Body Segment Lengths Research Articles

Measurement of posture by triangulation using potentiometers

To measure the posture of a paraplegic while standing up, an economical method has been developed. Markers, glued over the joints, hook onto strings which run to rotary potentiometers mounted on a fixed frame. Springs maintain a near-constant small tension in the strings, and the potentiometers rotate as the strings wind onto pulleys. The positions are calculated by triangulation, using two potentiometers per joint, assuming that body segment lengths are constant, or three potentiometers without this assumption. Using a second-order polynomial fit, the random error in length measurement for each potentiometer is less than ±2 mm for the string length from 0 mm to 1100 mm, or less than ±1 mm in actual range from 600 mm to 1000 mm. With two potentiometers per joint, using a second-order polynomial fit and assuming the ankle position is known exactly, an estimate of the resulting errors in the knee and hip marker positions are 4 and 8.5 mm, respectively.

Size Dependence in Prosimian Locomotion and Its Implications for the Distribution of Body Mass

The mechanical requirements for arboreal life are reviewed and the constraints which these requirements impose on the body of a prosimian are defined. The mechanical necessities can be fulfilled only by animals which possess the appropriate morphological characters. It is incorrect to refer to these morphological traits directly as ‘adaptations’. Instead their a priori existence must be considered as the precondition for the acquisition of a certain life-style. Once such a life-style has been acquired, a strong selective pressure acts towards a further refinement of such ‘adaptations’ or ‘pre-adaptations’. Postcranial morphology must be seen in a context of following natural laws and is strictly related to the mechanics of posture and locomotion. The traits emphasised and explained here are body proportions – specifically the relative lengths of body segments and the distribution of (muscle) mass on these segments.

Cross-sectional survey of growth of urban and rural "cape coloured" schoolchildren: anthropometry and functional tests.

The patterns of physical growth (height, weight, length of body segments, circumferences, and widths) and function (grip strength, reflexes, and pulse rates) of "Cape Coloured" schoolchildren were studied. Urban and rural groups were selected with maximum contrasting socioeconomic status (SES). Data were collected between 1986 and 1988 and included 906 males and 1,068 females of high SES between 5 and 20 years in the Cape Town urban area and 834 males and 940 females of low SES between 5 and 19 years in the Little Karoo region. Means and standard deviations of 20 characteristics by age are presented separately for males and females and urban and rural groups. The heights and weights of prepubertal urban children match American reference data, but postpubertally they decline somewhat, whereas these measurements of the rural children consistently lie ∼1 standard deviation below the urban group. Skinfold thicknesses of urban children match or exceed the American reference, implying that their nutritional needs are being met well. Functional indicators of rural children are much poorer than those of urban children. The results of the urban children may provide a target for the improvement in growth status of rural children. Am. J. Hum. Biol. 10:73-85, 1998. © 1998 Wiley-Liss, Inc.

Ontogeny of locomotion in rhesus macaques (Macaca mulatta): I. Early postnatal ontogeny of the musculoskeletal system

Abstract This study compares age-related changes in linear dimensions of each body segment with simultaneous changes in its mass, and the location of its center of mass, in immature Macaca mulatta . Particular emphasis is placed on early post-natal development. Animals were flora the free-ranging colony on Cayo Santiago in Puerto Rico, and the exact age of each animal was known. Results of this study demonstrate that, although ontogenetic changes in mass and length of body segments follow the general pattern of increases being greatest to least in the trunk, hindlimb and forelimb, respectively, and greatest to least in the proximal to distal segments of each limb, there are also changes within individual segments. The most notable of the ontogenetic changes in the musculoskeletal system occurs during the first year of life, when there is a shift from the newborn pattern of a balance between the forelimb and hindlimb to the clear dominance of the propulsive mass of the hindlimb in the yearling.

