Body composition Flashcards
3 things that are considered to be important componenets of athletic performance
body size
shape
composition
Body composition can give you
An
Why can’t you say that a person needs to be exactly this weight?
They need a range of where there’s a balance between leanness and power
strength and power athletes have
increased fat free mass
Low fat body composition may not be beneficial for
Performance
as athletes must move their own mass, they must have
increased power/weight ration - cyclist
Whys body composition so much harder to do?
Because you can’t dope
diff _______ are set up for competitions to be fair
weight divisions
Body composition
The partitioning of body mass into fat free mass (weight or percentage) and fat mass (weight or percentage)
acrobatic sports have
biomechanical advantages
Fat free weight 5
Muscle, bone, skin, blood, organs
judged sports body composition
increased fat free mass and decreased body fat
2 fat weight
Storage fat: visceral and subcutaneous fat
Essential far - bone marrow,CNS, cell membranes, heart, lungs, liver-5%, spleen, kidneys, intestines, muscles. Males 3%, females 12%
body weight and body composition are often
important focal points for athletes given that these attributes can be manipulated.
Lean body mass
Fat free weight and essential fat
is body composition a sole predictor of athletic performance?
no, a rigid body composition should not be recommended for any sport or gp of athletes
Exercises that use essential body fat
Are not healthy
can you say that a person needs to be exactly this weight
no because they need to have a range where that balance is between leanness and po
Direct analysis of body composition
Cadaver analysis
Chemical analysis - determine mixture or fat and far free components
Physical dissection analysis of fat, far free adipose tissue, muscle, and bone
Indirect measure of body composition 7
Densitometry- hydrostatic weight and displacement plethysmography (bod pod) Dual energy x ray absorptiometry DXA bio electrical impedance analysis BIA skin folds Circumferences Computed tomography (CT) Magnetic resonance imaging (MRI)
Densitometry
Measurement of mass/unit volume
Density of body
Body mass(g)/body volume (ml)
Two compartment model of body composition (fat and fat free weight)
Density of fat is 0.9 g/ml, lean body mass is 1.1, with a measurement of total body density, a percent body fat can be calculated using a prediction formula
How do you determine the volume of the body
Submerge them in water in graduated cylinder
Archimedes principle
Principle that a partially or fully submerged object will experience an upward buoyant force equal to the weight or the volume of fluid displaces by the object
How do we find the volume of the body according the Archimedes principle?
Subtract the underwater weight from the land weight
Who will weigh more underwater and why?
Density of bone and muscle is greater than that of far, so someone with a lower percent body far will weight more
Bod pod
Air displacement system to determine volume of body
- measures residual volume on lungs
Volume of body used to determine %BF - similar formulas to the ones used for hydrostatic weighing
High level of accuracy but may underestimate body far by 2-3%
5 potential sources if error with Densitometry
Determination of residual volume Determination of GI volume Body gravity spaces Protocol errors Assume that densities of lean tissue compartments remain the same among ind.
Reasons of density fluctuation of bones and muscles
from the constant of 1.1g/ml depending on gender, age, race, etc
how much will densitometry body fat measurements differ from true body fat %
+/- 2-4%
dual energy x-ray absorptiometry (5)
3 compartment model of body composition that uses low dose x-ray absorption to measure
- lean soft tissue
- fat soft tissue
- bone
whole body and regional assessment of body composition
lowest standard error of body composition
takes 3 min
darker is muscle
bioelectrical impedance analysis (4)
low intensity electrical current to assess body composition
- lean tissue has more water and electrolyte content which conduct current more readily than fat
- great resistance/impedance of current indicates a higher % body fat
high degree of error because hydration status can significantly reduce results
Skin folds/fat fold measures
calipers to gauge thickness of a fold of skin at selected sites
a skin fold is the double thickness of skin plus the adipose tissue between the parallel layers of skin
highest standard of error in measurement of body composition
- landmaring, amt of skinfold pinched, site selection, calipers, tester, subject
highly trained testers get an accuracy of +/- 3-5% relative to hydrostatic weighing
How to use skin fold measurements
different equations to determine body density
Siri equation for body fat %
multitude of equations to choose from depending on the population of study - age and sex adjusted formulas required
Body mass index
ratio of total body weight to height
limitations of BMI (3)
not always a good predictor of body fat
provides no indication of fat distribution
no absolute BMI standard to classify children and adolescents overweight and/or obese
Why is BMI not always a good predictor of body fat (3)
athletes have high BMI but acceptable body fat levels
older age have a higher %body fat for a given BMI
ethnicity - asian pop. may have a higher %BF for a given BMI
why do we still use BMI
not a good predictor of individual health but works well for assessing health on a population level
Android vs Gynoid
excess fat in android region (apple) is associated with higher risk for diabetes, heart disease, and hypertension compared to fat stored in the gynoid/pear shaped.
