Blunted Myoglobin and Quadriceps Soreness After Electrical Stimulation During the Luteal Phase or Oral Contraception

Menstrual cycle phase differences in myofiber damage and macrophage infiltration following electrical stimulation-induced muscle injury

The purpose of this study was to examine the effects of menstrual cycle phase on myofiber injury, regenerative events, and inflammation after electrical stimulation (ES)-induced myofiber damage. Twenty-eight premenopausal women (20.8 ± 2 yr) were randomized into early follicular (EF; n = 14) and late follicular (LF; n = 14) groups. After menstrual cycle tracking and phase confirmation, subjects underwent 200 electrically stimulated eccentric muscle contractions 1 wk after providing a muscle biopsy. Seven days post-ES, subjects provided a final biopsy. Primary outcomes included serum estradiol, indirect markers of muscle damage, direct indicators of myofiber necrosis and regeneration, satellite cell number, and macrophage infiltration. Women in the LF group had higher serum estradiol (122.1 ± 23.4 vs. 81.7 ± 30.8 pg/mL; P < 0.001) than in the EF group on the day of ES. Although the EF group recovered baseline maximal isometric strength by 4 days post-ES, the LF group did not. Only women in the LF group showed significant and consistent evidence of myofiber necrosis and regeneration pre- to post-ES. Despite showing more evidence of myofiber damage, women in the LF group also experienced reduced total and CD206+ macrophage infiltration relative to the EF group. Satellite cell quantity increased significantly post-ES in both groups, with no differences between groups. Collectively, the data suggest that the high-estrogen LF phase may be associated with increased susceptibility to myofiber injury while also limiting the subsequent intramuscular inflammatory response.NEW & NOTEWORTHY The menstrual cycle has widespread physiological effects across many systems, including skeletal muscle. In this study, we show that women in the late follicular phase of the menstrual cycle may be more susceptible to myofiber necrosis following electrical stimulation. We also show reduced evidence of inflammation in the late follicular phase. This is the first study to demonstrate a difference in the response of human skeletal muscle to a necrotic stimulus across a menstrual cycle.

RNA-seq Based Transcriptome Analysis Reveals Role of Myoglobin in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease which manifests as joint destruction and bone erosion, could be caused by both genetic and environmental factors. Currently, the causes of RA are unknown, and targeted therapies are often associated with side effects and contraindications. The detection rate of RA in women is higher than men (3:1), however, there is still a lack of comprehensive understanding of the relationship between sex and RA. We hypothesized gender differences in RA prevalence and their associated mechanisms by performing genome-wide transcriptome analysis of synovial biopsy samples. The results indicated that myoglobin (MB) was differentially expressed between males and females, with higher expression in males than females in healthy populations, while the opposite was observed in RA patients. MB interacted with HLA class II histocompatibility antigen, DM beta (HLA-DMB) and the inflammatory factor interleukin 6 (IL-6) in the human synovial cell line MH7A.

Auditing the representation of hormonal contraceptives in studies assessing exercise performance in women

Hormonal contraceptive (HC) users have a different ovarian hormonal profile compared to eumenorrheic women. Due to the prevalence of HC use amongst sportswomen, there has been increased research efforts to understand their impact on exercise performance. The aim was to audit this research. Studies identified were assessed for HC type, athlete calibre, performance outcome, study design, and quality of methodological control regarding ovarian hormonal profiles. Sixty-eight different HCs were reported across 61 studies. Monophasic combined oral contraceptive (OCP) pills represented 60% of HCs, followed by other pills [34%, phasic-combined, progestogen-only, and un-specified], phasic and long acting reversible contraceptives [5%, vaginal ring, patch, implant, injection, intrauterine system] and unspecified HCs (1%). Eleven percent of participants using HCs were classified as highly trained or elite/international with no participants being classed as world class. Whilst the number of studies involving HCs has increased two-fold over the past decade, the number of studies ranked as gold standard has not increased (HC; 2003-57%, 2011-55%, 2022-43%. OCP; 2003-14%, 2011-17%, 2022-12%). Future research assessing HCs and exercise performance should adopt high-quality research designs and include a broader range of HCs in highly trained to world-class populations to increase the reach and impact of research in this area.

