Increasing participation of women in sport has increased the interest in physiological and metabolic responses of women to exercise.1 In the last decade, studies have been conducted to understand the relationship between physical activity and menstrual cycle often focusing on the mechanism of hormones involved in menstruation. At each stage of the menstrual cycle, hormonal changes and different physiology occur in the body of athlete women affecting their working capacity; awareness of the women physiological ability has an irrefutable significance in understanding the interactions between physical activity and various phases of the menstrual cycle.1

The menstrual cycle can affect performance. Hormonal disorders during the menstrual cycle can cause changes in muscle strength, endurance, and metabolism.2 Many biological factors, such as menstrual cycles, use of contraceptive pills, physical fitness, nutritional status, and stress can affect the interaction between physical training and hormonal responses.3 Some physiological factors and athletes performance may vary throughout the menstrual cycle. The changes seen in these physiological characteristics in various systems are related to hormonal levels fluctuations affecting the neuromuscular system and metabolic function of the body.4

One of the most important and controversial issues in this regard is how interactions between different phases of the menstrual period affect some hormones and physiological capabilities such as strength, muscular endurance, and anaerobic power. At each stage of the menstrual cycle, hormonal and different physiological changes occur in the body of women affecting their physical working capacity. Every month, from the onset of the first menstruation until the menopause, one of the two ovaries produces an ovum that is released into the abdominal cavity during ovulation and transported to the uterus. If ovum is not fertilized, the endometrium breaks down and is excreted with ovum in the menstrual flow within 3–5 days.2 The mean duration of each period is 28 days, which can vary between 20 and 45 days in normal women. The ovaries are stimulated by the anterior pituitary gonadotropic hormones, which are FSH and LH. The ovaries also secrete estrogen and progesterone hormones. In each sex, there is a periodic increase and decrease in secretion of this hormones.2 During a normal menstrual period, women are subject to constant changes in sex steroid hormones. Estrogen begins to increase in the middle of the follicular phase reaching its peak before ovulation. Estrogen and progesterone increase in the middle of the luteal phase causing extensive physiological effects.5 Throughout the cycle, reproductive performance in women is controlled by the hypothalamus–pituitary axis and as a result of large and predictable fluctuations in estradiol and progesterone. Sex steroid hormones can affect the central nervous system at the plasma level, which is because steroids can easily pass through the blood–brain barrier because of high fat solubility.6

At each stage of the menstrual cycle, there are potential and hidden changes in the level of sex hormones such as estrogen, as well as different physiological changes in the body of women affecting their physical working capacity. Some researchers have argued that increasing estrogen accelerates the function of respiratory nerves. From the past, many studies have been carried out on the effects of various biological conditions on the various sports activities and vice versa. One of these biological factors is the three menstrual cycles phase in women. In the past, they believed that hard exercises were not useful to women and did not affect their physical strength. However, many investigations have violated this theory7 and the cause of women increased power is due to increased ability to strengthen and coordinate movements. Most women are advised to restrict or stop their sport activities during menstrual cycle. These recommendations are more serious about endurance and strength exercises and important competitions, and generally encourage women to do the least exercise during menstrual cycle. Various theories have been presented to explain the relationship between different types of athletic and menstrual cycles. Some argue that increasing or decreasing certain hormones may affect strength and endurance.1 However, these theories or other theories are not explicitly approved and there are ambiguities around them. In some studies, it has been shown that a group of weight lifters women had a weaker performance before menstruation, while they showed better records at menstruation. Also, they achieved better results at post menstruation.1

During the year, the level of production of female hormones varies according to the menstrual cycle. The four hormonal markers of the menstrual cycle (estrogen, progesterone, FSH and LH) exhibit constant changes throughout the cycle. These female steroid hormones affect the automatic nervous system and metabolism. Therefore, physiological behaviors along with menstrual cycles can affect the performance parameters of the sport activities.8 However, the effect of the phases of the menstrual cycle on physical function, especially muscular strength and muscular endurance is unknown. In some studies, the effects of menstrual cycles on athletic exercise are vague. Focusing on studies, the use of hormonal effects and electrical stimulation to ensure maximal neuronal activation show that the fluctuations of female sex hormones throughout the menstrual cycle do not affect the contraction of muscle. However, the menstrual cycle may have an effect on anaerobic exercise performance, endurance, and muscle strength. However, research are lacking to prove these theories (the ineffectiveness of exercise with menstrual cycle or the effectiveness of physical activity with the menstrual cycle) and limited studies have investigated the ineffectiveness of several physical factors and menstruation ages not ending in a clear and conclusive result. Therefore, it seems that an examination of the ambiguities in this field can be helpful in solving questions about women time of activities and competition. Accordingly, we will attempt to compare the difference and relationship between strength, endurance, anaerobic power and hormonal changes (FSH, LH) with the triple (follicular, ovulation, luteal) phase of the menstrual cycle of active young girls.

