Blood oxidative stress biomarkers in women: influence of oral contraception, exercise, and N-acetylcysteine.

PURPOSE: To compare physiological responses to submaximal cycling and sprint cycling performance in women using oral contraceptives (WomenOC) and naturally cycling women (WomenNC) and to determine whether N-acetylcysteine (NAC) supplementation mediates these responses. METHODS: Twenty recreationally trained women completed five exercise trials (i.e., an incremental cycling test, a familiarisation trial, a baseline performance trial and two double-blind crossover intervention trials). During the intervention trials participants supplemented with NAC or a placebo 1 h before exercise. Cardiopulmonary parameters and blood biochemistry were assessed during 40 min of fixed-intensity cycling at 105% of gas-exchange threshold and after 1-km cycling time-trial. RESULTS: WomenOC had higher ventilation (ß [95% CI] = 0.07 L·min-1 [0.01, 0.14]), malondialdehydes (ß = 12.00 mmol·L-1 [6.82, 17.17]) and C-reactive protein (1.53 mg·L-1 [0.76, 2.30]), whereas glutathione peroxidase was lower (ß =  22.62 mU·mL-1 [- 41.32, - 3.91]) compared to WomenNC during fixed-intensity cycling. Plasma thiols were higher at all timepoints after NAC ingestion compared to placebo, irrespective of group (all p < 0.001; d = 1.45 to 2.34). For WomenNC but not WomenOC, the exercise-induced increase in malondialdehyde observed in the placebo trial was blunted after NAC ingestion, with lower values at 40 min (p = 0.018; d = 0.73). NAC did not affect cycling time-trial performance. CONCLUSIONS: Blood biomarkers relating to oxidative stress and inflammation are elevated in WomenOC during exercise. There may be an increased strain on the endogenous antioxidant system during exercise, since NAC supplementation in WomenOC did not dampen the exercise-induced increase in malondialdehyde. Future investigations should explore the impact of elevated oxidative stress on exercise adaptations or recovery from exercise in WomenOC.

Temporal changes in blood oxidative stress biomarkers across the menstrual cycle and with oral contraceptive use in active women.

PURPOSE: To examine the temporal changes in blood oxidative stress biomarkers in recreationally-trained women that were naturally-cycling (WomenNC) or using oral contraceptives (WomenOC) across one month. METHODS: Blood samples were acquired at three timepoints of the menstrual cycle (1: early-follicular, 2: late-follicular and 3: mid-luteal) and oral contraceptive packet (1: InactiveOC, 2: Mid-activeOC and 3: Late-activeOC) for determination of estradiol, progesterone, oxidative stress, C-reactive protein (CRP) and other cardiometabolic biomarkers in plasma and serum. RESULTS: There was a Group by Time effect on estradiol (p < 0.001, partial η2 = 0.64) and progesterone (p < 0.001, partial η2 = 0.77). Malondialdehyde, lipid hydroperoxides and CRP concentrations were higher in WomenOC during Late-activeOC compared to InactiveOC (+ 96%, + 23% and + 104%, respectively, p < 0.05). However, there were no changes in these biomarkers across the menstrual cycle in WomenNC (p > 0.05). At all timepoints (i.e., 1, 2 and 3), WomenOC had elevated lipid hydroperoxides (+ 28, + 48% and + 50%) and CRP (+ 71%, + 117% and + 130%) compared to WomenNC (p < 0.05, partial η2 > 0.25). There was no Group by Time effect on non-enzymatic antioxidants or glutathione peroxidase; however, glutathione peroxidase was lower in WomenOC, i.e., main effect of group (p < 0.05, partial η2 > 0.20). CONCLUSION: These findings demonstrate that WomenOC not only have higher oxidative stress and CRP than WomenNC, but also a transient increase across one month of habitual oral contraceptive use. Since changes in oxidative stress and CRP often relate to training stress and recovery, these outcomes may have implications to workload monitoring practices in female athletes.

Reliability of a point-of-care device to determine oxidative stress in whole blood before and after acute exercise: A practical approach for the applied sports sciences.

