Human Diversity

BioMechanics Class Presentation

Human DiversitySajid Khan

Image and Communication LabDept. of Electronics and Communication Engineering

BioMechanics Class Presentation

Contents

• Gender Difference(Male and female attributes)• Variation in Body Proportions• Variation in Strength

• Ethnic Differences• Growth and Development• Secular Trend(Alterations in measureable characteristics)• Social class and Occupation• Ageing

BioMechanics Class Presentation

Gender differences

• Stature• Related to body dimensions

and bodily proportions• Women are 7% shorter than

men

BioMechanics Class Presentation

Cont…

• Muscular strength• Women are 66% as strong as men

• Men exceeds women in all linear body dimensions except hip breadth

BioMechanics Class Presentation

Cont…

• Comparing strengths of men and women by selecting them randomly is called chance encounter• Differences of chance encounter (mean) and (standard Deviation) are

given as

=+• Descriptive index reflecting analysis of variances

BioMechanics Class Presentation

Variation in body proportion

• Men• Lengths of upper and lower limbs

• Women• Buttock-knee length• Proportion of fat(13.5% in men and 24.2% in women calculated in 1967)

• Head length or head breadth is same in both

BioMechanics Class Presentation

Variation in strength

• F/M ratio is 61%(close to two third)• Men shows a faster and greater increase in streangth than

women(Hettinger, 1961; Klafs and Lyon, 1978)• Due to difference of fat distribution and muscle bulk• Relative concentrations of sex hormones(androgens in male and progestogens

in female)• Testrosterone is produced in large quantities in men as compared to women

• Women having relatively high level of plasma testerone bulk up like men in response to intense weight training(Klafs and Lyon, 1978)

BioMechanics Class Presentation

BioMechanics Class Presentation

Ethnic Differences

• Population of individuals• Inhabit a specified geographical distribution• Certain physical characteristics

• Falls in few categories• Negroid• Caucasoid• Mangoloid

BioMechanics Class Presentation

BioMechanics Class Presentation

• Body size of varieties increases with decreasing mean temperature of the habitat(Bergman’s rule)• Size of exposed portions of the body decreases with decreasing

temperature(Alien’s rule)• Body weight is negatively correlated with mean annual

temperature(Roberts, 1973).

BioMechanics Class Presentation

Growth and Development

• At birth• Weight is 3.3 kg• Height is 500 mm

• Height increases rapidly till age of accelerates again till age of 14 (earlier in girls), then decelerates as maturity is approached

BioMechanics Class Presentation

BioMechanics Class Presentation

• Effects of age on bodily proportions• SH=sitting height• BK=buttock-knee length• KH=knee height• HL=head length• FL=foot length• BD=bideltoid breadth• BD=biacromial breadth• HB=hip breadth• for female• for male

BioMechanics Class Presentation

BioMechanics Class Presentation

The Secular Trend

• Alterations in measureable characteristics of a population with passage of time• Changes occurred during a century • Increase in rate of growth of children• Earlier onset of puberty• Increase in adult stature• Decrease in the age at which adult stature is reached

BioMechanics Class Presentation

• Approximate rate of change(For European countries from 1880 to 1960)• 15 mm per decade in stature• .5 kg per decade in weight at 5 to 7 years• 25 mm and 2 kg per decade during time of adolescence• 10 mm per decade in adult stature

BioMechanics Class Presentation

• Increased in stature observed for Japanese boys(between 1957 and 1967)• 31 mm at 6 years• 62 mm at 14 years• 33 mm at 17 years

• Decreased in stature observed for Japanese boys(between 1967 and 1977)• 17 mm at 6 years• 35 mm at 14 years• 19 mm at 17 years

BioMechanics Class Presentation

BioMechanics Class Presentation

BioMechanics Class Presentation

BioMechanics Class Presentation

Social Class and Occupation

• Population divided into five categoriesi. Professionalii. Intermediateiii. (A) Skilled non-manual

(B) Skilled manualiv. Semi-skilled manualv. Unskilled manual

BioMechanics Class Presentation

• According to survey done in Great Britain in 1984• Average stature of 1755 mm for men and 1625 mm for women in classes i and

ii• Average stature of 1723 mm for men and 1596 mm for women in classes iv

and v• Averages differ due to regional differences as well

BioMechanics Class Presentation

Ageing

• Age is also a factor to change parameters like body weight and stature

BioMechanics Class Presentation

BioMechanics Class Presentation

BioMechanics Class Presentation

BioMechanics Class Presentation