Exploring the Impact of Menstrual Cycle Phases on Agility Performance in Semiprofessional Female Soccer Players

1. Introduction

Greater emphasis should be placed on studies involving women in the field of sports science, as the representation is notably low, with participation rates below 35% [1,2] It is essential to consider the complexity in women's sports as well, given the unique characteristic of women experiencing a menstrual cycle (MC) with hormonal fluctuations each month [3]. Nevertheless, the number of women engaging in sports continues to rise, with football being one of the most prominent disciplines, both at training and elite levels. Consequently, the MC emerges as a critical factor to consider, not only for athletic performance but also for training planning [4]

The MC is a physiological process of the body with different hormonal variations. This cycle spans the time between two menstrual or bleeding phases, encompassing distinct stages, and is considered normal or eumenorrheic if it lasts between 21 and 35 days [5] During this period, women undergo the different phases of the cycle: menstrual, follicular, ovulatory, and luteal. These phases are characterized by hormonal fluctuations [3] which influence the function of organs and tissues in the body, as well as energy levels, perceived exertion, mood, and various other factors that may impact athletic performance [6]

During the menstrual phase or early follicular phase (EFP), hormone levels of estrogen and progesterone are low (days 1–5 of the MC). In the late follicular phase (LFP), it has an estrogen peak (days 6–12 of the MC), which is often associated with an enhanced anabolic response to exercise. And in the mid-luteal phase (MLP), characterized by progesterone peaks (days 20–24 of the MC), a possible catabolic effect is observed [7,8,9]. These phases are therefore more likely to exhibit variations or differences in performance [9,10]

Currently, scientific literature has not identified clear evidence regarding how the phases of the MC may influence athletic performance [9]. Neither is it clear in more specific capacities such as strength, as Colenso-Semple et al. [11] comment that there is no influence, while Niering et al. [12] do observe some differences towards the LFP, while in endurance performance variables, Taylor et al. [13] also found no differences according to MC phases. Understanding how hormonal fluctuations throughout the MC can impact athletic performance is therefore essential for coaches and physical trainers, as female athletes will undergo training and competitions during the various phases of the cycle [14,15]. This knowledge is key to optimizing the training process, improving load adaptation, and implementing preventive strategies, taking into account the specific characteristics of each phase of the cycle [16].

Performance in football is influenced by numerous physical, physiological, psychological, social, technical, and tactical variables [17], making its analysis through performance indicators inherently complex [18]. So agility is defined as the ability to change body position quickly and effectively [19]. This skill is essential in football, as it enhances players' ability to move rapidly and efficiently across the field. Given that the MC is an additional variable to consider in women's sports, it may influence athletes' agility due to hormonal fluctuations [20] or alterations in muscle elasticity and tone [21], and other physical and physiological changes occurring throughout the cycle. Nowadays, it is not clear how exactly the MC phases affect the performance in football [22]. Understanding how the MC affects agility could serve as an effective tool for designing training plans aimed at improving agility, thereby enhancing performance, preventing injuries, improving directional changes, dribbling skills, and even reaction times in unexpected situations [23]

Due to the controversy, lack of knowledge, and researches regarding how the phases of the MC may influence athletic performance [1,3,9,11,12,14,24], so there is a recognized need to examine the influence of MC phases on agility in female athletes. Therefore, the objective of this study are to analyze how the different phases of the MC affect agility in female football players and to analyze the influence of MC phases on perceptual variables.

2. Results

2.1. T-Test and MC Phases

No significant differences were found between the phases of MC and the Agility test (F_(2,20) = 1.86; p = 0.18). There was a trend towards improvement in the mid-luteal phase (11.34s) compared to the menstrual (11.58s) and follicular (11.47s) phases, with these differences being more notable in the first part of the T-test (Table 1).

2.2. Perceptual Variables and MC Phases

No significant differences were found between any of the perceptual variables or RPE and the phases of the MC (p > 0.05). Better results were obtained in the late follicular phase for all perceptual variables related to the WQ (Table 2).

