Relationships between anthropometric, body composition and bone mineral parameters in 7-8-year-old rhythmic gymnasts compared with controls

The aim of the study was to investigate the relationships between specific anthropometric (9 skinfolds, 13 girths, 8 lengths and 8 breadths), body composition (body fat %, fat free mass [FFM], fat mass [FM]) parameters and bone mineral parameters (bone mineral density [BMD], bone mineral content [BMC) in young rhythmic gymnasts and same age controls. Eighty nine 7-8-year-old girls participated in this study and were divided to the rhythmic gymnast's (n = 46) and control (n = 43) groups. Body composition was determined by dual energy X-ray absorptiometry (FFM, FM, body fat %, BMD and BMC). Body fat % and FM were lower and BMD and BMC values at lumbar spine (L2-L4) and femoral neck were higher in rhythmic gymnasts compared with controls. All measured skinfold thicknesses were thicker in controls. In girths, lengths and widths there were only few significant differences between the groups. Stepwise multiple regression analysis indicated that skinfold thicknesses (supraspinale and medial calf) influenced L2-L4 BMD only in controls 38.2% (R2x100). Supraspinale and iliac crest skinfold thicknesses characterised L2-L4 BMC 43.9% (R2x100). Calf girths influenced BMD in L2-L4 52.3% (R2x100) in controls. BMC in L2-L4 was dependent only on mid-thigh girths 35.9% (R2x100). BMD in L2-L4 was dependent on tibiale-laterale height 30.0% (R2x100). Biiliocristal breadths together with sitting height characterised BMC in L2-L4 BMD 62.3% (R2x100). In conclusion, we found that the relationships between anthropometry, body composition and bone parameters in young rhythmic gymnasts are weak. In control group first of all lower body anthropometric parameters significantly correlated with BMD and BMC in spine.     

Effects of dietary protein content on IGF-I, testosterone, and body composition during 8 days of severe energy deficit and arduous physical activity.

Energy restriction coupled with high energy expenditure from arduous work is associated with an altered insulin-like growth factor-I (IGF-I) system and androgens that are coincident with losses of fat-free mass. The aim of this study was to determine the effects of two levels of dietary protein content and its effects on IGF-I, androgens, and losses of fat-free mass accompanying energy deficit. We hypothesized that higher dietary protein content would attenuate the decline of anabolic hormones and, thus, prevent losses of fat-free mass. Thirty-four men [24 (SD 0.3) yr, 180.1 (SD 1.1) cm, and 83.0 (SD 1.4) kg] participated in an 8-day military exercise characterized by high energy expenditure (16.5 MJ/day), low energy intake (6.5 MJ/day), and sleep deprivation (4 h/24 h) and were randomly divided into two dietary groups: 0.9 and 0.5 g/kg dietary protein intake. IGF-I system analytes, androgens, and body composition were assessed before and on days 4 and 8 of the intervention. Total, free, and nonternary IGF-I and testosterone declined 50%, 64%, 55%, and 45%, respectively, with similar reductions in both groups. There was, however, a diet x time interaction on day 8 for total IGF-I and sex hormone-binding globulin. Decreases in body mass (3.2 kg), fat-free mass (1.2 kg), fat mass (2.0 kg), and percent body fat (1.5%) were similar in both groups (P = 0.01). Dietary protein content of 0.5 and 0.9 g/kg minimally attenuated the decline of IGF-I, the androgenic system, and fat-free mass during 8 days of negative energy balance associated with high energy expenditure and low energy intake.     

Fatness, fitness, and insulin sensitivity among 7- to 9-year-old children

Objective: The purpose of this study was to examine the relationships among fatness and aerobic fitness on indices of insulin resistance and sensitivity in children. Research Design and Methods: A total of 375 children (193 girls and 182 boys) 7 to 9 years of age were categorized by weight as normal‐weight, overweight, or obese and by aerobic fitness based on a submaximal physical working capacity test (PWC). Fasting blood glucose (GLU) and insulin (INS) were used to calculate various indices of insulin sensitivity (GLU/INS), the homeostasis model assessment (HOMA), and the quantitative insulin sensitivity check index (QUICKI). Surrogate measures of pancreatic β cell function included the insulinogenic index (INS/GLU) and the HOMA estimate of pancreatic β‐cell function (HOMA %B). Results: Insulin sensitivity and secretion variables were significantly different between the normal‐weight children and the overweight and obese subjects. Fasting insulin (FI), HOMA, QUICKI, and INS/GLU were significantly different between the overweight and obese subjects. Likewise, the high fitness group possessed a better insulin sensitivity profile. In general, the normal‐weight–high fit group possessed the best insulin sensitivity profile and the obese‐unfit group possessed the worst insulin sensitivity profile. Several significant differences existed among the six fat‐fit groups. Of particular note are the differences within BMI groups by fitness level and the comparison of values between the normal‐weight–unfit subjects and the overweight and obese subjects with high fitness. Conclusions: The results indicate that aerobic fitness attenuates the difference in insulin sensitivity within BMI categories, thus emphasizing the role of fitness even among overweight and obese children.     

