Chemie | Biochemie | Medizin
Olivia Schmid, 2000 | Reinach, BL
Hormones involved in the menstrual cycle, especially oestradiol and progesterone, vary during the different phases of the menstrual cycle, i.e., menstruation, follicular phase and luteal phase. These hormones also affect the carbohydrate metabolism. The purpose of this study was to explore whether there is a relationship between menstrual phases and athletic performance in aerobic and anaerobic exercises. During the three mentioned phases, a total of 13 women were tested on fitness bikes. Six women performed the anaerobic Wingate test and seven the aerobic Conconi test. In both tests, their performance was better in the luteal compared to the menstrual phase. The Wingate group showed the smallest fatigue index and the Conconi group lasted for almost two minutes longer on average. Therefore, athletic performance may indeed be affected by the different phases of the menstrual cycle.
(I) Is there a relationship between different phases of the menstrual cycle and performance in sports? (II) Are both aerobic and anaerobic exercises influenced by the menstrual cycle? Based on a study by Hackney (1990), my hypothesis was that the great fluctuations of the different hormones, mainly oestradiol and progesterone, will lead to the weakest athletic performance during menstruation and the best during the luteal phase.
The 13 selected participants were tested three times: within the first 48 hours of menstruation onset, in the mid-follicular phase and in the mid-luteal phase. Six of them performed the anaerobic Wingate test, during which they had to pedal as fast as possible for 30 seconds. The remaining seven participants completed the aerobic Conconi test, during which they had to pedal at a constant velocity while the resistance level was increased after each minute. Both tests were performed on the same fitness bike. All data was collected and analysed in excel spread sheets. The statistical analysis was done using IBM SPSS Statistics, Version 27, and included Wilcoxon signed-rank tests and Friedman’s tests.
For the Wingate test, one of the significant differences was found in the fatigue index: with a median of 15.35%, it was lowest during the luteal phase and highest during menstruation, with 27.45%. This shows that the participants pedalled considerably more consistently and showed the least fluctuations during the luteal phase. For the Conconi test, the participants reached an average maximal resistance of 9.1 during menstruation, 9.4 in the follicular phase and 10.8 in the luteal phase. The difference between the menstrual and luteal phases was significant. This shows that participants were able to increase the maximal resistance levels during the luteal phase by two compared to the menstrual phase. In both performance tests, the results of the follicular phase were always between menstruation and the luteal phase.
The results of the Wingate test were similar to the study by Masterson (1999) despite the different numbers, which were due to the different setup of the fitness bike. The original setup was not possible with the given equipment, which should be considered and altered in future studies. The Conconi and the Wingate test showed the same trend, with the best performance in the luteal phase, followed by the follicular phase and then menstruation. This might be due to the fact that more muscle glycogen is stored in muscles during the luteal phase, leading to an increased availability of energy. However, not all participants showed this trend. One participant even showed her best performance during menstruation. One explanation for this might be that this particular participant does not experience any kind of menstrual pain, whereas most women do. Further studies should be optimised by including a higher number of participants and testing over several cycles instead of just one, since each cycle may be different. If possible, the best method to determine the menstrual phase would be by measuring the ratio of oestradiol to progesterone. I can confirm my hypothesis and affirm my first leading question. But I was not able tell what type of exercise, aerobic or anaerobic, was influenced more. This leaves room for future studies to investigate.
There is a clear trend showing the best performance in the luteal phase and the weakest during menstruation. These results may find practical application for women competing in aerobic and anaerobic sports. It remains open whether one of the two types of sports exercise is more influenced than the other, which leaves room for further investigation.
Würdigung durch die Expertin
Dr. Miriam Schrafl-Altermatt
In der vorgelegten Arbeit ist Olivia Schmid einer hochaktuellen Fragestellung nachgegangen. Mit grossem Engagement und viel Enthusiasmus hat sie einen wissenschaftlich wertvollen Beitrag geleistet zum Verständnis des Einflusses der weiblichen Hormone auf die sportliche Leistung. Neben der interessanten Fragestellung und dem gut strukturierten Aufbau besticht die Arbeit auch durch die sorgfältige Ausarbeitung der Resultate und die fundierte Diskussion.
Sonderpreis Weizmann Institut – International Summer Science Institute (ISSI)
Gymnasium Münchenstein, Münchenstein
Lehrerin: Dr. Claudia Zwahlen