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Leg Length (leg + length)
Selected AbstractsLeg length and age of puberty among men and women from a developing population: The Guangzhou Biobank Cohort studyAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2010C.M. Schooling Objectives: Leg length and relative leg length are considered to be reliable markers of prepubertal living conditions. Cessation of leg growth, driven by estrogen, occurs earlier in puberty in girls than boys. We hypothesized that leg length and relative leg length, as sitting height to leg ratio, might have sex-specific associations with age of puberty. Methods: We used multivariable linear regression in 10,046 older (,50 years) Chinese from the Guangzhou Biobank Cohort Study (Phase 3) to examine the associations of recalled age of puberty (women: age of menarche, and men: mean age of first nocturnal emission, voice breaking, and first pubic hair) with subischeal leg length, sitting height to leg ratio, and sitting height. Results: Leg length and sitting height to leg ratio had different associations with age of puberty in men and women (P -values for interaction <0.001), but sitting height did not. Per year earlier puberty, legs were longer among men by 0.09 cm (95% confidence interval (CI) 0.01,0.18) and shorter among women by ,0.16 cm (95% CI ,0.20 to ,0.12). Further adjustment for age, hip size (as a marker of buttock fat), and several markers of childhood conditions did not obviate the difference in association by sex. Conclusions: Adult leg length and relative leg length (sitting height to leg ratio) may be biomarkers of different exposures in men and women, with corresponding implications for their interpretation as a biomarker of early life exposures. Am. J. Hum. Biol. 22:683,687, 2010. © 2010Wiley-Liss, Inc. [source] The effects of morphology and substrate diameter on climbing and locomotor performance in male spidersFUNCTIONAL ECOLOGY, Issue 2 2010John Prenter Summary 1.,Spiders are the most sexually size dimorphic terrestrial animals and the evolution of this dimorphism is controversial. Patterns of sexual size dimorphism (SSD) in spiders have been related to individual performance and size. In 2002 Moya-Laraño, Halaj & Wise proposed the ,gravity hypothesis' to explain patterns of sexual size dimorphism in spiders whereby species building webs high in the vegetation are predicted to show greater SSD than those that build lower down. They advocated an advantage in climbing speed in smaller males searching for females in high places. The gravity hypothesis predicts a negative relationship between male size and climbing speed. In 2007 Brandt & Andrade questioned this interpretation and proposed that the pattern of SSD in spiders is better explained by an advantage for larger males of low-dwelling species to run faster along the ground. 2.,We induced male spiders to run a standard distance up vertical poles of different diameters to examine the predicted relationship between size and climbing speed. We tested two species of extremely size-dimorphic orb-web spiders, Argiope keyserlingi and Nephila plumipes, that differ in the height at which females tend to build webs, and one species of jumping spider, Jacksonoides queenslandica, with low levels of size dimorphism. We also examined morphological determinants of horizontal motility by inducing males to run along a raceway. 3.,Substrate diameter was consistently found to influence climbing performance. In N. plumipes, climbing speed was slowest on the widest diameter substrate. In A. keyserlingi, size-adjusted leg length and substrate diameter interacted to determine climbing speed, while in J. queenslandica, there was an interaction between body size and substrate diameter on climbing speed. In the effect of substrate diameter, we have identified a potential bias in previous tests of the gravity hypothesis. 4.,Our results do not support the prediction of the gravity hypothesis. There was no evidence of a negative relationship between body size and climbing speed in the two orb-web species with high levels of SSD. Our results are also not consistent with a recent modification of the gravity hypothesis that suggests a curvilinear relationship between climbing speed and size. 5.,Body size was positively associated with maximum running speed only in the cursorial hunter J. queenslandica. For this spider, results are more consistent with Brandt & Andrade's explanation for variation in SSD in spiders, that larger males are selected for superior running ability in low-dwelling species, rather than selection for smaller size for climbing to females in high-dwelling species. [source] Metabolic correlates of leg length in breeding arctic shorebirds: the cost of getting highJOURNAL OF BIOGEOGRAPHY, Issue 3 2005Ralph V. Cartar Abstract Aim, We test the hypothesis that tarsus length in all shorebirds breeding in the Canadian arctic shows an evolutionary response to average metabolic