Acute ingestion of acetaminophen improves cognitive and repeated high intensity short-term maximal performance in well-trained female athletes: a randomized placebo-controlled trial

This study examined the effect of acute acetaminophen (ACTP) ingestion on physical performance during the 5 m shuttle run test (5mSRT), attention, mood states, and the perception of perceived exertion (RPE), pain (PP), recovery (PRS), and delayed onset of muscle soreness (DOMS) in well-trained female athletes. In a randomized, placebo-controlled, double-blind, crossover trial, fifteen well-trained female athletes (age 21 ± 2 years, height 165 ± 6 cm, body mass 62 ± 5 kg) swallowed either 1.5 g of ACTP or 1.5 g of placebo. The profile of mood states (POMS) and digit cancellation (DCT) were assessed 45 min postingestion, and 5mSRT was performed 60 min postingestion. The RPE and PP were determined immediately after each 30-s repetition of the 5mSRT, and the PRS and DOMS were recorded at 5 min and 24 h post-5mSRT. For the 5mSRT, ACTP ingestion improved the greatest distance (+ 10.88%, p < 0.001), total distance (+ 11.33%, p = 0.0007) and fatigue index (+ 21.43%, p = 0.0003) compared to PLA. Likewise, the DCT score was better on the ACTP (p = 0.0007) than on the PLA. RPE, PP, PRS, and DOMS scores were improved after ACTP ingestion (p < 0.01 for all comparisons) compared to PLA. POMS scores were enhanced with ACTP ingestion compared to PLA (p < 0.01). In conclusion, this study indicates that acute acetaminophen ingestion can improve repeated high intensity short-term maximal performance, attention, mood states, and perceptions of exertion, pain, recovery, and muscle soreness in well-trained female athletes, suggesting potential benefits for their overall athletic performance and mood state.

Effects of the Menstrual Cycle and Hormonal Contraceptive Use on Metabolic Outcomes, Strength Performance, and Recovery: A Narrative Review

The effects of female sex hormones on optimal performance have been increasingly recognized as an important consideration in exercise and sport science research. This narrative review explores the findings of studies evaluating the effects of menstrual cycle phase in eumenorrheic women and the use of hormonal contraception (oral contraceptives and hormonal intrauterine devices) on metabolism, muscular strength, and recovery in active females. Ovarian hormones are known to influence metabolism because estrogen is a master regulator of bioenergetics. Importantly, the menstrual cycle may impact protein synthesis, impacting skeletal muscle quality and strength. Studies investigating muscular strength in eumenorrheic women report equivocal findings between the follicular phase and luteal phase with no differences compared to oral contraceptive users. Studies examining recovery measures (using biomarkers, blood lactate, and blood flow) do not report clear or consistent effects of the impact of the menstrual cycle or hormonal contraception use on recovery. Overall, the current literature may be limited by the evaluation of only one menstrual cycle and the use of group means for statistical significance. Hence, to optimize training and performance in females, regardless of hormonal contraception use, there is a need for future research to quantify the intra-individual impact of the menstrual cycle phases and hormonal contraceptive use in active females.

Sex differences in muscle-quality recovery following one week of knee joint immobilization and subsequent retraining

This manuscript represents the second phase of a clinical trial designed to examine the effects of knee joint immobilization and retraining on muscle strength and mass. In Phase 2, we examined sex differences in the recovery of multiple indices of muscle quality after a resistance training-based rehabilitation program. Following 1 week of immobilization, 27 participants (16 males, 11 females) exhibiting weakness underwent twice weekly resistance training sessions designed to re-strengthen their left knee. Unilateral retraining sessions utilizing leg press, extension, and curl exercises were conducted until participants could reproduce their pre-immobilization knee extension isometric maximal voluntary contraction (MVC) peak torque. Post-immobilization, both sexes demonstrated impaired MVC peak torque (males = -10.8%, females = -15.2%), specific torque (-9.8% vs. -13.1%), echo intensity of the vastus lateralis (+6.9% vs. +5.9%) and rectus femoris (+5.9% vs. +2.1), and extracellular water/intracellular water ratio (+7.8% vs. +9.0%). The number of retraining sessions for peak torque to return to baseline for males (median = 1, mean = 2.13) versus females (median = 2, mean = 2.91) was not significantly different, though the disparity in recovery times may be clinically relevant. Following retraining, specific torque was the only muscle-quality indicator that improved along with MVC peak torque (males = 20.1%, females = 22.4%). Our findings indicate that measures of muscle quality demonstrate divergent recovery rates following immobilization, with muscle mass lagging behind improvements in strength. Greater immobilization-induced strength loss among females suggests that sex-specific rehabilitation efforts may be justified.

