The aim of this study was to examine whether variables commonly used in aerobic exercise testing are influenced by menstrual cycle phases and use of oral contraceptive (OC) in female rowers. Twenty-four eumenorrheic female rowers distinguished on the basis of both menstrual status and athleticism participated in this study and were divided into competitive cyclic athletes (n = 8), recreationally trained cyclic athletes (n = 7), and recreationally trained athletes taking OC pills (ROC; n = 9). Rowers performed 2 incremental tests to voluntary exhaustion on a rowing ergometer during 2 different phases of the menstrual cycle: the follicular phase (FP) and the luteal phase (LP). The study variables were power output (Pa), heart rate (HR), oxygen consumption (VO2), carbon dioxide production (VCO2), minute ventilation (VE), the mean respiratory exchange ratio, and ventilatory equivalents of O2 (VE/VO2)) and CO2 (VE/VCO2), which were measured at maximal and at the aerobic-anaerobic transition intensities. In addition, maximal blood lactate (La) values after the test were obtained. When comparing Pa, &OV0312;o2, HR, and La values, no significant differences (p > 0.05) between FP and LP at maximal load and at threshold intensity were found in all 3 groups of the rowers studied. However, we observed higher values (p < 0.05) for VE/VCO2 at both intensities in LP compared with FP in the ROC group. In conclusion, sport-specific endurance performance was not influenced by the phase of the normal menstrual cycle and the synthetic menstrual cycle of the OC users in the rowers studied. Therefore, normally menstruating female rowers and female rowers taking OC pills should not be concerned about the timing of their menstrual cycle with regard to optimized sport-specific endurance performance.

The aim of this investigation was to examine the effects of menstrual cycle phase on substrate oxidation and lactate concentration during exercise. Eleven eumenorrheic female rowers (18.4 ± 1.9 years; 172.0 ± 4.0 cm; 67.2 ± 8.4 kg; 27.7 ± 4.8% body fat) completed 1 h rowing ergometer exercise at 70% of maximal oxygen consumption (VO(2max)) during two different phases of the menstrual cycle: the follicular phase (FP) and the luteal phase (LP). Resting and exercise measurements of the whole body energy expenditure, oxygen consumption (VO(2)), respiratory exchange ratio (RER), substrate oxidation and lactate blood levels were made. Energy expenditure, VO(2) and heart rate during the 1-h exercise were not significantly different (P > 0.05) among menstrual cycle phases. Resting RER and RER during the entire 1 h exercise period were not significantly different among menstrual cycle phases. There was an increase (P < 0.05) in RER in the transition between rest and exercise and a further increase in RER occurred after the first 30 min of exercise at both menstrual cycle phases. Blood lactate concentrations significantly increased in the transition between rest and exercise and remained relatively constant during the whole 1 h of exercise in both menstrual cycle phases. No menstrual cycle phase effect (P > 0.05) was observed for blood lactate concentrations. In conclusion, our results demonstrated no effect of menstrual cycle phase on substrate oxidation and blood lactate concentration during rowing exercise at 70% of VO(2max) in athletes. Normally menstruating female rowers should not be concerned about their menstrual cycle phase with regard to substrate oxidation in everyday training.

Background The aim of this study was to investigate physical fitness and physical activity (PA) of 6-7-year-old children just before entering school according to their sports club (SC) participation and weight status, and to examine possible associations of their body mass index, fat mass and fat-free mass with physical fitness and PA. Methods A total of 256 preschoolers aged 6 to 7 years participated in the study. Physical fitness was assessed using PREFIT test battery and objective PA by 7 day accelerometry. Body composition was estimated using two skinfold thickness parameters. SC participation and parental data were assessed by questionnaires. Results Children participating in SC had higher moderate-to-vigorous PA, vigorous PA and cardiorespiratory fitness than children not participating in SC. Overweight children had lower results in cardiorespiratory fitness and all weight-bearing fitness tests, and better results in handgrip strength test in comparison with normal weight children. Significant associations were found between body composition indices and physical fitness tests. PA level was associated with fat-free mass and physical fitness but not with fatness indices. Conclusions Weight-status and body composition together with PA level were associated with physical fitness level. The differences in physical fitness based more upon weight status than SC participation among 6-7-years old children.

Aim We explored the cognitive abilities, health behaviour and cardiorespiratory fitness of preschool Estonian children aged 6–7 and any association with parental education, attending sports clubs and gender. Methods Data were obtained from 256 children recruited from 13 randomly chosen kindergartens in Tartu, Estonia. Cognitive abilities were assessed using the modified Boehm Test of Basic Concepts – Third Edition. Objective physical activity (PA) intensity and sedentary levels were measured over seven days by accelerometry. To assess cardiorespiratory fitness, we used the 20‐m shuttle run from the PREFIT test battery. Parents reported their educational attainment, together with their child's sports club attendance, sleep duration and screen time. Results Children from more highly educated families had significantly better test results for conceptual skills, verbal abilities and cardiorespiratory fitness. PA levels, cardiorespiratory fitness and perception and conceptual skills test results were better in children who attended sports clubs. Higher cardiorespiratory fitness level, shorter screen time and sleep duration were associated with better conceptual skills. Conclusion Conceptual skills and verbal abilities were better in the children of more highly educated families and if they attended sports clubs. Children's cognitive abilities may benefit from better cardiorespiratory fitness, reduced sedentary activity and less screen time.

