Influence of Menstrual Cycle and Oral Contraceptive Phases on Bone (re)modelling Markers in Response to Interval Running.

To explore how sex hormone fluctuations may affect bone metabolism, this study aimed to examine P1NP and ß-CTX-1 concentrations across the menstrual and oral contraceptive (OC) cycle phases in response to running. 17ß-oestradiol, progesterone, P1NP and ß-CTX-1 were analysed pre- and post-exercise in eight eumenorrheic females in the early-follicular, late-follicular, and mid-luteal phases, while 8 OC users were evaluated during the withdrawal and active pill-taking phases. The running protocol consisted of 8 × 3min treadmill runs at 85% of maximal aerobic speed. 17ß-oestradiol concentrations (pg·ml-1) were lower in early-follicular (47.22 ± 39.75) compared to late-follicular (304.95 ± 235.85;p = < 0.001) and mid-luteal phase (165.56 ± 80.6;p = 0.003) and higher in withdrawal (46.51 ± 44.09) compared to active pill-taking phase (10.88 ± 11.24;p < 0.001). Progesterone (ng·ml-1) was higher in mid-luteal (13.214 ± 4.926) compared to early-follicular (0.521 ± 0.365; p < 0.001) and late-follicular phase (1.677 ± 2.586;p < 0.001). In eumenorrheic females, P1NP concentrations (ng·ml-1) were higher in late-follicular (69.97 ± 17.84) compared to early-follicular (60.96 ± 16.64;p = 0.006;) and mid-luteal phase (59.122 ± 11.77;p = 0.002). ß-CTX-1 concentrations (ng·ml-1) were lower in mid-luteal (0.376 ± 0.098) compared to late-follicular (0.496 ± 0.166; p = 0.001) and early-follicular phase (0.452 ± 0.148; p = 0.039). OC users showed higher post-exercise P1NP concentrations in withdrawal phase (61.75 ± 8.32) compared to post-exercise in active pill-taking phase (45.45 ± 6;p < 0.001). Comparing hormonal profiles, post-exercise P1NP concentrations were higher in early-follicular (66.91 ± 16.26;p < 0.001), late-follicular (80.66 ± 16.35;p < 0.001) and mid-luteal phases (64.57 ± 9.68;p = 0.002) to active pill-taking phase. These findings underscore the importance of studying exercising females with different ovarian hormone profiles, as changes in sex hormone concentrations affect bone metabolism in response to running, showing a higher post-exercise P1NP concentrations in all menstrual cycle phases compared with active pill-taking phase of the OC cycle.

Sex and educational level differences in physical activity and motivations to exercise among Spanish children and adolescents.

Children and adolescents worldwide, especially girls, do not meet moderate to vigorous physical activity (MVPA) guidelines, a situation which is related to obesity and other comorbidities. Sex/gender differences in the practice of MVPA and motivations to engage in physical activity have not been previously examined among Spanish students considering different educational levels. Therefore, the purpose of this study was to explore these differences and analyse if motivations mediate the relationship between educational levels and MVPA in a large sample of students. From different schools in the Madrid region (primary: 11,122; lower secondary: 12,379; upper secondary: 3228) 26,729 students (13,491 boys and 13,238 girls; 9-19 years old) were recruited to participate in this study. The short form of the International Physical Activity Questionnaire and the third version of the Behavioural Regulation in Exercise Questionnaire were used to evaluate, MVPA and motivations to exercise, respectively. Two-way ANCOVA and a mediation analysis were performed. Female students were found to be less active than males (43.4±38.7 and 58.6±45.9 min of MVPA; p < 0.001; ηp2 = 0.023) and showed lower intrinsic (ηp2 = 0.003), and integrated (ηp2 = 0.007) motivations than their male counterparts (p < 0.001). Primary school students were more active than lower and upper secondary students (53.3±44.2, 49.9±42.3 and 48.0±42.8 min of MVPA; p < 0.001; ηp2 = 0.002) and also presented higher intrinsic (ηp2 = 0.011) and integrated (ηp2 = 0.010) motivation than secondary school students (p < 0.001).    Conclusion:   Among Spanish children and adolescents, females showed lower levels of MVPA and intrinsic and integrated motivation across all the educational levels, and among primary school students in comparison to secondary school. This suggests that inner motivation is more determinant of increased engagement in MVPA and thus, there is need to reinforce it before the transition to secondary school and with special focus on females' preferences. What is Known: •Many children and adolescents worldwide, do not meet physical activity (PA) recommendations. • Within the self-determination theory, autonomous motivation seems to be the main responsible of greater PA levels. What is New: •This study shows for the first time sex and educational level differences in PA levels in a representative sample of Spanish students (9-19 yrs). •Autonomous motivation decreased from primary school onwards and was lower in female students than in their male counterparts.

