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.     

Estimation of male and female body segment parameters of the Bulgarian population using a 16-segmental mathematical model

Based on a large-scale anthropometric measurements of 5290 individuals (2435 males and 2855 females) of the Bulgarian population aged between 30 and 40 years, we present 16-segmental 3D geometrical model of the human body of the average Bulgarian male and female and calculate mass, volume, location of the mass center and moments of inertia for all the segments for both genders. This study extends current anthropometrical data pool of Caucasian. Wherever possible, the comparison between our model results and data reported in literature for other Caucasian shows an overall good agreement, thus supporting the validity of the described method.     

The measurement of body segment inertial parameters using dual energy X-ray absorptiometry

Accurate body segment parameter (BSP) information is required for dynamic analyses of motion and the current methods available for obtaining these BSPs have been criticized. The purpose of this study was to determine whether dual energy X-ray absorptiometry (DXA) could accurately measure the BSPs of scanned objects and thus be used as a tool for measuring the BSPs of human subjects. Whole body mass (WBM) of 11 males was measured from a DXA scan and the values were compared to criterion scale-measured values by calculating the mean percent error. Two objects (plastic cylinder, human cadaver leg) were also scanned and DXA measurements of mass, length, centre of mass location (CM) and moment of inertia about the centre of mass (I_CM) were made using custom software. Criterion BSP measurements were then made and compared to DXA BSP values by calculating the percent error. Criterion I_CM measurements of the two objects were made using a pendulum technique and a second criterion I_CM calculation was made for the cylinder using a geometric formula. A mean percent error of −1.05% ±1.32% was found for WBM measurements of the human subjects. Errors for the cylinder and cadaver leg were under 3.2% for all BSPs except for I_CM when DXA was compared to the pendulum method (14.3% and 8.2% for cylinder and leg, respectively). The errors between DXA and the pendulum method were attributed to uncertainty in the pendulum technique (J. Biomech. 2002, in Review). I_CM error of the cylinder when DXA was compared to the geometric calculation was 2.63%. This error, combined with the low errors for all other BSPs, indicated that DXA can be used as a simple and accurate means of obtaining direct BSP information on living humans.     

Estimating subject-specific body segment parameters using a 3-dimensional modeller program

The estimation of body segment properties is important in the biomechanical analysis of movement. Current subject-specific estimation methods however can be expensive and time-consuming, while other methods do not adequately take into account individual or group variability. We describe a simple procedure for estimating subject-specific geometric properties, independent of joint centres. The method requires only a small number of anthropometric measurements and digital images of the segment or subject, a 3-dimensional modeller program and simple mathematical calculations to estimate segment volumes and centroids. Assuming that the segment is of uniform density, it's mass and moment of inertia can also be derived. Future work should include generating segment density profiles for particular populations, to increase the accuracy of the method, and comparing the accuracy of the results obtained with those produced by other techniques.     

The effect of perturbing body segment parameters on calculated joint moments and muscle forces during gait

This study examined the effect of body segment parameter (BSP) perturbations on joint moments calculated using an inverse dynamics procedure and muscle forces calculated using computed muscle control (CMC) during gait. BSP (i.e. segment mass, center of mass location (com) and inertia tensor) of the left thigh, shank and foot of a scaled musculoskeletal model were perturbed. These perturbations started from their nominal value and were adjusted to ±40% in steps of 10%, for both individual as well as combined perturbations in BSP. For all perturbations, an inverse dynamics procedure calculated the ankle, knee and hip moments based on an identical inverse kinematics solution. Furthermore, the effect of applying a residual reduction algorithm (RRA) was investigated. Muscle excitations and resulting muscle forces were calculated using CMC. The results show only a limited effect of an individual parameter perturbation on the calculated moments, where the largest effect is found when perturbing the shank com (MS_com,shank, the ratio of absolute difference in torque and relative parameter perturbation, is maximally −7.81 N m for hip flexion moment). The additional influence of perturbing two parameters simultaneously is small (MS_{mass+com,thigh} is maximally 15.2 N m for hip flexion moment). RRA made small changes to the model to increase the dynamic consistency of the simulation (after RRA MS_com,shank is maximally 5.01 N m). CMC results show large differences in muscle forces when BSP are perturbed. These result from the underlying forward integration of the dynamic equations.     

Reliability of anthropometric methods and replicate measurements

The Spearman-Brown Prophesy formula, derived from psychometrics, may be used in anthropometric studies to describe the relationship between the intraclass reliability coefficient for a single measurement and the reliability resulting from the mean of replicate measurements. This theory may be applied to determine expected reliabilities of anthropometric protocols using replicate measurements and to determine the numbers of replicate measurements necessary to achieve desired levels of reliability.     

