How long your legs should be

Share on Pinterest Lunges. Share on Pinterest Bridges. Share on Pinterest Seated hamstring stretch. Share on Pinterest Downward dog. Share on Pinterest Squats. Other athletic activities. Can an inversion table make my legs longer? Is there a surgery to have longer legs?

Do legs grow after puberty? Read this next. Is Crossing Your Legs Dangerous? Medically reviewed by William Morrison, M. Medically reviewed by Deborah Weatherspoon, Ph. What Helps with Hip Replacement Recovery? Bone Graft. Medically reviewed by Catherine Hannan, M. What to Expect from Shoulder Replacement Surgery. Recommended Posts. Admin Posted January 26, Posted January 26, Link to comment Share on other sites More sharing options Replies Created 11 yr Last Reply 1 yr.

Top Posters In This Topic 1 2 1. Popular Posts kokodus June 19, Lynne July 17, Guest Troopercars Posted January 26, Guest suzushii Posted January 26, Guest yoosufan Posted January 26, My inseam is 74cm..

Guest myego Posted January 26, Guest sojuiicy Posted January 26, Mine is Guest vanessa Posted January 26, Guest missavvy Posted January 26, Relative to trunk length, humans have the longest legs and shortest arms. Credits, Homo sapiens , SlideWrite Plus, 4.

Long bone indices of Humans and Chimpanzees [ 20 ]. All indices are based on measurements of the maximum length of the long bones.

Human adult body proportions are brought about by differential growth of the body segments [ 21 ]. At birth, head length is approximately one quarter of total body length, while at 25 years of age the head is only approximately one-eighth of the total length.

There are also proportional changes in the length of the limbs, which become longer relative to total body length during the years of growth [ 22 ]. The cartoons of Figure 6 shows the typical changes that take place in people from birth to age 25 years. Human beings follow a cephalocaudal gradient of growth and development, the pattern common to most mammals.

There are, however, some species-specific features of human body plan development. In a classic article, Schultz [ 23 ] published his sketches of the body proportions of hominoid fetuses, reproduced here as Figure 7.

Another difference, not noted by Schultz, in proportion is the size of the cranium relative to the face, which is larger in the human fetus than in the chimpanzee, orangutan or gibbon. Changes in body proportion during human growth after birth.

Ages for each profile are, from left to right, newborn, 2 years, 6 years, 12 years, 25 years. This human pattern of change in body proportions during gestation to birth and then to adulthood may be explained, in part, by the evolution of bipedalism interacting with the evolution of a large and complex brain. Apes have a pattern of brain growth that is rapid before birth and relatively slower after birth.

Humans have rapid brain growth both before and after birth [ 24 , 25 ]. Human newborns are bigger brained than any of the apes, although not so much bigger in terms of brain-body mass ratio Table 2. More than brain mass, it is brain metabolic activity that is, perhaps, the crucial difference. With such high metabolic demands from its brain, the human infant and child may well have been naturally selected to make trade-offs in the allocation of limited nutrients, oxygen, and other resources required to grow the brain versus other body parts.

Trade-offs between the growth, development and maturation of body parts are common across the diversity of animal and plant life histories [ 27 — 29 ], including the human species [ 30 , 31 ]. From this perspective, the ultimate level reason that human leg growth is delayed during fetal and infant development is that it allows for rapid growth of the brain.

Neonatal and adult brain weight and total body weight for the great apes and human beings. Adult body weight is the average of male and female weight. Data from [ ]. The proximate level controls of the trade-offs in the growth of body segments and organs are not well known. Genetic, hormonal and nutrient supply factors are likely to be involved. In a review of bone growth biology Rauch [ 32 , p.

Longitudinal growth is controlled by systemic, local paracrine and local mechanical factors. With regard to the latter, a feedback mechanism must exist which ensures that bone growth proceeds in the direction of the predominant mechanical forces.

How this works is unknown at present. Quantitative trait locus QTL mapping of laboratory mice has identified genomic regions associated with phenotypic differences in length of the femur, tibia, humerus and ulna [ 34 ].

Changes in genomic growth regulation, such as Hox expression patterns are known to be associated with growth of primate forearm segments [ 35 ]. Changes in the sensitivity of bone growth plates to growth promoting and inhibiting factors at different times during development, and at different sites of the skeleton, are also known to be responsible for differential growth of body segments [ 36 , 37 ].

A further speculation is that blood circulation of the fetus may contribute to the brain-leg growth trade-off. Blood in the fetal ascending aorta has higher oxygen saturation than does the blood descending to the common iliac artery Figure 8. Additionally, the umbilical arteries carry some of the blood descending toward the leg back to the placenta. This pattern of fetal circulation is common to most mammals and is likely to be evolutionarily ancient.

Combined with the more recently evolved metabolic demands of the human fetal brain, the ancient circulatory pattern may leave the human fetal legs with reduced supply of oxygen and nutrients, further slowing leg growth and development compared with more cephalic regions of the body. We can find no experimental support for this proposal. There is human clinical case study evidence that increased blood flow to the limbs is associated with greater amount of growth [ 38 ].