Menstrual cycle affects iron homeostasis and hepcidin following interval running exercise in endurance-trained women.

PURPOSE: Menstrual cycle phase affects resting hepcidin levels, but such effects on the hepcidin response to exercise are still unclear. Thus, we investigated the hepcidin response to running during three different menstrual cycle phases. METHODS: Twenty-one endurance-trained eumenorrheic women performed three identical interval running protocols during the early-follicular phase (EFP), late-follicular phase (LFP), and mid-luteal phase (MLP). The protocol consisted of 8 × 3 min bouts at 85% of the maximal aerobic speed, with 90-s recovery. Blood samples were collected pre-exercise and at 0 h, 3 h and 24 h post-exercise. RESULTS: Data presented as mean ± SD. Ferritin were lower in the EFP than the LFP (34.82 ± 16.44 vs 40.90 ± 23.91 ng/ml, p = 0.003), while iron and transferrin saturation were lower during the EFP (58.04 ± 19.70 µg/dl, 14.71 ± 5.47%) compared to the LFP (88.67 ± 36.38 µg/dl, 22.22 ± 9.54%; p < 0.001) and the MLP (80.20 ± 42.05 µg/dl, 19.87 ± 10.37%; p = 0.024 and p = 0.045, respectively). Hepcidin was not affected by menstrual cycle (p = 0.052) or menstrual cycle*time interaction (p = 0.075). However, when comparing hepcidin at 3 h post-exercise, a moderate and meaningful effect size showed that hepcidin was higher in the LFP compared to the EFP (3.01 ± 4.16 vs 1.26 ± 1.25 nMol/l; d = 0.57, CI = 0.07-1.08). No effect of time on hepcidin during the EFP was found either (p = 0.426). CONCLUSION: The decrease in iron, ferritin and TSAT levels during the EFP may mislead the determination of iron status in eumenorrheic athletes. However, although the hepcidin response to exercise appears to be reduced in the EFP, it shows no clear differences between the phases of the menstrual cycle (clinicaltrials.gov: NCT04458662).

Cardiorespiratory Responses to Endurance Exercise Over the Menstrual Cycle and With Oral Contraceptive Use.

ABSTRACT: Barba-Moreno, L, Cupeiro, R, Romero-Parra, N, Janse de Jonge, XA, and Peinado, AB. Cardiorespiratory Responses to Endurance Exercise Over the Menstrual Cycle and With Oral Contraceptive Use. J Strength Cond Res 36(2): 392-399, 2022-Female steroid hormone fluctuations during the menstrual cycle and exogenous hormones from oral contraceptives may have potential effects on exercise performance. The aim of this study was to investigate the effects of these fluctuations on cardiorespiratory responses during steady-state exercise in women. Twenty-three healthy endurance-trained women performed 40 minutes of running at 75% of their maximal aerobic speed during different phases of the menstrual cycle (n = 15; early follicular phase, midfollicular phase, and luteal phase) or oral contraceptive cycle (n = 8; hormonal phase and nonhormonal phase). Ventilatory parameters and heart rate (HR) were measured. Data were analyzed using a mixed linear model. For the eumenorrheic group, significantly higher oxygen uptake (p = 0.049) and percentage of maximum oxygen uptake (p = 0.035) were observed during the midfollicular phase compared with the early follicular. Heart rate (p = 0.004), oxygen ventilatory equivalent (p = 0.042), carbon dioxide ventilatory equivalent (p = 0.017), and tidal volume (p = 0.024) increased during luteal phase in comparison with midfollicular. In oral contraceptive users, ventilation (p = 0.030), breathing frequency (p = 0.018), oxygen ventilatory equivalent (p = 0.032), and carbon dioxide ventilatory equivalent (p = 0.001) increased during the hormonal phase. No significant differences were found for the rest of the parameters or phases. Both the eumenorrheic group and oral contraceptive group showed a significant increase in some ventilatory parameters during luteal and hormonal phases, respectively, suggesting lower cardiorespiratory efficiency. However, the lack of clinical meaningfulness of these differences and the nondifferences of other physiological variables, indicate that the menstrual cycle had a small impact on submaximal exercise in the current study.

Influence of oral contraceptive phase on cardiorespiratory response to exercise in endurance-trained athletes.

