Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Body Size”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed2003

Artificial fish schools: collective effects of school size, body size, and body form.

Individual-based models of schooling in fish have demonstrated that, via processes of self-organization, artificial fish may school in the absence of a leader or external stimuli, using local information only. We study for the first time how body size and body form of artificial fish affect school formation in such a model. For a variety of group sizes we describe how school characteristics (i.e., group form, spread, density, polarization, turning rate, and speed) depend on body characteristics. Furthermore, we demonstrate that the nearest neighbor distance and turning rate of individuals are different for different regions in the group, although the agents are completely identical. Our approach shows the significance of both self-organization and embodiment in modeling of schools of artificial fish and, probably, in structuring schools of real fish.

Animals↗
PubMed1998

Intrauterine growth retardation, body size, body composition and physical performance in adolescence.

Studies about effects of IUGR on growth in childhood as well as on body size, body composition and physical performance in adolescence and adulthood are reviewed. The review is based on 12 studies that distinguished IUGR from other types of low birthweight and compared outcomes of IUGR cases with those of non-IUGR controls. This information is complemented by results of a follow-up study of IUGR cases and controls carried out in Guatemalan adolescents and young adults. In Guatemala as well as in other countries, IUGR newborns showed partial catch-up growth during the first one or two years of life, and then maintained their achieved place in the growth distribution. Guatemalan IUGR cases were shorter, lighter and weaker than non-IUGR controls as adolescents and young adults. The differences in adult body size observed in Guatemala between cases and controls are similar to those found in more affluent countries (i.e. about 5 cm in height and 5 kg in weight).

Adolescent↗
PubMedDate not supplied

Energetics of nose and mouth breathing, body size, body composition, and nose volume in young adult males and females.

This research tests the relative ability of body size factors and sex to explain variation in nose volume and to explain metabolic measures during rest and moderate exercise in 50 young adults. It uses standard anthropometric measures plus two new measures of nose morphology (nose/face angle and nose volume) and evaluates body composition with a device for air displacement plethysmography. Standard physiological measures were obtained in nose-only and mouth-only breathing conditions with subjects at rest and using moderate exercise. A factor representing linear and bulk measures of body size and a factor representing lean body mass explain subjects' variation in nose volume, resting volume of oxygen consumed (VO2), and resting ventilation volume (VV) better than subject's sex does. By contrast, during exercise, sex explains VO2 and VV better than do body size factors, probably because hormone-mediated muscularity in males produced greater work output. Nose breathing was found to be more energetically efficient in most but not all subjects, but additional research is needed to explore this finding further. Qualitative comparisons between modes of breathing and the application of this research protocol to studies of climate-related patterns of nasal variation are discussed.

Adolescent↗
PubMed2004

Body size, body composition, and fat distribution: a comparison of young New Zealand men of European, Pacific Island, and Asian Indian ethnicities.

AIMS: To investigate body size and body fat relationships and fat distribution in young healthy men drawn from New Zealand European, Pacific Island, and Asian Indian populations. METHOD: A total of 114 healthy men (64 European, 31 Pacific Island, 19 Asian Indian) aged 17-30 years underwent measurements of height, weight, and body composition by total body dual-energy X-ray absorptiometry (DXA). Body mass index (BMI) was then calculated. Percent body fat (%BF), fat-free mass, bone mineral content, bone mineral density, abdominal fat, thigh fat, and appendicular skeletal muscle mass (ASMM) were obtained from the DXA scans. RESULTS: For the same BMI, %BF for Pacific Island men was 4% points lower and for Asian Indian men was 7-8% points higher compared to Europeans. Compared to European men for the same %BF, BMI was 2-3 units higher for Pacific Island, and 3-6 units lower for Asian Indian. The ratio of abdominal fat to thigh fat, adjusted for height, weight, and %BF, was significantly higher for Asian Indian men than European (p=0.022) and Pacific Island (p=0.002) men. ASMM, adjusted for height and weight, was highest in Pacific Island and lowest in Asian Indian men. CONCLUSIONS: The relationship between %BF and BMI is different for European, Pacific Island, and Asian Indian men which may, at least in part, be due to differences in muscularity. Asian Indians have more abdominal fat deposition than their European and Pacific Island counterparts. Use of universal BMI cut-off points are not appropriate for comparison of obesity prevalence between these ethnic groups.