Participants characteristic that completed the study are shown in Table 1. The results of ANOVA suggested that no difference were found between leg press and bench press 1RM in three phases (F=3.27, P=0.23; F=1.96, P=0.13, respectively). It was also demonstrated that muscular endurance of legs and chest had no significant difference (F=0.64, P=0.50; F=1.36, P=0.33, respectively). There was no significant difference for anaerobic power in three phases (F=1.36, P=0.45). However, Significant differences were observed in LH and FSH levels in three phases (F=57.76, P=0.001; F=258.23, P=0.001, respectively, Table 3).

The results of LSD test showed that changes were significant in LH and FSH levels between follicular phases with ovulation, follicular with luteal and ovulation with luteal (P≤0.05, Fig. 1).

Figure 1.

Mean data (±SD) for LH (A) and FSH (B) in the three phase (follicular, ovulation, luteal) of menstrual cycle. *P≤0.05 between groups.

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The results of Pearson correlation coefficient indicated no independent association between the leg press and bench press strength and muscular endurance in three phases (follicular-ovulation: r=0.31, P=0.55; follicular-luteal: r=−0.44, P=0.42; ovulation-luteal: r=0.18, P=0.63, for muscular strength leg press; follicular-ovulation: r=0.10, P=0.79; follicular-luteal: r=−0.39, P=0.29; ovulation-luteal: r=0.17, P=0.09, for muscular strength bench press; follicular-ovulation: r=0.23, P=0.55; follicular-luteal: r=−0.10, P=0.42; ovulation-luteal: r=0.16, P=0.63, for muscular endurance leg press; follicular-ovulation: r=0.23, P=0.79; follicular-luteal: r=−0.12, P=0.69; ovulation-luteal: r=0.18, P=0.19, for muscular endurance bench press, Table 2). Also, there was no independent association in anaerobic power between follicular with ovulation and follicular with luteal phases (r=0.29, P=0.48; r=0.18, P=0.65, respectively). To the contrary, significant relationship was observed in anaerobic power between ovulation with luteal phase (r=0.78, P=0.03). The results indicated that there was no association in the LH between follicular with ovulation phases, follicular with luteal phase, ovulation with luteal phases (r=0.27, P=0.48; r=−0.20, P=0.39; r=−0.10, P=0.67, respectively). Also, no association in FSH between follicular with ovulation phases, ovulation with luteal phases (r=−0.06, P=0.80; r=0.15, P=0.51, respectively). Nevertheless, the results indicated a moderate and significant negative relationship in the FSH between follicular with luteal phases (r=−0.48, P=0.03, Table 2).

The purpose of this study was to investigate and compare the relationship between strength, muscular endurance, anaerobic power and hormonal changes with three phase (follicular, ovulation, luteal) in menstrual cycle of active young girls. The results of the study showed that there was no significant difference between strength, endurance and anaerobic power in the three phases of menstruation. In contrast, there was a significant difference between the levels of LH and FSH in follicular, ovulation and luteal phase.

The menstrual cycle can be divided into three phase, separated by estrogen and progesterone ratios: in the follicular phase, there is low estrogen and progesterone, in the ovulation phase, estrogen is high and progesterone is low, and in the luteal phase, estrogen and progesterone levels are high.13 Estrogen appears to enhance carbohydrate tolerance through its effect on lipolytic enzymes and glucose regulating hormones such as growth hormone, catecholamines and insulin, but progesterone has a counterproductive effect.13

The results of this study indicated that there was no significant difference between strength and muscular endurance in different phase of menstrual cycle. In this regard, Vaiksaar et al.14 indicated that endurance activities were not affected by the natural phase of the normal cycle. Most studies have examined the effect of endurance training on blood androgen concentration. It has been observed that plasma concentrations of total testosterone, free testosterone and androstenedione increased after long term endurance exercises under laboratory and environmental conditions.15,16 Recently, a study investigated the effect of long-term training on young women with a different hormonal status (age range from 18 to 30 years) including eumenorrheic women and women using oral contraceptives. Their results indicated that there was no significant change in exercise activity in relation to the menstrual cycle.17 Also, the research conducted by Vaiksaar et al.18 on women showed that the menstrual cycle steps have no effect on the oxidation of the substrate and the concentration of lactate during rowing exercises with 70% VO2max. In their study, they found that there was no difference in the maximum power between the luteal and follicular phases, and female athletes should not be concerned about their menstrual cycles and its impact on exercise. Does not seem, muscle strength to have a significant fluctuation during the ovulation phase of the cycle.13 Investigations have shown that there was no significant change in the strength of quadriceps muscle in three phases of menstrual cycle and there was no significant relationship between strength indices and the concentration of female reproductive hormones.13 Also, Sunaga et al.19 concluded that changes in female hormones in the menstrual cycle had no effect on the muscle strength and hypertrophy. The results of Bennal et al.20 showed that there was no significant change in the maximum voluntary contraction of handgrip strength during different phases of the menstrual cycle.

