Estimation of body composition from bioelectrical impedance of body segments

This study provides values of anthropometric measurements and specific impedance, for a sample of 104 adults. The hypothesis that the body composition can be estimated more accurately from measurements of lengths and impedance values of the body segments than from the whole body was tested. The impedance of upper and lower extremities (arm and leg) and trunk were used to compute estimates of body composition parameters (FFM, FM, %F, TBW, ECW). The results were compared with those estimated by the impedance of the whole body. These comparisons demonstrated that significative differences resulted from body composition obtained by segmental impedance and by the whole body.     

Age and body mass index associations with body segment parameters

Body segment parameters (BSPs) such as segment mass, center of mass, and radius of gyration are required in many ergonomic tools and biomechanical models to estimate injury risk, and quantify muscle and joint contact forces. Currently, the full effects of age and obesity have not been taken into account when predicting BSPs. The goal of this study is to quantify the impact of body mass index (BMI) and age on BSPs, in order to provide more representative measures necessary for modeling inputs. A whole body dual energy X-ray absorptiometry (DXA) scan was collected for 280 working men and women with a wide range of BMI and aged 21 to 70 years. Established DXA processing methods were used to determine in-vivo estimates of the mass, center of mass, and radius of gyration for the upper arm, forearm, torso, thigh, and shank for males and females. Regression models were used to determine if age and BMI terms, as well as their interactions, were associated with these BSPs. The variability in BSPs explained by BMI alone ranged from 4 to 51%, and age explained an additional 3–19%. Thus, BMI and age are significant correlates of BSPs, and need to be taken into account when predicting certain BSPs in order to obtain accurate and representative results in biomechanical models.     

Relationship of body composition to somatotype.

The purpose of this study is to determine the relationship in college-aged women between somatotype using both Sheldon's ('69) and Heath and Carter's ('67) procedures, and body composition, as measured by whole-body 40K counting and body density. Sheldon's endomorphy is closely associated with height and weight; Heath and Carter's first component is significantly related to weight and body fatness. Lean body mass (LBM) as a weight or as a percent is not closely related to Sheldon's mesomorphy or Heath and Carter's second component. However, when LBM and height are used as independent variables to estimate somatotype, both variables are significantly related to Heath and Carter's second component, accounting for 61% of the variance. Thus Heath and Carter's second component is significantly associated with LBM for a given body height. Most of the variation in Sheldon's ectomorphy and Heath and Carter's third component can be accounted for by weight and height. Sheldon's somatotype for all three components is not as closely related to body composition as Heath-Carter's. Body composition, as measured by either 40K counting or body density, is found to be important in accounting for variation in Heath and Carter's first and second components.     

Measured versus self-reported body height

Students (105 males and 298 females) of the Faculty of Natural Sciences of University of Wrocław of 19–28 years of age were examined. The questionnaire and body height measurements were conducted in February and March of the year 2000. The measured as well as self — reported body height were analyzed depending on socio — economic variables such as the students' parents' education, the students' place of residence and their families' financial status, until the students' 14 year of age. The analysis of the mean self — reported and measured body height values demonstrated insignificant differences for men and the significant ones for women. Tall women declare greater than actual body height and only tall men appeared to be insignificantly taller than their questionnaire answers suggested. The analysis of the mean differences with regard to the size and kind of the place of residence didn't show significant differences. Similarly, neither the educational level nor the financial status constitute a differentiating factor with regard to the analyzed characteristics.     

