Eumenorrhea, or normal menstrual periods, is an easily disrupted phenomenon and chronically low levels of ovarian hormones are not uncommon in female athletes. However, the impact of this variation of hormone levels in both regularly and abnormally menstruating athletes and its relation to athletic performance and condition has not been extensively studied. Not only does irregular menstrual function affect performance, but also menstrually related symptoms during regular menstrual cycles may affect competitive fitness. The research presented in this thesis was undertaken to 1) Quantitatively evaluate water retention and its influence on athletic performance during regular menstrual cycles, 2) examine the current state of the female athletic triad (FAT) in Japanese college athletes, 3) quantify muscle damage response due to differing ovarian hormone levels after acute heavy exercise, and 4) examine muscle damage response due to differing ovarian hormone levels after a 4-day training camp. In the first study, fluid retention in the calves of eumenorrheic female students (non-competitive athletes) was quantitatively evaluated over their menstrual cycle using magnetic resonance imaging (MRI) and the relationship between cyclical water retention and athletic performance were determined. The menstrual cycle was divided into 5 phases: menstrual, follicular, ovulatory, early luteal, and late luteal with sampling done in either morning (AM) or afternoon (PM) sessions. At each phase, MRI of the calf (7:00-8:00, 14:00-16:00), body composition and hormones (7:00-8:00), and athletic performance (14:00-16:00) were evaluated. Estradiol levels decreased significantly in the menstrual phase and the follicular phase compared to the early luteal phase. Menstrual phase estradiol levels were significantly lower compared to the ovulatory phase, and the late luteal phase. Progesterone levels decreased significantly in the menstrual phase and the follicular phase compared to the ovulatory phase, the early luteal phase, and the late luteal phase. AM T2 signals were significantly lower in the menstrual phase compared to the ovulatory phase but no other phases. PM T2 signals increased significantly in the menstrual phase compared to the follicular phase, ovulatory phase, and the late luteal phase, and the difference between the AM and PM values increased significantly in the menstrual phase compared to the other 4 phases. A negative correlation between fluid retention and agility was observed. Thus, fluid retention fluxing during menses could influence athletic agility. The effect of fluxing on athletic performance was shown to vary over the menstrual cycle correlating with water retention in the low ovarian hormone phase. However, the current state of irregular menstrual status and its effect on competitive performance has not been clearly explained in Japanese athletes. Therefore, the rates of dysmenorrhea, musculoskeletal injuries and poor nutrition in Japanese collegiate athletes were investigated in the second study and the correlation of sport intensity, training volume and competitive level to the risk factors of the female athlete triad (FAT) were examined. Female athletes suffer a higher rate of menstrual problems, muscle and/or skeletal injuries and poor nutrition intake than non-athletic women. Therefore, the link between these problems (known as the FAT and the intensity), training amount and competitive level of college sports in Japanese women were investigated. In this study, 531 Japanese collegiate athletes and 20 non-athletes responded to the Japanese-language questionnaire and a classification system that grouped sports by intensity types was used. Higher sport intensities were found to cause menstrual problems and poor nutrition intake, but higher sports training volume caused more injuries. Competitive level only related to menstrual problems but not as much as to intensity. Therefore, coaches in high intensity or high training volume sports are recommended to take special care (especially with regard to menstrual irregularities, including amenorrhea) to monitor their athletes for FAT risk and maintain competitive performance. In the third study, the effects of chronically low ovarian hormone levels (as opposed to normally cycling levels) on post-exercise muscle damage biomarkers and tendon stiffness were investigated. Nineteen female college athletes were enrolled into two groups: the menstrual dysfunction group (DYS) and the cyclic menstruation group (CYC). Test conditions (rest or exercise) were taken over a 3-week period. The exercise condition involved 6 sets of 5 squats at 90% 1-RM with a 3 minutes rest between each set while resting consisted of sitting quietly for 30 minutes. Blood chemistry, muscle soreness and tendon stiffness were measured before, immediately after, 30 minutes after, 60 minutes after, and 24 hours after each condition. Menstrual cycles were longer in DYS athletes and estrogen levels were lower in all weeks. CK level in DYS were significantly higher than the CYC group (DYS lowest value: 200U/L pre-exercise vs. CYC highest value: 200U/L 24h after exercise). Biceps femoris tendon stiffness significantly increased 24 hours post-exercise only in the DYS group. To conclude, a chronically low estrogen state due to menstrual irregularity adversely impacts post-exercise soreness, muscle damage and tendon stiffness which suggests that menstrual status must be factored into training and exercise recovery programs. In the fourth study, the effects of chronically low ovarian hormone levels (as opposed to normally cycling levels) on post-training camp muscle damage biomarkers and tendon stiffness were investigated. Twenty-eight female college basketball players were enrolled into two groups: the menstrual dysfunction group (DYS) and the cyclic menstruation group (CYC) according to their ovarian hormone levels. Ovarian hormone levels, muscle damage markers, blood pressure and heart rates, subjective muscle soreness, scores for emotional distress, and muscle stiffness were evaluated 2 weeks prior to a 4-day training camp (P1), the last day of the training camp (P2), the day after the last day of the training camp (P3), 2 days later (P4), and 2 weeks later (P5). Estradiol and progesterone levels were significantly lower in DYS compared to CYC. Serum CK and LD levels were elevated in P2 and P3 in both groups with showing a significant difference between groups in P1 and P2. Furthermore, biceps femoris muscle stiffness was significantly elevated in P2 and P3 in both groups while showing a significant difference between DYS and CYC in P3 and P4. Gastrocnemius stiffness was elevated significantly in P3 compared to P1, and only DYS in P4 showed a significant difference between CYC in P2 and P3. Therefore, a chronically low estrogen state due to menstrual irregularity adversely impacts posttraining camp muscle damage and tendon stiffness which suggests that menstrual status must be factored into training and exercise recovery program.
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