Mind the gap! A survey comparing current strength training methods used in men's versus women's first team and academy soccer

PURPOSE

Much less is known about strength and conditioning (S&C) practice in women's versus men's soccer. The aim of this study was to compare S&C practice between coaches working in men's or women's soccer, at first team or academy level, worldwide.

METHODS

A total of 170 participants, who were involved with S&C support at their soccer club (in Europe, USA and South America, within men's or women's first team or academy settings) completed a comprehensive online survey, designed to evaluate (i) their academic qualifications and S&C coaching experience; and their preferred methods for (ii) physical testing; (iii) strength and power development; (iv) plyometric training; (v) speed development; and (vi) periodization.

RESULTS

Women's academies had fewer weekly in-season S&C sessions than men's academies (1.6±0.6 vs. 2.3±0.9, p=0.005). Relatively, fewer women's academy S&C coaches (6%) used Olympic weightlifting movements than men's academy S&C coaches (32%, p=0.030). Relatively, more women's academy coaches (47%) used the Nordic hamstring exercise (NHE) compared to men's academy coaches (15%, p=0.006), but relatively more women's vs. men's first team coaches (61% vs. 38%, p=0.028) and women's vs. men's academy (61% vs. 38% coaches, p=0.049) utilised rating of perceived exertion-based load prescriptions.

CONCLUSION

Notable differences in S&C practice exist between coaches of men's and women's soccer squads, particularly at academy level. Fewer weekly S&C sessions in women academy players may have implications for physical development, while the greater use of subjective load prescriptions in both academy and first team women's squads may lead to sub-optimal performance gains.

Influence of Menstrual Cycle on Leukocyte Response Following Exercise-Induced Muscle Damage

We investigated the influence of the menstrual cycle (MC) on leukocyte response after exercise-induced muscle damage (EIMD). During the early follicular (E-FP, n = 12) or mid-luteal phase (M-LP, n = 12), 24 untrained females with eumenorrhea performed 60 eccentric exercises using nondominant arms. Blood samples were collected at pre- and 4, 48, and 96 h postexercise to analyze estradiol and progesterone concentrations, leukocyte count and fractionation, and creatine kinase (CK) activity. We also assessed the maximal voluntary isometric contraction torque of elbow flexion, range of motion in the elbow joint, upper-arm circumference, and muscle soreness as indirect muscle damage markers at pre-; immediately post-; and 4, 48, and 96 h postexercise. The percent change in neutrophil counts from pre- to 4 h postexercise was lower in M-LP than in E-FP (E-FP, 30.7% [15.9–65.7%] vs. M-LP, 10.3% [−2.3–30.0%]; median [interquartile range: 25–75%]; p = 0.068). Progesterone concentration at pre-exercise was significantly negatively correlated with the percent change in neutrophil counts from pre- to 4 h postexercise in M-LP (r = −0.650, p = 0.022). MC did not affect CK activity or other muscle damage markers. Thus, progesterone concentration rather than MC may be related to neutrophil response following EIMD.

Considerations for Sex-Cognizant Research in Exercise Biology and Medicine

As the fields of kinesiology, exercise science, and human movement developed, the majority of the research focused on male physiology and extrapolated findings to females. In the medical sphere, basing practice on data developed in only males resulted in the removal of drugs from the market in the late 1990s due to severe side effects (some life-threatening) in females that were not observed in males. In response to substantial evidence demonstrating exercise-induced health benefits, exercise is often promoted as a key modality in disease prevention, management, and rehabilitation. However, much like the early days of drug development, a historical literature knowledge base of predominantly male studies may leave the exercise field vulnerable to overlooking potentially key biological differences in males and females that may be important to consider in prescribing exercise (e.g., how exercise responses may differ between sexes and whether there are optimal approaches to consider for females that differ from conventional approaches that are based on male physiology). Thus, this review will discuss anatomical, physiological, and skeletal muscle molecular differences that may contribute to sex differences in exercise responses, as well as clinical considerations based on this knowledge in athletic and general populations over the continuum of age. Finally, this review summarizes the current gaps in knowledge, highlights the areas ripe for future research, and considerations for sex-cognizant research in exercise fields.