中国少数民族体成分的变化

本文对中国少数民族23352例（男10070例,女13282例）的体成分进行了分析,以了解中国少数民族脂肪率、肌肉量的现状,探讨体成分随年龄增长的变化规律。研究发现,男性和女性总体上属于超重水平,还没有达到肥胖水平。与南方族群男性相比,北方阿尔泰语系族群的男性四肢脂肪率高、内脏脂肪等级高、水分率低。南方族群中,藏缅语族群、苗瑶语族群、壮侗语族群的四肢脂肪率、内脏脂肪等级、水分率相对接近;南亚语系族群与这3个南方族群差距较大。与南方族群女性相比,北方阿尔泰语系族群的女性躯干、四肢肌肉量大,骨骼重;南方4个族群女性躯干、四肢肌肉量较小,骨骼较轻,骨量、肌肉量彼此接近。随年龄增长,男性骨量下降,水分率增大;上肢脂肪率减小,躯干脂肪率增大,内脏脂肪等级增大,即脂肪向躯干集中,全身总体脂率增大;下肢肌肉量减少,躯干肌肉量下降,最终导致全身总肌肉量下降。随年龄增长,女性上肢的脂肪率和肌肉量没有明显变化,下肢的脂肪率下降,躯干脂肪率和内脏脂肪等级增大,总体脂率增大;躯干肌肉量下降,总肌肉量下降。男性推定骨量下降的节点是50岁,女性是60岁。男性总肌肉量下降的节点是40岁,女性是50岁。男性、女性身体水分率增加的节点都是60岁,内脏脂肪等级增加的节点都是30岁,总脂肪率下降的节点都是60岁,躯干脂肪率增加的节点都是30岁,躯干肌肉量下降的节点都是40岁。研究还发现,体脂率、内脏脂肪等级与血糖呈显著正相关。研究结果反映了中国少数民族从青年到老年的体成分变化的基本规律。     

环境温度和体内储备物共同影响煤山雀夜间体重的下降(英文)

环境温度和体内储备物水平被认为是鸟类在静止状态下能量利用的重要调节因子(夜间体重降低).然而,以往的研究没有把环境温度和体内储备物对夜间能量维持加以明确的区分.为了研究环境温度是否是为煤山雀(Periparus ater)夜间体重调节的直接因子,在自由取食条件下,实验室控制日-日和日-夜环境温度.温度变化模拟西班牙中部地中海山区秋季日-夜温度的变化.夜间体重取决于黄昏时的体重以及前一天体重的增加值.当前一日白天煤山雀体重增加最大时,记录夜间体重最大降低的比率.然而,环境温度的不可预见性没有影响煤山雀夜间体重降低,可以解释煤山雀内在的生理能量平衡.这些结果提示,当一些环境因子如温度变得不可预见时,鸟类在狭小范围内保持体内储备物     

Age variations in the relation of body mass indices to estimates of body fat and muscle mass

In some chronic disease studies, distinctions have been made regarding the importance of body mass index (BMI) as a risk factor in younger versus older men and women. In order to determine the significance of these differences in BMI-disease associations, we determined the extent of age-dependent variations in the relation of BMIs to body composition in large probability samples of U.S. men and women from the First and Second U.S. National Health and Nutrition Examination Surveys (NHANES I and II). BMIs are more highly correlated with estimates of body fat in younger than in older men and women, and with muscle mass in older than in younger adults. Caution should be exercised in interpreting the significance of BMI as a risk factor for chronic disease, particularly in comparison of age groups.     

A factor analysis of body build in the rat

Following a survey of the problems associated with the comparative study of measures of physique in domesticated and laboratory animals, techniques were developed for the measurement of body build in the adult albino laboratory rat (Rattus norvegicus). They involved anesthetisation of the animals and the use of calipers and a simple apparatus devised for the purpose. The 17 measures taken on 100 rats, 50 of each sex, are detailed and the reasons for excluding others given. Intercorrelations of all the measures and their reliability co-efficients, which were judged satisfactory, are presented. The tables of intercorrelations, one for each sex, were factor analysed separately, and rotations to simple structure performed. Two factors were identified, one having factor saturations on measures of body length and the other similarly defining body width. This pattern was similar for the two sexes and a single index of body build was therefore proposed in which the length of the rear foot is divided by the width of the shoulder girdle and multiplied by 100 to avoid decimals. The use of the index in other investigations is mentioned.     