OBJECTIVE: The aim of the study was to analyse the cardiorespiratory response to exercise during an oral contraceptive (OC) cycle in endurance-trained women. METHODS: Sixteen low-dose monophasic OC pill (OCP) users performed an interval-running protocol. The protocol consisted of eight 3 min bouts at 85% of participants' maximal aerobic speed (vV̇o2peak) with a 90s recovery at 30% vV̇o2peak in two OC phases: a withdrawal phase (WP) and an active pill phase (APP). The non-parametric Wilcoxon test was applied to analyse differences (p < 0.05) in performance variables between OC cycle phases. RESULTS: Throughout the high-intensity intervals, higher ventilation (WP 80.90 ± 11.49 L/min, APP 83.10 ± 13.33 L/min; p < 0.001) and relative perceived exertion (WP 14.51 ± 2.58, APP 15.11 ± 3.11; p = 0.001) during the APP were found, whereas carbon dioxide production (WP 2040.92 ± 262.93 mL/min, APP 2010.25 ± 305.68 mL/min; p = 0.003) was higher in the WP. During the active recovery intervals, ventilation (WP 65.78 ± 9.90 L/min, APP 67.88 ± 12.66 L/min; p < 0.001) was higher in the APP, while heart rate (WP 159.93 ± 10.26 bpm, APP 159.74 ± 12.83 bpm; p = 0.029) was higher in the WP. CONCLUSION: An increase in ventilation occurs during the APP, which is accompanied by higher perceived exertion. Therefore, coaches and athletes should be aware of these variations, especially perceived exertion, in regard to women's training programmes, in order to improve their performance, wellness and adherence to physical activity.

Hepcidin response to interval running exercise is not affected by oral contraceptive phase in endurance-trained women.

The use of oral contraceptives (OCs) by female athletes may lead to improved iron status, possibly through the regulation of hepcidin by sex hormones. The present work investigates the response of hepcidin and interleukin-6 (IL-6) to an interval exercise in both phases of the OC cycle. Sixteen endurance-trained OC users (age 25.3 ± 4.7 years; height 162.4 ± 5.7 cm; body mass 56.0 ± 5.7 kg; body fat percentage 24.8 ± 6.0%; peak oxygen consumption [VO2peak ]: 47.4 ± 5.5 mL min-1 kg-1 ) followed an identical interval running protocol during the withdrawal and active pill phases of the OC cycle. This protocol consisted of 8 × 3 minutes bouts at 85% VO2peak speed with 90 seconds recovery intervals. Blood samples were collected pre-exercise, and at 0 hour, 3 hours, and 24 hours post-exercise. Pre-exercise 17ß-estradiol was lower (P = .001) during the active pill than the withdrawal phase (7.91 ± 1.81 vs 29.36 ± 6.45 pg/mL [mean ± SEM]). No differences were seen between the OC phases with respect to hepcidin or IL-6 concentrations, whether taking all time points together or separately. However, within the withdrawal phase, hepcidin concentrations were higher at 3 hours post-exercise (3.33 ± 0.95 nmol/L) than at pre-exercise (1.04 ± 0.20 nmol/L; P = .005) and 0 hour post-exercise (1.41 ± 0.38 nmol/L; P = .045). Within both OC phases, IL-6 was higher at 0 hour post-exercise than at any other time point (P < .05). Similar trends in hepcidin and IL-6 concentrations were seen at the different time points during both OC phases. OC use led to low 17ß-estradiol concentrations during the active pill phase but did not affect hepcidin. This does not, however, rule out estradiol affecting hepcidin levels.

Cardiorespiratory response to exercise in endurance-trained premenopausal and postmenopausal females.

PURPOSE: To assess the influence of different hormonal profiles on the cardiorespiratory response to exercise in endurance-trained females. METHODS: Forty-seven eumenorrheic females, 38 low-dose monophasic oral contraceptive (OC) users and 13 postmenopausal women, all of them endurance-trained, participated in this study. A DXA scan, blood sample tests and a maximal aerobic test were performed under similar low-sex hormone levels: early follicular phase for the eumenorrheic females; withdrawal phase for the OC group and at any time for postmenopausal women. Cardiorespiratory variables were measured at resting and throughout the maximal aerobic test (ventilatory threshold 1, 2 and peak values). Heart rate (HR) was continuously monitored with a 12-lead ECG. Blood pressure (BP) was measured with an auscultatory method and a calibrated mercury sphygmomanometer. Expired gases were measured breath-by-breath with the gas analyser Jaeger Oxycon Pro. RESULTS: One-way ANCOVA reported a lower peak HR in postmenopausal women (172.4 ± 11.7 bpm) than in eumenorrheic females (180.9 ± 10.6 bpm) (p = 0.024). In addition, postmenopausal women exhibited lower VO2 (39.1 ± 4.9 ml/kg/min) compared to eumenorrheic females (45.1 ± 4.4 ml/kg/min) in ventilatory threshold 2 (p = 0.009). Nonetheless, respiratory variables did not show differences between groups at peak values. Finally, no differences between OC users and eumenorrheic females' cardiorespiratory response were observed in endurance-trained females. CONCLUSIONS: Cardiorespiratory system is impaired in postmenopausal women due to physiological changes caused by age and sex hormones' decrement. Although these alterations appear not to be fully compensated by exercise, endurance training could effectively mitigate them. In addition, monophasic OC pills appear not to impact cardiorespiratory response to an incremental running test in endurance-trained females.