The effects of menstrual cycle phases on immune function and inflammation at rest and after acute exercise: A systematic review and meta-analysis

The immune system plays an important role in mediating exercise responses and adaptations. However, whether fluctuating hormone concentrations across the menstrual cycle may impact these processes remains unknown. The aim of this systematic review with meta-analysis was to compare baseline concentrations as well as exercise-induced changes in immune and inflammatory parameters between menstrual cycle phases. A systematic literature search was conducted according to the PRISMA guidelines using Pubmed/MEDLINE, ISI Web of Science, and SPORTDiscus. Of the 159 studies included in the qualitative synthesis, 110 studies were used for meta-analysis. Due to the designs of the included studies, only the follicular and luteal phase could be compared. The estimated standardized mean differences based on the random-effects model revealed higher numbers of leukocytes (-0.48 [-0.73; -0.23], p < 0.001), monocytes (-0.73 [-1.37; -0.10], p = 0.023), granulocytes (-0.85 [-0.1.48; -0.21], p = 0.009), neutrophils (-0.32 [-0.52; -0.12], p = 0.001), and leptin concentrations (-0.37 [-0.5; -0.23], p = 0.003) in the luteal compared to the follicular phase at rest. Other parameters (adaptive immune cells, cytokines, chemokines, and cell adhesion molecules) showed no systematic baseline differences. Seventeen studies investigated the exercise-induced response of these parameters, providing some indications for a higher pro-inflammatory response in the luteal phase. In conclusion, parameters of innate immunity showed cycle-dependent regulation at rest, while little is known on the exercise responses. Due to a large heterogeneity and a lack of cycle phase standardization among the included studies, future research should focus on comparing at least three distinct hormonal profiles to derive more specific recommendations for exercise prescription.

The Effect of Monophasic Oral Contraceptives on Muscle Strength and Markers of Recovery After Exercise-Induced Muscle Damage: A Systematic Review

CONTEXT

Oral contraceptives (OCs) manipulate hormonal fluctuations of the menstrual cycle and affect physical performance. Most investigations on the effect of OCs on physical performance did not discriminate between different types of OCs. Thus, the effects of monophasic OCs (MOCs) - the most common type of OCs - on muscle strength and recovery from exercise are largely unknown.

OBJECTIVE

To examine the effect of MOC use on muscle strength and markers of recovery after exercise-induced muscle damage (EIMD) in premenopausal women.

DATA SOURCES

Electronic databases Embase, PubMed, SportDiscus, and Web of Science were searched for studies examining the effect of MOCs on acute muscle strength and recovery.

STUDY SELECTION

Keywords applied for the study selection were oral contraceptive* AND muscle strength or oral contraceptive* AND muscle damage.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Lowest quality assessed for an included study in this review was serious risk of bias using ROBINS-I tool made from Cochrane for nonrandomized studies.

DATA EXTRACTION

A total of 104 studies on muscle strength were identified, of which 11 met the inclusion criteria. Concerning recovery, 51 studies were identified, of which 4 met the inclusion criteria.

RESULTS

Of the 11 studies included, 10 showed no effect of MOCs on acute muscle strength. Of the 4 studies on recovery, 2 found a greater decrease in muscle strength, and 3 found higher creatine kinase (CK) levels after EIMD in MOC users than in nonusers. The included studies were all rated with moderate-to-serious risk of bias.

CONCLUSION

These findings suggest that MOCs may impair recovery from EIMD as indicated by lowered muscle strength and elevated CK levels. There is insufficient evidence to conclude whether MOCs acutely affect muscle strength. Moderate-to-serious risk of bias in studies makes interpretation challenging.

Impact of Training Protocols on Lifting Velocity Recovery in Resistance Trained Males and Females

It has been suggested that sex differences exist in recovery following strength training. This study aimed to investigate the differences in recovery kinetics between resistance trained males and females following two different back squat (BSq) protocols. The first protocol (eight females and eight males) consisted of five sets of five repetitions at 80% of their one-repetition maximum (1RM) in the BSq (SMRT), while the second (seven females and eight males) consisted of five sets to muscular failure (MF) with a 4–6RM load (RMRT). The recovery was quantified with the mean concentric velocity (MV) at 80% of the 1RM immediately before and 5 min, 24, 48, and 72 h after the training protocol. Following the SMRT, a significant between-sex difference, favoring the females, was observed at 5 min, 24 h, and 48 h following the SMRT (p < 0.05, Effect Size (ES) = 1.01–2.25). Following the RMRT, only the males experienced a significant drop in performance after 5 min compared to the baseline (p = 0.025, ES = 1.34). However, no sex differences were observed at any timepoint (p > 0.05). These results suggest that males experienced more fatigue than females following a protocol where the volume relative to the 1RM was matched, while no differences in fatigue were evident following a protocol in which multiple sets were performed to MF.

