The Female Menses and Performance
Standardizing research practices and considering menstrual cycle phases can offer insights for optimizing female athletes’ training and performance.
Reference:
Did you know that within the sport performance literature examining female athletes and women’s sports, only 32-37% of research participants are female? The Canadian Sport Information Resource Centre (SIRC). (2024, June 27). Knowledge Nugget: Blog. https://sirc.ca/knowledge-nuggets/
Many coaches, especially males, may be unaware of the factors that can influence female performance during ovulation and menses, as the fluctuating performances are often interpreted as a ‘female thing.’ However, there are aspects unique to female athletes: the fluctuation of female sex hormones, the menstrual cycle, and the potential link to the risk of injuries. Dr. Kristin Johnson, a former professional softball player, established a career in female sports injury prevention research at the University of Iowa, foremost to study women’s ability to regulate areas of their central nervous systems that are important for movement and the potential influence of sex hormones (such as fluctuations in estrogen and progesterone). In addition, she studied how female athletes’ knee movement control, which can affect anterior cruciate ligament (ACL) injuries, changes during different parts of their menstrual cycles.
… Most athletes report that either their menstrual cycle or hormonal contraception interferes with their competitive performance…However, our understanding of hormonal influences on sports performance and injury is currently limited by a lack of robust research in this area …Healthcare treatment and sports training strategies are largely informed by studies of male athletes, she said, and only 6% of studies focused exclusively on female athletes…While a person’s sex is not relevant to every performance outcome, there are key sex differences in injury rates, which highlights the need for sports medicine research to include female athletes …
I interjected personal humor at an ASCA World Swimming Congress Presentation when asking male coaches in the front row: Are you married? YES! Do you understand your Wife? Hell, No! So, you coach 37 female swimmers? And… you have no clue about your wife? How about 37 females with 37 different monthly emotional swings? Lots of laughter on that one! Seriously, it is a big issue because hormonal changes before the monthly menses can add fluid up to 3-5 pounds! About 50% of high-level athletes use hormonal contraception. It is commonly assumed that hormonal contraception eliminates adverse physical side effects of the menstrual cycle and that it even prevents injury. These assumptions are incorrect as hormonal contraception, like the menstrual cycle, causes adverse side effects for many athletes, and current evidence does not support a protective effect from injury. Hormonal contraception will remain an important and necessary treatment for many female athletes for many different reasons. Still, we need to better understand the varying effects of different types of contraception (shot, pill, implant) on performance and injury. We must understand how the nervous system regulates movement to better understand athletic injury. A growing body of evidence indicates that the neural areas important for movement are sensitive to fluctuations in estrogen and progesterone. These findings support the potential for female sex hormones to influence injury rates by disrupting neural control of movement.
Legeriotz and Nobis (2022) state, “It is time to take on the challenge of investigating the complex effect of fluctuating female hormones on injury risk as this offers a chance to improve female athletes’ health and performance. New insights have been offered regarding the association of certain menstrual cycle phases, injury prevalence, and relationships between hormone levels and musculoskeletal changes such as ligamentous stiffness and knee laxity. However, uncovering real effects and truly understanding the physiological responses may reflect on potential bias regarding research questions and current approaches.
Menstrual Cycle and Postural Stability
Hormonal fluctuation or changes could have an indirect effect by impairing postural control. However, there is no consensus on whether and when postural control is impaired during the menstrual cycle. One explanation for those varying results may be that pronounced hormonally induced impairments in postural control only occur in a specific subpopulation of women: those who suffer from premenstrual symptoms. Postural stability in women with premenstrual symptoms is generally reduced compared to women without symptoms may be related to changes in kinesthesia, as women with premenstrual symptoms also displayed a greater threshold for detection of passive movement in the knee (Legeriotz and Nobis, 2022).
Menstrual Cycle and Cognitive Functioning
Hormonal changes during the menstrual cycle can affect not only physical and functional variables, such as knee laxity, postural control, or kinesthesia, which are related to movement control but also affect movement control itself, our brain. Sex hormones may have a far-reaching impact on brain function, with behavioral consequences and changes in neuropsychological processing (Horning, Lewis, and Derntl, 2020). It has been suggested that healthy women show small fluctuations in cognitive performance across the menstrual cycle, with low performance scores in the luteal phase for visuospatial and motor skills, attention and concentration, verbal memory, visual memory, working memory, and reaction time. However, associations between prefrontal cognitive functioning and hormone levels across the female menstrual cycle detected in one cycle can not necessarily be replicated when analyzing a second cycle, suggesting the occurrence of false-positive findings attributable to random variation, particularly in small samples.
Menstrual Cycle and Behavior
Hormone-associated changes in brain function may also change women’s behavior during the menstrual cycle, impacting injury prevalence. The motivation to train and compete is elevated around ovulation. It may be speculated that increased motivation changes movement characteristics, such as movement intensity, thereby affecting the risk of injury. In addition, behavioral experiments have indicated that risk-taking behavior changes along the menstrual cycle, with women willing to take higher risks around ovulation. It seems likely that increased risk-taking behavior may positively affect performance and competition outcomes while at the same time increasing the risk of injury.