The Effect of the Oral Contraceptive Cycle Phase on Exercise-Induced Muscle Damage After Eccentric Exercise in Resistance-Trained Women.

ABSTRACT: Romero-Parra, N, Rael, B, Alfaro-Magallanes, VM, Janse de Jonge, X, Cupeiro, R, and Peinado, AB; On Behalf of the IronFEMME Study Group. The effect of the oral contraceptive cycle phase on exercise-induced muscle damage after eccentric exercise in resistance-trained women. J Strength Cond Res 35(2): 353-359, 2021-To evaluate the influence of the active pill phase versus withdrawal phase of a monophasic oral contraceptive (OC) cycle on exercise-induced muscle damage and inflammation after eccentric resistance exercise. Eighteen resistance-trained female OC users (age: 25.6 ± 4.2 years, height: 162.4 ± 5.0 cm, and body mass: 58.1 ± 5.7 kg) performed an eccentric squat-based exercise during the active pill phase and withdrawal phase of their OC cycle. Muscle soreness, counter movement jump (CMJ), and blood markers of muscle damage and inflammation were evaluated before and postexercise (0, 2, 24, and 48 hours). Creatine kinase (CK) values were higher in the withdrawal (181.8 ± 89.8 U·L-1) than in the active pill phase (144.0 ± 39.7 U·L-1) (p < 0.001). The highest CK concentrations and muscle soreness values were observed 24 hours postexercise (217.9 ± 117.5 U·L-1 and 44.7 ± 19.7, respectively) compared with baseline (115.3 ± 37.4 U·L-1 and 4.4 ± 9.2, respectively; p < 0.001). In addition, a decrease in CMJ immediately postexercise (20.23 ± 4.6 cm) was observed in comparison with baseline (24.2 ± 6.1 cm), which was not yet recovered 24 hours postexercise (21.9 ± 5.9 cm; p < 0.001). No other phase or time effects were observed. An eccentric squat-based exercise session elicits muscle damage but no inflammation response in resistance-trained women. Furthermore, the highest CK concentrations observed in the withdrawal phase suggest that this phase might be more vulnerable to muscle damage and, therefore, less adequate to administer high training loads. However, the lack of differences in other muscle damage variables between OC phases does not warrant any guidance on the active pill versus withdrawal phase.

Exercise-Induced Muscle Damage During the Menstrual Cycle: A Systematic Review and Meta-Analysis.

ABSTRACT: Romero-Parra, N, Cupeiro, R, Alfaro-Magallanes, VM, Rael, B, Rubio-Arias, JA, Peinado, AB, and Benito, PJ, IronFEMME Study Group. Exercise-induced muscle damage during the menstrual cycle: A systematic review and meta-analysis. J Strength Cond Res 35(2): 549-561, 2021-A strenuous bout of exercise could trigger damage of muscle tissue, and it is not clear how sex hormone fluctuations occurring during the menstrual cycle (MC) affect this response. The aims of this study were to systematically search and assess studies that have evaluated exercise-induced muscle damage (EIMD) in eumenorrheic women over the MC and to perform a meta-analysis to quantify which MC phases display the muscle damage response. The guidelines of the Preferred Reported Items for Systematic Reviews and Meta-Analysis were followed. A total of 19 articles were analyzed in the quantitative synthesis. Included studies examined EIMD in at least one phase of the following MC phases: early follicular phase (EFP), late follicular phase (LFP), or midluteal phase (MLP). The meta-analysis demonstrated differences between MC phases for delayed onset muscle soreness (DOMS) and strength loss (p < 0.05), whereas no differences were observed between MC phases for creatine kinase. The maximum mean differences between pre-excercise and post-exercise for DOMS were EFP: 6.57 (4.42, 8.71), LFP: 5.37 (2.10, 8.63), and MLP: 3.08 (2.22, 3.95), whereas for strength loss were EFP: -3.46 (-4.95, -1.98), LFP: -1.63 (-2.36, -0.89), and MLP: -0.72 (-1.07, -0.36) (p < 0.001). In conclusion, this meta-analysis suggests that hormone fluctuations throughout the MC affect EIMD in terms of DOMS and strength loss. Lower training loads or longer recovery periods could be considered in the EFP, when sex hormone concentrations are lower and women may be more vulnerable to muscle damage, whereas strength conditioning loads could be enhanced in the MLP.

