptake (VO2max). The quadriceps muscle diameter was measured by ultrasound.
DHEA-S was significantly higher in the quasi-follicular phase compared to the quasi-luteal phase. There was no difference for estradiol, total testosterone, progesterone, IGF-1 and free testosterone. VO2max increased significantly after the 12 weeks for both phases of training. Maximal power increased after the 12 weeks with no difference between the two phases. The quadriceps muscle diameter did not change as a result of training.
Implication. Maximal power increased as a result of training and did not differ between phases. This is in contrast to findings in women who do not use of oral contraceptives, who show a tendency for a higher increase of endurance capacity after the follicular phase compared to luteal phase. The use of oral contraceptives allows women to achieve graeter levels of training adaptation.
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