State of Knowledge on Molecular Adaptations to Exercise in Humans: Historical Perspectives and Future Directions

For centuries, regular exercise has been acknowledged as a potent stimulus to promote, maintain, and restore healthy functioning of nearly every physiological system of the human body. With advancing understanding of the complexity of human physiology, continually evolving methodological possibilities, and an increasingly dire public health situation, the study of exercise as a preventative or therapeutic treatment has never been more interdisciplinary, or more impactful. During the early stages of the NIH Common Fund Molecular Transducers of Physical Activity Consortium (MoTrPAC) Initiative, the field is well-positioned to build substantially upon the existing understanding of the mechanisms underlying benefits associated with exercise. Thus, we present a comprehensive body of the knowledge detailing the current literature basis surrounding the molecular adaptations to exercise in humans to provide a view of the state of the field at this critical juncture, as well as a resource for scientists bringing external expertise to the field of exercise physiology. In reviewing current literature related to molecular and cellular processes underlying exercise-induced benefits and adaptations, we also draw attention to existing knowledge gaps warranting continued research effort. © 2021 American Physiological Society. Compr Physiol 12:3193-3279, 2022.

Injury Incidence Across the Menstrual Cycle in International Footballers

Objectives: This study aimed to assess how menstrual cycle phase and extended menstrual cycle length influence the incidence of injuries in international footballers.

Methods: Over a 4-year period, injuries from England international footballers at training camps or matches were recorded, alongside self-reported information on menstrual cycle characteristics at the point of injury. Injuries in eumenorrheic players were categorized into early follicular, late follicular, or luteal phase. Frequencies were also compared between injuries recorded during the typical cycle and those that occurred after the cycle would be expected to have finished. Injury incidence rates (per 1,000 person days) and injury incidence rate ratios were calculated for each phase for all injuries and injuries stratified by type.

Results: One hundred fifty-six injuries from 113 players were eligible for analysis. Injury incidence rates per 1,000 person-days were 31.9 in the follicular, 46.8 in the late follicular, and 35.4 in the luteal phase, resulting in injury incidence rate ratios of 1.47 (Late follicular:Follicular), 1.11 (Luteal:Follicular), and 0.76 (Luteal:Late follicular). Injury incident rate ratios showed that muscle and tendon injury rates were 88% greater in the late follicular phase compared to the follicular phase, with muscle rupture/tear/strain/cramps and tendon injuries/ruptures occurring over twice as often during the late follicular phase compared to other phases 20% of injuries were reported as occurring when athletes were “overdue” menses.

Conclusion: Muscle and tendon injuries occurred almost twice as often in the late follicular phase compared to the early follicular or luteal phase. Injury risk may be elevated in typically eumenorrheic women in the days after their next menstruation was expected to start.

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.

Menstrual Cycle Effects on Exercise-Induced Fatigability

Estrogen and progesterone have distinct concentrations across the menstrual cycle, each one promoting several physiological alterations other than preparing the uterus for pregnancy. Whether these physiological alterations can influence motor output during a fatiguing contraction is the goal of this review, with an emphasis on the obtained effect sizes. Studies on this topic frequently attempt to report if there is a statistically significant difference in fatigability between the follicular and luteal phases of the menstrual cycle. Although the significant difference (the P-value) can inform the probability of the event, it does not indicate the magnitude of it. We also investigated whether the type of task performed (e.g., isometric vs. dynamic) can further influence the magnitude by which exercise-induced fatigue changes with fluctuations in the concentration of ovarian hormones. We retrieved experimental studies in eumenorrheic women published between 1975 and 2019. The initial search yielded 921 studies, and after manual refinement, 46 experimental studies that reported metrics of motor output in both the follicular and luteal phases of the menstrual cycle were included. From these retrieved studies, 15 showed a statistical difference between the luteal and follicular phases (seven showing less fatigability during the luteal phase and eight during the follicular phase). The effect size was not consistent across studies and with a large range (-6.77; 1.61, favoring the luteal and follicular phase, respectively). The inconsistencies across studies may be a consequence of the differences in the limb used during the fatiguing contraction (upper vs. lower extremity), the type of contraction (isometric vs. dynamic), the muscle mass engaged (single limb vs. full body), and the techniques used to define the menstrual cycle phase (e.g., serum concentration vs. reported day of menses). Further studies are required to determine the effects of a regular menstrual cycle phase on the exercise-induced fatigability.