Serum iron availability, but not iron stores, is lower in naturally menstruating than in oral contraceptive athletes.

This study measured serum markers of iron status in naturally menstruating and oral contraceptive (OC) athletes during the main hormonal milieus of these two profiles to identify potential differences confounding the diagnosis of iron deficiency in female athletes. Resting blood samples were collected from 36 naturally menstruating athletes during the early-follicular phase (EFP), mid- late-follicular phase (MLFP) and mid-luteal phase (MLP) of the menstrual cycle. Simultaneously, blood samples were collected from 24 OC athletes during the withdrawal and active-pill phase of the OC cycle. Serum iron, ferritin, transferrin, transferrin saturation (TSAT), C-reactive protein (CRP), interleukin-6 and sex hormones were analyzed. Naturally menstruating athletes showed lower levels of TSAT, iron and transferrin than OC athletes when comparing the bleeding phase of both profiles (p<0.05) as well as when comparing all analyzed phases of the menstrual cycle to the active pill phase of the OC cycle (p<0.05). Interestingly, only lower transferrin was found during MLFP and MLP compared to the withdrawal phase of the OC cycle (p>0.05), with all other iron markers showing no differences (p>0.05). Intracycle variations were also found within both types of cycle, presenting reduced TSAT and iron during menstrual bleeding phases (p<0.05). In conclusion, in OC athletes, serum iron availability, but not serum ferritin, seems higher than in naturally menstruating ones. However, such differences are lost when comparing the MLFP and MLP of the menstrual cycle with the withdrawal phase of the OC cycle. This should be considered in the assessment of iron status in female athletes.Highlights Naturally menstruating athletes present lower TSAT, iron and transferrin in all analyzed phases of the menstrual cycle compared to OC athletes during their active pill phase. However, both the mid-late follicular and mid-luteal phases of the menstrual cycle do not differ from the withdrawal phase of the oral contraceptive cycle.Intracycle variations are found for TSAT and iron in both naturally menstruating and oral contraceptive athletes, which are mainly driven by a reduction in TSAT and iron during menstrual bleeding phases.As serum iron availability changes significantly as a function of the athlete's hormonal status, it should be considered in the assessment of the athlete's iron status as well as standardise the phase of the menstrual cycle in which to assess iron markers to avoid misdiagnosis or misleading results.In contrast, the assessment of iron stores through serum ferritin is substantially stable and the athlete's hormonal status does not seem to be of relevance for this purpose.

Effect of Menstrual Cycle Phase on the Recovery Process of High-Intensity Interval Exercise-A Cross-Sectional Observational Study.

Although the study of the menstrual cycle influence on endurance exercise has recently increased, there is a lack of literature studying its influence on females' cardiorespiratory recovery. Thus, the aim of the present work was to assess menstrual cycle influence on post-exercise recovery following a high intensity interval exercise in trained females. Thirteen eumenorrheic endurance-trained females performed an interval running protocol in three menstrual cycle phases: early follicular phase (EFP), late follicular phase (LFP), and mid-luteal phase (MLP). The protocol consisted of 8 × 3-min bouts at 85% of their maximal aerobic speed (vVO2peak) with a 90-s rest between bouts and a final 5-min active recovery at 30% vVO2peak. All variables were averaged every 15 s, obtaining 19 moments during recovery (time factor). To analyze the effects of the menstrual cycle on the final active cardiorespiratory recovery, an ANOVA for repeated measures was performed. ANOVA showed an effect on menstrual cycle phase on ventilation (EFP: 1.27 ± 0.35; LFP: 1.19 ± 0.36; MLP: 1.27 ± 0.37), breathing frequency (EFP: 35.14 ± 7.14; LFP: 36.32 ± 7.11; MLP: 37.62 ± 7.23), and carbon dioxide production (EFP: 1120.46 ± 137.62; LFP: 1079.50 ± 129.57; MLP: 1148.78 ± 107.91). Regarding the interaction results (phase x time), ventilation is higher at many of the recovery times during the MLP, with less frequent differences between EFP and LFP (F = 1.586; p = 0.019), while breathing reserve is lower at many of the recovery times during MLP, with less time differences between EFP and LFP (F = 1.643; p = 0.013). It seems that the menstrual cycle affects post-exercise recovery specially during the MLP, rising ventilation and lowering breathing reserve, giving rise to an impaired ventilatory efficiency.

Influence of sex hormones status and type of training on regional bone mineral density in exercising females.

