https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:45048 n = 25) or experiencing natural menstrual cycles (MC; n = 22) completed an incremental exercise test to volitional exhaustion followed by a square-wave step-transition protocol to moderate (90% of power output at ventilatory threshold) and high intensity (Δ50% of power output at ventilatory threshold) exercise on two separate occasions. Time-to-fatigue, pulmonary oxygen uptake on-kinetics, cardiac output, and heart rate on-kinetics, and tissue saturation index responses were assessed prior to, and following 12 sessions of sprint interval training (10 min × 1 min efforts at 100–120% PPO in a 1:2 work:rest ratio) completed over 4 weeks. Results: Time-to-fatigue increased in both groups following training (p < 0.001), with no difference between groups. All cardiovascular on-kinetic parameters improved to the same extent following training in both groups. Greater improvements in pulmonary oxygen up-take kinetics were seen at both intensities in the MC group (p < 0.05 from pre-training) but were blunted in the OC group (p > 0.05 from pre-training). In contrast, changes in tissue saturation index were greater in the OC group at both intensities (p < 0.05); with the MC group showing no changes at either intensity. Discussion: Oral contraceptive use may reduce central adaptations to sprint interval training in women without influencing improvements in exercise performance - potentially due to greater peripheral adaptation. This may be due to the influence of exogenous oestradiol and progestogen on cardiovascular function and skeletal muscle blood flow. Further investigation into female-specific influences on training adaptation and exercise performance is warranted.]]> Wed 26 Oct 2022 11:42:29 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:33583 2peak); however, whether it also influences adaptations to training has yet to be determined. This study aimed to examine the influence of OC use on peak performance (peak power output [PPO]) and physiological adaptations (̇VO_2peak and peak cardiac output [̇Q_peak]) after sprint interval training (SIT) in recreationally active women. Methods: Women taking an OC (n = 25) or experiencing natural regular menstrual cycles (MC; n = 16) completed an incremental exercise test to assess ̇VO_2peak, PPO, and ̇Q_peak before, immediately after, and 4 wk after 12 sessions of SIT. The SIT consisted ten 1-min efforts at 100% to 120% PPO in a 1:2 work–rest ratio. Results: Though ̇VO_2peak increased in both groups after SIT (both P < 0.001), the MC group showed greater improvement (OC, +8.5%; MC, +13.0%; P = 0.010). Similarly, ̇Q_peak increased in both groups, with greater improvement in the MC group (OC, +4.0%; MC, +16.1%; P = 0.013). PPO increased in both groups (OC, +13.1%; MC, +13.8%; NS). All parameters decreased 4 wk after SIT cessation, but remained elevated from pretraining levels; the OC group showed more sustained training effects in ̇VO_2peak (OC, −4.0%; MC, −7.7%; P = 0.010). Conclusion: SIT improved peak exercise responses in recreationally active women. However, OC use dampened ̇VO_2peak and ̇Q_peak adaptation. A follow-up period indicated that OC users had spared ̇VO_2peak adaptations, suggesting that OC use may influence the time course of physiological training adaptations. Therefore, OC use should be verified, controlled for, and considered when interpreting physiological adaptations to exercise training in women.]]> Wed 09 Feb 2022 15:57:59 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:33584 300 min/wk) women (age 23 ± 5 y), and 108 competitive (state-, national- or international-level) female athletes (age 23 ± 4 y) completed a self-administered questionnaire assessing OC-regimen habits and reasons for manipulation of menstruation. Results: The majority (74%) of OC users reported having deliberately manipulated menstruation at least once during the previous year, with 29% reporting having done so at least 4 times. Prevalence of menstrual manipulation (at least once in the previous year) was not different between competitive athletes, subelite recreationally active women, and recreationally active women (77% vs 74% vs 72%; P > .05). The most cited reasons for manipulating menstruation were special events or holidays (rated by 75% as important/very important), convenience (54%), and sport competition (54%). Conclusions: Menstrual manipulation through extended OC regimens is common practice in recreationally and competitively active young women, for a range of reasons relating to convenience that are not limited to physical activity. This strategy may help reduce hormone-related barriers to exercise participation, thereby positively affecting participation and performance.]]> Wed 06 Apr 2022 14:03:04 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:17557 Sat 24 Mar 2018 08:03:52 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:19646 p < 0.001) trials compared to 120 and 180 min following ingestion for the 6 and 9 mg kg⁻¹ fed trials, respectively (p < 0.001). Peak concentration was greater in the 9 mg kg⁻¹ fasted trial than the corresponding fed condition (70 ± 9 μmol L⁻¹ and 56 ± 6 μmol L⁻¹, respectively) and both were greater than the 6 mg kg⁻¹ conditions (44 ± 8 μmol L⁻¹ and 38 ± 8 μmol L⁻¹ for 6 mg kg⁻¹ fasted and fed, respectively). Area under the caffeine curve was significantly greater (p < 0.001) in the 9 mg kg⁻¹ fasted trial (3262 μmol L⁻¹ h⁻¹), whilst areas were lowest in the 6 mg kg⁻¹ fed trial (1644 μmol L⁻¹ h⁻¹). Conclusions: A high carbohydrate meal consumed prior to caffeine ingestion significantly reduced serum caffeine concentrations and delayed time to peak concentration. Differences in research findings between caffeine supplementation studies may, at least in part, be related to variations in postprandial timing of caffeine intake. The influence of postprandial timing should be considered when athletes consume caffeine with the aim of enhancing performance.]]> Sat 24 Mar 2018 08:01:09 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:19647 2max = 64.8 ± 4.5 mL·kg⁻¹·min⁻¹; mean ± SD) undertook four cycling time trials (TT), each requiring the completion of a set amount of work (7 kJ·kg⁻¹ BM) in the shortest possible time. Participants were randomized into a fed or nonfed condition and orally ingested 2.8 mg·kg⁻¹ BM of PSE or a placebo (PLA) 90 min before exercise; in the fed trials, they consumed a meal providing 1.5 g·kg⁻¹ BM of CHO. Venous blood was sampled at 30, 50, and 70 min and pre–warm-up and postexercise for the analysis of plasma PSE and catecholamine concentrations, and urine was also collected for the analysis of PSE concentration. Results: Independent of the preexercise meal, 2.8 mg·kg⁻¹ BM of PSE did not significantly improve cycling TT performance. The fed trials resulted in lower plasma PSE concentrations at all time points compared with the nonfed trials. Both plasma epinephrine and blood lactate concentrations were higher in the PSE compared with the PLA trials, and preexercise and postexercise urinary PSE concentrations were significantly higher than the threshold (150 µg·mL⁻¹) used by WADA to determine illicit PSE use. Conclusion: Irrespective of the preexercise meal, cycling TT performance of approximately 30 min was not improved after PSE supplementation. Furthermore, 2.8 mg·kg⁻¹ BM of PSE taken 90 min before exercise, with or without food, resulted in urinary PSE concentrations exceeding the present WADA threshold.]]> Sat 24 Mar 2018 08:01:08 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:19160 Sat 24 Mar 2018 07:52:20 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:19161 2.3mgkg⁻¹ > placebo; p<0.001). Conclusions: There was large individual variation in plasma pseudoephedrine concentration between subjects following pseudoephedrine administration. A number of factors clearly influence the uptake and appearance of pseudoephedrine in the blood and these are not yet fully understood. Combined with subsequent differences in plasma pseudoephedrine between individuals, this may partially explain the present findings and also the inconsistencies in performance following pseudoephedrine administration in previous studies.]]> Sat 24 Mar 2018 07:52:20 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:31192 Fri 01 Apr 2022 09:26:37 AEDT ]]>