assessment of waist circumference and waist/hip ratio
some indication of metabolic health risk
Why is subcutaneous fat better than visceral fat
not as readily available
What waist conference is high risk for metabolic diseases?
f 89, 88 in canada
m 99, 102 in canada
average waist to hip ratio
17-39 0.8f, 0.9m
40 and up 0.9f, 0.98m
high risk for metabolic disease
20-60 f0.84, m0.99
60-70 f0.90, 1.03 m
what does the waist hip ratio tell you
index of relative fat distribution
healthy body fat %
no universally accepted %bf standard
obesity is +5% above normal bf%
essential fat and minimal fat for men and women
3-5%, 5% for men
8-12%, 10-12% for women
athletic fat in men and women
5-13 for men
12-22 for women
recommended bf% for men and women, less than 34, 35-55, after 56
8-22, 10-25
20-35, 23-38, 25-38
How many fat cells do we have
30-50billion- females have 50% more than men
hyperplasia
growth in tissue or organ trough an increase in the number of cells, occurs at critical periods in life - later childhood/puberty
hypertrophy
increase in size of cells, fat cells can increase in size by a factor of ten in order to store more triglycerides
white vs brown adipose cell
large lipid vacuole and little mitochondria
small lipid droplets and lots of mitochondria - many when we were young to give off heat
3 types of body fat distribution patterns
android - visceral
gynoid - gluteofemoral
intermediate pattern
Lipoprotein lipase
promotes fat storage in adipose and muscle because it plucks fat off the lipoproteins
ppl with high LPL
store fat very efficiently
gender specific hormones and fat cell metabolism
in women fat cells in breasts, hips and thighs produce more LPL and in men cells in abdomen produce more LPL
why is it harder to lose gynoid/gluteofemoral fat?
enzymes controlling breakdown of fat less active in lower body
weight loss and LPL expression
increases - more efficient in getting fat back
obesity prevalence in canada (3)
26% of adult have obesity
5th in the world
steady increase after 1980
general health risks of overweight and obesity (6)
hypertension CV disease Gallbladder disease and hypercholesterolemia diabetes mellitus - type 2 cancer miscellaneous disorders
diabetes insipidus
pancreatic inefficiency
abdomen fat can release
inflammatory cytokines
health risks from mass of fat (6)
osteoarthritis sleep apnea respiratory problems lower back patin skin stretch marks congestive heart failure
increased PA improves ___________ regardless of weight
metabolic health - adjusted relative risk is always lower
you can have a high amount of bf% but be
metabolically healthy
why does complication arise with obesity
inflammation
new assessment of obesity intervention?
medical, mental and functional aspects, if they’re all okay then there’s no treatment
weight bias
beliefs about a person’s values, skills, abilities and personality based on their body weight and shape
weight stigma
disapproval or discontent with a person or gp based on perceptions and stereotypes
the public voice for canadians with obesity (3)
remove stigma and bring positivity and respects
change how we perceive and discuss obesity
connection to a community and make a difference
why shouldnt one discriminate obesity
there may be a genetic piece and not solely a lifestyle
instead of fat (less stigmatizing)
weight
instead of morbidly obese (less stimatizing)
unhealthy weight or high BMI
instead of fat (more motivating)
unhealthy weight
instead of morbidly obese/chubby (more motivating)
overweight
ind experiencing weight discrimination are more likely to have (4)
maladaptive eating patterns, avoid PA, develop stress induced pathophysiology and avoid medical care
submerged object experiences
an upward buoyant force equal to the weight of the volume of the fluid displaced by the object