The primary objective of this study was to examine the influence of hormonal ovarian profile and training characteristics on spine, pelvis, and total body bone mineral density (BMD) in a group of well-trained females. Forty-two eumenorrheic females, twenty-eight monophasic oral contraceptive (OC) users and thirteen postmenopausal females participated in this study. Body composition was measured by total body dual-energy X-ray absorptiometry (DXA) to determine BMD of the areas of interest. Endurance-trained premenopausal females showed lower spine BMD compared to resistance-trained premenopausal females (1.03 ± 0.1 vs. 1.09 ± 0.09 g/cm2; p = 0.025). Postmenopausal females reported lower BMD level in comparison to eumenorrheic females in pelvis (1.079 ± 0.082 vs 1.19 ± 0.115 g/cm2; p = 0.005), spine (0.969 ± 0.097 vs 1.069 ± 0.109 g/cm2; p = 0.012) and total (1.122 ± 0.08 vs 1.193 ± 0.077 g/cm2; p = 0.018) and OC users whose duration of OC use was less than 5 years (OC < 5) in pelvis (1.235 ± 0.068 g/cm2; p < 0.001) and spine (1.062 ± 0.069 g/cm2; p = 0.018). In addition, lower BMD values were found in OC users who had been using OC for more than 5 years (OC ≥ 5) than eumenorrheic females in pelvis (1.078 ± 0.086 g/cm2; p = 0.029) and spine (0.966 ± 0.08 g/cm2; p = 0.05). Likewise, OC ≥ 5 showed lower values than and OC < 5 in pelvis (p = 0.004) and spine (p = 0.047). We observed a lower spine BMD value in premenopausal endurance-trained females compared to premenopausal resistance-trained females. Moreover, this research observed that prolonged use of OCs may reduce bone mass acquisition in the spine and pelvis, even in well-trained females. Finally, postmenopausal showed lower BMD despite being exercising women.Trial registration: ClinicalTrials.gov identifier: NCT04458662.Highlights Ovarian hormonal profile should be considered when assessing BMD in female athletes.The duration of oral contraceptive use influences spine and pelvis regional BMD in exercising females.Postmenopausal women show lower BMD when compared to premenopausal females despite being exercising females.

Response to physical activity of females with multiple sclerosis throughout the menstrual cycle: a protocol for a randomised crossover trial (EMMA Project).

The relationship between multiple sclerosis (MS) and females is a crucial aspect in the development of the disease, with the ovarian hormonal cycle being a sensitive stage, especially in females with relapsing-remitting multiple sclerosis. The objectives of the study are to identify moderating variables that modify satisfaction with physical activity practice throughout the menstrual cycle (MC) in females in or out of their MC, during high-intensity interval training (HIIT) and strength training sessions and to compare the acute effects of different types of physical activity sessions in females with and without MS. This protocol is the methodology used in the EMMA Study, a randomised, single-blind crossover trial study conducted in females with MS who were matched 1:1, based on age, lifestyle factors and country of residence, with females without MS, to analyse the effect of physical activity practice on satisfaction, functionality, fatigue and inflammatory profile through their MC. Participants will visit the facilities approximately 10 times (4 preliminary familiarisation visits and 6 visits to carry out a physical activity session in each phase of the MC) for 3-4 months. A total sample of 30 females (15 females without MS and 15 with MS) is necessary for the study. The evaluation will comprise clinical, nutritional and psychological interviews, including different variables. It is hypothesised during the luteal phase, females with MS are expected to exhibit different acute responses to HIIT and strength training sessions as compared with females without the disease. Before starting the study, all participants will read and sign an informed consent form. Trial registration number: This research protocol is registered with ClinicalTrials.gov to ensure transparency and accessibility of study information (NCT06105463). The university's ethics committee number for this study is UALBIO2022/048.

Gradual Strength Training Improves Sleep Quality, Physical Function and Pain in Women with Fibromyalgia.

BACKGROUND: Fibromyalgia (FM) is characterized by chronic and generalized musculoskeletal pain. There is currently no cure for FM, but alternative treatments are available. Among them, gradual strength training programs (ST) which on daily activities are a valid option to improve some of the pronounced symptoms of FM that affect quality of life, such as fatigue, pain, sleep quality, and physical function. However, there is a need for more information on optimal training programs to improve anxiety and fatigue symptoms. AIM: To analyze the effects of a 24-week gradual and progressive ST on sleep quality, fatigue, pain domains, physical function, and anxiety-state. METHODS: 41 women with FM participated in the 24 weeks of intervention based on gradual and progressive ST. Two, 60 min, training sessions per week were con-ducted. Participants were evaluated before the ST program (week 0), in week 12 and at the end of the ST program (week 24). The Revised Fibromyalgia Impact Questionnaire was used to assess sleep quality and fatigue scales. Anxiety-state was evaluated with the State Anxiety Inventory, and pain domains by means of the Brief Pain Inventory. Senior Fitness Test was used for physical function measurements. One-way analysis of variance (ANOVA) was applied to assess the mean differences between phases, and Spearman's correlations were used to assess the associations between physical and psychological symptoms, and physical function. RESULTS: The results demonstrated that 24 weeks of ST improves physical function, sleep quality and pain domains (p ≤ 0.05). Higher anxiety and pain interference scores were related to worsening physical function. CONCLUSIONS: Gradual ST significantly improves sleep quality, pain, and physical function, but not anxiety and fatigue.

