Female Endurance Athletes Research Articles

System Analysis for Oxygen Uptake Kinetics with Step and Pseudorandom Binary Sequence Exercise in Endurance Athletes

We examined whether the system analysis for step and pseudorandom binary sequence (PRBS) exercises could be useful to characterize oxygen uptake (VO2) kinetics of female sedentary subjects and endurance athletes. Breath-by-breath VO2 was determined during step- and PRBS-cycle ergometer exercises. The time course of the VO2 kinetics was evaluated by the time constant of the second phase, which should reflect the adjustment of the oxidative metabolism at the skeletal muscle level. The VO2 kinetics were significantly faster in long-distance runners than in sedentary subjects for both exercises. A significant relationship was observed in the VO2 kinetics obtained from step and PRBS exercises. In each group, there was no significant difference in the VO2 kinetics for step and PRBS exercises. These results indicated that the system analysis with PRBS exercises revealed the faster VO2 kinetics in endurance athletes than in sedentary subjects.

Maximal Lipidic Power and Crossover Point in High Competitive Level Endurance Cyclists and Triathletes

PURPOSES: 1) To evaluate the maximum fat oxidation rate (Fatmax) and the crossover point (COP); 2) to establish the relationships between Fatmax, COP, the minimum fat oxidation rate (Fatmin) and the maximum carbohydrate oxidation rate (CHOmax) and 3) to study the relationship between COP and Fatmax with respect to the minimum blood lactate value ([La-]min), the lactic threshold (LT) and the individual lactic threshold (ILT), on high level endurance cyclists and triathletes. METHODS: Thirty-four male and female endurance athletes underwent a progressive cycloergometer test until exhaustion. [La-]min, LT, ILT, Fatmax, Fatmax zone, COP, Fatmin and CHOmax were determined. Oxidation rate were estimated by stoichiometric equations. The different variables were compared using an ANOVA one-way and the relationships with a multiple correlation. The level of significance was established at P < 0.05. RESULTS: The mean Fatmax, Fatmax zone and COP were at 52.1 ± 6.8 % VO2max, from 43.3 ± 6.6 to 62.3 ± 7.0 % VO2max, and at 75.9 ± 6.4 % VO2max, respectively. A significant relation was found between Fatmax, COP and Fatmin and CHOmax (Table 1). COP was significantly higher with respect to LT (264 ± 39 vs. 228 ± 44 W; 75.9 ± 6.4 vs. 70.7 ± 0.7 % VO2max, P < 0.001). No significant differences were found between COP and ILT (264 ± 39 vs. 268 ± 35 W; 75.9 ± 6.4 vs. 75.2 ± 6.6 % VO2max). [La-]min was significantly lower than Fatmax (42.0 ± 16.9 vs. 52.1 ± 6.8 % VO2max, P < 0.001), while LT was significantly higher (64.6 ± 8.9 vs. 52.1 ± 6.8 % VO2max, P < 0.001). No significant differences were found for [La-]min with respect to the lower part of Fatmax zone (−20 to −5 % Fatmax) (42.0 ± 16.9 vs. 33.1 ± 6.4 − 48.1 ± 6.8 % VO2max), nor for LT with respect to the higher part of Fatmax zone (+10 % Fatmax to be precise) (Figure 1). CONCLUSIONS: 1) COP is the same work intensity as the proposed concept of ILT. 2) LT and [La-]min are different than Fatmax, but they belong to the Fatmax zone. 3) There is a positive relationship between Fatmax, COP, Fatmin and CHOmax that supports the crossover concept hypothesized by Brooks and Mercier (1994). 4) Fatmax and COP open a new perspective for the prescription of physical exercise and for the determination of training zones.