Paludo, Paravlic, Dvoráková, and Gimonová (2022) examined the perceptual responses during the menstrual cycle with a hypothesis that in phases with major ovarian hormone concentration, an improvement of positive feelings and attenuation of negative ones will be perceived by athletes. As the main findings, the current review identified that some perceptual responses were better during ovulation (e.g., motivation and competitiveness) compared to the luteal or follicular phase. Negative perceptual responses were exacerbated during pre-menstruation (e.g., mood disturbance) and the menstruation period (e.g., menstrual symptoms and drop in vigor) compared to luteal and ovulation phases. Other responses, such as perceived effort, stress, and muscle soreness, were not found to be affected by the menstrual cycle.
A positive relation between ovulation and perceptual responses has been shown earlier, whereby women seem to present an increase in libido, energy, and competitiveness with mates (Motta-Mena and Puts, 2017). Therefore, it is reasonable to consider the period close to ovulation as an advantage for female athletes to maximize their performance in training settings. From a practical point of view, the coaches and practitioners can seize the opportunity to adjust the athletes' training load and/or intensity, which could lead to a major training adaptation. All the same, Julian and Sargent (2020) suggested some practical and future research considerations of a training periodization based on the menstrual cycle phase. The authors describe the importance of investigating the relationship between menstrual hormones and training responses in a longitudinally designed manner to verify a possible effect. However, it could be an expensive and impractical venture for small clubs. Validation of practical and cost-effective methods for monitoring hormone levels (e.g., calendar-calculation vs. hormone concentration), particularly for ovulation detection, can help optimize training periodization and link athletes' perceptual responses to training performance.
A study by Martines-Fortuny, Alonso-Calvete, Cuña-Carrera & Abalo-Núñez (2023) proposes that the number of female athletes has increased in recent years, but so has the incidence rate of injuries in female sports. Multiple factors, including hormonal agents, condition these injuries. It is estimated that the menstrual cycle may be related to the predisposition to suffer an injury. However, a causal relationship has not yet been established. The authors examined 138 articles, but only eight studies were found to meet the selection criteria for their study. Peak estradiol is associated with increased laxity, strength, and poor use of neuromuscular control. Thus, the ovulatory phase seemingly may be associated with an increased risk of injury. They conclude that hormonal fluctuations throughout the menstrual cycle alter values such as laxity, strength, body temperature, and neuromuscular control. This fact causes women to constantly adapt to hormonal variations, which exposes them to a higher risk of injury. In the authors’ review, the most susceptible to injury was the ovulatory phase, and only one study reported higher risk at the follicular phase. In comparison, two studies reported higher risk in the luteal phase. The reason for such discrepancies between the current results is the difference in establishing the menstrual cycle phases. In agreement, studies used self-reported cycle length to estimate the menstrual phase. Despite the discordance, five of the articles found greater injury during the ovulation phase. This recent study showed that estradiol concentrations and joint laxity were higher in the ovulatory phase.
Continuing with the injury etiology, strength, proprioception, and neuromuscular variations were also found, in addition to increased strength during the ovulatory phase. This fact can be explained by estradiol being closely related to muscle strength. Thus, estrogen seemed to improve the intrinsic quality of skeletal muscle by binding myosin to actin, improving muscle contractions. In contrast, neuromuscular control was inferior in the follicular and ovulatory phases. Prior research supported that the menstrual cycle can negatively alter neuromuscular control. These findings might be explained in the ovulation phase, where peak estradiol produces increased quadriceps strength, decreased muscle relaxation time, and increased muscle fatigability. On the other hand, other studies affirmed that estrogen or progesterone may influence the central nervous system and thus have a negative impact on neuromuscular recruitment. Considering the characteristics of the participants, the mean age of the women was homogeneous, ranging from 14 to 25. This is compatible with the fact that the mean age of onset of menarche in Spain is 12.6 years.
Conclusion:
Hormone variations during menstrual cycles appear to be related to an increased risk of injury, especially during ovulation. Moreover, laxity, neuromuscular control, and strength oscillate throughout the menstrual cycle, peaking in the ovulatory phase and coinciding with an estrogenic peak. For these reasons, women need to constantly adapt to hormonal variations, which exposes them to a higher risk of injury. The lack of scientific evidence is remarkable, and further research is needed. Likewise, sports injuries have a multifactorial etiology, and future research should consider all aspects of female athletes and sports practices to prevent them from being injured. What can we take from this research data? I agree with Julian and Sargent (2020), who suggested practical and future research considerations for training periodization based on the menstrual cycle phase: that longitudinal studies are needed to verify the effects. However, I agree with the researchers that further studies would be expensive and impractical for small clubs.
Nonetheless, we can assume that validating practical and cost-effective methods for monitoring hormone levels (e.g., calendar calculation vs. hormone concentration), particularly for ovulation detection, can help optimize training periodization and link athletes' perceptual responses to training performance. The most important outcome of the studies is a) the discovery that the menstrual cycle indeed plays a part in the performance of female athletes., b) may be linked to injuries during certain phases within the menses, and c) coaches who deal with the training of female athletes have to be more knowledgeable on this aspect.
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