Adolescent↗
PubMed2000

Body size, body shape, and long bone strength in modern humans.

To identify behaviorally significant differences in bone structure it is first necessary to control for the effects of body size and body shape. Here the scaling of cross-sectional geometric properties of long bone diaphyses with different "size" measures (bone length, body mass, and the product of bone length and body mass) are compared in two modern human populations with very different body proportions: Pecos Pueblo Amerindians and East Africans. All five major long bones (excluding the fibula) were examined. Mechanical predictions are that cortical area (axial strength) should scale with body mass, while section modulus (bending/torsional strength) should scale with the product of body mass and moment arm length. These predictions are borne out for section moduli, when moment arm length is taken to be proportional to bone length, except in the proximal femoral diaphysis, where moment arm length is proportional to mediolateral body breadth (as would be expected given the predominance of M-L bending loads in this region). Mechanical scaling of long bone bending/torsional strength is similar in the upper and lower limbs despite the fact that the upper limb is not weight-bearing. Results for cortical area are more variable, possibly due to a less direct dependence on mechanical factors. Use of unadjusted bone length alone as a "size" measure produces misleading results when body shape varies significantly, as is the case between many modern and fossil hominid samples. In such cases a correction factor for body shape should be incorporated into any "size" standardization.

Adult↗
PubMed2004

Correlation of blood sex steroid hormones with body size, body fat distribution, and other known risk factors for breast cancer in post-menopausal Chinese women.

OBJECTIVE: Estrogen plays a central role in breast cancer. It has been suggested that many known breast cancer risk factors may exert their effect via levels of endogenous sex hormones. The objective of this analysis is to evaluate the association between measures of body size, dietary macronutrient intake, and reproductive factors with levels of endogenous sex hormones among women living in Shanghai, China. METHODS: Included in this study were 420 post-menopausal healthy women randomly selected from the general population as controls who participated in the Shanghai Breast Cancer Study, a population-based case-control study conducted in Shanghai, China between 1996 and 1998. Comprehensive dietary and reproductive information was collected using a structured questionnaire during an in-person interview and anthropometrics were measured by trained interviewers according to a standard protocol. Hormone levels were log-transformed and Pearson correlation coefficients were calculated to determine the correlation between hormone levels and selected breast cancer risk factors. RESULTS: Measures of body size were strongly correlated with hormone levels. In particular, weight, waist circumference, and hip circumference were significantly positively correlated (p < 0.05) with levels of testosterone, estradiol, estrone, and significantly negatively correlated with sex hormone binding globulin. Macronutrient intake and reproductive factors were not correlated with endogenous sex hormone levels. CONCLUSIONS: These data suggest that breast cancer risk associated with measures of body size may be mediated, at least partially, by levels of endogenous sex hormones.

Adult↗
PubMedDate not supplied

Relationship of body size, body image, and self-esteem in African American, European American, and Mexican American middle-class women.

In this study we examined the influence of ethnicity on weight, body image, and self-esteem among adult women while controlling for socioeconomic status (SES). Fifty women of African American (AA), European American (EA), and Mexican American (MA) descent completed interviews and questionnaires related to body size and self-esteem, and were measured for weight and height. AA women were significantly heavier than EA women, but MA women did not differ materially from either grouping. Regardless of ethnic descent, all reported congruence between real and ideal body size. In addition no differences were found in self-esteem. This new comparative study calls into question variations previously attributed to race or ethnicity. It also provides a view of middle-class women missing from recent research. Based on the outcomes of our research, we suggest that socioeconomic differences could be more important than ethnic background. Health educators and providers may find these data helpful when designing prevention and intervention strategies for middle-class women regardless of their ethnic origin.

Adult↗
PubMed2006

Body size, body proportions, and encephalization in a Middle Pleistocene archaic human from northern China.