Physical, Biochemical, and Neuromuscular Responses to Repeated Sprint Exercise in Eumenorrheic Female Handball Players: Effect of Menstrual Cycle Phases

Graja, A, Kacem, M, Hammouda, O, Borji, R, Bouzid, MA, Souissi, N, and Rebai, H. Physical, biochemical, and neuromuscular responses to repeated sprint exercise in eumenorrheic female handball players: effect of menstrual cycle phases. J Strength Cond Res XX(X): 000-000, 2020-Very few studies have been interested in the relationship between ovarian hormones and physiological function in female athletes. The aim of this study was to assess the effect of menstrual phases (MP) on physical, neuromuscular, and biochemical responses after repeated sprint exercise (RSE) in female handball players. Ten eumenorrheic athletes (22.5 ± 1.5 years, 1.70 ± 0.04 m) participated in 3 study visits (follicular phase [FP], luteal phase [LP], and premenstrual phase [PMP]). During each MP, they performed 20 × 5-second cycle sprints interspersed with 25 seconds of rest. Maximal voluntary contraction (MVC) tests of the knee extensor muscles at 90° of knee flexion were performed before and after RSE. Peak force and electromyography (EMG) signals were measured during the MVC tests. Blood samples were collected before and 3 minutes after each session. The percentage of decrement in peak power output over the 20 × 5-second cycle test (i.e., fatigue index) calculated between sprints 1 and 20 decreased significantly during PMP (-43.3% ± 5.7%) but not in LP (-39.2% ± 7.7%) compared with FP (-32.44% ± 6.3%) (p < 0.05). Moreover, no significant difference was found between MP in all frequency components of EMG before RSE (p > 0.05). Maximal voluntary contraction, neuromuscular efficiency, and median frequency values of vastus lateralis and rectus femoris were significantly decreased in PMP compared with FP and LP (p < 0.05). Creatine kinase (CK) levels were significantly higher in PMP compared with FP and LP after RSE (p < 0.05). These findings suggest that RSE induces more peripheral fatigue associated with muscle damage in PMP. This might be attributable to hormonal variation across MP. Therefore, FP seems to be the right time for intense training to improve strength performance.

The Effect of the Menstrual Cycle and Oral Contraceptives on Acute Responses and Chronic Adaptations to Resistance Training: A Systematic Review of the Literature

BACKGROUND

Resistance training is well known to increase strength and lean body mass, and plays a key role in many female athletic and recreational training programs. Most females train throughout their reproductive years when they are exposed to continuously changing female steroid hormone profiles due to the menstrual cycle or contraceptive use. Therefore, it is important to focus on how female hormones may affect resistance training responses.

OBJECTIVE

The aim of this systematic review is to identify and critically appraise current studies on the effect of the menstrual cycle and oral contraceptives on responses to resistance training.

METHODS

The electronic databases Embase, PubMed, SPORTDiscus and Web of Science were searched using a comprehensive list of relevant terms. Studies that investigated the effect of the menstrual cycle phase or oral contraceptive cycle on resistance training responses were included. Studies were also included if they compared resistance training responses between the natural menstrual cycle and oral contraceptive use, or if resistance training was adapted to the menstrual cycle phase or oral contraceptive phase. Studies were critically appraised with the McMasters Universities Critical Review Form for Quantitative Studies and relevant data were extracted.

RESULTS

Of 2007 articles found, 17 studies met the criteria and were included in this systematic review. The 17 included studies had a total of 418 participants with an age range of 18-38 years. One of the 17 studies found no significant differences in acute responses to a resistance training session over the natural menstrual cycle, while four studies did find changes. When assessing the differences in acute responses between the oral contraceptive and menstrual cycle groups, two studies reported oral contraceptives to have a positive influence, whilst four studies reported that oral contraceptive users had a delayed recovery, higher levels of markers of muscle damage, or both. For the responses to a resistance training program, three studies reported follicular phase-based training to be superior to luteal phase-based training or regular training, while one study reported no differences. In addition, one study reported no differences in strength development between oral contraceptive and menstrual cycle groups. One further study reported a greater increase in type I muscle fibre area and a trend toward a greater increase in muscle mass within low-androgenic oral contraceptive users compared with participants not taking hormonal contraceptives. Finally, one study investigated androgenicity of oral contraceptives and showed greater strength developments with high androgenic compared with anti-androgenic oral contraceptive use.