An anthropometric assessment of Huntington's disease patients and families

An anthropometric investigation was designed to evaluate patterns of physical deterioration in Huntington's disease (HD). In this study a comprehensive set of measurements was taken including height, weight, body circumferences, skinfold thickness, and craniofacial, linear, and breadth components of the body, on 44 normal, 26 affected, and 70 at-risk individuals between 14 and 88 years of age. The anthropometric data were converted to z-scores using standards to adjust for age and sex differences. These scores were then adjusted for inter-family variation. There were significant differences among normal and affected individuals for all dimensions of body mass, as well as for several craniofacial and linear components of the body. Several significant differences were also found between normals and particular age cohorts of at-risk persons. HD gene carrier status was further assessed by factor analysis of the adjusted scores.     

Lower serum leptin concentrations in rugby players in comparison with healthy non-sporting subjects--relationships to anthropometric and biochemical parameters

Leptin is a protein hormone synthesized by adipocytes. Its serum concentrations reflect the total body fat content. Serum leptin concentrations are significantly higher in obese than in lean people and in women than in men. However little information about the influence of physical activity on serum leptin concentrations is available. We have compared the body weight, the body mass index (BMI), the body fat content (measured by caliper as skinfold thickness) and the serum concentrations of leptin, triglycerides, total, high density and low density lipoprotein (LDL) cholesterol in 14 top rugby players and 10 healthy controls. We found that serum leptin, total and LDL cholesterol concentrations were significantly lower in the rugby players group than in the control subjects. The body weight and BMI were significantly higher in the rugby players, while the body fat content was only slightly (non-significantly) higher in the control group. The serum leptin concentrations in both groups positively correlated with the BMI and body fat content and also with LDL concentrations in the control group. The serum leptin concentrations in the rugby players were lower than in the non-sporting subjects despite a similar body fat content in both groups. We would therefore suggest the possibility that regular hard physical training decreases serum leptin concentrations not only by the decrease of total body fat content, but also by a separate mechanism, which is not directly dependent on the changes in the amount of body adipose tissue.     

中国人群的体部指数

本文通过对63452例18～97岁的中国人体部12项指数值的统计分析,得出目前该年龄段中国人的体部形态特征。研究发现,中国人总体体型为长躯干型、中肩型、中骨盆型、中腿型。男性为中胸型,女性为宽胸型。随着年龄增长,上半身会显得更短一些,上半身与下半身比例更小一些,胸部更显宽厚一些,躯干下部显得更宽一些,腿显得更长一些。与南方族群相比,蒙古语族群、突厥语族群身体更壮实一些,胸部更显得宽厚一些,上身更高一些,上肢显得短一些,躯干的上部(肩部)相对窄一些,躯干的下部(骨盆)相对更宽一些,上肢长和下肢长度比例更小一些。研究还发现,同等身高的男性和女性相比,男性的上肢长度、下肢长度一般都小于女性,而女性比男性有一个更大的坐高值。从躯干长度来比较,女性确实比男性腿短一些。下身长相等的中国男性、女性之间相比,女性的坐高大于男性。同等身高情况下,中国人的坐高比欧亚人种、非洲人种的坐高要大,即有较高的上半身高度。     

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.     

The influence of estimated body segment parameters on predicted joint kinetics during diplegic cerebral palsy gait

Inverse Dynamic calculations are routinely used in joint moment and power estimates during gait with anthropometric data often taken from published sources. Many biomechanical analyses have highlighted the need to obtain subject-specific anthropometric data (e.g. Mass, Centre of Mass, Moments of Inertia) yet the types of imaging techniques required to achieve this are not always available in the clinical setting. Differences in anthropometric sets have been shown to affect the reactive force and moment calculations in normal subjects but the effect on a paediatric diplegic cerebral palsy group has not been investigated. The aim of this study was to investigate the effect of using different anthropometric sets on predicted sagittal plane moments during normal and diplegic cerebral palsy gait. Three published anthropometric sets were applied to the reactive force and moment calculations of 14 Cerebral Palsy and 14 Control subjects. Statistically significant differences were found when comparing the different anthropometric sets but variability in the resulting sagittal plane moment calculations between sets was low (0.01–0.07 Nm/kg). In addition, the GDI-Kinetic, used as an outcome variable to assess whether differences were clinically meaningful, indicated no clinically meaningful difference between sets. The results suggest that the effects of using different anthropometric sets on the kinetic profiles of normal and diplegic cerebral palsy subjects are clinically insignificant.     