3. Discussion

The results obtained show that participants performed better in the agility test (T-Test) during the MLP compared to the EFP (0.24s) and the LFP (0.13s), although no significant differences were observed. The perceptual variables showed better results in the LFP, with greater differences in fatigue, stress, and the total WQ score.

Currently, there are few studies which have analyzed how the phases of the menstrual cycle influence agility performance. Agility is essential as it combines accelerations and decelerations as quickly as possible, reflecting the developed force ratio capacity [33]. According to hormonal impact, strength capacity is greatly influenced by estrogen and progesterone, as estrogen has a positive effect, providing a neuroexcitatory effect, and progesterone inhibits cortical excitability [34]. In contrast, [9], after analyzing 78 studies, found only a trivial effect of worse performance in the menstrual phase compared to the others. Likewise, Carmichael et al. [10] did not found differences in anaerobic performance. These findings align with the results obtained in the present study, which also did not show significant differences in agility performance, although the trend was more favorable towards the MLP.

More specifically, in studies analyzing agility tests, Juillard et al. [35] observed that in the Illinois agility test performed with football players, the results were very similar across the different phases of the MC. This was also observed by Oğul et al. [36] with physically active women, although with a slight tendency toward the MLP. This could be due to the fact that stiffness does not seem to vary significantly during the MC [37]. On the other hand, Sawai et al. [38] found that agility performance worsened during the EFP, possibly due to fluid retention during this phase. Our results seem to align with the current evidence, showing no significant differences, although there is a slight trend towards improvement in the MLP. However, further specific study is needed to better understand the effect that the phases of the menstrual cycle have on agility performance.

Sports performance should not only be measured objectively, also the subjective and perceptive aspects should also be taken into account, as these perceptual variables are an important aspect in studies related to women and the MC [10]. In general, women experience more negative symptoms related to the MC during the EFP, with over 50% of athletes reporting such symptoms [39], followed by the late luteal phase, which can affect up to 83% of athletes, leading to more fatigue or poorer physical performance perception [40]. In our findings, an improvement in all perceptual variables is observed during the late follicular phase, possibly due to the increased production of estrogen, which indirectly leads to an increase in serotonin hormone [41], potentially improving the mood and fatigue of athletes.

Sleep quality can be affected by the phases of the MC, mainly showing poorer quality during the premenstrual and menstrual phases [42], with possible improvement during the transition from the follicular to the luteal phase [43]. In this case, the perceived sleep quality of our athletes was worse during the menstrual phase, as also observed by Osmani et al. [44], possibly due to menstrual symptoms. The RPE does not show differences based on the phases of the menstrual cycle, which is corroborated by several studies reviewed by Ekenros et al. [45], who also found no differences in this variable. According to the results obtained, perceptual variables based on the menstrual cycle should be taken into account to properly periodize training. This aligns with the comments made by Julian et al. [46], but further studies should continue to focus on objective performance while considering perceptual variables, in order to eventually fit this into the practical context with correct individualization for each athlete.

Despite the findings obtained, some limitations should be considered. First, hormone concentration measurements were not performed through blood analysis; however, LH ovulation kits and self-recording of menstrual cycle phases via a mobile application were used to determine the phases of the menstrual cycle as objectively as possible, as recommended by McNulty et al. [47]. Second, the number of participants was limited (n = 11), but with "moderate statistical power" for this sample. Third, although the participants were familiar with the agility test and performing direction changes, there may have been a learning effect through the different test attempts.

4. Materials and Methods

Experimental Approach to the Problem

A cross-sectional cohort experimental study with repeated measures was conducted to analyze the effect of the menstrual cycle (MC) phases on agility, perceptual variables from the Hopper scale, and the subjective perception of effort (RPE). The MC phases were determined using two tools: a calendar and a luteinizing hormone (LH) urine kit [25] Participant assessments were conducted during three phases of the menstrual cycle: the menstrual phase or early follicular phase, the preovulatory phase or late follicular phase, and the postovulatory phase or mid-luteal phase.