CONCLUSIONS

The reviewed articles reported conflicting findings, and were often limited by small participant numbers and methodological issues, but do appear to suggest female hormones may affect resistance training responses. The findings of this review highlight the need for further experimental studies on the effects of the menstrual cycle and oral contraceptives on acute and chronic responses to resistance training.

Effects of oral contraceptive use on female sexual salivary hormones and indirect markers of muscle damage following eccentric cycling in women

PURPOSE

To determine the effects of oral contraceptive (OC) use on salivary concentrations of testosterone, estrogen, progesterone, and its effects on the changes in indirect markers of muscle damage following eccentric cycling in women.

METHODS

10 oral contraceptive users at follicular phase (OC-FOL), 10 non-oral contraceptives users at follicular phase (NOC-FOL), and 10 non-oral contraceptives users at ovulation phase (NOC-OV) participated. Subjects performed 30 min of eccentric cycling at 90% of their maximal concentric power output (PO). Maximal voluntary isometric contraction (MVC), creatine kinase activity (CK), muscle soreness (SOR), and pain pressure threshold of vastus lateralis (PPT-VL) was assessed before, immediately after, and 24-96 h after cycling. Salivary estrogen, progesterone and testosterone concentrations were measured before, 72 and 96 h after exercise.

RESULTS

No difference in estrogen levels between users and non-users was observed. Testosterone was 45% lower in OC-FOL than NOC-FOL at 96 h post-exercise (P = 0.01). Progesterone was 30.8-fold higher in NOC-OV than OC-FOL and 9.7-fold higher than NOC-FOL at 96 h post-exercise. The NOC-FOL recovered all indirect markers of muscle damage by 72 h post-exercise (P > 0.05). NOC-OV recovered MVC strength and muscle soreness (SOR and PPT-VL) by 96 h post-exercise (P > 0.05). OC-FOL did not recover baseline values of MVC, SOR, CK, and PPT-VL by 96 h.

CONCLUSION

These results suggest that recovery after exercise-induced muscle damage took longer in OC-FOL, followed by NOC-OV and by NOC-FOL, respectively. Furthermore, testosterone and progesterone levels may affect recovery of indirect markers of muscle damage in women.

Muscle damage responses to resistance exercise performed with high-load versus low-load associated with partial blood flow restriction in young women

The aim of this study was to compare if an acute exercise session of high-load resistance training (HL-RT, e.g. 70% of 1 repetition-maximum, 1 RM) induces a higher magnitude of muscle damage compared with a RT protocol with low-loads (e.g. 20% 1 RM) associated with partial blood flow restriction (LL-BFR), and investigate the recovery in the days after the protocols. We used an unilateral crossover research design in which 10 young women (22(2) y; 162(5) cm; 66(11) kg) performed HL-RT and LL-BFR in a randomized, counterbalanced manner with a minimum interval of 2 weeks between protocols. Indirect muscle damage markers were evaluated before and once a day for 4 days into recovery. Main results showed decreases of 8-12% at 24-48 h in maximal voluntary isometric and concentric contraction torques (P < 0.03), and changes in muscle architecture markers (P < 0.03) for HL-RT and LL-BFR, with no differences between protocols (P > 0.05). Moreover, delayed onset muscle soreness increased only after LL-BFR (P < 0.001). We conclude that an acute bout of low volume HL-RT or LL-BFR to failure resulted in edema-induced muscle swelling, but do not induce major or long-lasting decrements in muscle function and the level of soreness promoted from LL-BFR was mild.

Sex Differences in the Temporal Recovery of Neuromuscular Function Following Resistance Training in Resistance Trained Men and Women 18 to 35 Years