Measuring alterations in redox homoeostasis in athletes can provide insights into their responses to training such as adaptations or fatigued states. However, redox monitoring is impractical in athletes given the time burden of venepuncture and subsequent laboratory assays. The ability of point-of-care tests (POC): 1) Free Oxygen Radical Test (FORT) and 2) Free Oxygen Radical Defence (FORD), to reliably measure whole blood oxidative stress between days and after exercise is unknown as well as their relationship with laboratory measures (F2-isoprostanes, total antioxidant capacity; TAC). Participants completed two trials performed on separate days comprising blood sampling at rest (n=22) and after treadmill-running (n=14). Between-day CVs for FORT (4.6%) and FORD (4.8%) were acceptable at rest. There was no difference in the between-day magnitude of change in any biomarker from pre- to post-exercise (p>0.05), yet the within-trial change in FORD was variable (trial one: +4.5%, p=0.15; trial two: +6.3%, p<0.05). TAC and FORD were significantly correlated pre- and post-exercise (r=~0.53, p<0.05), whereas F2-isoprostanes and FORT had a significant correlation pre-exercise only (r=0.45, p=0.03). Overall, the POC tests are reliable and could be used for baseline longitudinal redox monitoring. More data is required on POC tests for assessing redox perturbations induced by exercise.

Strong, Fast, Fit, Lean, and Safe: A Positional Comparison of Physical and Physiological Qualities Within the 2020 Australian Women's Rugby League Team.

ABSTRACT: Minahan, C, Newans, T, Quinn, K, Parsonage, J, Buxton, S, and Bellinger, P. Strong, Fast, Fit, Lean, and Safe: A positional comparison of physical and physiological qualities within the 2020 Australian Women's Rugby League team. J Strength Cond Res 35(12S): S11-S19, 2021-The purpose of the present study was to report the physical and physiological characteristics of elite women Rugby League (RL) players. Thirty-nine women (25.6 ± 4.3 years, 171.3 ± 7.7 cm, 83.5 ± 13.9 kg) from the 2020 Australian women's RL squad were recruited for this study. Players were categorized as adjustables (n = 7), backs (n = 15), or forwards (n = 17) for analysis. Each player was assessed for anthropometry, body composition (dual-energy X-ray absorptiometry), speed (5, 10 and 20 m sprint times), lower-body power (countermovement jump), upper-body power (medicine ball throw and explosive push up force), estimated one repetition maximum (e1RM) bench press, squat and bench pull, isometric mid-thigh pull strength, eccentric knee flexor strength, isometric hip abduction and adduction, and intermittent endurance performance (30-15 intermittent fitness test; 30-15 IFT). Linear mixed models were performed to compare positional groups. Forwards were significantly heavier and had greater fat mass, fat-free mass, and body fat percentage compared with backs and adjustables (P < 0.01). Backs were faster over 20 m compared with forwards (P = 0.025), whereas forwards had a lower 30-15 IFT peak velocity and estimated V̇o2peak compared with backs and adjustables. Nonetheless, when including body mass in the model, there were no differences between groups in 30-15 IFT peak velocity. There were no significant differences in other variables. These results provide contemporary benchmark physical, physiological, and anthropometric data for elite women RL players, which can inform recruitment, selection, training, and testing.

Repeated Treadmill Sprints Impair Cognitive Performance in Amateur Team-Sport Athletes When Performed in Normobaric Hypoxia.

This study determined if a single bout of repeated-sprint running under hypoxic (RSH) conditions was associated with impaired cognitive function when compared with repeated-sprint running under normoxic (RSN) conditions. Eleven amateur team-sport athletes performed a repeated-sprint running protocol (4 sets of 4, 4-s all-out sprints; i.e., RSR444) under both conditions (14.5% and 20.9% O2) on a non-motorized treadmill. Changes in SpO2, pre-frontal cortex total haemoglobin (Δ[THb]), oxyhaemoglobin (Δ[O2Hb]), deoxyhaemoglobin (Δ[HHb]) and cognitive function (detection task: DET; identification task: IDN; one card learning task: OCL; performed pre and 20 min post RSR444) were examined. During RSH, SpO2 was lower following each set (p ≤ 0.05), while [HHb] was higher after each set (p ≤ 0.05) compared with RSN. In addition, while there was no effect of condition on DET (p = 0.20) or IDN (p = 0.14), OCL accuracy was lower after, compared with before, RSH (p=0.04), but not RSN (p = 0.52). A significant relationship was observed between Δ[HHB] and ΔOCL accuracy (r = -0.68, p = 0.01). Performance of a single bout of RSH with 14.5% O2 resulted in impaired cognitive function in amateur team-sport athletes. Coaches should be mindful of timing of RSH prescription with regard to other training sessions that challenge speed and movement accuracy.