Subjects

11 female football players were selected from the 3rd tier of the Spanish Football Federation (3rd RFEF), corresponding to TIER 3 level [26], (mean ± standard deviation): age = 18.7 ± 3.3 years; height = 1.62 ± 0.07 m; weight = 58.6 ± 6.7 kg. The inclusion criteria were: i) having a regular MC (21-35 days) in the last 6 months; ii) at least 2 years of football experience; iii) not using contraceptives; iv) not suffering from any disease or injury. The procedure and instruments to be used were explained to the participants prior to the start of the protocol. Informed consent was signed by each participant, which addressed the protection of personal data and ethical criteria for human experimentation, as well as the highest confidentiality and scientific rigor as detailed in the 1975 Declaration of Helsinki. Furthermore, the study was previously approved by the Ethics Committee (CEI 03-2024). The sample size was selected based on convenience, and a post hoc power analysis was conducted using G*Power software (version 3.1.9.7) with α = 0.05, power (1 − β) = 0.8, and an effect size of 0.25, with the statistical test ANOVA: repeated measures within factors, yielding a moderate power of 0.37.

Protocol

The participants were scheduled 3 times during the study, corresponding to their training field and during the 3 phases of the MC to be analyzed: i) menstrual phase, between days 1-5; ii) late follicular phase, between days 6-12; and iii) mid-luteal phase, between days 20-24.

Determination of the MC phases: The MC of the participants was monitored using the mobile application (Clue® Period Tracker, BioWink GmbH, Berlin, Germany) and the LH ovulation kit (Ovulation LH Test Strip, Cuckool, Nantong, China). The tests were conducted during the menstrual phase (2.82 ± 1.08 days), late follicular phase (10.2 ± 1.17 days), and mid-luteal phase (21.8 ± 1.33 days). Once a positive LH result was confirmed, the test was repeated a few days later, approximately between days 20-24 of the menstrual cycle. The average day on which the players tested positive with the ovulation kit was 14.7 ± 1.27 days.

Agility Test (T-Test): This test was chosen to assess the agility of each player, being a valid and reliable test for this purpose [27,28]. Two valid attempts were made, with a 3-minute rest between them to ensure complete recovery [28,29]. The players started the test with both feet behind the sensor (BlazePod® Reaction Training System, BlazePod Ltd., Tel Aviv, Israel), ran forward 9.14 meters, and touched the next sensor. Then, the players moved 4.57 meters to the right to touch another sensor with their right hand, followed by a lateral movement to the left for 9.14 meters to touch the sensor with their left hand. They then moved again 4.57 meters to the right to touch the second-to-last sensor. Finally, the players ran backward to reach the final sensor. Tests in which players crossed their feet, missed a BlazePod sensor, or did not face forward were considered invalid [30]

Perceptual Variables: During the intervention days, the wellness questionnaire (WQ) test was administered before the test. It was also used the day after the test to assess the participants' sleep quality, fatigue, muscle soreness, and stress variables, with values ranging from 1 to 7, where 1 represented very good and 7 represented very bad [31]. The range of perceived effort (RPE) (scale 1-10) [32] was also recorded after each T-Test to determine the participants' subjective effort perception. All participants were familiarized and trained on the proper use of these tools.

Statistical analysis

A descriptive analysis was conducted, with data presented as mean ± standard deviation (SD). All data were recorded in an Excel database, and the statistical analyses were performed using Jamovi software. A repeated measures ANOVA was conducted to compare execution time, T-test sector performance, and perceptual variables across the three phases of the CM. Normality was assessed using the Shapiro–Wilk test (p < 0.05).

5. Conclusions

No significant differences were found regarding the influence of MC phases on agility, although there was a slight trend of improvement in the MLP. The results on perceptual variables show an improvement in the LFP, without statistical significance, which could be an aspect to consider when creating a correct individualized training periodization in a real-world context for athletes. Both objective and perceptual variables should be taken into account for any study or training based on the MC.