Variation in Human Size and Body Proportions BPK303 Variation in Human Size and Body Proportions

Somatotype William Sheldon Photoscopic ratings based on listed criteria Endomorphy – Mesomorphy – Ectomorphy Ratings 1 to 7 3-4-3, 1-1-7, 2-6-2

Lindsay Carter & Barbara Heath-Roll Heath-Carter Anthropometric Somatotype Endomorphy (the first component) refers to relative fatness in physique. Mesomorphy (the second component) refers to relative development of the musculo-skeletal system. Ectomorphy (the third component) refers to relative linearity of physique. Ratings 0.5 to >7 Lindsay Carter & Barbara Heath-Roll circa 1983

Extreme Ectomorphy Dinka tribe of the Sudan are the most naturally ectomorphic ethnic group reported. Manute Bol former NBA player with his then team mate Spud Webb

Comparison of Mean Somatotypes of Female Ethnic samples Young Manus Females

KIN-Scale Proportionality Profile KIN-Scale data composed of data from Kin 303 students 2004-2011. Means and SEMs of z-values for KIN-Scale Males (n=230) and Females (n=336) Visual test of significance allows for a lot of information to be portrayed in one figure

Sexual Dimorphism in KIN-Scale subjects No difference in proportional weight Male-Female difference greatest in: Triceps, Biceps, Front Thigh and Medial Calf Skinfolds Secondary sexual adiposity

Sexual Dimorphism in KIN-Scale subjects

Representative Measures Muscle Mass Muscle X-sectional Area Skinfold-Adjusted Arm Girth – Muscularity Indicator Ga = G - (3.14xS) S G G Ga S = Skinfold Thickness G = Girth Ga = Skinfold adjusted Girth

Girth adjusted for Skinfold at that site s.a. Girth (cm) = Girth (cm) - (Π x Skinfold (mm) / 10) Girth Skinfold s.a. Arm girth Relaxed Arm Girth Triceps s.a. Chest girth Chest Subscapular s.a. Thigh girth Thigh Front Thigh s.a. Calf girth Calf Medial Calf s.a. Forearm girth Maximum Forearm Forearm

Sexual Dimorphism in KIN-Scale subjects s.a. Girths are Muscularity indicators Greatest differences between the sexes in the upper body Greatest potential for hypertrophy in the upper body Muscularity profile is very sensitive to the specific activity of the individual

Sexual Dimorphism in KIN-Scale subjects Proportionally larger sitting height in females Males tend to have proportionally longer limbs. Biggest difference in distal segments

Sexual Dimorphism in KIN-Scale subjects Humerus to Femur Width differences reflects muscularity differences Males have broader and deeper chests proportionally. Classic hip-shoulder dimorphism: Males proportionally wider shoulders Females have proportionally wider hips

Shoulder-Hip Dimorphism   Sex N Mean Std. Deviation Biacromial/Biiliocristal Breadth Male 69 1.44 0.12 Female 115 1.31

(2nd digit length to 4th digit length ratio) 2D:4D Ratio (2nd digit length to 4th digit length ratio) Sex N Mean Std. Deviation Male 136 0.947 0.029 Female 137 0.965 0.026 a Allison A. Bailey, Peter L. Hurda, Department of Psychology, University of Alberta. 2004 2D 4D

2D:4D Ratio Ratio determined in utero Larger ratio in females 2D:4D is negatively correlated with prenatal testosterone and positively correlated with prenatal estrogen Larger ratio in females Married women had higher 2D:4D ratios than unmarried women Significant negative associations were found between 2D:4D in men and reproductive success and significant positive relationships between 2D:4D in women and reproductive success Found to be related to: Aggression Competitive success Sexual orientation

Racial/Ethnic and Individual Differences Chinese South Asian European