Ghrelin Blood Profiles in Athletes from Different Sports

PURPOSE: Endogenous Ghrelin is secreted from the stomach to circulate in the bloodstream and act directly on the pituitary to release GH. Therefore, ghrelin will induce all the effects well known from GH. It seems very likely that, like GH, ghrelin may also be effective in improving training adaptation processes, especially increasing muscle mass and shortening regeneration processes. It is not known whether Ghrelin plasma concentrations differ between male and female athletes in different sports. METHODS: We determined endogenous active Ghrelin concentrations in 42 healthy and normal weight male and female power and endurance athletes (age between 18 and 40 yrs), once without any nutritional intake for 12 hrs, and once under carbo-loading and glucose substitution. Subjects did not do any physical activity in the blood sampling period of 180 min with a sampling frequency of 60 min, starting at 8 PM. Ghrelin concentrations were determined using a radioimmunoassay. RESULTS: There was no significant effect of kind of sport (endurance or power), gender, or nutritional intake (no meal vs. carboloading) on active ghrelin blood concentration in athletes at rest. CONCLUSION: As neither kind of sport nor nutrirional status or gender have any influence on active ghrelin, it seems to play - if any - only a minor role in adaptation processes concerning training and its effects on the growth hormone axis.

The Special Needs of Female Endurance Athletes

The Special Needs of Female Endurance Athletes

The Special Needs of Female Endurance Athletes

The Special Needs of Female Endurance Athletes

Amenorrhea in Female Athletes Is Associated with Endothelial Dysfunction and Unfavorable Lipid Profile

The aim of this study was to evaluate endothelial function measured as flow-mediated dilatation (FMD) of the brachial artery and blood markers of cardiovascular disease in young female endurance athletes with menstrual disturbance. Age- and body mass index-matched groups of young endurance athletes with amenorrhea (n = 14), oligomenorrhea (n = 9), and regular cycles (n = 12) and sedentary controls (n = 12) were compared with respect to endothelial function, lipid profile, markers of inflammation, and endocrine status. We found a significantly decreased FMD in the amenorrheic athletes, compared with all other groups. Amenorrheic athletes also had the most unfavorable lipid profile with significantly higher total cholesterol and low-density lipoprotein, compared with the other athlete groups. The oligomenorrheic athletes had the lowest levels of total cholesterol, low-density lipoprotein, and apolipoprotein B of all groups and significantly lower in comparison with the amenorrheic group. However, with respect to FMD, the oligomenorrheic group represented an intermediate between amenorrheic and regularly cycling subjects. There was a gradual impairment of FMD and the lipid profile to the degree of menstrual disturbance supporting an association with estrogen status. We conclude that amenorrhea in young endurance athletes is associated with endothelial dysfunction and unfavorable lipid profile. Additional studies are needed to elucidate the clinical implications of these results with regard to long-term risk for cardiovascular disease.

Oral contraceptives perform well in female endurance athletes

Oral contraceptives perform well in female endurance athletes

Age at first oral contraceptive use as a major determinant of vertebral bone mass in female endurance athletes

It was the aim of this retrospective analysis to examine the influence of low-dose monophasic oral contraceptives (OCs) on bone mineral density (BMD) of the femoral neck and of the spine in young female endurance athletes. Data on training intensity, dietary intake, menarche, menstrual cycle disorders, years of OC use, and age at first OC use were determined by a self-report questionnaire. Only athletes performing regular endurance exercise for more than 3 years with more than 3 h of exercise per week were included in this study and underwent a clinical assessment including measurement of weight, height, spine, and hip BMD by dual-energy X-ray absorptiometry, and collection of a blood sample. The data from 75 regularly exercising endurance athletes aged 18–35 years (26.5 ± 4.8 years) were initially included in this analysis. Six athletes were later excluded due to oligo-/amenorrhea. Subjects were allocated into the OC group when they reported OC use for more than 3 years in women younger than 22 years of age, or when they reported OC use for more than 50% of the time after menarche in women aged 22–35 years. There were no differences in age, weight, height, body mass index (BMI), body fat, menarche, training intensity, age at start of training, or any serum parameters between OC users ( n = 31) and control subjects ( n = 38). However, OC users had 7.9% lower spine BMD and 8.8% lower proximal femur BMD ( P < 0.01 for both sites). When the relationship between BMD of the spine and OC use was further analyzed by a stepwise model of multiple regression analysis using OC years, age at OC initiation, BMI, and menarche as independent variables, age at first OC use was found to be the best predictor of vertebral BMD, while the only significant predictor of femoral neck BMD was BMI. We conclude that OC use is associated with decreased BMD of the spine and the femoral neck in female endurance athletes, and that early age at initiation of OC use may be an important risk factor for low peak bone mass in young women.

