The effect of the menstrual cycle on collagen metabolism, growth hormones and strength in young physically active women.

This study aimed to investigate the effect of the menstrual cycle on strength, functioning of the GH/IGF-1 axis and collagen metabolism in physically active women. Twenty-four physically active and eumenorrheic women volunteered to participate in the study (body mass 60.3 ± 9.18 kg, age 21.8 ± 0.92 years). Blood samples were obtained between the 5th and 8th days (the follicular phase) and between the 19th and 22th days (the luteal phase) of the menstrual cycle to determine sex steroid concentrations (follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), oestradiol (E2) and progesterone (P)). Also insulin-like growth factor 1 (IGF-1) and collagen metabolism markers (synthesis (PICP) and breakdown (ICTP)) and maximum voluntary contraction (MVC) were measured. MVC was higher in the luteal phase 164.1 ± 34.77 [N m] (F(1.23) = 4.59; p = 0.043). The recorded collagen synthesis marker (PICP = 296.4 ± 35.61 [ng/ml]) was at the upper level of the reference range (30-300), with an insignificant decrease in the luteal phase (Z = 1.612; p = 0.107) and a significant increase in oestradiol concentration (Z = 4.286; p = 0.0001). The marker of collagen breakdown (ICTP = 4.16 ± 0.68 [µg/l]) was reduced by 6.8% in the same phase (Z = 1.764; p = 0.137). The variability of physical abilities (MVC) during the menstrual cycle showed that menstrual status should be taken into account in determination of the training loads. Increasing the load in the luteal phase seems to be favoured by a beneficial change in collagen metabolism (lower synthesis decrease, lower breakdown increase) observed in physically active women.

Body shape index versus body mass index as correlates of health risk in young healthy sedentary men.

Recently a new simply calculated index of body composition -a body shape index (ABSI) has been introduced as an index more reliable than BMI of association between body composition and all-cause mortality. However, until now associations between ABSI and metabolic risk factors have not been evaluated. A total of 114 male university students not engaged in any planned physical activity participated in the present study. Anthropometric measurements (weight, height, waist circumference) were recorded. Body mass index (BMI) was calculated from weight and height, body shape index (ABSI) was calculated from waist circumference, weight, height and BMI. Blood was withdrawn after an overnight fast from the antecubital vein. Triacylglycerols, total cholesterol and HDL-cholesterol levels in plasma were determined using colorimetric methods and Randox commercial kits. Plasma LDL-cholesterol concentrations were calculated according to the Friedewald formula. Circulating insulin was assayed using a standard radioimmunological method with monoclonal antibodies against insulin and BioSource commercial kits. BMI was slightly, but significantly correlated only with circulating TG (r=0.330, p < 0.001) In contrast, ABSI was slightly, but significantly correlated with plasma levels of insulin (r=0.360, p<0.001), TC (r=0.270, p<0.002), LDL-C and non-HDL-C (r=0.300, p<0.001). In participants at the upper quartile of BMI circulating TG was higher (by 50%, p<0.05) than in their counterparts at the lower BMI quartile. Subjects representing the upper quartile of ABSI were characterized by higher plasma levels of insulin, TC, LDL-C and non-HDL in comparison with subjects at the lower ABSI quartile. (by 92 %, 11. %, 29 % and 21 % respectively, p<0.001). ABSI, a new simply calculated index of body fat seems to more accurately depict the variability in circulating insulin and lipoproteins than BMI at least in young, healthy male subjects.

Effect of rest duration between sets on fatigue and recovery after short intense plyometric exercise.