Barriers to Physical Activity in Spanish Children and Adolescents: Sex and Educational Stage Differences.

According to worrisome childhood obesity and inadequate physical activity (PA) levels worldwide, especially exacerbated in adolescents girls, this work aimed to identify sex and educational stage differences in barriers to meet PA requirements and international guidelines in Spanish children and adolescents considering the entire educational pathway (primary, secondary, and college). The Short Form of the International PA Questionnaire and the Scale of Perceived Barriers were administered to primary, secondary, and college education students (13,491 boys and 13,238 girls, 9-19 yrs). Two-way ANOVA was performed to analyze barriers to PA according to sex and educational stage with physical status as covariate. Higher disliking and time barriers were reported by females (1.5 ± 1.2 and 3.2 ± 1.5 points) in comparison to males (1.2 ± 1.0 and 2.8 ± 1.4), while primary students showed lower disliking and time (1.2 ± 1.0 and 2.8 ± 1.5) and higher safety (3.1 ± 1.8) constraints in comparison to secondary (1.4 ± 1.1, 3.1 ± 1.4, and 2.8 ± 1.7) and college (1.5 ± 1.2, 3.2 ± 1.5, and 2.8 ± 1.6; p < 0.05 for all comparisons). College females showed higher disliking (1.7 ± 1.2) and time (3.5 ± 1.4) barriers than secondary females (1.5 ± 1.2 and 3.3 ± 1.4; p < 0.05). Sex and educational stage were determinant for time and dislike of PA barriers, which were rated higher by female students in comparison to their male counterparts and from primary education onwards. Altogether this, suggests promotion strategies should carefully consider girls and the step into secondary school.

Exercise-Induced Muscle Damage in Postmenopausal Well-Trained Women.

BACKGROUND: Sex hormone deprivation derived from menopause may affect exercise-induced muscle damage (EIMD). No studies have previously evaluated this response between postmpenopausal and premenopausal eumenorrheic women over the menstrual cycle. HYPOTHESIS: Postmenopausal women will present higher EIMD markers than premenopausal women, especially in comparison with the menstrual cycle phases where sex hormone concentrations are higher. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: Thirteen postmenopausal and 19 eumenorrheic women, all of them resistance-trained, performed an eccentric squat-based exercise. The postmenopausal group performed 1 bout of exercise, while the eumenorrheic group performed 3 bouts coinciding with the early follicular, late follicular, and mid-luteal phases ot their menstrual cycle. Muscle soreness, countermovement jump, creatine kinase (CK), myoglobin, lactate dehydrogenase, interleukin-6, tumor necrosis factor-α, and C-reactive protein were evaluated before and postexercise. RESULTS: The expected differences in sex hormones were observed between groups (P < 0.001) according to their reproductive status. Postexercise increases in CK, myoglobin, and muscle soreness (168.2 ± 45.5 U/L, 123.1 ± 41.5 µg/L, and 20.7 ± 21.3 mm, respectively) were observed in comparison with baseline (136.2 ± 45.5 U/L, 76.9 ± 13.8 µg/L, and 2.7 ± 4.2 mm, respectively). Myoglobin values at baseline in postmenopausal women were higher compared with premenopausal women in the aforementioned menstrual cycle phases, respectively (62.8 ± 8.2, 60.4 ± 7.2, and 60.1 ± 10.6 µg/L; P < 0.001 for all comparisons), which was supported by large effect sizes (0.72-1.08 standardized d units). No postexercise differences were observed between groups in any markers (P > 0.05). CONCLUSION: Despite higher resting levels of myoglobin and lower strength values in postmenopausal than in premenopausal women, EIMD was similar between both reproductive profiles. This suggests a potential benefit of being physically active despite aging and sex hormone deprivation. CLINICAL RELEVANCE: Sex hormone deprivation derived from menopause seems not to influence muscle damage reponse to eccentric exercise in resistance-trained postmenopausal women.

Indirect Markers of Muscle Damage Throughout the Menstrual Cycle.