Skeletal growth patterns of Thoroughbred horses

SUMMARY The influence of sex of foal and date of birth on growth rate from 14 – 448 days of age was examined in 106 Thoroughbred horses. An asymptotic regression model was used to compare the effect of sex of foal and date of birth on body size at 14 d of age and at maturity. Rates of gain in body weight and body segment lengths were similar to those reported in the literature. Colts were similar is size to the fillies at 14 d of age, however the colts grew at a faster rate than the fillies. Estimated hip height, body length, depth of girth and width of chest at maturity were greater (P

Relationships among anthropometric and stroking characteristics of college swimmers

A theoretical model was developed to identify anthropometric variables relevant to success in swimming. Frontal areas, cross-sectional areas (XSA), and lengths of body segments were measured on twelve members of a men's college team using a photographic procedure. Motion-picture films were taken of the subjects competing in freestyle events and were analyzed to determine the average stroke length (SL), average stroke frequency (SF), and average stroking speed (S). Correlation and multiple regression procedures were used to determine the relationships among the anthropometric variables and SL, SF, and S, respectively. Of the 21 anthropometric variables selected with the aid of the theoretical model, 6 were found to be significantly related to one or more of the measures of swimming performance when the influence of event distance was partialled out (P less than or equal to 0.05). The anthropometric variables characterizing the subjects accounted for 89% (SL), 41% (SF), and 17% (S) of the variances in the measured characteristics of their strokes. The axilla XSA was shown to have the largest influence on both SL and SF, accounting for 57% of the variance in the SL and 24% in the SF. These results suggest that although S is little influenced by the physique of a swimmer, the combination of SL and SF used to attain a given S is very much a function of his physique.

A Multivariate Method of Classif in Bod Form Variation for Sizing Women's Apparel

The purpose of this study was to develop a multivariate method for structuring a sizing system for women's apparel. The I 977 suvey of U.S. Army women was the data base. The sample was limited to 1217 subjects who were White or Black and 17-3 5 years old. The methodology underlying PS 42-70, the current U.S. sizing standard, was studied relative to recent changes in body form classification, apparel production, and merchandising which support development of multivariate methodology. Examination of PS 42-70 as a classification system for the sample showed inadequate proportioning of overall body dimensions, particularlyshoulder breadth and body segment lengths. The experimental method used components 1 and 2 to summarize body form variation as the relationship between body thickness and length. A Principal Component Sizing System (PCSS) was constructed by partitioning the distribution of principal components 1 by 2 into 26 sizes. A per subject comparison of "goodness of fit" of PS 42-70 and PCSS showed PCSS consistently closer to subjecfs' overall body proportions than PS 42-70. The multivariate relationship between body thickness and length is fundamental to body form and size variation. Our results indicate that PCSS better represents that relationship for the sample studied.

Determination of 3D human body postures from a single view

In this paper a method is proposed to recover and interpret the 3D body structures of a person from a single view, provided that (1) at least six feature points on the head and a set of body joints are available on the image plane, and (2) the geometry of head and lengths of body segments formed by joints are known. First of all, the feature points on the head in the head-centered coordinate system and their image projections are used to determine a transformation matrix. Then, the camera position and orientations are extracted from the matrix. Finally, the 3D coordinates of the head points expressed in the camera-centered coordinate system are obtained. Starting from the coordinates of the neck, which is a head feature point, the 3D coordinates of other joints one-by-one are determined under the assumption of the fixed lengths of the body segments. A binary interpretation tree is used to represent the 2 n − 1 possible body structures, if a human body has n joints. To determine the final feasible body structures, physical and motion constraints are used to prune the interpretation tree. Formulas and rules required for the tree pruning are formulated. Experiments are used to illustrate the pruning powers of these constraints. In the two cases of input data chosen, a unique or nearly unique solution of the body structure is obtained.

Scaling segmental moments of inertia for individual subjects

The purpose of this investigation was to validate methods of scaling human segmental moments of inertia for the transverse principal axis. Firstly, two methods of scaling Chandler et al.'s (Pamphlets DOT HS-801 430 and AMRL TR-74-137, Wright Patterson Air Force Base, OH, 1975) mean subject data to estimate the segmental moments of inertia were used. Chandler et al.'s data were scaled using body mass and segment length (formula 1) or body mass and standing height (formula 2). These data were then compared with a procedure of using the cadaver whose anthropometric measurements most closely match those of the subject. The difference between the criterion data (Chandler's subject data) and scaled values were plotted on scatter diagrams with confidence limits of p < 0.05 at d. f. = 17. For procedure 1, 43% of the scaled values were plotted within the confidence limits using formula (2) (mass and standing height), compared with 26% for formula (1) (mass and segment length). Formula (1) markedly underestimated the tallest and heaviest subjects. In procedure 2, only 16% and 21% of the scaled values, using formula (1) and (2), respectively, fell within the confidence limits. Results suggested that scaling formulae approximate the moment of inertia of body segments with only limited accuracy. However, if scaling was to be adopted then mean moment of inertia data from an appropriate data set, using the formula that incorporates subject mass and standing height, gave results closest to the criterion value.