The unusual discovery of associated cranial and postcranial elements from a single Middle Pleistocene fossil human allows us to calculate body proportions and relative cranial capacity (encephalization quotient) for that individual rather than rely on estimates based on sample means from unassociated specimens. The individual analyzed here (Jinniushan) from northeastern China at 260,000 years ago is the largest female specimen yet known in the human fossil record and has body proportions (body height relative to body breadth and relative limb length) typical of cold-adapted populations elsewhere in the world. Her encephalization quotient of 4.15 is similar to estimates for late Middle Pleistocene humans that are based on mean body size and mean brain size from unassociated specimens.

Animals↗
PubMed2006

Body size, body proportions, and mobility in the Tyrolean "Iceman".

Body mass and structural properties of the femoral and tibial midshafts of the "Iceman," a late Neolithic (5,200 BP) mummy found in the Tyrolean Alps, are determined from computed tomographic scans of his body, and compared with those of a sample of 139 males spanning the European early Upper Paleolithic through the Bronze Age. Two methods, based on femoral head breadth and estimated stature/bi-iliac (pelvic) breath, yield identical body-mass estimates of 61 kg for the Iceman. In combination with his estimated stature of 158 cm, this indicates a short but relatively wide or stocky body compared to our total sample. His femur is about average in strength compared to our late Neolithic (Eneolithic) males, but his tibia is well above average. His femur also shows adaptations for his relatively broad body (mediolateral strengthening), while his tibia shows adaptations for high mobility over rough terrain (anteroposterior strengthening). In many respects, his tibia more closely resembles those of European Mesolithic rather than Neolithic males, which may reflect a more mobile lifestyle than was characteristic of most Neolithic males, perhaps related to a pastoral subsistence strategy. There are indications that mobility in general declined between the European Mesolithic and late Neolithic, and that body size and shape may have become more variable throughout the continent following the Upper Paleolithic.

Adult↗
PubMed2001

Hydrodynamic drag of diving birds: effects of body size, body shape and feathers at steady speeds.

For birds diving to depths where pressure has mostly reduced the buoyancy of air spaces, hydrodynamic drag is the main mechanical cost of steady swimming. Drag is strongly affected by body size and shape, so such differences among species should affect energy costs. Because flow around the body is complicated by the roughness and vibration of feathers, feathers must be considered in evaluating the effects of size and shape on drag. We investigated the effects of size, shape and feathers on the drag of avian divers ranging from wing-propelled auklets weighing 75 g to foot-propelled eiders weighing up to 2060 g. Laser scanning of body surfaces yielded digitized shapes that were averaged over several specimens per species and then used by a milling machine to cut foam models. These models were fitted with casts of the bill area, and their drag was compared with that of frozen specimens. Because of the roughness and vibration of the feathers, the drag of the frozen birds was 2-6 times that of the models. Plots of drag coefficient (C(D)) versus Reynolds number (Re) differed between the model and the frozen birds, with the pattern of difference varying with body shape. Thus, the drag of cast models or similar featherless shapes can differ both quantitatively and qualitatively from that of real birds. On the basis of a new towing method with no posts or stings that alter flow or angles of attack, the dimensionless C(D)/Re curves differed among a size gradient of five auklet species (75-100g) with similar shapes. Thus, extrapolation of C(D)/Re curves among related species must be performed with caution. At lower speeds, the C(D) at a given Re was generally higher for long-necked birds that swim with their neck extended (cormorants, grebes, some ducks) than for birds that swim with their head retracted (penguins, alcids), but this trend was reversed at high speeds. Because swimming birds actually travel at a range of instantaneous speeds during oscillatory strokes, species variations in drag at different speeds must be considered in the context of accelerational stroking.

Animals↗
PubMed2001

The influence of genetic and environmental factors in estimations of current body size, desired body size, and body dissatisfaction.

The objective was to investigate the genetic epidemiology of figural stimuli. Standard figural stimuli were available from 5,325 complete twin pairs: 1,751 (32.9%) were monozygotic females, 1,068 (20.1%) were dizygotic females, 752 (14.1%) were monozygotic males, 495 (9.3%) were dizygotic males, and 1,259 (23.6%) were dizygotic male-female pairs. Univariate twin analyses were used to examine the influences on the individual variation in current body size and ideal body size. These data were analysed separately for men and women in each of five age groups. A factorial analysis of variance, with polychoric correlations between twin pairs as the dependent variable, and age, sex, zygosity, and the three interaction terms (age x sex, age x zygosity, sex x zygosity) as independent variables, was used to examine trends across the whole data set. Results showed genetic influences had the largest impact on the individual variation in current body size measures, whereas non-shared environmental influences were associated with the majority of individual variation in ideal body size. There was a significant main effect of zygosity (heritability) in predicting polychoric correlations for current body size and body dissatisfaction. There was a significant main effect of gender and zygosity in predicting ideal body size, with a gender x zygosity interaction. In common with BMI, heritability is important in influencing the estimation of current body size. Selection of desired body size for both men and women is more strongly influenced by environmental factors.

