HPE110 Lecture Notes - Lecture 8: Body Mass Index, Bone Resorption, Radiography
HB101-Lecture 8
Body composition
Factors affecting
Measurements
Modifications
Proportionality
Implications
Measurements
Suitability for sport
BODY COMP:
Physical composition of body mass
Three main categories for functional anatomy;
Bone mass – Structural support
Adipose tissue – Energy storage
Lean muscle mass - Movement
Important for both health and sports performance
Factors Affecting Body Composition
Genetics
Growth
Aging
Nutrition
Activity
Genetics
Nature vs nurture
Difficult to establish direct affects on body composition (which is the greatest
influencer?)
Reasonable to suggest that affects the way individuals interact and respond to
environment(al)
Always going to be a complex interaction, therefore hard to measure
More than likely only half the story
Growth
Fat Mass
Naturally high in infancy
Decreases through childhood
Muscle Mass
Sharp increase through infancy as mobility & wt bearing increases
Gender differences at puberty and hormonal accumulation
Bone Mass and Growth
Bone grows longitudinally from epiphyseal plates
Most individuals at full height by early adulthood
Epiphyseal plates closed no extra bone growth
find more resources at oneclass.com
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Australian children, school fortnight,
(ABS 2009)
25% of Aus children 5-17 yrs overweight or obese (ABS, 2008)
BMD accrual in adolescence can equal that lost post- menopause therefore, BMD
development in adolescence is vital
Activity in adolescence can significantly
reduce osteoporotic fracture risk
Aging
Australias agig population
Predicted to increase from 12.7% in 2002 to 27.1% of population in 2051
Body Composition and Aging
Adipose Tissue (fat)
Increase due to decreased activity
Muscular Tissue and Bone Mass
Decrease due to decreased activity
Australia is headed towards a frail and medical dependent aging population
Good for allied health professionals! i.e. ex phys
Bone Mass and Aging
Osteoporosis
Decrease in BMD and
increase in fracture risk
Bone resorption greater
than formation
Particular decline post-menopause in female
Baseline levels from youth affect final levels
Weight bearing activity effective in bone formation
Strength training beneficial for muscle mass also
Nutrition and Activity
Interaction between consumption and expenditure greatly influences body composition
Biggest loser – 1000cal in, 3000cal out
Adipose tissue essentially accumulation of energy stores when consumption greater than
expenditure
Measuring Body Composition
Densitometry
Known density of body tissues
measured relative to water
Fat mass ~0.9g/mL
Fat free mass ~1.1g/mL
Water ~1.0g/mL
Fat mass is the only body tissue that floats
Hydrostati eight opared to oral eight
Provides % of body fat
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Important for both health and sports performance. Difficult to establish direct affects on body composition (which is the greatest influencer?) Reasonable to suggest that affects the way individuals interact and respond to environment(al) Always going to be a complex interaction, therefore hard to measure. More than likely only half the story. Sharp increase through infancy as mobility & wt bearing increases. Most individuals at full height by early adulthood. Epiphyseal plates closed no extra bone growth. 25% of aus children 5-17 yrs overweight or obese (abs, 2008) Bmd accrual in adolescence can equal that lost post- menopause therefore, bmd development in adolescence is vital. Predicted to increase from 12. 7% in 2002 to 27. 1% of population in 2051. Australia is headed towards a frail and medical dependent aging population. Good for allied health professionals! i. e. ex phys. Decrease in bmd and increase in fracture risk. Baseline levels from youth affect final levels. Weight bearing activity effective in bone formation.