Bilateral frontal theta-waves in EEG of 7-8-year-old children with learning difficulties: qualitative and quantitative analysis

We analyzed EEG recorded in the rest condition (eye closed) in 22 children aged from 7 to 8 years old who experienced learning difficulties and whose EEG recordings were characterized by sporadic short-term appearance of bilateral synchronous slow waves over the frontal and/or central cortices--frontal theta-waves (FTW). The vector autoregressive modeling was used in order to assess the strength of directed cortico-cortical functional connectivity pattern for FTW and for surrounding EEG. The comparison of the two patterns showed that FTW is characterized by diffuse strengthening of the functional links connecting frontal, central and (to some extent) temporal cortices as well as the links directed to the above regions from the other cortical areas. The results of the study suggest that FTW is most probably caused by the common for the fronto-central cortices neuronal theta activity synchronized via cortico-subcortical links. This suggestion is in a good agreement with the view that FTW reflects the alterations in functioning of fronto-thalamic system.     

Influence of body size and gender on control of ventilation

Hypoxic (HVR) and hypercapnic (HCVR) ventilatory responses are influenced by both metabolic activity and hormonal factors. By studying 67 subjects of both sexes, including those at the extremes of stature, we examined the influence of gender, CO2 production (VCO2), O2 consumption (VO2), body surface area (BSA), and vital capacity (VC) on resting ventilation (VE), HVR, and HCVR. We measured resting VE, VO2, and VCO2 and then performed isocapnic progressive hypoxic and hypercapnic ventilatory responses. The effect of stature was reflected in higher VE and metabolic rate (both P less than 0.001) in tall men compared with short men that was ablated by correction for BSA. Perhaps because their heights vary less than those of the men, tall women were not statistically distinguishable from short women in any of these measured parameters. Tall men tended to have greater hypoxic chemosensitivity than short men but this was not significantly different (P = 0.07). Gender affected the control of ventilation in a number of ways. Men had higher VE (P less than 0.05) and metabolic rate (P less than 0.001) than women. Even after correction for BSA men still had higher metabolic rates. Women had higher VE/VCO2 than men (P less than 0.05) and lower resting end-tidal Pco2 (PETCO2) values (P less than 0.05). Both A, the shape parameter of the hyperbolic HVR curve, and HVR determined from mouth occlusion pressure (AP) were greater in women than in men, although only AP reached statistical significance. However, corrections of A for BSA (P less than 0.05), VCO2 (P less than 0.01), and VC (P less than 0.001) amplified these differences.(ABSTRACT TRUNCATED AT 250 WORDS)     

Movement-related brain potentials in 6- to 7-year-old children]

Spatial distribution and component structure of movement-related brain potentials (MRBP) were studied in 6-7-years-old children. The structure of Bereitschaftspotentials was found to be complex and heterogeneous the latency of P200 component being shorter than that in adults. MRBP recorded contained specific for children late negative wave that had been called postaction negativity, or PAN. The amplitudes of almost all MRBP components in children under study was the highest in the frontal areas. The results obtained may reflect neurophysiological changes associated with motor development.     

Visuo-motor synchronization in children of 7-8 years old

The group of 22 children of 7-8 years old and the group of 17 adults participated in the experiment in which they were asked to synchronize their movements (pressing a button) with an isochronous sequence of visual stimuli. The period of the sequence was varied between 500 to 2000 ms with the 300 ms step. Two successive phases of visuo-motor synchronization were studied: the synchronization phase and the initiation phase which corresponds to the process of transition between reacting to a visual stimulus and the stable synchronization. The initiation phase was characterized by the shape and duration of the asynchrony time course (relaxation curve). The statistical properties of asynchrony were analyzed in the framework of the phase correction of the central timer. It is shown that (1) the range of successful visuo-motor synchronization is narrower in children of 7-8 than in adults and it spans from 600-700 ms to approx. 1700 Mc; (2) The initiation phase lasts about the same time in children of 7-8 and adults and typical shapes of individual relaxation curves are similar in both adults and children. (3) Although the statistical properties of asynchrony are comparable in children and adults, the mechanism of phase correction of the central timer operates with a lower value of the correction gain factor in children than in adults. In children, the phase correction process is also characterized by a substantially higher level of the central and motor noise which leads to a higher asynchrony variability and more frequent and longer lasting synchronization losses.     

