ECSS Paris 2023: OP-PN30
INTRODUCTION: Combined oral contraceptive pills (OCP) containing synthetic estradiol and one type of progestin are used by 27 to 41% of female athletes in various European countries [1-3]. Previous research indicates a potential slightly reduced exercise performance in OCP users compared to non-OCP users [4]. However, the acute effect of OCP intake on athletic performance has not been studied. During OCP use, the endogenous levels of sex hormones are downregulated to fairly constant low levels. However, serum concentrations of the exogenous sex hormones from the OCP peak between one and two hours after pill intake [5, 6], but already after eight hours, the concentrations of exogenous hormones have declined to low levels. Whether these fluctuations affect exercise performance remains undetermined. We aimed to investigate a potential acute effect of OCP intake on strength, power, and endurance performance in trained females. METHODS: Twenty-two trained young females using monophasic 2nd generation OCPs were tested in a randomized cross-over controlled study. Participants completed a physical performance test protocol twice during the active OCP period. In randomized order, the participants completed the tests one hour after intake of the OCP and 24 hours after intake of the OCP respectively. The physical tests included a balance stand test, a muscular endurance push-up test, an agility test, and measurements of isometric handgrip strength, countermovement jump height, flexibility and a maximal oxygen uptake bike test. In addition, a questionnaire about psychological wellbeing was completed before testing. Time of the day, energy intake and exercise 24 hours preceding the tests was standardized and participants were familiarized with the tests beforehand. Serum and saliva hormone analysis ensured OCP compliance and exact levels of exogenous hormones at the time of testing. RESULTS: No significant difference in exercise performance parameters was observed between the test days; OCP intake one hour before testing versus 24 hours before testing. CONCLUSION: Collectively, timing of OCP intake in young, trained females did not significantly affect exercise performance parameters. This study indicates, that female athletes using OCPs and pursuing to optimize their physical performance, can omit concerns on when to take their OCP. References 1. Martin, D., et al., 2018, Int J Sports Physiol Perform. 2. Oxfeldt, M., et al., 2020, Int J Sports Physiol Perform. 3. Ekenros, L., et al., 2022, Frontiers Media S.A. 4. Elliott-Sale, K.J., et al., 2020, Springer. 5. Jung-Hoffmann, C., et al., 1991, Karger Publishers. 6. Stanczyk, F.Z., 2002, Springer. p. 211-224.
Read CV Mette Smith BisgaardECSS Paris 2023: OP-PN30
INTRODUCTION: The influence of the menstrual cycle (MC) on female athletic performance and its underlying mechanisms have been largely investigated with conflicting results. A recent study by Ansdell et al. (J Appl Physiol. 2019;126:1701–12) revealed that time-to-exhaustion during a submaximal task was higher on Day 21 [mid-luteal] compared to Day 2 [early follicular] without differences in the strength, voluntary activation and decline in contractile function of the knee extensors. However, endurance performance (i.e., time-to-exhaustion) is not only influenced by neuromuscular but also perceptual factors. Therefore, the present study aimed to investigate time-to-exhaustion and the perceptual responses during the same exercise used by Ansdell et al. across the MC. Furthermore, the influence of trait fatigue and trait mood (assessed over the last 7 days) was examined. METHODS: Fifteen eumenorrheic females (24.1±3.3yrs, 63.4±4.8kg, 166.2±5.0cm) participated in a pseudo-randomized, counterbalanced cross-over study. Participants completed a familiarization session and three experimental trials on different days during the MC (Day 2 [early follicular], 14 [late follicular], and 21 [midluteal]). The fatiguing exercise consisted of isometric knee extensions at 60% of maximal voluntary isometric contraction (MVIC) torque until exhaustion. The protocol consisted of sets with 12 repetitions (3s contraction/ 2s rest). On each 12th repetition, a MVIC was performed to quantify the performance reduction (i.e., motor performance fatigue) At the end of each set perceived motor fatigue, affective valence, arousal, pain and effort percep-tion were queried. Furthermore, motivation to perform the fatiguing task (Dundee Stress State Questionnaire), trait fatigue (Modified Fatigue Impact Scale), and trait mood (Profile of Mood States) were recorded before each experimental session. RESULTS: There were no differences in time-to-exhaustion, the MVIC decline and the perceptual responses during exercise across the 3 trials. However, motivation to perform the fatiguing task was lower on Day 2 compared to Day 21 (p=0.030. d=0.45) and trait mood was worse on Day 2 compared to Day 14 (p=0.007, d=0.85). Of note, a high but non-significant effect was found for trait fatigue (p=0.081, ηp2=0.18) with higher values on Day 2 compared with Day 14 (p=0.079, d=0.56). CONCLUSION: The MC had an effect on motivation to perform the fatiguing task and trait mood as well as trait fatigue with the worst values on Day 2. However, time-to-exhaustion, motor performance fatigue, and the perceptual responses during exercise were not affected. These results indicate that MC-related alterations in motivation, trait mood and trait fatigue do not inevitably affect motor task performance and/or motor performance fatigue.