Comparative study of anthropometric measurements of the same subjects in two different institutes

The objectivity of several anthropometric measurements were tested in two institutes on the same subjects. In many cases systematic differences are to be expected: 1. Girth measurements tend to differences in the same direction. 2. The comparability of skeletal measurements is often uncertain; some measurements tend to give lower, other ones higher figures. Biacromial diameter and radio-ulnar epicondylar width do not reveal systematic differences. 3. Skinfold thicknesses measured do not reveal systematic differences.     

中老年女性血清铁蛋白（SF）水平与年龄和体质指数（BMI）之间的关系的 流行病学研究

目的：评估中老年女性血清铁蛋白（SF）水平与年龄和体质指数（BMI）之间的关系。方法：选自中国4046 名健康女性进行横 断面研究，受试者年龄均在45-70 岁并签署了知情同意书。所有受试者血清铁蛋白水平采用放射免疫分析法测定。采用Spearman 秩相关检验分析血清铁蛋白与各指标之间的相关性。不同组别SF 差异的显著性用Kruskal-Wallis 秩和检验来比较。结果： Spearman 相关性分析显示血清铁蛋白与年龄（r = 0.425；p < 0.05）和BMI（r = 0.238；p < 0.05）均呈正相关。Kruskal-Wallis 秩和检 验显示不同年龄组和不同BMI组的血清铁蛋白水平均有显著性差异（p < 0.05）。65-70 岁人群的血清铁蛋白平均水平比45-50 岁 人群高出近两倍。并且肥胖人群中血清铁蛋白水平要远远高于偏瘦人群。结论：中老年女性铁储存的增加与年龄的增长和体质指 数的增加呈现正相关关系。     

Influence of anthropometric,ball impact and landing location parameters on serve velocity in elite tennis competition

This study aimed (i) to analyse the associations between serve velocity (SV) and anthropometric, ball impact and landing location parameters in total serves (TS) and fastest serves (FS) performed during an ATP Tour event; (ii) to observe differences between first (S1) and second (S2) serves, and (iii) to determine a SV prediction model based on the relationship between the observed variables. Using Foxtenn technology, 30 S1 and 15 S2 were registered in 14 matches in twenty-one male professional tennis players. Ball impact (impact height [IH], impact projection angle [IPA] and relative impact height [RIH]), bounce landing (width and depth) location parameters, S1 and S2 SV in TS (TSV1 and TSV2) and FS (FSV1 and FSV2) alongside anthropometric characteristics of tennis players (body height [BH], body mass [BM] and body mass index [BMI]) were analysed. Significant moderate to large associations were found between BH and BM and TSV1, FSV1 and FSV2 (r = 0.315 to 0.593; p < 0.001), and between IH and IPA and TSV1 and TSV2 (r = 0.294 to -0.409; p < 0.001). BH and BM were the unique significant contributors of FS explaining 22 to 35% of FSV1 and FSV2. Only BM appears in the model to predict FSV1 and FSV2 (r² = 0.48 and 0.21). We concluded that all three anthropometric, ball impact and bounce landing location parameters small to moderately influence TSV. Anthropometric parameters show an impact on SV when tennis players serve at or near maximal speed, highlighting the influence of BM above BH.     

Measurement of body segment mass,center of gravity,and determination of moments of inertia by double pendulum in Lemur fulvus

The collection of data on physical parameters of body segments is a preliminary critical step in studying the biomechanics of locomotion. Little data on nonhuman body segment parameters has been published. The lack of standardization of techniques for data collection and presentation has made the comparative use of these data difficult and at times impossible. This study offers an approach for collecting data on center of gravity and moments of inertia for standardized body segments. The double swing pendulum approach is proposed as a solution for difficulties previously encountered in calculating moments of inertia for body segments. A format for prompting a computer to perform these calculations is offered, and the resulting segment mass data for Lemur fulvus is presented.     

Modeling of body mass index by Newton's second law

Since laws of physics exists in nature, their possible relationship to terrestrial growth is introduced. By considering the human body as a dynamic system of variable mass (and volume), growing under a gravity field, it is shown how natural laws may influence the vertical growth of humans. This approach makes sense because the non-linear percentile curves of different aspects of human physical growth from childhood to adolescence can be described in relation to physics laws independently of gender and nationality. Analytical relations for the dependence of stature, measured mass (weight), growth velocity (and their mix as the body mass index) on age are deduced with a set of common statistical parameters which could relate environmental, genetics and metabolism and different aspects of physical growth on earth. A relationship to the monotone smoothing using functional data analysis to estimate growth curves and its derivatives is established. A preliminary discussion is also presented on horizontal growth in an essentially weightless environment (i.e., aquatic) with a connection to the Laird-Gompertz formula for growth.