stress encountered across the breeding range, such that birds nesting in metabolically stressful environments have relatively shorter legs. Longer-legged birds living in colder environments will experience greater metabolic costs because their torsos are elevated farther away from the ground's wind-dampening boundary layer. Methods, We use weather data (temperature, wind speed, global solar radiation) from 27 arctic weather stations measured over 37 years, and a previously published model of heat transfer, to characterize the metabolic harshness over the breeding season of the ranges of each of the 17 shorebirds of the family Charadriidae nesting in the Canadian arctic. Results, After controlling for the lengths of two other body extremities (wing and bill), there was a significant negative relationship between tarsus length and mean metabolic harshness. This result was obtained whether species were treated as independent data points, or in a comparative analysis using standardized independent contrasts. Main conclusions, We support a unique extension of Allen's rule: body-supporting appendages of homeotherms may be shorter in colder environments so as to take advantage of a boundary layer effect, thereby reducing metabolic costs. [source] Peak Bone Mass After Exposure to Antenatal Betamethasone and Prematurity: Follow-up of a Randomized Controlled Trial,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 8 2006Stuart R Dalziel Abstract Small birth size is associated with reduced adult bone mass. We determined if antenatal betamethasone exposure, birth weight, or prematurity affects peak bone mass in 174 adults. Antenatal betamethasone exposure did not. Lower birth weight and prematurity predicted reduced adult height. Slower fetal growth rather than prematurity predicted lower bone mass, but this lower bone mass was appropriate for reduced adult height. Introduction: Small size at birth is reported to be associated with lower bone mass in adulthood. However, previous studies have not distinguished the relative contributions of length of gestation and fetal growth to size at birth. Fetal exposure to excess glucocorticoids has been proposed as a core mechanism underlying the associations between birth size and later disease risk. Antenatal glucocorticoids are given to pregnant women at risk for preterm delivery for the prevention of neonatal respiratory distress syndrome in their infants. We determined the relationship of antenatal exposure to betamethasone, birth weight, and prematurity to peak bone mass and femoral geometry in the adult survivors of the first randomized trial of antenatal glucocorticoids. Materials and Methods: We studied 174 young adults (mean age, 31 years) whose mothers participated in a randomized trial of antenatal betamethasone. Mothers received two doses of intramuscular betamethasone or placebo 24 h apart. Two thirds of participants were born preterm (<37 weeks gestation). We measured indices of bone mass and size and derived estimates of volumetric density and bone geometry from DXA assessments of the lumbar spine, femur, and total body. Results: There were no differences between betamethasone-exposed and placebo-exposed groups in any of the lumbar spine, femur, or total body DXA measures. There was no effect of antenatal betamethasone on adult height, although leg length was increased relative to trunk length (p = 0.002). A lighter birth weight (p , 0.001) and lower gestational age (p = 0.013) were associated with shorter stature (height Z scores) at age 31 years. Prematurity had no effect on peak bone mass or femoral geometry. However, lower birth weight, independent of gestational age, was associated with lower later bone mass (p < 0.001 for lumbar spine and total body, p = 0.003 for femoral neck BMC). These effects on bone mass were related to bone size and not to estimates of volumetric density. In the femur, lower birth weight, independent of gestational age, was associated with narrowing of the upper shaft and narrow neck regions. Conclusions: Antenatal betamethasone exposure does not affect peak bone mass or femoral geometry in adulthood. Birth weight and prematurity predict adult height, but it is slower fetal growth, rather than prematurity, that predicts lower peak bone mass. The lower peak bone mass in those born small is appropriate for their adult height. [source] Heterogeneity in the Growth of the Axial and Appendicular Skeleton in Boys: Implications for the Pathogenesis of Bone Fragility in MenJOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2000Michelle Bradney Abstract Men with spine fractures have reduced vertebral body (VB) volume and volumetric bone mineral density (vBMD). Men with hip fractures have reduced femoral neck (FN) volume and vBMD, site-specific deficits that may have their origins in growth. To describe the tempo of growth in regional bone size, bone mineral content (BMC), and vBMD, we measured bone length, periosteal and endocortical