Plyometric training is characterized by high-intensity exercise which is performed in short term efforts divided into sets. The purpose of the present study was twofold: first, to investigate the effects of three distinct plyometric exercise protocols, each with varying work-to-rest ratios, on muscle fatigue and recovery using an incline-plane training machine; and second, to assess the relationship between changes in lower limb muscle strength and power and the biochemical response to the three exercise variants employed. Forty-five adult males were randomly divided into 3 groups (n = 15) performing an exercise of 60 rebounds on an incline-plane training machine. The G0 group performed continuous exercise, while the G45 and G90 groups completed 4 sets of 15 repetitions, each set lasting 45 s with 45 s rest in G45 (work-to-rest ratio of 1:1) and 90 s rest in G90 (1:2 ratio). Changes in muscle torques of knee extensors and flexors, as well as blood lactate (LA) and ammonia levels, were assessed before and every 5 min for 30 min after completing the workout. The results showed significantly higher (p < 0.001) average power across all jumps generated during intermittent compared to continuous exercise. The greatest decrease in knee extensor strength immediately post-exercise was recorded in group G0 and the least in G90. The post-exercise time course of LA changes followed a similar pattern in all groups, while the longer the interval between sets, the faster LA returned to baseline. Intermittent exercise had a more favourable effect on muscle energy metabolism and recovery than continuous exercise, and the work-to-rest ratio of 1:2 in plyometric exercises was sufficient rest time to allow the continuation of exercise in subsequent sets at similar intensity.

Variability in HOMA-IR, lipoprotein profile and selected hormones in young active men.

Resistance to insulin actions is contributing to many metabolic disturbances. Such factors as age, sex, nutrition, body fat, and physical activity determine body insulin resistance. Present study attempted to asses insulin resistance and its metabolic effects with respect to energy intake in young, lean, and active men. A total of 87 men aged 18-23 participated in the study. Plasma levels of glucose, insulin, lipoproteins, cortisol, and TSH were determined. Insulin resistance was expressed as Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) and calculated using homeostatic model. The median value of HOMA-IR (1.344) was used to divide subjects into two groups. Men did not differ in anthropometric parameters, daily physical activity, and plasma TSH and cortisol levels. However, in men with higher HOMA-IR significantly lower daily energy intake was observed concomitantly with higher TG, TC, and HDL-C concentrations in plasma versus their counterparts with lower HOMA-IR. Exclusively in subjects with higher HOMA-IR significant and positive correlation was noted between HOMA-IR and TC and LDL-C. We concluded that despite a normal body weight and physical activity, a subset of young men displayed unfavorable changes in insulin sensitivity and lipid profile, probably due to insufficient energy intake.

Diet Inflammatory Index among Regularly Physically Active Young Women and Men.

Recently, special attention has been paid to the relationship between diet and inflammation in the body. A factor that influences both diet and inflammation is physical activity. The aim of this study was to assess the inflammatory potential of the diets of young people engaging in regular physical activity. The participants were physical education students (n = 141 men and n = 151 women). The measurements included basic anthropometric parameters and a 4-day nutritional history from which the dietary inflammatory index (DII) was calculated. The average DII for female students was 2.09 ± 1.52, and that for male students was 0.21 ± 1.69. Consumption of all macro- and micronutrients was significantly higher among women and men with the lowest DII value (corresponding to an anti-inflammatory diet). The female and male students consuming anti-inflammatory diets were characterized by greater lean body mass (LBM), and, for the male students, a lower body fat content, compared to those whose diets were pro-inflammatory. Young and regularly physically active people are also exposed to the pro-inflammatory nature of their diets, whose long-term effects may lead to health problems.

Metabolic Risk Factors in Young Men With Healthy Body Fat But Different Level of Physical Activity.

The study was performed to evaluate metabolic risk in young lean individuals characterized by different physical activity. A total of 194 students (93 active with 5-7 h weekly physical activity and 101 inactive) were accepted for the study. The following percentages of body fat were accepted as characteristic for lean men: 14% to 17% in active and 18% to 24% in inactive participants. Circulating glucose, insulin, triacylglycerols (TG), total cholesterol (TC), and high-dendity lipoprotein (HDL)-cholesterol (HDL-C) were assayed. Daily intake of energy and macronutrients was briefly assessed from 24 h food records collected over 4 days preceding blood collection. Insulin and TG differed with respect to physical activity and was lower by 37.5% and 12.5%, respectively, in active versus inactive participants. In active students with upper quartile of body fat percentage, the only significant difference was found between circulating insulin (by 28%, p < .04). In inactive participants with upper quartile of body fat, significant differences were found between levels of insulin and TG (by 25% and by 37.5%, respectively). Diet composition did not differ with respect to the percentage of energy derived from protein, fat, and carbohydrates. An inverse association between insulin level and the percentage of body fat seems to be physiological one because it has been noted in both active and inactive individuals. On the contrary, elevation in circulating TG found exclusively in inactive subjects seems to be secondary to the changes in adiposity and circulating insulin and is followed by tendency to higher levels of TC.