Experimental analyses of body image in the chimpanzee

It is difficult to study body image in animals. In this study, it is assumed that the perception of the body of others reflects body image. The perception of the human face was examined in a series of six experiments with a chimpanzee. Delayed-matching-to-sample tasks were employed. Although the chimpanzee mastered the tasks and showed transfer of performance to new faces, subtle changes in the matching face resulted in the deterioration of performance. Responses of the chimpanzee were often controlled by factors other than the facial stimuli. Thus, although the chimpanzee has a body image as humans do, it may not be as clear and as segmented.     

Distinct brain oscillatory responses for the perception and identification of one’s own body from other’s body

The body recognition process includes complex visual processing, the sensation, perception, and distinction stages of the stimulus. This study examined this process by using the time–frequency analysis of EEG signals and analyzed the obtained data by using the event-related oscillations method. This study aimed to examine the oscillatory brain responses and distinguish one’s own body from other’s body. In the present study, 17 young adults were included and the EEGs were recorded with 32 electrodes placed in different locations. Event-related power spectrum and phase-locking analyzes were performed. ITC and ERSP data were analyzed using 2 (condition) × 11 (location) × 2 (hemisphere) ANOVA Design. As we observed a prolonged response in the theta band in the grand averages, we included the time variable in the overall model. As a result, we found that the phase-locking and the event-related power spectrum of the theta response in recognizing one’s own body were higher when compared to the phase-locking and the event-related power spectrum of the theta response in recognizing others’ body (p < 0.05). When the time variable was included, the early theta response was more phase-locked and had a higher power spectrum compared to the late theta response (p < 0.05). As a result of the power spectrum analysis, the condition × hemisphere interaction effect in the beta band was higher in the left hemisphere regarding increased responses in recognizing one’s own body (p < 0.05). As a result of ITC, the main effect of the condition was higher in the recognition of the stimulus of one’s own body (p < 0.05). Finally, the theta oscillator response stood out in distinguishing one’s own body from other’s body. Similarly, the power spectrum in the beta response was higher in the left hemisphere, and this finding is consistent with the literature.     

黎族的体成分与体质特征

1982年和1988年已经有学者报道了黎族体质人类学研究资料,近年来又报道了黎族的分子人类学研究成果。目前未见关于黎族身体组成成分的研究,也没有当前黎族的体质人类学数据。2014年11月,在海南省五指山市5个黎族村寨进行607例(男为308例,女为299例)黎族成人的人体测量。研究发现,黎族人偏瘦,肌肉较发达。随年龄增长,黎族男性体脂率的增加,主要是躯干脂肪率增大造成的,与四肢脂肪率关系不大。男性由于骨量、躯干和四肢肌肉量的下降造成瘦体质量的逐渐减小。随年龄增长,黎族女性的体脂率呈线性增大,总肌肉量呈线性减小。体脂率的逐渐增大是由于躯干和四肢的脂肪率逐渐增加造成的,总肌肉量的逐渐减小是左下肢肌肉量、躯干肌肉量逐渐下降造成的。黎族男女均为圆头型、高头型、中头型、阔面型、中鼻型、中躯干型、中胸型、宽肩型、中骨盆型、中腿型。与30年前黎族头面部资料相比,本文测量的黎族头宽、面宽值较大,头更圆些、更阔些,面更阔些,红唇较薄,形态面高值较小,男性鼻宽值较小。     

Predictive regression modeling of body segment parameters using individual-based anthropometric measurements

Body segment parameters such as segment mass, center of mass, and radius of gyration are used as inputs in static and dynamic ergonomic and biomechanical models used to predict joint and muscle forces, and to assess risks of musculoskeletal injury. Previous work has predicted body segment parameters (BSPs) in the general population using age and obesity levels as statistical predictors (Merrill et al., 2017). Estimated errors in the prediction of BSPs can be as large as 40%, depending on age, and the prediction method employed (Durkin and Dowling, 2003). Thus, more accurate and representative segment parameter inputs are required for attempting to predict modeling outputs such as joint contact forces, muscle forces, and injury risk in individuals. This study aims to provide statistical models for predicting torso, thigh, shank, upper arm, and forearm segment parameters in working adults using whole body dual energy x-ray absorptiometry (DXA) scan data along with a set of anthropometric measurements. The statistical models were developed on a training data set, and independently validated on a separate test data set. The predicted BSPs in validation data were, on average, within 5% of the actual in vivo DXA-based BSPs, while previously developed predictions (de Leva, 1996) had average errors of up to 60%, indicating that the new models greatly increase the accuracy in predicting segment parameters. These final developed models can be used for calculating representative BSPs in individuals for use in modeling applications dependent on these parameters.     