Cerebral oxygenation declines but does not impair peak oxygen uptake during incremental cycling in women using oral contraceptives.

PURPOSE: To compare prefrontal cortex oxygenation in recreationally-active women using oral contraceptives (WomenOC; n = 8) to women with a natural menstrual cycle (WomenNC; n = 8) during incremental exercise to exhaustion. METHODS: Participants performed incremental cycling to exhaustion to determine lactate threshold 1 (LT1) and 2 (LT2) and peak oxygen uptake (VO2peak). Prefrontal cortex oxygenation was monitored via near-infrared spectroscopy through concentration changes in oxy-haemoglobin (Δ[HbO2]), deoxy-haemoglobin (Δ[HHb]), total-haemoglobin (Δ[tHb]) and tissue saturation index (TSI). RESULTS: 17ß-oestradiol and progesterone were lower in WomenOC (35 ± 26; 318 ± 127 pmol·L-1, respectively) than WomenNC (261 ± 156; 858 ± 541 pmol·L-1, respectively). There were no differences in full blood examination results or serum nitric oxide (p > 0.05). However, WomenOC presented lower concentrations in ferric-reducing ability of plasma (- 8%; effect size; ES - 0.52 ± 0.61), bilirubin (- 32%; ES - 0.56 ± 0.62) and uric acid (- 17%; ES - 0.53 ± 0.61). Cardiopulmonary parameters were similar between groups during cycling, including VO2peak (p = 0.99). While there was a significant effect of time on all parameters measured by near-infrared spectroscopy during incremental cycling, there was no effect of OC at LT1, LT2 or exhaustion calculated as a change from baseline (TSI; p = 0.096, Δ[HbO2]; p = 0.143, Δ[HHb]; p = 0.085 and Δ[tHb]; p = 0.226). The change in TSI from LT1 to LT2 was significantly different between groups (WomenNC; mean difference + 2.06%, WomenOC; mean difference - 1.73%; p = 0.003). CONCLUSION: Prefrontal tissue oxygenation declined at a lower relative exercise intensity in WomenOC as compared to WomenNC, however, this did not influence VO2peak. The results provide the first evidence for variance in the cerebral oxygenation response to exercise, which may be associated with female sex hormones.

Immune Response in Women during Exercise in the Heat: A Spotlight on Oral Contraception.

This study compared the immune and stress response of oral contraceptive users (WomenOC; n = 9) to normally-menstruating women (WomenNM; n = 9) at rest and during exercise in temperate (TEMP; 22°C) and hot (HEAT; 35°C) conditions. Participants performed a 3-stage cycling trial in each condition at 90% (Stage 1; 30 min), 135% (Stage 2; 15 min), and 180% (Stage 3; 7.5 min) of lactate threshold 1. C-reactive protein (CRP) and immune cell counts were measured at rest, and serum cytokines (IL-1ß, IL-1RA, IL-6, IL-8, IL-10, and TNF-α) and salivary cortisol were evaluated before and after exercise in both the TEMP and HEAT conditions. There were no differences in resting immune cell counts between groups, nor any differences in cortisol or any of the pro- or anti-inflammatory cytokines measured at rest or after completion of the exercise trials (p > 0.05). However, a trend for a higher resting CRP concentration was observed in WomenOC relative to WomenNM (1.102 ± 1.182 and 0.326 ± 0.228, respectively, p = 0.07). The results obtained in the current study indicate similar immunoendocrine function in WomenOC and WomenNM both at rest and after exercise in temperate and hot environments.

Response of women using oral contraception to exercise in the heat.