Use of the Dietary Inflammatory Index to Assess the Diet of Young Physically Active Men.

BACKGROUND: Chronic inflammation can lead to the development of obesity, diabetes and other chronic diseases. One of the factors causing inflammation is diet. The aim of this study was to assess the inflammatory potential of the diet, expressed by the DII index, in young physically active men. METHODS: A total of 94 physically active students aged 19-23 participated in the study. The subjects' diets were assessed on the basis of 4-day dietary records, which were then analyzed using the computer program "Diet 5.0". The DII was calculated for each participant based on the individual consumption of the selected dietary components. The concentration of CRP protein was also determined. RESULTS: Participants was divided into groups according to values of DII. Diets with different DIIs provided similar amounts of calories, but differed significantly in the content of many nutrients. Participants whose diets showed the most anti-inflammatory effects consumed significantly more protein, magnesium, iron, zinc, antioxidant vitamins, and B vitamins compared to others. The highest concentration of CRP protein was observed in men whose diet was described as the most pro-inflammatory (Q4 group). A significant relationship was found between DII and body fat (%) in men in the most anti-inflammatory (Q1 group) and neutral diet (Q2-Q3 group). CONCLUSIONS: The Dietary Inflammatory Index is a promising method of describing the effect of dietary intake on the risk of inflammation in young, healthy individuals engaging in regular physical activity.

High-Intensity Training and Saffron: Effects on Breast Cancer-related Gene Expression.

PURPOSE: Exercise training and some herbal components have an anticancer function and can suppress tumor growth. However, the role of these protective factors in altering breast cancer-related gene expression is still unknown. Thus, this study aimed to assess the effect of 4 wk of high-intensity interval training (HIIT) and saffron (Crocus sativus L.) aqueous extract (SAE) on Sirtuin-1 (SIRT1), human telomerase reverse transcriptase (hTERT), and p53 gene expression in female mice breast tumor tissue induced by 4T1 cell line. METHODS: This study was performed on female BALB/c mice. The 4T1 breast cancer cells were subcutaneously implanted, and mice were randomly sorted into the following groups: control, HIIT, SAE, HIIT + SAE (n = 10 mice per group), and sham (n = 4 mice per group). Mice were sacrificed at the end of the intervention period, and the expression of SIRT-1, hTERT, and p53 was determined by real-time polymerase chain reaction. RESULTS: The mRNA level of SIRT1 was increased in the HIIT + SAE group compared with the HIIT and control groups (P = 0.007 and P = 0.03, respectively). Moreover, the amount of mRNA of p53 was increased after a 4-wk HIIT compared with the control and HIIT + SAE groups in tumor tissue (P = 0.03 and P = 0.02, respectively). No change was found in the mRNA expression of hTERT between groups (P = 0.92). CONCLUSIONS: These findings suggest that HIIT may reduce tumor burden through the upregulation of p53 associated with tumor suppression pathway. In contrast, the combination of HIIT and SAE did not alter p53 and SIRT1 expression levels and may suppress tumor growth by other mechanisms.

Relationships between bone mineral density and new indices of body composition in young, sedentary men and women.

INTRODUCTION: Data concerning the relationship between body fat and BMD are equivocal since both positive and negative effects have been noted. Recently, the index of fat mass (IFM) representing subjects with different body fat and similar lean mass and index of lean mass (ILM) representing subjects with different lean body mass and similar body fat, have been used to evaluate body composition effect on BMD in middle-aged women. This study aimed at determination of ILM and IFM association with BMD in young men and women. MATERIAL AND METHODS: A total of 212 university students of Public Health (125 women and 87 men) participated in the study. Body composition was determined by the bioelectrical impedance method (BIA) using BC 418 MA equipment (Tanita Co., Japan). Fat mass and fat free mass were used to calculate ILM and IFM. Bone mineral density was measured on the wrist of the non-dominant hand using the DEXA method and EXA 3000 equipment (HFS Ltd., Korea). BMD was evaluated using Z-score, with values lower than -2.0 indicating inadequate BMD for subject chronological age. RESULTS: Exclusively in women, IFM was markedly and positively correlated with Z-score (r=0.366, P<0.001). In both genders, a significant relationship was found between ILM and Z-scores (r=0.420; p<0.001 and r=0.220; p<0.02 in men and women, respectively). Women with lower than median IFM but similar ILM, were characterized by significantly lower Z-scores vs. women with higher IFM (-1.016 vs. -0.512; p<0.001). Irrespective of gender, participants with higher ILM but similar IFM, were characterized by markedly higher Z-score vs. their counterparts with low ILM. CONCLUSIONS: The use of IFM and ILM in the present study, allowed the observation that in young adults lean body mass was associated with BMD, regardless of gender, while fat mass is significant for bone mineral density only in women.