Effect of competitive training on T-cell mediated immune function in Master's female athletes.

Interest in the effects of intense exercise training on immune function has grown over the past decade. Currently, data on the immunocompetence of female endurance athletes are limited and do not present a clear picture. The objective of this study was to compare the T-cell mediated immune function of female Master's athletes (41 +/- 4.3 yr) during peak training with age-matched non-athletes (42 +/- 3.6 yr) using non-specific and antigen-specific stimulation. Samples of peripheral venous blood were taken at rest for determination of total circulating T-cell number, sub-population number and CD4 + helper T-cell function. No significant difference in total circulating T-cell number or in the number of cells in each of the tested lymphocyte subpopulations was detected between athletes (n = 19) and non-athletes (n = 20). In athletes, 7.9 % of cells responding to non-specific (PMA and ionomycin) stimulation produced IL-2 versus 3.9 % of responding cells in non-athletes (p < 0.05). No statistical difference was noted between athletes and non-athletes in the percentages of antigen-responding CD4 + helper T-cells producing IL-2 (2.4 % and 2.3 %, respectively). Results of this study suggest that T-cell mediated immune function may not be compromised in female Master's athletes during periods of competitive training.

The assessment of bone metabolism in female elite endurance athletes by biochemical bone markers

Premature osteoporosis is a frequent problem in female athletes. Current concepts suggest that a disruption of the hypothalamic-pituitary axis leads to hypoestrogenism, which then causes amenorrhea and osteoporosis. However, the underlying mechanisms have been insufficiently investigated. Osteoprotegerin (OPG) and soluble TNF-alpha receptor antagonist ligand (sRANKL) regulate the balance of osteoblasts and osteoclasts. Their role in the pathogenesis of osteoporosis in female athletes has not been studied yet. We measured OPG and sRANKL in relation to biochemical bone markers [osteocalcin (OC), bone alkaline phosphatase (BAP), serum beta-crosslaps (CTx)] and female sex hormones [estradiol (E2) and luteinizing hormone (LH)] in fastening blood samples from 25 female elite endurance athletes and 25 matched controls. Athletes exhibited significantly higher levels of the bone resorption marker CTx than controls (0.61 +/- 0.26 vs. 0.44 +/- 0.15 ng/ml). OPG and sRANKL were not changed. Subgroup analysis revealed that athletes using oral contraceptives [A-OCC(-)] had significantly higher levels of CTx (0.82 +/- 0.20 vs. 0.50 +/- 0.14 ng/ml), BAP [37.3 (23.2-54.4) U/l vs. 25.2 (20.3-35.6) U/l] and OPG (3.4+/-0.8 vs. 2.7+/-0.8 ng/ml) than controls who did not use oral contraceptives [C-OCC(-)]. While the difference for CTx exceeded the least significant change in this marker by approximately 30%, the differences for the bone formation markers OC and BAP were close to the least significant change. In athletes using oral contraceptives [A-OCC(+)] we found no differences compared to controls. A-OCC(-) athletes have increased bone turnover with a particular stimulation of bone resorption. The increased bone resorption is not accompanied by a shift of the OPG/sRANKL relationship towards an osteoclastogenic constellation. Since increased bone resorption was not detectable in A-OCC(+) athletes, it can be suggested that OCC use might protect bone health in female athletes.

Past, present and future of arterial endofibrosis in athletes: a point of view.

Exercise-induced arterial endofibrosis (EIAE) is now a 20-year-old concept. Initially observed in highly trained cyclists, it has been found in many other male and female endurance athletes. Most stenoses are located on the first centimetres of the external iliac artery but other localisation may be found. The disease is defined by specific histological findings showing fibrosis of the intimal and medial wall of the artery. Ankle pressure measurement plays a key role in the diagnosis of EIAE provided that the exercise tests reproduce symptoms and are performed with the subject being highly trained, and that pressure measurements are performed early following exercise. Various cut-off values have been proposed in the literature. Magnetic resonance imaging or arteriography or ultrasound imaging should be performed by trained operators only. Surgical 'endofibrosectomy' is preferable in young cyclists generally associated with a saphenous enlargement patch. We do not recommend angioplasty. Athletes are generally allowed to return to competition within 3-4 months following surgery. Many unanswered questions remain, specifically about the pathophysiology of this disease. Mechanical and pressure strain play a central role in the development of EIEA, but nutritional and haemorrheological factors, hormonal changes and a genetic predisposition are likely to contribute. New techniques could facilitate the diagnosis of EIAE.