To investigate sex differences in the temporal recovery of neuromuscular function following resistance training (RT), eleven men and eight women 18-35 years completed a single RT bout (barbell back-squats, 80 % 1RM, 5 sets × 5 reps, 25 % duty cycle, then 1 set × max reps). Measures of muscle function (isometric, concentric, eccentric knee extensor strength, and countermovement jump (CMJ) height), serum creatine kinase activity (CK) and lower-body muscle pain were assessed before RT (0 h), +4 h, +24 h, +48 h, and +72 h post-RT. Data are mean % change from PRE (SD) and effect size (ω², d). Men and women had similar RT-experience (men, 2.1 (0.8) years vs. women 2.4 (1.0) years, P = 0.746, and d = 0.3) and 1RM strength per kg lean mass (men, 1.9 (0.2) kg⋅kg^-1 vs. women, 1.8 (0.3) kg⋅kg^-1, P = 0.303, and d = 0.3). A 36 (12)% increase in lower-body muscle pain was reported following RT (P < 0.05, d > 0.9). There was an absence of any overt change in CK [+24 h, 74 (41) IU⋅L^-1; pooled mean (SD)]. Decrements in knee extensor strength and CMJ height were observed +4 to +72 h for both men and women (P < 0.05, ω² = 0.19-0.69). Sex differences were apparent for CMJ height (+24 h men, -10 (6)% vs. women, -20 (11)%, P < 0.001, and d = 1.8) and isokinetic concentric strength (+24 h men, -10 (13)% vs. women -25 (14)%, P = 0.006, and d = 1.8), with a more pronounced loss and prolonged recovery in women compared to men (e.g., CMJ + 72 h men, -3 (6)% vs. women, -13 (12)%, P = 0.051, and d = 1.1). We conclude that the different temporal recovery patterns between men and women are not explicable by differences in muscle strength, RT performance, experience, muscle damage or fatigability.

Montmorency tart cherry (Prunus cerasus L.) supplementation accelerates recovery from exercise-induced muscle damage in females

Tart Montmorency cherry concentrate (MC) has been reported to attenuate the symptoms of exercise-induced muscle damage (EIMD) and to accelerate exercise recovery, which has been attributed to its high anti-inflammatory and antioxidant properties. Although these data are promising, there are no data regarding exclusively female populations. Therefore, the aim of this investigation was to examine the efficacy of MC on recovery following EIMD in females. In a randomised, double-blind, placebo-controlled study, twenty physically active females (mean ± SD age 19 ± 1 y; stature 167 ± 6 cm; body mass 61.4 ± 5.7 kg) consumed MC or a placebo (PL) for eight days (30 mL twice per day). Following four days of supplementation, participants completed a repeated-sprint protocol and measures of muscle soreness (DOMS), pain pressure threshold (PPT), limb girth, flexibility, muscle function, and systemic indices of muscle damage and inflammation were collected pre, immediately post (0 h) and 24, 48 and 72 h post-exercise. Time effects were observed for all dependent variables (p < 0.05) except limb girth and high sensitivity C-reactive protein. Recovery of countermovement jump height was improved in the MC group compared to PL (p = 0.016). There was also a trend for lower DOMS (p = 0.070) and for higher PPT at the rectus femoris (p = 0.071) in the MC group. The data demonstrate that MC supplementation may be a practical nutritional intervention to help attenuate the symptoms of muscle damage and improve recovery on subsequent days in females.

Milk: An Effective Recovery Drink for Female Athletes

Milk has become a popular post-exercise recovery drink. Yet the evidence for its use in this regard comes from a limited number of investigations utilising very specific exercise protocols, and mostly with male participants. Therefore, the aim of this study was to investigate the effects of post-exercise milk consumption on recovery from a sprinting and jumping protocol in female team-sport athletes. Eighteen females participated in an independent-groups design. Upon completion of the protocol participants consumed 500 mL of milk (MILK) or 500 mL of an energy-matched carbohydrate (CHO) drink. Muscle function (peak torque, rate of force development (RFD), countermovement jump (CMJ), reactive strength index (RSI), sprint performance), muscle soreness and tiredness, symptoms of stress, serum creatine kinase (CK) and high-sensitivity C-reactive protein (hsCRP) were determined pre- and 24 h, 48 h and 72 h post-exercise. MILK had a very likely beneficial effect in attenuating losses in peak torque (180°/s) from baseline to 72 h (0.0 ± 10.0% vs. −8.7 ± 3.7%, MILK v CHO), and countermovement jump (−1.1 ± 5.2% vs. −10.4 ± 6.7%) and symptoms of stress (−13.5 ± 7.4% vs. −18.7 ± 11.0%) from baseline to 24 h. MILK had a likely beneficial effect and a possibly beneficial effect on other peak torque measures and 5 m sprint performance at other timepoints but had an unclear effect on 10 and 20 m sprint performance, RSI, muscle soreness and tiredness, CK and hsCRP. In conclusion, consumption of 500 mL milk attenuated losses in muscle function following repeated sprinting and jumping and thus may be a valuable recovery intervention for female team-sport athletes following this type of exercise.