Contrary to these findings, some studies have shown better performance in some phase of the menstrual cycle. The results of research by Julian et al.21 showed that endurance function decreases in the middle of the luteal phase. In addition, researchers have argued that estrogen may improve endurance activities by altering the metabolism of carbohydrates and lipids with progesterone antagonistic action.22 Pallavi et al.4 concluded that cyclic changes in endogenous sex hormones increase muscle strength in the follicular phase of the menstrual cycle. Therefore, these hormones seem to adjust these parameters in the age group before menopause. Also, Sung et al.23 showed that strength training based follicular phase had a greater effect on muscle strength, diameter of muscle fibers of type II and nuclei-to-fiber ratio in comparison with the strength training based on luteal phase in untrained and moderately trained women. Marília et al.24 showed that women had a significant reduction in the maximum ratio of hamstring muscle strength to quadriceps during the follicular phase compared to the luteal phase. Also, Tenan et al.25 showed a reduction in maximum knee extensors strength in the middle of the luteal phase. Tenan et al.26,27 concluded that the reduction of MVC (maximal voluntary contraction) in the luteal phase may be due to the effects of neuroinhibitory progesterone in the motor cortex and the effect of the menstrual cycle on both engines and the autonomic nervous systems. The lack of similar results may be due to differences in age, hormonal levels, progesterone levels, progesterone receptor sensitivity, genetic factors, menstrual cycle length, and differences in the counting of days at each stage of the menstrual cycle.

The findings of the present study indicated that there was no significant difference between the anaerobic powers of the subjects in the three phase of the menstrual cycle. In this regard, Tsampoukos et al.1 investigated the effects of menstrual cycle on speed performance (30s sprint with 2min of recovery) and concluded that hormonal changes caused by menstrual cycles were not associated with maximum intensity sprint and metabolic responses due to exercise. Also, Wiecek et al.28 concluded that hormonal changes in the menstrual cycle had no effect on the anaerobic function, speed start, or the women anaerobic endurance. In the study of Julian et al.21 there was no difference in speed between different phases of the menstrual cycle at 30m. They concluded that the sprint times of 5m, 10m and 30m were not affected by the steps of the menstrual cycle. The ineffectiveness of the various phases of the menstrual cycle in speed performance has also been reported in some previous studies.29 Also, the results of Julia et al.21 showed that people jumping is not affected by the menstrual cycle.

However, in some studies, it has been shown that the anaerobic power can be different in the menstrual cycle. The results of Somboonwong et al.30 showed that speed performance along with an increased basal body temperature is improved during luteal phase. In addition, it seems that ovarian hormones may affect the sprint or recovery through effect on strength.

In some studies, it has been claimed that carbohydrate loading and basal metabolism increase in the luteal phase, and at this stage, better performance in physical fitness tests is expected than the other phase of the menstrual cycle. However, due to the fact that tests such as power and strength take a little time, the glycogen storage, however small, is sufficient for this period.31,32 In other words, the effects of different phase of menstruation on changes in glucose consumption can be seen only when the demand for glucose consumption exceeds the critical level.31 Therefore, there should be no difference between the different phases of menstrual cycle in the implementation of these activities.

The results of this study indicated a significant difference between the levels of LH and FSH in follicular, ovulation and luteal phase. No research has been done in this regard, but, as stated, hormonal changes in FSH, LH, estrogen and progesterone are constantly changing throughout menstrual cycles. This cycle can be divided into halves. The first half of the menstrual cycle is called follicular phase, and the pituitary hormones, FSH and LH are dominant.2 The second half is called the luteal phase characterized by an increase in the steroid hormones of the ovary, estrogen and progesterone. The hypothalamic release agent (the gonadotropin releasing factor) stimulates the secretion of follicle stimulating hormone. This material then stimulates the release and growth of the dominant follicle in the ovary. The ovaries secrete 17-boestradiol (17 beta-estradiol) in response to increased levels of FSH and LH in the 24-h peak before ovulation. Increasing estradiol through positive feedback stimulates the hypothalamus–pituitary axis to secrete LH, thereby increasing the mediators of the menstrual cycle during ovulation. After ovulation, the remaining cells in the ovary produce estradiol and progesterone. These hormones act through negative feedback for inhibiting the production of more FSH and LH. If the ovum is not fertilized, then fertilization is malignant and the cycle begins again.2 In addition, the difference in the half-life of FSH (170min) and LH (60min) affects their plasma concentrations, and therefore, their amount varies in different phase of development of sexual maturation and various phase of menstrual cycle.33

In summary, the present study showed that muscle strength, muscular endurance and anaerobic power of young women are not different at different phase of the menstrual cycle, but the levels of LH and FSH have varied throughout the different phase. Accordingly, it seems physical activity in different phase of women's menstrual cycle does not have a negative effect on their performance, and young women can continue their sports activities during the menstrual cycle.

“All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.”

Authors declare that they don’t have any conflict of interests.