Comparison of variations between percentage of body fat, body mass index and daily physical activity among young Japanese and Thai female students

ABSTRACT: BACKGROUND: In our series of investigations concerning the causes of seasonal change in fat accumulation in young university students, we could not find any contribution of seasonal variation in the ratio of carbohydrate and fat metabolism to that of body fat percentage in Japanese and Thai participants. After our previous study, we examined the effect of daily physical activity on body fat percentage to look for the major causes of seasonal change in fat accumulation in young university students. FINDINGS: In this study, we measured participants' (young Japanese and Thai university students) daily physical activity by a uniaxial accelerometer in addition to the measurements of body fat percentage and body mass index by a bioelectrical impedance meter. We found that there was significant and moderate negative correlation between body fat percentage and daily step counts among Japanese but not Thai participants. We observed significant, moderate and positive correlations between the percentage of body fat and body mass index among Japanese and Thai participants. CONCLUSIONS: Daily physical activity plays an important role in the seasonal variation of body fat percentage of Japanese female students. Our present study also confirmed the importance of daily physical activity for controlling body mass index and for the prevention of obesity.     

Phase-contrast imaging for body composition measurement

PurposeIn this paper, we propose a novel method for human body composition measurement, especially for the bone mineral density (BMD) measurement. The proposed method, using the absorption and differential phase information retrieved from X-ray grating-based interferometer (XGBI) to measure the BMD, has potential to replace dual-energy X-ray absorptiometry (DEXA), which is currently widely used for body composition measurement.MethodsThe DEXA method employs two absorption images acquired at two different X-ray spectra (high energy and low energy) to calculate the human body composition. In this paper, a new method to calculate BMD using a single X-ray measurement is proposed. XGBI is a relatively new X-ray technique that provides absorption, phase and scattering information simultaneously using a single X-ray spectrum. With the absorption and differential phase information retrieved from XGBI, BMD can be measured using only one single X-ray spectrum. Numerical simulations are performed with a body phantom of bone (Cortical, ICRU-44) surrounded by soft tissue (Soft, ICRU-44). BMD is calculated with both the DEXA method and the proposed method.ResultsResults show that BMD can be measured accurately with the proposed method; moreover, better signal-to-noise ratio (SNR) is obtained compared to DEXA.ConclusionWith the proposed method, BMD can be measured with XGBI setup. Further, the proposed method can be realized using current X-ray phase-contrast imaging (XPCI) apparatus without any hardware modification, suggesting that this technique can be a promising supplementary function to current XPCI equipment.     

Body surface temperature distribution in relation to body composition in obese women

Adipose tissue levels and human obesity are known to be associated with increased heat production. At the same time, subcutaneous adipose tissue provides an insulating layer that impedes heat loss. The energy implications of obesity and body thermoregulatory mechanisms remain relatively poorly understood. This study attempted to examine the potential relationship between body composition (subcutaneous and visceral fat) determined by bioimpedance as well as BMI (body mass index), and skin surface temperature distribution recorded at rest.One specific aim of this study was to draw a thermal map of body areas in obese women and compare this with women of normal body mass, and thus to identify body regions within which heat transfer is particularly impeded. As high fat content is a good insulator, it could reduce the body‘s ability to respond effectively to changes in environmental temperature, which would be problematic for thermal homeostasis. Our results showed that core temperature did not differ between obese and normal body mass participants, while skin temperature of most body surfaces was lower in obese subjects.The results of regression analysis showed that the mean body surface temperature (T_mean) decreased with increasing percentage of body fat (PBF) of the abdominal area. The opposite relationship was observed for the front area of the hand (simultaneous increase in T_mean and PBF). We also found a negative correlation between BMI and T_mean of the thigh areas, both the front and the back. From this it could be concluded that the mean body surface temperature is dependent on body fat.     