Acute effects of different foam rolling volumes in the interset rest period on maximum repetition performance

Background:

Foam rolling (FR) is a ubiquitous intervention utilised for the purpose of acutely increasing the range of motion without subsequent decreases in performance. Thus, it is commonly used during the periworkout period—that is, prior to, during, or after an athlete's workout.

Objective:

This study investigated how different FR durations applied to the quadriceps during the interset rest periods affects the numbers of repetitions in the knee extension exercise.

Methods:

Twenty-five females completed four sets of knee extensions with 10 repetitions of maximum load to concentric failure on four occasions. Between each set, a 4-minute rest interval was implemented in which participants either passively rested or performed FR for different durations (60 seconds, 90 seconds, and 120 seconds). The 95% confidence intervals revealed a dose-dependent relationship in which longer durations of FR resulted in fewer completed repetitions.

Results:

On average, the number of repetitions with PR was 13.8% greater than that in FR120, 8.6% greater than that in FR90, and 9.1% greater than that in FR60.

Conclusion:

For the purposes of performance and likely adaptation, interset FR seems to be detrimental to a person's ability to continually produce force, and should not be applied to the agonist muscle group between sets of knee extensions.

Effect of alcohol after muscle-damaging resistance exercise on muscular performance recovery and inflammatory capacity in women

PURPOSE

To investigate the effect of acute alcohol consumption on muscular performance recovery, assessed by maximal torque production, and on inflammatory capacity, assessed by lipopolysaccharide (LPS)-stimulated cytokine production, following muscle-damaging resistance exercise in women.

METHODS

Thirteen recreationally resistance-trained women completed two identical exercise bouts (300 maximal single-leg eccentric leg extensions) followed by alcohol (1.09 g ethanol kg^-1 fat-free body mass) or placebo ingestion. Blood was collected before (PRE), and 5 (5 h-POST), 24 (24 h-POST), and 48 (48 h-POST) hours after exercise and analyzed for LPS-stimulated cytokine production (TNF-α, IL-1β, IL-6, and IL-8 and IL-10). Maximal torque production (concentric, eccentric, isometric) was measured for each leg at PRE, 24 h-POST, and 48 h-POST.

RESULTS

Although the exercise bout increased LPS-stimulated production of TNF-α (%change from PRE: 5 h-POST 109%; 24 h-POST 49%; 48 h-POST 40%) and decreased LPS-stimulated production of IL-8 (5 h-POST -40%; 24 h-POST -50%; 48 h-POST: -43%) and IL-10 (5 h-POST: -37%; 24 h-POST -32%; 48 h-POST -31%), consuming alcohol after exercise did not affect this response. Regardless of drink condition, concentric, eccentric, and isometric torque produced by the exercised leg were lower at 24 h-POST (concentric 106 ± 6 Nm, eccentric 144 ± 9 Nm, isometric 128 ± 8 Nm; M ± SE) compared to PRE (concentric 127 ± 7 Nm, eccentric 175 ± 11 Nm, isometric 148 ± 8 Nm). Eccentric torque production was partially recovered and isometric torque production was fully recovered by 48 h-POST.

CONCLUSIONS

Alcohol consumed after muscle-damaging resistance exercise does not appear to affect inflammatory capacity or muscular performance recovery in resistance-trained women. Combined with previous findings in men, these results suggest a gender difference regarding effects of alcohol on exercise recovery.

The Effect of Gender and Menstrual Phase on Serum Creatine Kinase Activity and Muscle Soreness Following Downhill Running

Serum creatine kinase (CK) activity reflects muscle membrane disruption. Oestrogen has antioxidant and membrane stabilising properties, yet no study has compared the CK and muscle soreness (DOMS) response to unaccustomed exercise between genders when all menstrual phases are represented in women. Fifteen eumenorrhoeic women (early follicular, EF (n = 5); late follicular, LF (n = 5); mid-luteal, ML (n = 5) phase) and six men performed 20 min of downhill running (−10% gradient) at 9 km/h. Serum CK activity and visual analogue scale rating of perceived muscle soreness were measured before, immediately, 24-h, 48-h and 72-h after exercise. The 24-h peak CK response (relative to pre-exercise) was similar between women and men (mean change (95% confidence interval): 58.5 (25.2 to 91.7) IU/L; 68.8 (31.3 to 106.3) IU/L, respectively). However, serum CK activity was restored to pre-exercise levels quicker in women (regardless of menstrual phase) than men; after 48-h post exercise in women (16.3 (−4.4 to 37.0) IU/L; 56.3 (37.0 to 75.6) IU/L, respectively) but only after 72-h in men (14.9 (−14.8 to 44.6) IU/L). Parallel to the CK response, muscle soreness recovered by 72-h in men. Conversely, the women still reported muscle soreness at 72-h despite CK levels being restored by 48-h; delayed recovery of muscle soreness appeared mainly in EF and LF. The CK and DOMS response to downhill running is gender-specific. The CK response recovers quicker in women than men. The CK and DOMS response occur in concert in men but not in women. The DOMS response in women is prolonged and may be influenced by menstrual phase.