Read CV Robert BielitzkiECSS Paris 2023: OP-PN30
INTRODUCTION: Estradiol (E2) and progesterone (P4) are suggested to influence substrate use during exercise [1]. Previous literature indicates higher fat oxidation during submaximal continuous exercise in the luteal phase (LP) of the menstrual cycle (MC) compared to the follicular phase (FP) [2]. Evidence regarding fat oxidation during exercise in women using hormonal contraceptives (HC) is sparse but indicates no clear differences between active (AP) and inactive hormonal phases (IP) [3]. This study aimed to examine differences in peak fat oxidation (PFO) between hormonally confirmed MC phases in naturally menstruating women (NoOC) and HC phases in women using combined monophasic oral contraceptives (COC). METHODS: Healthy untrained women (Tier 1) [4] aged 18–35 years with a body mass index between 19.5 and 35 kg/m² were recruited to this study and divided into NoOC- (n=35) and COC-group (n=19). Participants were measured after overnight fast in the FP/LP or the AP/IP of the MC or HC cycle, respectively. E2 and P4 were measured using immunoassays and body composition via bioimpedance. Fat oxidation was measured using indirect calorimetry during a graded treadmill PFO test consisting of 4-min stages. The initial speed and gradient were 4.5 km/h and 1.2°, respectively. The speed increased by 1 km/h in the first two stages and the gradient increased by 1.2° from the third stage onwards until participants reached a respiratory exchange ratio of 0.95 [5]. Fat oxidation was calculated for the last minute of each stage and the highest rate achieved was selected as the PFO. MC or HC phases were compared using paired t-test. Associations between E2/P4 and PFO were analyzed with multiple linear regression using fat free mass (FFM) as a covariate. RESULTS: All participants in the NoOC-group had P4 level ≥16 mmol/l in the LP and higher E2 and P4 concentrations in the LP than in the FP (p<0.001). E2 and P4 did not change from AP to IP in the COC-group. In the NoOC-group, PFO was 0.40 g/min (SD 0.09) in the FP and 0.43 g/min (SD 0.12) in the LP (mean difference 0.03, 95% CI -0.02–0.07, p=0.253). In the COC-group, PFO was 0.44 g/min (SD 0.11) in the AP and 0.48 g/min (SD 0.12) in the IP (mean difference 0.04, 95% CI -0.01–0.09, p=0.099). E2/P4 were not significantly (p>0.05) associated with PFO in any of the MC/HC phases. CONCLUSION: E2 and P4 fluctuations during the MC cycle or the use of COC do not notably affect PFO. This discrepancy with previous work may result from the use of different testing protocols, as most studies reporting higher fat oxidation during the LP have used prolonged single-stage exercise, which is known to be crucial for maximal lipolysis [6]. REFERENCES: 1. Oosthuyse & Bosch. 2010. Sports Med 2010, 40, 207–227 2. Hackney et al. 1994. Int J Sport Nutr 4(3):299–308 3. Williams et al. 2023. J Appl Physiol 135(3), 642–654 4. McKay et al. 2021. Int J Sports Physiol Perform 17(2):317–31 5. Amaro-Gahete et al. 2019. 7(23):10:909 6. Wolfe. 1998. Adv Exp Med Biol 441:147-56
Read CV Ida LöfbergECSS Paris 2023: OP-PN30