ACTN3 Genotype Is Associated with Human Elite Athletic Performance

There is increasing evidence for strong genetic influences on athletic performance and for an evolutionary "trade-off" between performance traits for speed and endurance activities. We have recently demonstrated that the skeletal-muscle actin-binding protein alpha-actinin-3 is absent in 18% of healthy white individuals because of homozygosity for a common stop-codon polymorphism in the ACTN3 gene, R577X. alpha-Actinin-3 is specifically expressed in fast-twitch myofibers responsible for generating force at high velocity. The absence of a disease phenotype secondary to alpha-actinin-3 deficiency is likely due to compensation by the homologous protein, alpha-actinin-2. However, the high degree of evolutionary conservation of ACTN3 suggests function(s) independent of ACTN2. Here, we demonstrate highly significant associations between ACTN3 genotype and athletic performance. Both male and female elite sprint athletes have significantly higher frequencies of the 577R allele than do controls. This suggests that the presence of alpha-actinin-3 has a beneficial effect on the function of skeletal muscle in generating forceful contractions at high velocity, and provides an evolutionary advantage because of increased sprint performance. There is also a genotype effect in female sprint and endurance athletes, with higher than expected numbers of 577RX heterozygotes among sprint athletes and lower than expected numbers among endurance athletes. The lack of a similar effect in males suggests that the ACTN3 genotype affects athletic performance differently in males and females. The differential effects in sprint and endurance athletes suggests that the R577X polymorphism may have been maintained in the human population by balancing natural selection.

Effects of different sodium concentrations in replacement fluids during prolonged exercise in women

Objective: To investigate the effect of different sodium concentrations in replacement fluids on haematological variables and endurance performance during prolonged exercise. Methods: Thirteen female endurance athletes completed three four hour...

Effects of the menstrual cycle on exercise performance.

This article reviews the potential effects of the female steroid hormone fluctuations during the menstrual cycle on exercise performance. The measurement of estrogen and progesterone concentration to verify menstrual cycle phase is a major consideration in this review. However, even when hormone concentrations are measured, the combination of differences in timing of testing, the high inter- and intra-individual variability in estrogen and progesterone concentration, the pulsatile nature of their secretion and their interaction, may easily obscure possible effects of the menstrual cycle on exercise performance. When focusing on studies using hormone verification and electrical stimulation to ensure maximal neural activation, the current literature suggests that fluctuations in female reproductive hormones throughout the menstrual cycle do not affect muscle contractile characteristics. Most research also reports no changes over the menstrual cycle for the many determinants of maximal oxygen consumption (VO2max), such as lactate response to exercise, bodyweight, plasma volume, haemoglobin concentration, heart rate and ventilation. Therefore, it is not surprising that the current literature indicates that VO2max is not affected by the menstrual cycle. These findings suggest that regularly menstruating female athletes, competing in strength-specific sports and intense anaerobic/aerobic sports, do not need to adjust for menstrual cycle phase to maximise performance. For prolonged exercise performance, however, the menstrual cycle may have an effect. Even though most research suggests that oxygen consumption, heart rate and rating of perceived exertion responses to sub-maximal steady-state exercise are not affected by the menstrual cycle, several studies report a higher cardiovascular strain during moderate exercise in the mid-luteal phase. Nevertheless, time to exhaustion at sub-maximal exercise intensities shows no change over the menstrual cycle. The significance of this finding should be questioned due to the low reproducibility of the time to exhaustion test. During prolonged exercise in hot conditions, a decrease in exercise time to exhaustion is shown during the mid-luteal phase, when body temperature is elevated. Thus, the mid-luteal phase has a potential negative effect on prolonged exercise performance through elevated body temperature and potentially increased cardiovascular strain. Practical implications for female endurance athletes may be the adjustment of competition schedules to their menstrual cycle, especially in hot, humid conditions. The small scope of the current research and its methodological limitations warrant further investigation of the effect of the menstrual cycle on prolonged exercise performance.