Increases in M-wave latency of biceps brachii after elbow flexor eccentric contractions in women

PURPOSE

Eccentric contractions (ECCs) induce muscle damage that is indicated by prolonged loss of muscle function and delayed onset muscle soreness. It is possible that ECCs affect motor nerves, and this may contribute to the prolonged decreases in force generating capability. The present study investigated the hypothesis that M-wave latency of biceps brachii would be increased after maximal elbow flexor ECCs resulting in prolonged loss of muscle strength.

METHODS

Fifteen women performed exercise consisting of 60 maximal ECCs of the elbow flexors using their non-dominant arm. M-wave latency was assessed by the time taken from electrical stimulation applied to the Erb's point to the onset of M-wave of the biceps brachii before, immediately after, and 1-4 days after exercise. Maximal voluntary isometric contraction (MVC) torque, range of motion (ROM) and muscle soreness using a numerical rating scale were also assessed before and after exercise.

RESULTS

Prolonged decreases in MVC torque (1-4 days post-exercise: -54 to -15 %) and ROM (1-2 days: -32 to -22 %), and increased muscle soreness (peak: 4.2 out of 10) were evident after exercise (p < 0.05). The M-wave latency increased (p < 0.01) from 5.8 ± 1.0 ms before exercise to 6.5 ± 1.7 ms at 1 day and 7.2 ± 1.5 ms at 2 days after exercise for the exercised arm only. No significant changes in M-wave amplitude were evident after exercise.

CONCLUSION

The increased M-wave latency did not fully explain the prolonged decreases in MVC torque after eccentric exercise, but may indicate reversible motor nerve impairment.

Dietary intervention restored menses in female athletes with exercise-associated menstrual dysfunction with limited impact on bone and muscle health

Exercise-related menstrual dysfunction (ExMD) is associated with low energy availability (EA), decreased bone mineral density (BMD), and increased risk of musculoskeletal injury. We investigated whether a 6-month carbohydrate-protein (CHO-PRO) supplement (360 kcal/day, 54 g CHO/day, 20 g PRO/day) intervention would improve energy status and musculoskeletal health and restore menses in female athletes (n = 8) with ExMD. At pre/post-intervention, reproductive and thyroid hormones, bone health (BMD, bone mineral content, bone markers), muscle strength/power and protein metabolism markers, profile of mood state (POMS), and energy intake (EI)/energy expenditure (7 day food/activity records) were measured. Eumenorrheic athlete controls with normal menses (Eumen); n = 10) were measured at baseline. Multiple linear regressions were used to evaluate differences between groups and pre/post-intervention blocking on participants. Improvements in EI (+382 kcal/day; p = 0.12), EA (+417 kcal/day; p = 0.17) and energy balance (EB; +466 kcal/day; p = 0.14) were observed with the intervention but were not statistically significant. ExMD resumed menses (2.6 ± 2.2-months to first menses; 3.5 ± 1.9 cycles); one remaining anovulatory with menses. Female athletes with ExMD for >8 months took longer to resume menses/ovulation and had lower BMD (low spine (ExMD = 3; Eumen = 1); low hip (ExMD = 2)) than those with ExMD for <8 months; for 2 ExMD the intervention improved spinal BMD. POMS fatigue scores were 15% lower in ExMD vs. Eumen (p = 0.17); POMS depression scores improved by 8% in ExMD (p = 0.12). EI, EA, and EB were similar between groups, but the intervention (+360 kcal/day) improved energy status enough to reverse ExMD despite no statistically significant changes in EI. Similar baseline EA and EB between groups suggests that some ExMD athletes are more sensitive to EA and EB fluctuations.