Early-life determinants of total and HDL cholesterol concentrations in 8-year-old children; the PIAMA birth cohort study

Background

Adult cholesterol concentrations might be influenced by early-life factors, such as breastfeeding and birth weight, referred to as “early programming”. How such early factors exert their influence over the life course is still poorly understood. Evidence from studies in children and adolescents is scarce and conflicting. We investigated the influence of 6 different perinatal risk factors on childhood total and HDL cholesterol concentrations and total-to-HDL cholesterol ratio measured at 8 years of age, and additionally we studied the role of the child''s current Body Mass Index (BMI).

Methods

Anthropometric measures and blood plasma samples were collected during a medical examination in 751 8-year-old children participating in the prospective Prevention and Incidence of Asthma and Mite Allergy (PIAMA) birth cohort study. Linear and logistic regression were performed to estimate associations of total and HDL cholesterol concentrations with breastfeeding, birth weight, infant weight gain, maternal overweight before pregnancy, gestational diabetes and maternal smoking during pregnancy, taking into account the child''s current BMI.

Results

Linear regressions showed an association between total-to-HDL cholesterol ratio and maternal pre-pregnancy overweight (β = 0.15, Confidence Interval 95% (CI): 0.02, 0.28), rapid infant weight gain (β = 0.13, 95%CI: 0.01, 0.26), and maternal smoking during pregnancy (β = 0.14, 95%CI: 0.00, 0.29). These associations were partly mediated by the child''s BMI.

Conclusion

Total-to-HDL cholesterol ratio in 8-year-old children was positively associated with maternal pre-pregnancy overweight, maternal smoking during pregnancy and rapid infant weight gain.     

Effects of ration, temperature and body size on the body composition, energy content and condition of the minnow, Phoxinus phoxinus (L.)

The effects of ration and temperature on the body composition, energy content and indices of condition of the minnow. Phoxinus phoxinus (L.) (Cyprinidae). were studied experimentally. Five ration levels over the range starvation to ad libitum and five temperatures over the range 5–15°C were used. The fish weighed 1-5-4 g. At each temperature, the relative dry matter content, lipid content and energy content increased with increased ration. The response of the protein content to ration was temperature-dependent. Temperature had a significant effect on body composition and energy content, but this effect was irregular. The Fulton condition factor was less sensitive to ration than the wet or dry liver-somatic index. Temperature had a significant effect on the condition factor and liver indices. Significant, positive correlations were found between growth rate, lipid content and the indices of condition. The liver indices were better predictors of growth rate than the condition factor or lipid content and may provide useful information on the physiological condition offish in field studies.     

Attention and time estimation in 5- and 8-year-old children: a dual-task procedure

This experiment tested the effect of a dual-task on time reproduction in 5- and 8-year-olds. Children had to reproduce a stimulus duration lasting for 6 or 12 s, during which they either did or did not perform a concurrent non-temporal task (i.e. picture naming) both in low (LA) and high (HA) attentional demand conditions. The results showed that children reproduced shorter durations in the dual-task than in the single-task condition, whatever the duration value used. However, this shortening effect was greater in the 5-year-olds than in the 8-year-olds. Furthermore, in the 5-year-olds, temporal reproductions were significantly shorter in both dual-tasks (LA or HA) than in the single-task, whereas, in the 8-year-olds, differences reached significance only between the HA dual-task and the single-task. In the non-temporal task, the proportion of naming errors was also greater in the dual-task than in the single-task, especially under high attentional demand, but it did not significantly differ between the two age groups tested.     

Gender differences in regional body composition and somatotrophic influences of IGF-I and leptin.

This study evaluated the arm, trunk, and leg for fat mass, lean soft tissue mass, and bone mineral content (BMC) assessed via dual-energy X-ray absorptiometry in a group of age-matched (approximately 29 yr) men (n = 57) and women (n = 63) and determined their relationship to insulin-like growth factor I (IGF-I) and leptin. After analysis of covariance adjustment to control for differences in body mass between genders, the differences that persisted (P < or = 0.05) were for lean soft tissue mass of the arm (men: 7.1 kg vs. women: 6.4 kg) and fat mass of the leg (men: 5.3 kg vs. women: 6.8 kg). Men and women had similar (P > or = 0.05) values for fat mass of the arms and trunk and lean soft tissue mass of the legs and trunk. Serum IGF-I and insulin-like growth factor binding protein-3 correlated (P < or = 0.05) with all measures of BMC (r values ranged from 0.31 to 0.39) and some measures of lean soft tissue mass for women (r = 0.30) but not men. Leptin correlated (P < or = 0.05) similarly for measures of fat mass for both genders (r values ranging from 0.74 to 0.85) and for lean soft tissue mass of the trunk (r = 0.40) and total body (r = 0.32) for men and for the arms in women (r = 0.56). These data demonstrate that 1) the main phenotypic gender differences in body composition are that men have more of their muscle mass in their arms and women have more of their fat mass in their legs and 2) gender differences exist in the relationship between somatotrophic hormones and lean soft tissue mass.     