This investigation examined the effects of acute rowing exercise on a panel of 12 different inflammatory cytokines. Fifteen female rowers (18.3±1.6 yrs; 172.0±5.0 cm; 67.5±8.8 kg; maximal oxygen consumption [VO2max]: 47.2±7.9 ml.min.−1kg−1) completed a 1-h endurance exercise (distance: 12.1±1.1 km; energy expenditure [EE]: 639±69 kcal; heart rate: 151±7 beats.min−1; intensity: 79.6±3.5% of the second ventilatory turn point). Venous blood samples were analysed for interleukin (IL)-2, IL-4, IL-6, IL-8, IL-10, vascular endothelial growth factor (VEGF), interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), IL-1α, IL-1β, monocyte chemoattractant protein-1 (MCP-1) and epidermal growth factor (EGF) concentrations. Rowing exercise resulted increment (P<0.05) in IL-6, IL-8, VEGF and MCP-1. Exercise metabolic demand variables such as rating of perceived exertion (r=0.61), distance covered (r=0.60) and EE (r=0.57) were related (P<0.05) to changes in VEGF concentration. Cardiorespiratory fitness as measured by VO2max was correlated with changes in IL-6 (r=–0.55; P<0.05) level. In conclusion, acute exercise-induced inflammatory reaction was induced by a significant increase in IL-6, IL-8, VEGF and MCP-1 concentrations. Variance in exercise-induced increases in inflammatory cytokines in response to prolonged endurance exercise was characterised by exercise metabolic demand and cardiorespiratory fitness measures in female rowers.

Eight female rowers (M age = 21.0 yr., SD = 2.8), using a monophasic oral-contraceptive pill, performed a 1-hr. rowing ergometer test (intensity: 70% VO2max) during the active-pill and non active-pill phases of the oral contraceptive cycle. No significant differences were found in mean energy expenditure, oxygen consumption, respiratory exchange ratio, and heart rate during the endurance test at the two phases of the oral contraceptive cycle. Mean energy expenditure rate, carbohydrate energy expenditure, lipid energy expenditure, and blood lactate during the test were not statistically significantly different among the cycle phases. In conclusion, there was no observed difference in substrate oxidation and blood lactate level during endurance rowing at different phases of the oral contraceptive cycle in these endurance-trained rowers. Endurance-trained female athletes on oral contraceptives should not worry about the possible differences in substrate oxidation during everyday training at different phases of the oral contraceptive cycle.

Purpose: This study examined selected myokine responses to an endurance rowing training session, and whether metabolic demands of the acute aerobic rowing exercise together with training volume, aerobic capacity, and body composition variables affect potential exercise-induced changes in the myokine levels in female rowers.Methods: Fifteen national level female rowers [18.3 ± 1.6 years; 172.0 ± 5.0 cm, 67.5 ± 8.8 kg; maximal oxygen consumption (VO2max): 47.2 ± 7.9 ml.min.−1 kg−1] performed a 1-h rowing ergometer exercise at the intensity of 70% of VO2max [distance: 12.1 ± 1.1 km; energy expenditure (EE): 639 ± 69 kcal; heart rate (HR): 151 ± 7 beats.min−1] followed by a 30-min recovery period. Venous blood samples were collected before and after exercise, and analyzed for irisin, fibroplast growth factor-21 (FGF-21), and follistatin conentrations.Results: Plasma irisin and FGF-21 concentrations were increased (by 8%; p = 0.013 and by 13%; p &lt; 0.0001, respectively) immediately after the aerobic rowing exercise. Follistatin was significantly increased (by 11%; p = 0.001) only after the first 30 min of recovery. Exercise metabolic demand variables such as distance covered and total EE were correlated with the pre-to-post-exercise increases in FGF-21 concentrations (r = 0.52; p = 0.047 and r = 0.68; p = 0.005, respectively). Exercise-induced increases in irisin levels were related to aerobic capacity as measured by VO2max (r = 0.53; p = 0.041) and training stress as measured by weekly training volume (r = 0.54; p = 0.039) in female rowers.Conclusion: Acute negative energy balance induced by a single endurance rowing training session elicited significant increases in irisin, FGF-21, and follistatin levels in national level female rowers. While exercise-induced increases in FGF-21 levels were associated with exercise metabolic demand measures, exercise-induced increases in irisin concentrations were related to aerobic capacity and training stress measures in female rowers.

This study investigated the effects of acute exercise and menstrual phase on adiponectin and osteocalcin concentrations, and the possible role of these biomarkers in exercise-induced substrate oxidation in rowers. Thirteen female rowers (19.3 ± 2.3 years; height: 172.7 ± 3.9 cm; body mass: 66.5 ± 7.9 kg) performed 1-h rowing ergometer exercise at 70% of maximal oxygen consumption (VO 2 max) during follicular phase and luteal phase of the menstrual cycle. Oxygen consumption (VO 2 ), total energy expenditure (EE), carbohydrate EE, and lipid EE were assessed during the exercise. Venous blood samples were collected before and after ergometer exercise. No differences (p > 0.05) were observed in substrate oxidation values during exercise across menstrual cycle. Exercise resulted in an acute rise in osteocalcin and no changes in adiponectin at both menstrual cycle phases. Adiponectin and osteocalcin were not related across phase or time (r < 0.211; p > 0.05). Post-exercise adiponectin was related (p < 0.05) to mean VO 2 (r = 0.459) and total EE rate (r = 0.598), while post-exercise osteocalcin was correlated (p < 0.05) with mean total (r = 0.411) and lipid (r = 0.557) EE rates. In conclusion, menstrual cycle phase had no effect on substrate oxidation, and adiponectin and osteocalcin responses to acute exercise. It appears that adiponectin and osteocalcin may serve as signals for metabolic reaction to the energy cost of the acute exercise in female rowers.