Somatic characteristics and motor fitness of elite and sub-elite Polish male badminton players.

BACKGROUND: An appropriate level of somatic and fitness traits is believed to contribute to success in an international badminton competitions however, these have not been sufficiently explored in elite Polish badminton players. Therefore, the aim of the study was to assess somatic build and physical fitness of elite and sub-elite Polish badminton players and to identify key traits that determine achieving sporting success in badminton. METHODS: The study participants comprised 20 men from the Polish Badminton National Teams A (elite; N.=9) and B (sub-elite; N.=11). In all participants body height, arm span, body mass, body fat, fat free mass and Body Mass Index (BMI) were assessed. Fitness tests included two badminton-specific on-court movement tests and cycloergometer test to assess maximal oxygen uptake (VO2max). RESULTS: Studied players did not differ in body height and arm span however, elite players were heavier by about 10 kg and had significantly higher values of BMI and body fat. Irrespectively of sport level, elite and subelite badminton players achieved comparable results in both on-court tests as well as with respect to VO2max (55.9 and 57.2 mL/min/kg, respectively). Cluster analysis allowed to indirectly describe the profile of somatic traits and physical fitness that facilitates achieving success in badminton. CONCLUSIONS: Relatively small body size of badminton players can be considered advantageous in sport competitions. It also seems that aerobic capacity contributes to achieving sport success in badminton to a much lower degree than the badminton-specific on-court skills.

Relationship between the percentage of body fat and surrogate indices of fatness in male and female Polish active and sedentary students.

BACKGROUND: Limited data have indicated that body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR) and waist to height ratio (WHtR) of athletes and young adults provide misleading results concerning body fat content. This study was aimed at the evaluation of the relationship between different surrogate indices of fatness (BMI, WC, WHR, WHtR and body adiposity index (BAI)) with the percentage of body fat in Polish students with respect to their sex and physical activity. METHODS: A total of 272 students volunteered to participate in the study. Of these students, 177 physical education students (90 males and 87 females) were accepted as active (physical activity of 7 to 9 hours/week); and 95 students of other specializations (49 males and 46 females) were accepted as sedentary (physical activity of 1.5 hours/week). Weight, height, waist and hip circumferences were measured, and BMI, WHR, WHtR and BAI were calculated. Body fat percentage was assessed using four skinfold measurements. RESULTS: Classification of fatness according to the BMI and the percentage of body fat have indicated that BMI overestimates fatness in lean subjects (active men and women, sedentary men), but underestimates body fat in obese subjects (sedentary women). In all groups, BMI, WHR, WHtR and BAI were significantly correlated with the percentage of body fat (with the exception of WHR and hip circumference in active and sedentary women, respectively). However, coefficients of determination not exceeding 50% and Lin's concordance correlation coefficients lower than 0.9 indicated no relationship between measured and calculated body fat. CONCLUSION: The findings in the present study support the concept that irrespective of physical activity and sex none of the calculated indices of fatness are useful in the determination of body fat in young adults. Thus, it seems that easily calculated indices may contribute to distorted body image and unhealthy dietary habits observed in many young adults in Western countries, but also in female athletes.