Human fetal circulation, adapted from [ 39 ] The relative amount of oxygen in the fetal blood is greatest in the upper thorax, neck and head; indicated by the red color of the vessels ascending from the heart. Blood flowing to the abdomen and legs is less well oxygenated; indicated by the violet color of the vessels descending from the heart. The general pattern of human body shape development is a species-specific characteristic.

Historical artwork, sculpture and anatomical drawings from Renaissance Europe [ 40 , 41 ] and pre-Columbian Mexico[ 42 ] show fundamental commonalities in the depiction of body shape of late term fetuses, newborns and infants.

Discrete populations of living humans, however, present a diversity of body sizes and shapes. Mean stature for populations of adults varies from minimum values for the Efe Pygmies of Africa at There are also biologically and statistically significant variation between human populations in body shape. Eveleth and Tanner [ 45 , 46 ] published data for body proportions and leg length, estimated via the sitting height ratio, from dozens of human populations, distributed across most geographic regions of the world Figure 9.

The sitting height ratio SHR is a commonly used measure of body proportion. Measured stature minus sitting height may also be used to estimate leg length but this measure does not standardize for total height making it difficult to compare individuals with different statures. Mean SHR for populations of adults varies from minimum values, i. Sitting height ratio by age for the four geographic groups defined by Eveleth and Tanner [ 45 , 46 ].

Age 20 includes data for adults over the age of 18 years. Making sense of these world-wide comparisons is difficult because of the differences in lifestyle, environment, and genomics. Bergmann [ 47 ], in , observed that closely related mammalian species, such as bears, have greater body mass in colder climates.

Allen [ 48 ] added in 1, that the limbs and tails of such species tend to be shorter in cold climates and longer in warmer environments. Large body mass and relatively short extremities increase the ratio of volume-to-surface area and provide for a body shape that maximizes metabolic heat retention in a mammal.

Conversely, in warmer temperatures, relative long extremities increases surface areas relative to volume and allows for greater heat loss. It has been shown experimentally that mice and other non-human mammals raised in warmer temperature experience greater bone tissue growth and longer limb bones [ 49 ].

The usual explanation for this is greater vascularization, allowing for greater oxygen and nutrient perfusion. In , Roberts [ 50 ] published an analysis showing a significant relationship between body mass and latitude for human beings, with groups of people living at higher latitudes having greater body mass than those living closer to the equator.

Twenty-five years later, Roberts [ 51 ] updated and re-affirmed these findings. Other research shows that people living in colder regions also tend to have shorter limbs relative to total stature, compared with groups of people living in warmer regions [ 15 , 45 , 46 ].

These climate relationships, however, are not perfect. Katzmarzyk and Leonard analyze the sitting height ratio of human groups studied between and All of the human data analyzed by Roberts were collected prior to The slopes of the best fitting linear regression lines for the relation of mean annual temperature to sitting height ratio are half those reported by Roberts.

Katzmarzyk and Leonard p. In this case, during the years of growth and development more or less total food intake, more or less of any essential nutrient, more or less physical activity and the type of activity could influence body shape. Iodine deficiency during infancy and childhood results in reduced leg length, especially the distal femur, the tibia and the foot [ 54 ]. Maya children and adults spend considerable time and energy at heavy labor [ 55 ], which diverts available energy in the diet away from growth.

This nutrition and lifestyle combination is known to reduce total stature and leg length [ 56 ]. The body shape of people may have a genetic basis, especially for human groups who have resided in the same environment for many generations. A comparison of stature and body proportion between blacks African-Americans and whites European-Americans in the United States provides an example of genome-environment interactions and their affect on growth [ 57 ]. When the data are adjusted for differences between the two ethnic groups in income, education, urban or rural residence, and age, there is no significant difference in average height between black and white men.

Nor is there a significant difference in average height between black and white women. Although white and black adults in the United States have the same average stature, when education, income and other variables are controlled, the body proportions of the two groups are different.

Krogman [ 58 ] found that for the same height, blacks living in Philadelphia, USA had shorter trunks and longer extremities than whites, especially the lower leg and forearm. Hamill et al. A genomic contribution to the body proportion differences between blacks and whites seems likely, as the blacks tend to have more sub-Sahara African genomic origins than the whites. Few if any specific genes for human body proportions are known.

In a statistical pedigree analysis of two human samples, Livshits et al. These may be better described as familial effects because the authors analyzed families and also because they found significant common environmental effects for siblings as well as significant sex by age interactions. The range of the sources of variation in the analysis makes it difficult to compute simple genetic variance. At 40 weeks gestation, fetuses identified as African-Americans have, on average, relatively longer legs than fetuses identified as European-Americans [ 23 ].