Effects of nicotine on body weight, food consumption and body composition in male rats

The present study examined the effects of nicotine administration and cessation on body weight, food consumption, and body composition in rats. Administration of nicotine was associated with attenuated body weight gains and cessation was associated with accelerated body weight gains. Changes in fat composition paralleled changes in body weight, whereas changes in body water and protein did not. These results suggest that nicotine administration decreases body weight through its effects on fat stores in the body. After cessation of nicotine, body fat rapidly approached levels of control animals.     

A clinical and neuropsychological analysis of mental functions in 6- to 7-year-old children

The neuropsychological analysis of the state of higher mental functions (HMF) in children aged 6-7-years entering the first class of the school providing general education showed that the HMF of 52-73% of the future schoolchildren are underdeveloped with respect to their age. The underdevelopment of the emotional-volitional sphere, of the dynamic organization of object activity, audio-speech memory, sphere of images-representations, visually-image and verbally-logical forms of thinking has been revealed. The experimental data suggest the absence of the primary (structural) derangements of the studied HMF in the examined children and dependence of the extent of their formation on the extent of readiness of the voluntary organization of activity. Insufficient formation of the HMF with respect to age is manifested in the lag of the formation of the internal structure of the psychic process, i.e., the absence of interiorization of the psychic processes and formation of the internal mental act. The neuropsychological assessment of underdevelopment of the HMF in reference to age suggests an insufficient age-related maturity of subcortical structures and subcortical corticopetal pathways as well as a dysfunction of the frontal neocortex and a secondary dysfunction of the posterofrontal and TPO areas, non-auditory cortical temporal regions of the left hemisphere due to underdevelopment of connections of these areas with the frontal structures.     

Cognitive abilities, androgen levels, and body mass index in 5-year-old children

This study explores the potential relationship between a series of cognitive abilities and testosterone, dehydroepiandrosterone (DHEA), androstenedione, and body mass index (BMI) measurements in 5-year-old children. 60 boys and 69 girls were administered a test (K-BIT) which provided measurements of fluid intelligence (Matrices subtest), crystallized intelligence (Vocabulary subtest), and IQ composite (the combination of the two subtests); a sub-sample of 48 boys and 61 girls was also subjected to diverse tests related to theory of mind (affective labeling, appearance-reality distinction, display rules, and false belief). Testosterone, DHEA, and androstenedione levels were measured using an enzyme immunoassay technique in saliva samples. An analysis of variance failed to reveal any significant differences between boys and girls in any of the cognitive abilities assessed. The correlation analysis revealed a positive relationship between fluid intelligence and testosterone levels in boys, a negative relationship between crystallized intelligence and androstenedione levels in girls, and between affective labeling and androstenedione levels in boys. A multiple regression analysis indicated that androstenedione and BMI were the best predictors for some of the cognitive abilities assessed.     

Characteristics of cardiac activity in 5- to 7-year-old children during graded exercise

The characteristics of cardiac activity in 5–7-year-old children were studied at rest and during graded veloergometric exercise. The indices of central hemodynamics strongly correlated at rest and the closest correlations were in girls compared to boys. Minute volume increased with an increasing load (from 0.5 to 1.5 W/kg) which could be attributed to an increase in stroke volume. In the groups of 5- to 7-year-old boys and 7-year-old girls the stroke volume increased with an increasing load reaching a maximum at 1.5 W/kg. In the groups of 6-year-old boys and 5-year-old girls the stroke volume increased up to a load of 1.0 W/kg. Heart rate represents another mechanism of cardiac output regulation. The chronotropic response to physical exercise in 5- to 7-year-old children was found to be sex specific, which was especially pronounced at the loads of 1.0 and 1.5 W/kg. Sex difference in the chronotropic heart response to graded physical exercise appeared at the age of 5, and the difference in inotropic response at the age of 7 years substantiates the heterochronous development of chrono- and inotropic cardiac functions.