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.

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.

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.

The Effects of Oral Contraceptives on Exercise Performance in Women: A Systematic Review and Meta-analysis

BACKGROUND

Oral contraceptive pills (OCPs) are double agents, which downregulate endogenous concentrations of oestradiol and progesterone whilst simultaneously providing daily supplementation of exogenous oestrogen and progestin during the OCP-taking days. This altered hormonal milieu differs significantly from that of eumenorrheic women and might impact exercise performance, due to changes in ovarian hormone-mediated physiological processes.

OBJECTIVE

To explore the effects of OCPs on exercise performance in women and to provide evidence-based performance recommendations to users.

METHODS

This review complied with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A between-group analysis was performed, wherein performance of OCP users was compared with naturally menstruating women, and a within-group analysis was conducted, wherein performance during OCP consumption was compared with OCP withdrawal. For the between-group analysis, women were phase matched in two ways: (1) OCP withdrawal versus the early follicular phase of the menstrual cycle and (2) OCP consumption versus all phases of the menstrual cycle except for the early follicular phase. Study quality was assessed using a modified Downs and Black Checklist and a strategy based on the recommendations of the Grading of Recommendations Assessment Development and Evaluation working group. All meta-analyses were conducted within a Bayesian framework to facilitate probabilistic interpretations.

RESULTS

42 studies and 590 participants were included. Most studies (83%) were graded as moderate, low or very low quality, with 17% achieving high quality. For the between-group meta-analysis comparing OCP users with naturally menstruating women, posterior estimates of the pooled effect were used to calculate the probability of at least a small effect (d ≥ 0.2). Across the two between-group comparison methods, the probability of a small effect on performance favouring habitual OCP users was effectually zero (p < 0.001). In contrast, the probability of a small effect on performance favouring naturally menstruating women was moderate under comparison method (1) (d ≥ 0.2; p = 0.40) and small under comparison method (2) (d ≥ 0.2; p = 0.19). Relatively large between-study variance was identified for both between-group comparisons ([Formula: see text]0.5 = 0.16 [95% credible interval (CrI) 0.01-0.44] and [Formula: see text]0.5 = 0.22 [95% CrI 0.06-0.45]). For the within-group analysis comparing OCP consumption with withdrawal, posterior estimates of the pooled effect size identified almost zero probability of a small effect on performance in either direction (d ≥ 0.2; p ≤ 0.001).

CONCLUSIONS

OCP use might result in slightly inferior exercise performance on average when compared to naturally menstruating women, although any group-level effect is most likely to be trivial. Practically, as effects tended to be trivial and variable across studies, the current evidence does not warrant general guidance on OCP use compared with non-use. Therefore, when exercise performance is a priority, an individualised approach might be more appropriate. The analysis also indicated that exercise performance was consistent across the OCP cycle.

Influence of the Menstrual Cycle on Blood Markers of Muscle Damage and Inflammation Following Eccentric Exercise

The aim of this study was to evaluate whether the menstrual cycle and its underlying hormonal fluctuations affect muscle damage and inflammation in well-trained females following an eccentric exercise. Nineteen eumenorrheic women performed an eccentric squat-based exercise in the early follicular phase, late follicular phase and mid-luteal phase of their menstrual cycle. Sex hormones and blood markers of muscle damage and inflammation –creatine kinase, myoglobin, lactate dehydrogenase, interleukin-6, tumoral necrosis factor-α, and C reactive protein– were analyzed in each phase. No effect of menstrual cycle phase was observed (p > 0.05), while an interaction for interleukin-6 was shown (p = 0.047). Accordingly, a moderate effect size [0.68 (0.53)–0.84 (0.74)], indicated that interleukin-6 values 2 h post-trial (2.07 ± 1.26 pg/mL) were likely to be higher than baseline (1.59 ± 0.33 pg/mL), 24 h (1.50 ± 0.01 pg/mL) and 48 h (1.54 ± 0.13 pg/mL) in the mid-luteal phase. Blood markers of muscle damage and inflammation were not affected by the menstrual cycle in well-trained women. The eccentric exercise barely triggered muscle damage and hence, no inflammation was observed, possibly due to participants training status. The mid-luteal phase was the only phase reflecting a possible inflammatory response in terms of interleukin-6, although further factors than sex hormones seem to be responsible for this finding.