Polyphagy and adult body size in geometrid moths

We compared the average body size (wing span) of Finnish geometrid moth species in relation to their degree of polyphagy and quality of food. The first hypothesis, originally constructed for mammals and birds, states that smaller species should more often be specialists than large species, because of the different relationships between body size and home range size, and body size and daily energy requirements. According to the second hypothesis, smaller species should feed more often on herbs than do larger species, because of the different defence mechanisms of herbs and woody plants. The results support both of these hypotheses. Specialist species are smaller than oligophagous or polyphagous species, and small species concentrate on herbs. We conclude that quality and quantity of food resources may explain the pattern.     

Influence of prey body characteristics and performance on predator selection

At the time of settlement to the reef environment, coral reef fishes differ in a number of characteristics that may influence their survival during a predatory encounter. This study investigated the selective nature of predation by both a multi-species predator pool, and a single common predator (Pseudochromis fuscus), on the reef fish, Pomacentrus amboinensis. The study focused on the early post-settlement period of P. amboinensis, when mortality, and hence selection, is known to be highest. Correlations between nine different measures of body condition/performance were examined at the time of settlement, in order to elucidate the relationships between different traits. Single-predator (P. fuscus) choice trials were conducted in 57.4-l aquaria with respect to three different prey characteristics [standard length (SL), body weight and burst swimming speed], whilst multi-species trials were conducted on open patch reefs, manipulating prey body weight only. Relationships between the nine measures of condition/performance were generally poor, with the strongest correlations occurring between the morphological measures and within the performance measures. During aquaria trials, P. fuscus was found to be selective with respect to prey SL only, with larger individuals being selected significantly more often. Multi-species predator communities, however, were selective with respect to prey body weight, with heavier individuals being selected significantly more often than their lighter counterparts. Our results suggest that under controlled conditions, body length may be the most important prey characteristic influencing prey survival during predatory encounters with P. fuscus. In such cases, larger prey size may actually be a distinct disadvantage to survival. However, these relationships appear to be more complex under natural conditions, where the expression of prey characteristics, the selectivity fields of a number of different predators, their relative abundance, and the action of external environmental characteristics, may all influence which individuals survive.     

New estimates of early hominid body size

Body weights for 12 early hominid specimens are estimated based on an analysis of four variables shown to have high correlation with body size in living Old World primates. Average size estimates of around 36 kg are suggested for gracile early hominids and around 59 kg for robust early hominids. Size variation is considerably more pronounced in the robust group than in the gracile group, suggesting substantially greater sexual dimorphism in the former.     

Birth weight,adult body size,and risk of colorectal cancer

BackgroundEvidence suggests that birth weight may be associated with colorectal cancer (CRC) risk later in life. Whether the association is mediated by adult body size remains unexamined.MethodCox proportional hazards models (Hazard Ratio (HR) and 95 % Confidence Intervals (CI)) were used to evaluate the association between self-reported birth weight (<6 lbs, 6-<8 lbs, ≥8 lbs) and CRC risk among 70,397 postmenopausal women from the Women’s Health Initiative. Further, we assessed whether this association was mediated by adult body size using multiple mediation analyses.ResultsCompared with birth weights of 6-< 8 lbs, birth weight ≥ 8 lbs was associated with higher CRC risk in postmenopausal women (HR = 1.31, 95 % CI 1.16–1.48). This association was significantly mediated by adult height (proportion mediated =11.4 %), weight (11.2 %), waist circumference (10.9 %), and body mass index at baseline (4.0 %). The joint effect of adult height and weight explained 21.6 % of this positive association.ConclusionOur data support the hypothesis that the intrauterine environment and fetal development may be related to the risk of developing CRC later in life. While adult body size partially explains this association, further investigation is required to identify other factors that mediate the link between birth weight and CRC.