[Fat content in young adults determined by skinfolds and body composition analyzator]. / Zawartosc tkanki tluszczowej u mlodych doroslych oceniona na podstawie pomiaru faldów skórno-tluszczowych i wskazan analizatora skladu ciala

INTRODUCTION: Body composition analysis is essential in assessing the nutritional status, as well as the risk of developing diseases associated with abnormal body fat content. At present, many methods are available to measure the amount and distribution of body fat. Among them, of particular importance are those methods that are simple, do not require expensive equipment and allow the assessment of the body composition of a large number of people (population study). However, previous observations show that they provide different results, and, therefore, further analysis and comparisons should be conducted in different age, sex and body composition groups. AIM OF THE STUDY: The goal was to compare the anthropometric and bioelectrical impedance analysis (BIA) methods used to assess body composition in young women and men. MATERIAL AND METHODS: 65 women and 109 men, physical education students, took part in the study. Average chronological age of the women was 20.5±3.1 years and men 19.9±1.4 years. Body weight, height and thickness of 4 skinfolds (SF; over the biceps, triceps, subscapular, suprailiac) were measured. The percentage of body fat in the anthropometric method was calculated using the Durnin and Womersley's equation. Assessment of body composition was also made by the BIA method. All the measurements in every person were made on the same day. RESULTS: The mean BMI was 21.4±1.9 in women and 23.9±2.4 in men. The mean percentage of body fat obtained by anthropometric method was 16.7±7.1% in women and 10.2±6.6% in men. The amount of body fat estimated by the BIA method was higher than that calculated by skinfold thickness among female students by about 5% (p <0.001), while for male students by 3% (p <0.001). The correlation coefficients between the anthropometric method and BIA method for women and men were 0.448 (p <0.05) and 0.380 (p <0.05), respectively. CONCLUSIONS: The anthropometric and BIA methods provide different results of body fat content, especially in women, so they should not be used interchangeably.

The physique and body composition of students studying physical education: a preliminary report.

INTRODUCTION: Young people who study physical education are a priori regarded as having proper body structure and body composition. This assumption cannot be confirmed in the subject literature. AIM OF THE STUDY: To determine the basic auxological parameters in youth who study physical education. MATERIAL AND METHODS: 235 first-year students studying physical education were examined: 32% women (n=74) and 68% men (n=161). The students' body height, weight, waist, and hip circumference were measured. Body composition (bioimpedance method), specifying the body fat percentage (FM%) and fat free mass (FFM%) was also assessed. RESULTS: The mean normalized height of the female body was 0.48±1.07 SDS, and for the male body 0.51±1.04 SDS. The mean normalized weight for women was 0.4±0.94 SDS, and for men it was 0.83±0.9 SDS. The mean fat percentage in the body composition of women and men was, respectively, 21.5±5.06, ranging from 10.16% to 35.06%, and 12.5±3.97, ranging from 4.36% to 22.28%. In one-third of the women, the percentage of fat in the body composition was higher than 25%. CONCLUSIONS: 1. Young people who choose to study physical education and physical culture are characterized by greater height and greater body weight than the general population, regardless of gender. 2. Short persons study physical education less often than tall individuals. 3. The greater body weight observed in the majority of students studying physical education, in comparison to that of the general population, was caused by a dominant percentage of lean body mass in body composition; unexpectedly, however, some women were observed to have relatively high fat content. 4. Use of the body mass index and waist-hip ratio was not a sufficiently sensitive screening examination to detect fatness in physically active young adults; therefore, it should not substitute for the determination of fat content in body composition.

[Retrospective assessment of growth monitoring of subjects born between 1989-1991]. / Retrospektywna ocena monitorowania przebiegu wzrastania osób urodzonych w latach 1989-1991.

INTRODUCTION: Systematically taken measurements of body length, and--after 18 months of life--height, facilitate the correct monitoring of the course of physical development in children and teenagers. Measuring body mass only is incorrect and may lead to a faulty evaluation of the patient's condition. AIM OF STUDY: Assessment of frequency of measurements of body mass and height during the developmental period among students born between 1989-1991. MATERIAL AND METHODS: For 109 subjects (52% women), age 20.0±1.0 year, range 19.1-23.8 years of age, measurements at birth, duration of the mother's pregnancy and frequency of measurements of body mass and weight until the 18th year of life. RESULTS: The frequency of measurements of body length and height was the highest during the 1st and 2nd year of life, on average every 3 months during the 1st year and every 6 months during the 2nd year. However, during the 1st year as many as 1/3 of children were assessed incorrectly by having only their body mass measured. During the 2nd year, regardless of body mass at birth, measurements were taken more frequently than during the 1st year, which may suggest inadequate preparation of the medical personnel to take measurements of the baby's body length. Measurements of body height and even body mass during puberty and the growth spurt were carried out in a far too small percentage of subjects. CONCLUSIONS: 1. Body mass measurements are all too frequently not accompanied by measurements of body length or height, with the result that the physician is unable to assess the child's growth pattern. 2. Measurements of body height and mass were taken too infrequently during childhood and puberty, which in many cases makes it impossible to assess the subject's physical development.