In an analysis of the data shown in Figure 9 , Bogin et al. Discriminant function and cluster analysis shows, however, that coherence to groups defined by geographic origin is poor, with results barely better than chance. A more promising approach to understanding the control of human body proportions comes from genomic research. Hox genes and homeobox sequences, and a growing number of growth and signaling factors, are known to regulate the growth of body segments [ 66 ], and these genes are shared across all taxa.

There is observational and experimental evidence that Hoxd expression is linked with forearm, hand, and digit length differences in the apes [ 35 ]. The short stature homeobox-containing gene SHOX is another genomic region that may be relevant to human body proportions. Turner syndrome 45, XO karyotype results in approximately 20 cm deficit in stature. Some studies find that legs are disproportionately affected [ 68 , 69 ], but other studies find no disproportion [ 70 ].

More specific candidate genes for body shape are known from some non-human mammals [ 71 , 72 ] and in insects [ 27 ]. Another very active area of research is epigenetic regulation of body growth [ 73 ]. Epigenome effects may act through a number of genome e.

Plasticity refers to the concept that the development of the phenotype of an organism is responsive to variations in the quality and quantity of environmental factors required for life [ 74 ]. We employ this concept here to mean that during the years of growth and development, humans can grow more or less of various tissues and come to be adults of various sizes and shapes.

As adults these sizes and shapes are largely fixed, especially for total stature and the length of body segments.

Human growth is highly plastic during the years of growth and development, responding to the overall quality of living conditions [ 11 ].

From the perspective of developmental plasticity, leg length, both in terms of absolute size and relative to total stature, is an indicator of the quality of the environment for growth during infancy, childhood and the juvenile years of development.

The reason for this is the general principle that those body parts growing the fastest will be most affected by a shortage of nutrients, infection, parasites, physical or emotional trauma, and other adverse conditions. The cephalo-caudal principle of growth as applied to the human species means that the legs, especially the tibia, are growing faster relative to other body segments from birth to age 7 years.

Relatively short LL in adolescents and adults, therefore, is likely to be due to adversity during infancy and childhood leading to competition between body segments, such as trunk versus limbs and between organs and limbs. In the simplest case, such competition may be for the limited nutrients available during growth [ 31 , 56 , 61 ]. More complex explanations for competition relate to aspects of the thrifty phenotype hypothesis [ 75 , 76 ], the intergenerational influences hypothesis [ 77 , 78 ], the fetal programming hypothesis [ 79 ], and the predictive adaptive response hypothesis [ 80 , 81 ].

Discussion of these hypotheses is beyond the scope of this review [see reference 31 , and other articles in the same issue, for such discussion], but in essence each of these hypotheses predicts that the vital organs of the head, thorax, and abdomen of the body will be protected from adversity at the expense of the less vital tissues of the limbs.

Leitch [ 82 ] was the first medical researcher to propose that a ratio of LL to total stature could be a good indicator of the early life nutritional history and general health of an individual. Leitch p. One of the critical studies in her review is the Carnegie U.

Dietary and Clinical Survey, which recorded height, weight and iliac height IH. Leitch also reported that longer-legged children were also less susceptible to bronchitis, which was then a scourge of poorly fed children. Leitch was careful to state that leg length per se is not a direct cause of better or worse health and that children and adults with relatively short legs may be quite healthy. She viewed greater leg length as a correlate of an improved constitution.

This view anticipates current biomedical research on the development of somatic and cognitive reserve capacity [ 83 — 85 ] in relation to health and rate of senescence. By overshooting this necessary capacity an individual has reserve capacity which may be channeled into greater growth, better health, more successful reproduction, social and economic success, and slower rates of senescence.

Leg length relative to total stature may be one indicator of overall reserve capacity of a person or a group of people. In the past 10 years the number of publications on the relationship of leg length to human health has increased at a rapid rate. A systematic review of these studies is not provided here, instead we sample some of the literature to provide an overview of research. Table 3 summarizes several recent studies that show how leg length and body proportion ratios are powerful indicators of the quality of the environment and of the plasticity of the human body.

The table provides only a few studies, of which there are dozens. What is important to note is that regardless of the specific leg measure taken, longer LL is associated with better environments, better nutrition, higher SES, and better general health, overall. Summary of a few studies published since employing measures of leg length in relation to early life living conditions and health.

Poor childhood health, insufficient diet, adverse family circumstances and maternal smoking during pregnancy are each known to reduce leg length [ , — ]. But in men, shorter legs, the same length as the torso, are the most appealing. Tom Cruise, while shorter than his ex-wife, actually enjoys just such proportions. Researchers believe the attraction for long legs in women and shorter versions in men may have evolved for different reasons.

Long legs may be a sign of good health and good childbearing capabilities in women, while short legs may make men looked more muscular. Although there has been some research on the attractiveness of height, the new study by psychologists from Liverpool University and University College London has homed in on the ratio of leg and body length.

One such component, recognised in clinical research but neglected otherwise, is the leg-to-body ratio," they say.