The Influence of Post-exercise Macronutrient Intake on Energy Balance and Protein Metabolism in Active Females Participating in Endurance Training

The purpose of this investigation was to determine the influence of post-exercise macronutrient intake on weight loss, protein metabolism, and endurance exercise performance during a period of increased training volume. Ten healthy young female endurance athletes performed 4 60-min bouts of cycle ergometry at approximately 65% of VO2peak on 4 days (day 1, 3, 4, and 6) during 2 separate 1-week periods. On day 7, participants performed a ride to exhaustion at approximately 75% of VO2peak. One of the 7-day periods served as a control condition, where a placebo beverage was consumed following the exercise bouts on days 1, 3, 4, and 6 (CON). During the other 7-day protocol (POST), participants consumed a predefined formula beverage with added carbohydrate following the exercise bouts on days 1, 3, 4, and 6. Energy intake and macronutrient proportions were the same between the 2 trials; the only difference was the timing at which the macronutrients were consumed. Calculated fat oxidation was greater during exercise on day 6 during POST as compared to CON (p < .05). Glucose and insulin concentrations were significantly higher (p < .05) following exercise during POST as compared to CON. There was a trend (p = .06) for nitrogen balance to be greater on days 5 and 6 with POST as compared to CON. Time to exhaustion during exercise on day 7 was longer during POST as compared to CON (p < .05). POST resulted in a maintenance of body weight during the 7-day protocol, while there was a significant (p < .05) reduction with CON. It was concluded that post-exercise macronutrient intake following endurance exercise can attenuate reductions in body weight and improve nitrogen balance during 7 days of increased energy expenditure. Importantly, post-exercise supplementation improved time to exhaustion during a subsequent bout of endurance exercise.

Atrioventricular plane displacement in female endurance athletes.

A novel hypothesis for increased ventricular pumping describes the heart as a displacement pump, in which atrioventricular plane displacement (AVPD) is an important mechanism. The hypothesis predicts that AVPD increases at high heart rates. The aim of the present study was to determine whether AVPD increases during exercise at high heart rates. A secondary aim was to study the left ventricular function and dimensions in endurance-trained young female athletes. Eight female cross-country skiers (18.5 +/- 0.9 yr, 169.3 +/- 2.9 cm, 55.7 +/- 4.2 kg, and 64.8 +/- 3.7 mL x kg(-1) x min(-1) in maximal oxygen uptake) were compared with seven sedentary female controls (18.0 +/- 0.6 yr, 175.0 +/- 2.5 cm, 71.1 +/- 4.1 kg, and 42.8 +/- 3.0 mL x kg(-1) x min(-1) in maximal oxygen uptake). Cardiac anatomy and function were assessed by echocardiography. Whereas left ventricular ejection fraction (LVEF) increased in both groups, AVPD fell significantly during exercise. AVPD did not correlate with LVEF, and there were no differences in AVPD between groups either at rest or during exercise. Cardiac output index (mL x lean body mass(-0.67)) and stroke volume index (mL x lean body mass(-1)) were higher in the trained group. The trained group had a larger left ventricular mass, and left ventricular internal dimensions, scaled to lean body mass. This first study to examine AVPD at rest and during exercise in endurance-trained athletes did not indicate that AVPD is an important mechanism of increased cardiac pumping during exercise. Endurance-trained female athletes have larger left ventricular dimensions and increased function as compared with sedentary subjects.

女性持久性競技者の基礎代謝量

女性持久性競技者の基礎代謝量

Iron status in female endurance athletes and in non-athletes.