Adolescent↗
PubMed1998

Relationship of renal size, body size, and blood pressure in children.

Somatometric parameters, renal size, and systolic blood pressure (SBP) were studied in 406 patients referred to pediatric nephrology and urology clinics. These patients included 269 females (66%), 67 African Americans (17%), and 87 patients with essential hypertension (21%). Z scores for the study population were comparable to published standards for height, kidney length, and SBP. Weight and body mass index scores were significantly greater than predicted from the standards, especially in the subset of patients with essential hypertension. Age, height, weight, body mass index, kidney length, and SBP all correlated with one another; however, on multiple regression analysis of SBP with the other five independent variables, only weight proved to have a significant correlation. Furthermore, the relationship of kidney length with SBP was positive and hypertensive patients had greater kidney size than published standards. These data do not support reduced kidney size in the population with essential hypertension, nor is there support for a convincing correlation between kidney length and SBP in the general pediatric population. Body weight correlates best with blood pressure. These findings warrant further study in a less-select population. Prevention and treatment of obesity may thus be of prime importance in addressing hypertension in children.

Adolescent↗
PubMedDate not supplied

Body size, body composition and motor performances of mild-to-moderately undernourished Senegalese children.

Relationships between anthropometric dimensions (stature, weight, arm and calf circumferences, and four subcutaneous skinfolds), and motor performances (dash, standing long jump, throw for distance and grip strength) were considered in 348 mild-to-moderately undernourished Senegalese children 5-13 years of age (168 boys and 180 girls). Weights and statures are, on average, below the National Center for Health Statistics (NCHS) reference medians at each age, and deviations are more pronounced in children > 8 years of age and in boys more than girls. Boys, on average, perform better than girls on all tasks. Stature and weight explain about 30-50% of the variance in the performances of children < 10 years of age, while weight explains about 10-25% in children > 10 years of age. Indicators of body composition (estimated arm muscle and subcutaneous fat) have only a limited contribution to the remaining variance in motor performances. Fatness negatively affects the performances of girls > 10 years, but has no effect on performance of boys.

Adolescent↗
PubMed1996

Effects of body size, body density, gender and growth on underwater torque.

Two forces act on a human body motionless in water: weight (W) and buoyancy (B). They are applied to the center of mass (CM) and to the center of volume (CV) of the subject, respectively. CM and CV do not coincide; this generates a torque that is a measure of the tendency of the upper part of the body to rise, rotating around its center of mass. To quantify this tendency, Pendergast & Craig defined 'underwater torque' (T') as the product of the net force with which the feet of a subject lying horizontally in water tend to sink, times the distance between the feet and the center of volume of the lungs. In this paper we have investigated: (a) the relationships between T' and body weight (BW), height (H), body surface area (BS), body density (BD) and leg density (LD) in a group of 30 subjects (group A, 14 females and 16 males, age range 16-50 years); and (b) the effect of gender and growth on T' in a group of 110 subjects (group B, 67 girls and 43 boys, age range 12-17 years). In group A, T' was found to be linearly related with BW (r=0.833, P<0.001), H (r=0.803, P<0.001), BS (r=0.866, P<0.001), BD (r=0.617, P<0.001) and LD (r=0.549, P<0.005). A multiple linear regression analysis showed that BS and BD explained about 85% of the variability of T' (r2=0.85). In group B, T' was found to increase linearly with age (r=0.47, P<0.01), the increasing rate being three times higher in boys compared with girls. As a consequence, the T' ratio between boys and girls increased with age, from 1.69 at 13 years to 2.04 at 16 years.

Adolescent↗