diameters, BMC, and vBMD using dual-energy X-ray absorptiometry in 184 boys aged between 7 and 17 years. Before puberty, growth was more rapid in the legs than in the trunk. During puberty, leg growth slowed while trunk length accelerated. Bone size was more advanced than BMC in all regions, being ,70% and ,35% of their predicted peaks at 7 years of age, respectively. At 16 years of age, bone size had reached its adult peak while BMC was still 10% below its predicted peak. The legs accounted for 48%, whereas the spine accounted for 10%, of the 1878 g BMC accrued between 7 and 17 years. Peripubertal growth contributed (i) 55% of the increase in leg length but 78% of the mineral accrued and (ii) 69% of the increase in spine length but 87% of the mineral accrued. Increased metacarpal and midfemoral cortical thickness was caused by respective periosteal expansion with minimal change in the endocortical diameter. Total femur and VB vBMD increased by 30,40% while size and BMC increased by 200,300%. Thus, growth builds a bigger but only slightly denser skeleton. We speculate that effect of disease or a risk factor during growth depends on the regions maturational stage at the time of exposure. The earlier growth of a regions size than mass, and the differing growth patterns from region to region, predispose to site-specific deficits in bone size, vBMD, or both. Regions further from their peak may be more severely affected by illness than those nearer completion of growth. Bone fragility in old age is likely to have its foundations partly established during growth. [source] Sexual selection is not the origin of long necks in giraffesJOURNAL OF ZOOLOGY, Issue 4 2009G. Mitchell Abstract The evolutionary origin of the long neck of giraffes is enigmatic. One theory (the ,sexual selection' theory) is that their shape evolved because males use their necks and heads to achieve sexual dominance. Support for this theory would be that males invest more in neck and head growth than do females. We have investigated this hypothesis in 17 male and 21 female giraffes with body masses ranging from juvenile to mature animals, by measuring head mass, neck mass, neck and leg length and the neck length to leg length ratio. We found no significant differences in any of these dimensions between males and females of the same mass, although mature males, whose body mass is significantly (50%) greater than that of mature females, do have significantly heavier (but not longer) necks and heavier heads than mature females. We conclude that morphological differences between males and females are minimal, that differences that do exist can be accounted for by the larger final mass of males and that sexual selection is not the origin of a long neck in giraffes. [source] Leg length and age of puberty among men and women from a developing population: The Guangzhou Biobank Cohort studyAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2010C.M. Schooling Objectives: Leg length and relative leg length are considered to be reliable markers of prepubertal living conditions. Cessation of leg growth, driven by estrogen, occurs earlier in puberty in girls than boys. We hypothesized that leg length and relative leg length, as sitting height to leg ratio, might have sex-specific associations with age of puberty. Methods: We used multivariable linear regression in 10,046 older (,50 years) Chinese from the Guangzhou Biobank Cohort Study (Phase 3) to examine the associations of recalled age of puberty (women: age of menarche, and men: mean age of first nocturnal emission, voice breaking, and first pubic hair) with subischeal leg length, sitting height to leg ratio, and sitting height. Results: Leg length and sitting height to leg ratio had different associations with age of puberty in men and women (P -values for interaction <0.001), but sitting height did not. Per year earlier puberty, legs were longer among men by 0.09 cm (95% confidence interval (CI) 0.01,0.18) and shorter among women by ,0.16 cm (95% CI ,0.20 to ,0.12). Further adjustment for age, hip size (as a marker of buttock fat), and several markers of childhood conditions did not obviate the difference in association by sex. Conclusions: Adult leg length and relative leg length (sitting height to leg ratio) may be biomarkers of different exposures in men and women, with corresponding implications for their interpretation as a biomarker of early life exposures. Am. J. Hum. Biol. 22:683,687, 2010. © 2010Wiley-Liss, Inc. [source] Maturity-related differences in physical activity among 10- to 12-year-old girlsAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 1 2010Clemens Drenowatz Besides environmental and psycho-social factors explaining the variation in physical activity levels during adolescence, some evidence suggests that biological processes are involved in regulating habitual daily physical activity and energy expenditure. The purpose of this study was to examine the influence of biological