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The menstrual cycle and sport
The menstrual cycle is a part of women’s lives, yet we hardly ever talk about it. We want to change that, so in this post we are focusing on the menstrual cycle and women’s sporting performance.
Women are not (small) men
Although there is an obvious difference, gender barely plays a role in training. Despite the biological differences between men and women, it looks mostly very similar. This is primarily because, up till now, many sports science studies were conducted on men and their results were simply adjusted for women. “Women are not small men,” emphasises the American sports scientist Stacy Sims. Women can improve their performance and gain benefits by paying attention to their cycle. In just a moment you will learn how that works.
For a long time, men only were the subjects of sports science studies. One of the main reasons given for this was the desire to standardise scientific works, which is simpler to do with men as study subjects, because studies with women have to take into account which contraception method (e.g., the pill) they use and whether they have a cycle or not. This is much more laborious than an investigation with men, because only by considering all these parameters can comparable and reproducible study results be obtained.
Women and men – differences in performance
Women’s absolute sporting performance is almost always lower than men’s. The differences in performance range between six and 30 percent, depending on the type of sport and length of the competition. There are particularly large differences in brief, high-strength sports. Due to their higher testosterone levels, men have on average more muscle fibre and therefore a greater maximum strength. However, the contractile speed and strength per contractile unit is the same for men and women. With somewhat longer performances, men benefit from increased glycolytic capacity and greater oxygen transportation due to on average higher haemoglobin levels. In longer competitions, an increasing role is played by fat metabolism, which functions better overall in women. This means that, where the relative intensity is comparable, women can obtain a higher proportion of the necessary energy by burning fat. What is more, women have advantages in types of sport that require greater flexibility, as their ligaments and tendons are more elastic due to their higher levels of oestrogen.
As you have probably already noticed, hormones play a large role in the performance differences between men and women. This is where the menstrual cycle, with the associated hormone fluctuations and effects, comes into play.
The menstrual cycle – hormone fluctuations
The menstrual cycle normally lasts for between 21 and 35 days, where a new cycle always starts on the first day of the period.
The hormones FSH, LH, oestrogen and progesterone in particular change during a cycle. Ovarian function is affected primarily by LH and FSH, which regulate ovulation and the production of oestrogen and progesterone. During the cycle, oestrogen and progesterone are always active concurrently, but they are present in differing concentrations and dominate differently. Sportswomen clearly perceive this in part, especially in competitive sports. In a study of female rugby players, over 80% of the female athletes reported that their cycles affected their individual performances. In general, current research indicates that cycle-related fluctuations do not result, statistically speaking, in measurable differences in performance, in many studies. Mostly they are purely subjectively perceived influences that cannot be proved objectively. Regardless of cycle phase, however, very intensive, long-lasting endurance sports can result in a temporary increase in testosterone.
Every woman is different – the effects of the cycle
Many women suffer from physical and mental difficulties during their period. These include mild, moderate or even severe lower abdominal pain that frequently spreads into the back (dysmenorrhoea) as well as, e.g., mood swings. For some sportswomen, this means that rigorous training is not possible at this time. In isolated cases, the pain is so extreme that absolutely no physical activity is possible. Other female athletes feel incredibly powerful during the first half of their cycles. That is why it is important to adapt training to suit the individual and to consider the conditions affected by the cycle when planning, because every woman is different!
Scientific studies have shown that, during the first half of the cycle, a better effect can be achieved with maximum power training than when this is done in other phases of the cycle. Ovulation takes place in the middle of the cycle, during which some women briefly experience pain in the lower abdomen. In this phase of the cycle, the tendons and ligaments are also affected by oestrogen, which means greater mobility and hyperflexibility can be detected. This is also sometimes one of the reasons behind the demonstrably up to 8x higher frequency of injury to the anterior cruciate ligament in women as opposed to men.
The second half of the cycle also lasts for 14 days and is rather unpleasant for many women, especially in the last few days before the period starts. This is the phase in which we talk about premenstrual syndrome (PMS), in which women experience increased water retention and feel sluggish and tense. This can, for example, reduce a woman’s ability to adapt to a hot, humid climate, which primarily affects sportswomen in the middle of summer. Many women are also concomitantly aware of negative mood swings, which can affect both personal and professional relationships. Mental wellbeing is also very fragile in this phase of the menstrual cycle. Therefore it is important for women to take care of themselves at this time, to listen to the signals their bodies send them and to inform the people around them about the situation if necessary, in order to avoid misunderstandings. In addition to the symptoms described, the appetite may also increase in this phase of the cycle.
Until now, two studies have shown a reduced maximum endurance performance during the second half of the cycle. With regard to strength training, stabilising the new training stimulus from the first half of the cycle and general rest and relaxation is recommended in this phase of the cycle.
To discover whether you experience different effects on your sporting performance over your cycle, it is recommended that you include information about your cycle in your training diary or use a cycle app to record the possible effects. Frequently, these effects are only obvious when they are deliberately tracked in the context of your cycle. Creating an awareness of this will both help you to get to know your body better and will enable you to better incorporate the effects of your cycle into your training and, if need be, improve your sporting performance. We recommend that you take care when selecting an app, as some providers pass on individual data to social networks like Facebook or other interested institutions without your knowledge. So research the different cycle apps on the internet before you install one on your smartphone.
References:
Carmichael, M. A., Thomson, R. L., Moran, L. J., & Wycherley, T. P. (2021). The Impact of Menstrual Cycle Phase on Athletes’ Performance: A Narrative Review. International journal of environmental research and public health, 18(4), 1667.
Enea, C., Boisseau, N., Ottavy, M., Mulliez, J., Millet, C., Ingrand, I., … & Dugué, B. (2009). Effects of menstrual cycle, oral contraception, and training on exercise-induced changes in circulating DHEA-sulphate and testosterone in young women. European journal of applied physiology, 106(3), 365.
Findlay, R. J., Macrae, E., Whyte, I. Y., Easton, C., & Forrest Née Whyte, L. J. (2020). How the menstrual cycle and menstruation affect sporting performance: experiences and perceptions of elite female rugby players. British journal of sports medicine, 54(18), 1108–1113.
Herzberg, S. D., Motu’apuaka, M. L., Lambert, W., Fu, R., Brady, J., & Guise, J. M. (2017). The effect of menstrual cycle and contraceptives on ACL injuries and laxity: a systematic review and meta-analysis. Orthopaedic journal of sports medicine, 5(7),2325967117718781.
Lei, T. H., Stannard, S. R., Perry, B. G., Schlader, Z. J., Cotter, J. D., & Mündel, T. (2017). Influence of menstrual phase and arid vs. humid heat stress on autonomic and behavioural thermoregulation during exercise in trained but unacclimated women. The Journal of physiology, 595(9),2823-2837.
Matter Brügger, S. & Neuenschwander, M. (2020). Zyklus und Leistungssport. SEMS-journal – Sports & exercise medicine Switzerland.
Neumann, G. & Buhl, H. (1981). Biologische Leistungsvoraussetzungen und trainingsphysiologische Aspekte bei trainierenden Frauen. Med. Sport. Berlin. 154-160.
O’Leary, C. B., Lehman, C., Koltun, K., Smith-Ryan, A., & Hackney, A. C. (2013). Response of testosterone to prolonged aerobic exercise during different phases of the menstrual cycle. European journal of applied physiology, 113(9), 2419-2424.
Shakalio S, Hainc Scheller C, Gronwald T. (2020). Menstruations-Zyklus Basiertes Training im Leistungssport. Leistungssport. 1:28-31.