[Incidence of low birth weight in academic youth]. / Czestosc wystepowania niskiej urodzeniowej masy ciala w populacji studiujacej mlodziezy.

INTRODUCTION: Birth parameters are used to evaluate infant's maturity and to indicate children with a potential risk of growing disorders and metabolic complications in later life. Low birth weight can be connected with higher fat content, especially in the abdominal part in adult individuals. Low birth weight is recognized as one of the criteria of metabolic syndrome in non-obese individuals. AIM OF THE STUDY: The percentage of academic youth aged 19-25 years born with low birth weight was evaluated. MATERIAL AND METHODS: 146 students (52% women and 48% men) of Warsaw higher schools took part in the study. Data of birth parameters and gestational age (GA, weeks) were gained from the medical documentation retrospectively. Infant's mass ≤2999 g was recognized as decreased birth weight (LBW group). Body height and body mass, waist and hip circumferences were measured. WHR was calculated as well. Bioimpedance method was used to evaluate the body composition, height and weight were standardized using data for 18-year-old women and men from Warsaw population. RESULTS: Decreased birth weight has been identified in 18% studied population - LBW group: 65% women and 35% men. It has been shown that students with low birth weight were characterized by a significantly lower body height (-0.22±1.14 v. 0.38±1.02 SDS) and body mass (-0.11±1.15 vs. 0.70±1.15 SDS) in comparison with individuals born with normal birth parameters. Body fat content in students of studied groups was similar. It has been noted that WHR index was significantly lower (p=0.0009) in men of LBW group than in those of NBW group. CONCLUSIONS: 1. Decreased birth weight appears more frequently among girls. It's suggested that MONW are more common in females. 2. The relationship between birth parameters and height and weight in adults was confirmed. 3. In young men distribution of body fat is associated with birth weight.

[Physical activity for young adults born with low body weight on the background of peers]. / Zawartosc tkanki tluszczowej w skladzie ciala mlodych doroslych urodzonych z obnizona masa ciala jest zalezna od poziomu aktualnej aktywnosci fizycznej.

INTRODUCTION: Low birth parameters are associated with an increased risk of insulin resistance, type 2 diabetes, glucose intolerance and hypertension at later life. Regular physical activity can counteract these metabolic disorders. THE AIM OF THE STUDY: We determined the relation of the declared physical activity and body composition in young adults with respect to their birth weight. MATERIAL: A total of 156 subjects (52% women and 48% men) took part in the study (the average age 20.6±1.2 years). Participants who declared regular physical activity (minimum 3 times per week) were included in group I (n=66), others in group II (n=99). In each group, the percentage of people with small (SBW) and normal (NBW) birth weight was assessed. METHODS: Information about birth parameters and duration of pregnancy was obtained from medical records. Infant's mass ≤2999 g was recognized as small birth weight. Body height, body weight, waist and hips circumferences and body composition by BIA were measured. Frequency of physical activity was determined during an interview. RESULTS: Percentage of participants with small birth weight was respectively 17% in group I and 21% in group II. In group I standardized body height was significantly lower in subjects with SBW in comparison with those with NBW. Participants from group II with SBW had markedly lower standardized body weight and standardized BMI than adults with NBW. Independently of birth weight physically active persons characterized higher WHR values than their non active counterparts. Body fat content was significantly lower in group I (both in participants with SBW and NBW). Women and men from group I with SBW had also higher fat free mass in comparison with those from group II. CONCLUSIONS: Body fat content in young adults with small birth weight is related to their physical activity. People who regularly exercise had lower fat mass in comparison with non exercising ones. This is the confirmation of a protective influence of physical activity.

[The relationship between plasma insulin and glucose, maximal oxygen uptake and body composition in young, lean men and women]. / Zaleznosc miedzy stezeniem insuliny i glukozy w osoczu a maksymalnym poborem tlenu i skladem ciala u mlodych, szczuplych kobiet i mezczyzn.

