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BPK 303. Assessment of Body Proportions. Fall 2013. Height Distance & Velocity Curves. Adolescent growth spurt growth most rapid in first two years. Height Velocity Curves. Indicator of maturity Needs longitudinal data Other “systems” have similar curves. Upper Arm Maturity Gradient.
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BPK303 Assessment of Body Proportions Fall 2013
Height Distance & Velocity Curves • Adolescent growth spurt • growth most rapid in first two years
Height Velocity Curves • Indicator of maturity • Needs longitudinal data • Other “systems” have similar curves
Adult proportions are a result of complex genetic and environmental influences MaturityGradients
Quantifying Proportions • Allometry • a general assessment • Phantom • a detailed assessment
Allometry • Growth of one part in relation to the growth of another part • Isometry - same proportions maintained during growth (same shape)
Physical Dimensions [L] = Length [T] = Time [M] = Mass
VELOCITY = DISTANCE / TIME = [L]/[T] = [L]1[T]-1
Geometrical Similarity System with increase or decrease in size there is no change in shape or body composition
Geometrical Similarity System Length = [L]1 Mass = [L]3 Time = [L]1
VELOCITY = DISTANCE / TIME = [L]1/[L]1 = [L]1[L]-1 = [L]0
Huxley’s Allometric Curve Y = aXb
Huxley’s Allometric Curve Log10Y = log10a + blog10X Curve is linearized by “logging” both sides “b-value” is used to describe relative growth
Human Architecture Growth - longitudinal As children grow they tend to become more linear, less weight for height Head becomes proportionally smaller Limbs become proportionally longer Adult – Cross-sectional Tall more linear (less ponderous) Tall proportionally longer limbs Tall proportionally weaker
Allometric Analysis Geometrical Expectancy Slope = b = yd/xd Log10 Y [L]yd Actual Data Slope = b = ? Log10 X [L]xd
Doryphorus (Spearbearer) • Polykleitos (750 BC ) • Canon of ideal proportions • Combination of the best parts of 23 men
Da Vinci’s Vitruvian Man • Canon of perfect proportions • eg Navel is the centre of the circle described by the hands at head height and the feet when legs describe an equilateral triangle
Standard Score z-score (x - mean) / standard deviation
Phantom Formula • standard score in comparison to a unisex reference • proportionality score
Geometrical Similarity System with increase or decrease in size there is no change in shape or body composition
Geometrical Scaling d = 1 for linear measures [L]1 (lengths, skinfolds etc) d = 2 for measures of dimension [L]2 (areas, strength) d = 3 for measures of dimension [L]3 (weight, volumes) & weight)
Interpretation of z-values • Phantom is not a norm • Proportionally bigger (+) or smaller (-) than the Phantom (so what?) • Compare z-values
Bivariate Plotting of Z-values 2 1 0 -1 Time
Proportionality Profile -1 0 1 Weight Arm Length Triceps Skinfold Arm Girth
Visual Test of Significant Difference between Means 1 Standard Error of the Mean No significant difference Significant difference
Proportionality Profile -1 0 1 Weight Arm Length Triceps Skinfold Arm Girth
Kin 303Proportionality Profile Fall 2009 Males Black Boxes (n=10) Females Open Boxes (n=15) Means ± 1 SEM
KIN-ScaleProportionality 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
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) - (Πx Skinfold (mm) / 10)
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