PURPOSE: To compare the response of long-term oral contraceptive users (WomenOC; n = 8) to naturally menstruating women (WomenNM; n = 8) at rest and during exercise in temperate (TEMP; 22 °C) and hot (HEAT; 35 °C) conditions. METHODS: Participants performed a three-stage cycling trial in each condition at 90, 135, and 180% of lactate threshold 1 (total = 52.5 min). Heart rate (HR) and core temperature (T c) were recorded continuously, whereas blood pressure (BP), ratings of perceived exertion (RPE), blood lactate [La-], and skin blood flow (BFsk) were recorded every 7.5 min. RESULTS: Baseline T c was higher in WomenOC (37.5 ± 0.2, 37.6 ± 0.3 °C) than WomenNM (37.2 ± 0.2, 37.0 ± 0.4 °C) before the TEMP (p = 0.03) and HEAT (p < 0.01) trials, respectively. This difference remained for 22.5 min into both trials (p ≤ 0.05), after which time no between-group differences were found (p > 0.05). BFsk measured in WomenNM plateaued from 7.5 min in the HEAT, whereas BFsk measured in WomenOC increased for 15.0 min (p = 0.02) before plateauing. There were no between-group differences in HR, BP, or blood [La-] before or throughout either trial (p > 0.05). WomenOC had higher (p ≤ 0.04) RPE values than WomenNM in the HEAT, reporting 8 ± 1 and 6 ± 2 at the end of Stage 3, respectively. CONCLUSIONS: WomenOC concluded both trials with a comparable T c to WomenNM, but had a prolonged BFsk response and elevated RPE in the HEAT. Changes to BFsk and RPE observed in women using OC may have implications for exercise tolerance in hot conditions.

Movement Patterns and Match Statistics in the National Rugby League Women's (NRLW) Premiership.

As women's rugby league grows, the need for understanding the movement patterns of the sport is essential for coaches and sports scientists. The aims of the present study were to quantify the position-specific demographics, technical match statistics, and movement patterns of the National Rugby League Women's (NRLW) Premiership and to identify whether there was a change in the intensity of play as a function of game time played. A retrospective observational study was conducted utilizing global positioning system, demographic, and match statistics collected from 117 players from all NRLW clubs across the full 2018 and 2019 seasons and were compared between the ten positions using generalized linear mixed models. The GPS data were separated into absolute (i.e., total distance, high-speed running distance, and acceleration load) and relative movement patterns (i.e., mean speed, mean high speed (> 12 km·h-1), and mean acceleration). For absolute external outputs, fullbacks covered the greatest distance (5,504 m), greatest high-speed distance (1,081 m), and most ball-carry meters (97 m), while five-eighths recorded the greatest acceleration load (1,697 m·s-2). For relative external outputs, there were no significant differences in mean speed and mean high speed between positions, while mean acceleration only significantly differed between wingers and interchanges. Only interchange players significantly decreased in mean speed as their number of minutes played increased. By understanding the load of NRLW matches, coaches, high-performance staff, and players can better prepare as the NRLW Premiership expands. These movement patterns and match statistics of NRLW matches can lay the foundation for future research as women's rugby league expands. Similarly, coaches, high-performance staff, and players can also refine conditioning practices with a greater understanding of the external output of NRLW players.

Practice does not make perfect: A brief view of athletes' knowledge on the menstrual cycle and oral contraceptives.

OBJECTIVES: To assess the knowledge of Australian elite female athletes surrounding the menstrual cycle and oral contraceptives. DESIGN: Cross sectional survey. METHODS: Australian female athletes (n=189) representing their state and/or country in their respective sport completed a questionnaire comprising questions (multiple choice and short answer) relating to the menstrual cycle and oral contraceptives. A knowledge 'score' was calculated by allocating one point for each correct answer; the highest knowledge score that could be achieved was 14. Linear regression analysis was used to identify variables that were independently associated with menstrual cycle and oral contraceptive knowledge. RESULTS: Almost half (47.1 %) of the athletes surveyed were currently using hormonal contraception, the majority (75.3 %) of which used an oral contraceptive pill. Nevertheless, the mean knowledge score achieved by athletes on the questionnaire was 5.03±3.06, with only 8.5 % of athletes achieving a knowledge score of 10 or above. Hormonal contraceptive use and 'identifying as an individual athlete' were two factors that were significantly associated with overall knowledge score (p≤0.004), with current hormonal contraceptive users and individual athletes scoring 1.79 and 1.66 points on average higher than non-users and team sport athletes, respectively. CONCLUSIONS: Our findings indicate that knowledge surrounding the menstrual cycle and oral contraceptives was low in most elite athletes. Further education is warranted to enable athletes to make informed decisions regarding hormonal contraception, and any educational interventions should be implemented across all athlete groups.