CONTEXT: The indirect markers of muscle damage have been previously studied in females. However, inconclusive results have been found, possibly explained by the heterogeneity regarding monitoring and verification of menstrual-cycle phase. PURPOSE: To determine whether the fluctuations in sex hormones during the menstrual cycle influence muscle damage. METHODS: A total of 19 well-trained eumenorrheic women (age 28.6 [5.9] y; height 163.4 [6.1] cm; weight 59.6 [5.8] kg body mass) performed an eccentric-based resistance protocol consisting of 10 × 10 back squats at 60% of their 1-repetition maximum on the early follicular phase (EFP), late follicular phase, and midluteal phase of the menstrual cycle. Range of motion, muscle soreness, countermovement jump, and limb circumferences were evaluated prior to 24 and 48 hours postexercise. Perceived exertion was evaluated after each set. RESULTS: Differences in sex hormones indicated that tests were adequately performed in the different menstrual-cycle phases. Prior to exercise, muscle soreness was higher in the EFP (4.7 [7.7]) than in the late follicular phase (1.1 [3.2]; P = .045). No other variables showed significant differences between phases. Time-point differences (baseline, 24, and 48 h) were observed in knee range of motion (P = .02), muscle soreness, countermovement jump, and between sets for perceived exertion (P < .001). CONCLUSION: Although the protocol elicited muscle damage, hormonal fluctuations over the menstrual cycle did not seem to affect indirect markers of muscle damage, except for perceived muscle soreness. Muscle soreness was perceived to be more severe before exercise performed in EFP, when estrogen concentrations are relatively low. This may impair women's predisposition to perform strenuous exercise during EFP.

Body Composition Over the Menstrual and Oral Contraceptive Cycle in Trained Females.

PURPOSE: The influence of female sex hormones on body fluid regulation and metabolism homeostasis has been widely studied. However, it remains unclear whether hormone fluctuations throughout the menstrual cycle (MC) and with oral contraceptive (OC) use affect body composition (BC). Thus, the aim of this study was to investigate BC over the MC and OC cycle in well-trained females. METHODS: A total of 52 eumenorrheic and 33 monophasic OC-taking well-trained females participated in this study. Several BC variables were measured through bioelectrical impedance analysis 3 times in the eumenorrheic group (early follicular phase, late follicular phase, and midluteal phase) and on 2 occasions in the OC group (withdrawal phase and active pill phase). RESULTS: Mixed linear model tests reported no significant differences in the BC variables (body weight, body mass index, basal metabolism, fat mass, fat-free mass, and total body water) between the MC phases or between the OC phases (P > .05 for all comparisons). Trivial and small effect sizes were found for all BC variables when comparing the MC phases in eumenorrheic females, as well as for the OC cycle phases. CONCLUSIONS: According to the results, sex hormone fluctuations throughout the menstrual and OC cycle do not influence BC variables measured by bioelectrical impedance in well-trained females. Therefore, it seems that bioimpedance analysis can be conducted at any moment of the cycle, both for eumenorrheic women and women using OC.

Effect of Different Types of Face Masks on the Ventilatory and Cardiovascular Response to Maximal-Intensity Exercise.

The development of new models of face masks makes it necessary to compare their impact on exercise. Therefore, the aim of this work was to compare the cardiopulmonary response to a maximal incremental test, perceived ventilation, exertion, and comfort using FFP2 or Emotion masks in young female athletes. Thirteen healthy sportswomen (22.08 ± 1.75 years) performed a spirometry, and a graded exercise test on a treadmill, with a JAEGER® Vyntus CPX gas analyzer using an ergospirometry mask (ErgoMask) or wearing the FFP2 or the Emotion mask below the ErgoMask, randomized on 3 consecutive days. Also, menstrual cycle status was monitored to avoid possible intrasubject alterations. The results showed lower values for the ErgoMask+FFP2, compared to ErgoMask or ErgoMask+Emotion, in forced vital capacity (3.8 ± 0.2, 4.5 ± 0.2 and 4.1 ± 0.1 l, respectively); forced expiratory volume in 1 s (3.3 ± 0.2, 3.7 ± 0.2 and 3.5 ± 0.1 l); ventilation (40.9 ± 1.5, 50.6 ± 1.5 and 46.9 ± 1.2 l/min); breathing frequency (32.7 ± 1.1, 37.4 ± 1.1 and 35.3 ± 1.4 bpm); VE/VO2 (30.5 ± 0.7, 34.6 ± 0.9 and 33.6 ± 0.7); VE/VCO2 (32.2 ± 0.6, 36.2 ± 0.9 and 34.4 ± 0.7) and time to exhaustion (492.4 ± 9.7, 521.7 ± 8.6 and 520.1 ± 9.5 s) and higher values in inspiratory time (0.99 ± 0.04, 0.82 ± 0.03 and 0.88 ± 0.03 s). In conclusion, in young healthy female athletes, the Emotion showed better preservation of cardiopulmonary responses than the FFP2.