Some factors pertinent to the organization and control of arm movements

Trajectories of arm movement during a pointing task were shown to be unaffected by large loads. Moreover, when the effective arm length was changed, the target was still approached along a direct trajectory. It is concluded that: (1) compensation for load occurs automatically without affecting those constraints on the basis of which movements are organized; (2) that the effective lengths of body segments as well as joint angles constitute variables utilized in the organization of trajectories.

Reliability of a Measure of Forward Flexibility and its Relation to Physical Dimensions of College Women

Abstract The reliability of the bend and reach test as a measure of spinal forward flexibility was investigated together with its relationship to selected body measurements of 100 freshman college women. Reliability coefficients on four consecutive trials and the best trial ranged from .86 to .98. Significant differences existed between the means of best trial and trials one and two, with nonsignificance between the means of best trial and trials three and four. Nonsignificant r's were obtained between flexibility scores and length of body segments. Nonsignificant t's were obtained between the means of flexibility scores of the extreme groups when these groups were determined by segmental relationships, trunk plus arm minus leg, and the ratio of trunk plus arm over leg.

Relationship of Flexibility Measurements to Length of Body Segments

Abstract Measurements on the Wells and Dillon sit-and-reach flexibility test and measurements of leg length and of trunk length plus arm length were made on 116 college men. Measurements of prone back extension flexibility, of supine back extension flexibility, and of upper body length were made on 62 college men. Analysis of the data by correlation techniques and by application of the t test to upper and lower groups indicated: (a) no significant relationship between sit-and-reach flexibility and leg length, (b) a significant relationship between sit-and-reach flexibility and excess of trunk plus arm length over leg length, (c) no significant relationship between prone back extension flexibility and upper body length, and (d) no significant relationship between supine back extension flexibility and upper body length.

Relationship of Selected Measures of Acting Body Levers to Ball-Throwing Velocities

Abstract The purpose of the study was to determine the relationship between selected measures of body levers contributing to throwing and the ball velocities achieved in the overhand and underhand throws. Motion picture data were obtained of the throwing performance of 42 high school girls, arranged in three groups on the basis of differences in initial throwing velocity achievement. Structure length and moment-arm measures of acting body levers for trunk rotation, medial rotation and flexion of the arm, and flexion of the wrist were studied. These subjects demonstrated a pattern of acting lever length contribution to overhand throwing velocity. Moment-arm measures of acting levers were found to have considerable predictive power relative to the overhand throwing velocity achieved. A similar relationship was not found between structure-length measures and overhand throwing velocity. Results with the underhand throws indicated that neither length of body segments nor the position of the acting lever at the...

Hip Flexibility of Elementary School Boys as Related to Body Segments

Abstract One hundred and fifty-eight male pupils in elementary school were measured on two hip flexibility tests and several anthropometric measures. The primary purpose was to determine the relationship among the flexibility tests in the anteroposterior plane and the selected anthropometric measures. Results indicate that: (a) no significant relationship exists between flexibility of the hip joint and length of body segments; (b) satisfactory objectivity coefficients were obtained for the flexibility tests and measures of body length; (c) examination of the extremes of the distribution of lower limb length seems to support the fact that flexibility is independent of lower limb length; (d) 46.8 percent of the subjects failed the Wells Sit and Reach Test, while 54.4 percent could not pass the Adapted Kraus-Weber Floor Touch Test.

Hip Flexibility of College Women as Related to Length of Body Segments

Abstract Sixty-six college women were measured on three hip flexibility tests, an Adapted Kraus-Weber Floor Touch Test, Leighton Flexometer, and Wells Sit and Reach. The purpose of the study was to determine the relationship between the three selected tests of hip flexibility in the antero-posterior plane and the following anthropometric measures: distance from greater trochanter to floor, standing reach, and standing height. Results indicate: (1) No significant relationship between the flexibility of the hipjoint in the antero-posterior plane and the length of body segments; (2) The Adapted Kraus-Weber is the most objective of the three flexibility tests; (3) The Wells Sit and Reach and Adapted Kraus-Weber tests correlate .95.