maturity status on physical activity. Chronological age, standing height, sitting height, and body mass were measured cross-sectionally in 268 girls, aged 9.5 to 11.5 years. Biological maturity groups (Early, Average, Late) were created according to estimated age at peak-height-velocity (estAPHV). Habitual physical activity was determined with a pedometer (Yamax Digiwalker SW-200) over a 7-day period. Differences in steps/day across maturity groups were examined by ANCOVA, controlling separately for time the pedometer was worn, leg length, and body mass. Mean pedometer steps/day was 10,822 ± 2,639. As expected, body size varied by maturity status (e.g., early > average > late). Significant maturity group differences were found with early maturing girls showing lower activity levels compared to average or late maturers. These differences remained after controlling for time the pedometer was worn and leg length; however, the differences were no longer significant when controlling for body mass. The results suggest that biological maturity status influences physical activity levels in girls between 10 and 12 years of age but the relationship is not independent of body mass. Further research is needed to establish the complex inter-relationships among adiposity, biological maturation, and energy expenditure during puberty. Am. J. Hum. Biol., 2010. © 2009 Wiley-Liss, Inc. [source] Socioeconomic variation in the growth status of urban school children 6,13 years in Oaxaca, Mexico, in 1972 and 2000AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 6 2009Robert M. Malina Socioeconomic variation in the growth status of urban school children 6,13 years of age in 1972 and 2000 was compared. The children were resident in the city of Oaxaca and were students in the same primary school in each year. Socioeconomic status (SES) was based on parental occupation. Height, sitting height, estimated leg length, weight, and the body mass index in 218 boys and 191 girls in 1972 and 173 boys and 166 girls in 2000 were compared. Sex-specific MANCOVA was used to evaluate SES differences within each year, while sex- and SES-specific MANCOVA was used to evaluate differences between years. The prevalence of stunting, overweight and obesity was estimated. There were no SES differences among boys and girls in 1972 and boys in 2000; low-middle and middle SES girls were significantly taller and heavier with longer legs than low SES girls in 2000. Within each SES group, children in 2000 were significantly larger in body size and segment lengths except for sitting height in low SES children of both sexes. Estimated secular gains increased from low to low-middle to middle SES in both sexes. Inequitable gains by SES contributed to an increase in the magnitude of differences between SES groups, especially between low SES children on one hand and low-middle and middle SES children on the other hand. The prevalence of stunting declined while the prevalence of overweight and to a lesser extent in obesity increased from 1972 to 2000, more so in low-middle and middle SES than in low SES children. Am. J. Hum. Biol. 2009. © 2009 Wiley-Liss, Inc. [source] Nutritional, developmental, and genetic influences on relative sitting height at high altitude,AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2009Sara Stinson The study explores how nutritional status, developmental exposure to high-altitude hypoxia, and genetic ancestry influence relative sitting height in two groups of high-altitude Bolivian children aged 8 through 13 years of age: 253 rural Aymara children of very low socioeconomic status and 273 children of upper socioeconomic status from the capital city of La Paz. The rural Aymara children on average have longer trunks relative to stature, but there is also overlap in body proportions between the two groups of children. The 20% of each sample in the region of overlap was examined to investigate influences on relative sitting height. Nutritional effects on relative sitting height are suggested by the finding that Aymara children with relatively long legs are taller, heavier, and fatter than other Aymara children. Developmental and genetic influences on relative sitting height are suggested by the finding that high relative sitting heights in elite urban children are associated with a greater percentage of time lived at high altitude and with parents born in Bolivia. Separating developmental and ancestry effects is difficult because the two are closely interconnected in the urban children. The results of this study suggest that influences on growth in relative trunk and leg length are similar to those that affect other aspects of growth in Andean populations. They also highlight the fact that because relative sitting height gradually decreases prior to adolescence and then increases, the interpretation of variation in body proportions in children is not always straightforward. Am. J. Hum. Biol. 2009. © 2009 Wiley-Liss, Inc. [source] Height