Iron status was studied in 126 female endurance athletes and 52 control subjects, all aged 16-20 years. The study aimed at identifying factors responsible for iron deficiency. Twenty-six percent of athletes and 50% of controls had latent iron-deficiency without anemia symptoms. A too low intake of iron (especially heme iron: 0.3 mg daily), and of nutrients influencing iron metabolism, were identified as main causes of iron deficiency in control subjects. In athletes, whose iron intake was sufficient (14.6 mg), the principal cause of iron deficiency were blood losses due to menstruation. High level of physical activity, expressed as training volume and experience, did not adversely affect iron stores, as these were higher than in control subjects and the incidence of iron deficiency was much lower than in the control group. It was concluded that an increased intake of iron and of dietary factors involved in iron metabolism prevented possible exercise-induced losses of iron in young athletes.

Heart rate and blood pressure variability during heavy training and overtraining in the female athlete.

We investigated heavy training- and overtraining-induced changes in heart rate and blood pressure variability during supine rest and in response to head-up tilt in female endurance athletes. Nine young female experimental athletes (ETG) increased their training volume at the intensity of 70-90% of maximal oxygen uptake (VO2max) by 125% and training volume at the intensity of < 70% of VO2max by 100% during 6-9 weeks. The corresponding increases in 6 female control athletes were 5% and 10%. The VO2max of the ETG and the control athletes did not change, but it decreased from 53.0 +/- 2.2 ml x kg(-1) x min(-1) to 50.2 +/- 2.3 ml x kg(-1) x min(-1) (mean+/-SEM, p < 0.01) in five overtrained experimental athletes. In the ETG, low-frequency power of R-R interval (RRI) variability during supine rest increased from 6 +/- 1 ms2 x 10(2) to 9 +/- 2 ms2 x 10(2) (p < 0.05). The 30/15 index (= RRI(max 30)/RRI(min 15), where RRI(max 30) denotes the longest RRI close to the 30th RRI and RRI(min 15) denotes the shortest RRI close to the 15th RRI after assuming upright position in the head-up tilt test), decreased as a result of training (analysis of variance, p = 0.05). In the ETG, changes in VO2max were related to the changes in total power of RRI variability during standing (r = 0.74, p < 0.05). Heart rate response to prolonged standing after head-up tilt was either accentuated or attenuated in the overtrained athletes as compared to the normal training state. We conclude that heavy training could increase cardiac sympathetic modulation during supine rest and attenuated biphasic baroreflex-mediated response appearing just after shifting to an upright position. Heavy-training-/overtraining-induced decrease in maximal aerobic power was related to decreased heart rate variability during standing. Physiological responses to overtraining were individual.

Angiotensinogen gene M235T polymorphism predicts left ventricular hypertrophy in endurance athletes

OBJECTIVESWe studied whether left ventricular mass in athletes associates with polymorphisms in genes encoding components of the renin–angiotensin system.BACKGROUNDAdaptive left ventricular hypertrophy is a feature of the athlete’s heart. However, similarly training athletes develop left ventricular mass to a different extent, suggesting that genetic factors may modulate heart size.METHODSWe measured left ventricular mass by echocardiography in 50 male and 30 female elite endurance athletes aged 25 ± 4 (mean ± SD) years. Deoxyribonucleic acid samples were prepared for genotyping of angiotensinogen (AGT) gene M235T polymorphism, angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and angiotensin II type 1 receptor (AT1) gene A1166C polymorphism.RESULTSThe AGT gene M235T genotypes were significantly associated with left ventricular mass independently of blood pressure in both genders (p = 0.0036 for pooled data). TT homozygotes had greater mass compared with MM homozygotes in both men (147 ± 12 g/m vs. 132 ± 15 g/m, p = 0.032) and women (121 ± 12 g/m vs. 101 ± 13 g/m, p = 0.019). There was a gender difference in the relation between myocardial mass and AGT genotype, MT heterozygotes resembling MM homozygotes among women and TT homozygotes among men. The other studied gene polymorphisms were not associated with left ventricular mass.CONCLUSIONSAngiotensinogen gene M235T polymorphism is associated with the variability in left ventricular hypertrophy induced by endurance training, with athletes homozygous for the T allele having the largest hearts. We found no association between ACE gene I/D or AT1 gene A1166C polymorphisms and left ventricular mass.