INTRODUCTION: Data concerning gender differences in insulin sensitivity are conflicting indicating either similar, higher or lower sensitivity to hormone action in women in comparison with men. However, in most studies the participants were middle-aged or elderly, characterized by excess of body fat and unknown physical activity level. AIM OF THE STUDY: The present study aimed at the evaluation of the association between plasma insulin and glucose, maximal oxygen uptake, and body composition in young, lean women and men. MATERIAL AND METHODS: A total of 76 male students with body fat up to 20% and 75 female students with body fat not exceeding 30% participated in the study. Maximal oxygen uptake was measured during incremental bicycle ergometer test. Plasma glucose levels were assayed using the oxidase method and Randox commercial kits. Plasma insulin concentrations were determined using radioimmunoassay and BioSource kits. RESULTS: Both in men and women maximal oxygen uptake was significantly and inversely correlated with the percent of body fat (r=-0.234; p<0.05 and r=-0.340; p<0.003 in women and men, respectively). Neither in men nor in women were plasma glucose and insulin levels correlated with maximal oxygen uptake. Exclusively in males the tendency to higher plasma insulin with increasing body fat was noted (r=0,214; p<0.07). In female subjects plasma insulin levels were significantly and inversely related to lean body mass (r=-0.264; p<0.03). CONCLUSIONS: In young, lean men increased body fat contributes to the elevation in circulating insulin. On the contrary, in young lean women low lean body mass adversely affects plasma insulin levels.

[Physical fitness in relation to age and body build of young chess players]. / Sprawnosc fizyczna a wiek i budowa ciala mlodych szachistów.

INTRODUCTION: Specificity of chess training promotes sedentary lifestyle and may reduce chess players participation in different physical activities. Limited physical activity leads to decrease of physical fitness and may augment the risk of overweight and obesity. It is suggested that these athletes will characterize more frequently lower physical fitness and weight/height proportions disorders. The aim of the study was evaluation of physical fitness and its relationship with age and body build of athletes. MATERIAL AND METHODS: A sample of 73 individuals (35 girls--48% and 38 boys--52%) aged 8-19 years took part in this study. All competitors were members of national team and Polish representatives for the European and world chess championship. Chess players' physical fitness was measured by EUROFIT tests. RESULTS: With reference to the Polish population chess players characterized higher level of physical fitness. In six tests of EUROFIT chess players had better standardized results than controls. Sit ups (mean standardized result 0.842), shuttle run 10 x 5 m (0.577), standing broad jump (0.552) and flamingo balance (0.371) were very well performed by chess players. Only in one test, bent arm hang, sportsmen achieved worse results (-0.719). Permanent decrease of chess players' physical fitness with age was also observed. CONCLUSIONS: Although chess players' physical fitness was satisfied in comparison to age-matched control, it is recommended to include in their training more exercises developing strength. Because of changes in body build with age and decrease of physical fitness, chess players ought to participate in regular physical activity. Therefore chess organisers should provide the variety of active forms that can be chosen by competitors in their leisure time.

[Nutritional habits of young chess players]. / Nawyki zywieniowe dzieci i mlodziezy grajacych w szachy.

INTRODUCTION: Proper nutrition plays significant role in children's development and health protection in adults, as well. Therefore such a study is extremely important particularly among youth population. It is well known that adequate nutrition also helps to achieve high sport results. The aim of the study was the nutritional habits evaluation of young chess players. MATERIAL AND METHODS: A total of 75 chess players aged 8-19 years took part in the study. Among them there were 36 girls (48%) and 39 boys (52%). Subjects belonged to the Polish Chess Academy, medalists of the Polish, European and world youth championships and members of the Polish national team. Used questionnaire allowed to collect data about regular diet of young athletes. RESULTS: Recommended number of 4-5 meals per day was consumed only by 55% persons. Another observed disadvantageous nutritional habit among responders was missing first breakfasts (75%), especially during competitions. Less than half of subjects declared regular meals intake during the day (from 25 to 43%). Moreover, it was noticed, that 13,3% chess players ate vegetables and fruits only one time per day. Sweets were taken at least one time per day by 22 to 50% participants. CONCLUSIONS: Due to numerous nutritional mistakes in studied population it is compulsory to conduct nutritional education among athletes and among their parents and coaches as well.