and relative leg length as indicators of the quality of the environment among Mozambican juveniles and adolescentsAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 2 2009Cristina Padez The growth status of Mozambique adolescents was assessed to test the hypothesis that relative leg length is a more sensitive indicator of the quality of the environment than the total height. The sample comprised 690 boys and 727 girls, aged between 9 and 17 years, from Maputo. It is divided between those living in the Centre of Maputo and those living in the slums on the periphery of the city. Height, weight, and sitting height were measured and the sitting height ratio was calculated. The hypothesis that relative leg length is more sensitive than total stature as an indicator of environmental quality is not uniformly confirmed. Overall, mean stature is greater for the centre group than the slum group, but relative leg length as measured by the sitting height ratio does not differ. Compared with African-American references (NHANES II), all centre girls, 9- to 14-year-old slum girls, all slum boys, and the oldest centre boys show relatively shorter legs. These findings show that within the Mozambique sample, relative leg length is not sensitive enough to distinguish the quality of the living environment. Mozambique was a colony of Portugal until 1975. Civil unrest and warfare characterized the late Colonial period and the postindependence period until a peace settlement was concluded in 1992. It is possible that all socioeconomic status groups within the country suffered sufficiently to reduce relative leg length compared with the better-off African-American reference sample. Possible genetic influences on relative leg length are also discussed. Am. J. Hum. Biol. 2009. © 2008 Wiley-Liss, Inc. [source] The medial and lateral bellies of gastrocnemius: A cadaveric and ultrasound investigationCLINICAL ANATOMY, Issue 1 2008Tony Antonios Abstract It is commonly reported that the medial belly (MG) of the gastrocnemius muscle extends further distally than the lateral belly (LG). This observation is made in several standard anatomy texts with no explanation or quantitative data. In this study, the medial and lateral bellies of gastrocnemius in 45 embalmed cadavers were measured. The observed difference in length of the two bellies was found to be highly significant (mean difference in length = 1.74 cm, P < 0.001). In 8 out of 84 legs examined (9.5%), however, the MG was found to be shorter than the LG (three right legs, five left legs, bilateral in two individuals). Surprisingly, there was no correlation between the difference in muscle belly length in any individual and ipsilateral leg length or total body length, suggesting that the difference in belly length may be unrelated to biomechanical function. An ultrasound investigation into the activity pattern of the two bellies was carried out on five volunteers. Muscle activity was monitored during passive and active movements of the ankle and knee joints at different leg positions. During knee flexion and ankle plantarflexion, the LG contracted first in four of the five subjects, followed by the MG, then a period of either LG predomination or equal contraction. The fifth subject, who showed a reversed pattern of activity, had previously suffered an inversion injury of the ankle. We suggest that the initial activation of the LG may help to stabilize the ankle during plantarflexion. We found no evidence that gastrocnemius acts as a shunt muscle during distraction of the knee. Clin. Anat. 21:66,74, 2008. © 2007 Wiley-Liss, Inc. [source] Knee-heel length measurements in preterm infants: evaluation of a simple electronically equipped instrumentACTA PAEDIATRICA, Issue 2 2003E Engström Aim: To compare and evaluate a mini-knemometer with a simple and inexpensive electronic caliper with regard to precision, handling error (technical error) and estimation of growth velocity. Methods: Thirty-five prematurely born infants, with a median gestational age of 29 (range 24,33) wk and a median birthweight of 960 (range 480,2480) g, were measured on 409 different occasions with both instruments. On each occasion, five independent readings were made. Results: There was no significant difference in precision between the two instruments, when measuring growth velocity over a 4 wk period (median 0.41, range 0.10,0.59 mm d,1). The handling error in this study, calculated as the mean standard deviation, was 0.36 (SD 0.18, coefficient of variation 0.38%) mm for the simple electronic caliper and 0.59 mm for the mini-knemometer. Short-term growth was detectable within 2 d when growth velocity was normal. Conclusion: Longitudinal measurement of lower leg length is a gentle and useful complementary method for assessing growth in preterm infants. An inexpensive electronic caliper is well suited for routine use in clinical practice, with measurements taken once or twice a week. [source] | |||||||||||||