Lecture 6 Flashcards
What are the different field methods to assessing body composition
. Height and weight • Body Mass Index (BMI) • Skinfolds • Waist circumference • Waist-to-hip ratio
What equipment is needed for the height field method
• Height measured by Stadiometer
Describe the process for the height field method
• Remove shoes • Subject stands straight • Take a deep breath in and holds while looking straight ahead • You can assist subject into assuming Frankfort plane
What equipment is needed for the weight field method
Weight measured by calibrated scale
Describe the process for the weight method
- Remove shoes
- Also remove as much clothing as possible
- No wet hair
What is the BMI formula
BMI = weight (kg) ÷ height (m)2
Why is BMI used to determine overweight/obesity
Based on the concept that individuals with lower BF% will have a low BMI
What is the BMI range(adullts) for normal weight
Normal weight = BMI 18.5 - 24.9
What is the BMI range(adults) for overweight
Overweight = BMI 25 - 29.9
What is the BMI range (adults) for obesity
Obesity = BMI ≥30
What is the BMI range (adults) for severe obesity
Severe Obesity = BMI ≥35
What are the problems with the usage of BMI
- Does not measure the amount of fat
- Can over-report obesity compared to BF%
• Heavy athletes end up with a high BMI, even if they
have a low BF%
• Elderly: low BMIs due to ↓ muscle mass
despite a high BF%
• BMI increases as you age because height
decreases
Describe the skinfold assessment
Measures 2 layers of subcutaneous fat (beneath the
skin)
• Provides an estimate of a person’s overall body
fatness
Describe the process of the skinfold assessment technique
- Skinfold measurements are always taken on the right side of
the body - Carefully identify, measure and mark the skinfold site
- Grasp the skinfold between the thumb and index finger of
your left hand at the measurement site - Lift the fold gently, and place the calipers 1 cm below the
measurement site - Take skinfold measurement 2 seconds after releasing the
calipers - Open the calipers and release the skinfold
Where are the sites for skinfold assessment
. Chest
. Abdominal
. Thigh
. Triceps/Biceps
Describe the location for chest skinfold assessment
• Diagonal fold • Men: midway between anterior axilla and nipple • Women: 1/3 distance between anterior axilla and nipple
Describe the location for abdominal skinfold assessment
• Vertical fold
• 5 cm to the right of the
umbilicus (belly button)
Describe the location for thigh skinfold assessment
• Vertical fold • Anterior midline of the thigh • Midway between proximal patella (kneecap) and inguinal (hip) crease
Describe the location for triceps/biceps skinfold assessment
• Vertical fold • Posterior/anterior midline of upper arm • Midpoint between acromion (shoulder) and head of the radius (elbow)
Describe the location for subscapular skinfold assessment
• Diagonal fold
• 2 cm below the inferior
angle of the scapula (bottom
of shoulder blade)
Describe the location for medial calf skinfold assessment
• Vertical fold
• Most medial aspect at the point
of greatest girth
Describe the location for suprailiac skinfold assessment
• Diagonal fold
• Mid-axillary line
(superior to the iliac
crest; i.e. hip bone)
Describe the location for supraspinale skinfold assessment
• Diagonal fold
• At the level of iliac crest, on the
line between anterior axilla and
ASIS
What skinfold methods do females use to estimate body fat
Females use Withers (6-site), Jackson-Pollack (3-site) or Jackson, Pollack and
Ward (4-site) method
What skinfold methods do males use to estimate body fat
For males use Withers (7-site), Durnin and Womersley (4-site) or Katch and
McArdle (3-site) method
What method or equation do u convert the skinfold methods results into % body fat
Body Fat % = [(4.95 / body density) – 4.50] x 100
Why is circumference(girth) measurements used
Used as an estimation of body composition
Easy to learn, administer and inexpensive
- Ideal for documenting changes in body size
- Waist during a weight-loss program
- Muscle during a weight training program
Explain the procedure of circumference measurements
- Subjects stand erect but relaxed
- Identify/mark standardised sites
- Apply tape perpendicular to the long axis
- Tape should be taut, not tight (no skin compression)
- Read measurement to nearest millimeter
- Take 2 measurements and average
Name the sites for circumference assessments
. Waist . Hip . Upper arm . Chest . Mid thigh . Thigh . Forearm . Calf
Describe the location of the circumference assessment Waist
• Narrowest point of the abdomen: o Between the lower costal border and the top of the iliac crest
Describe the location of the circumference assessment Hip
• Greatest posterior
protrusion of the buttocks
Describe the location of the circumference assessment Upper arm
Midpoint between acromion
(shoulder) and radial head
(elbow)
Describe the location of the circumference assessment Chest
• Mid-point of the sternum
(at level of 4th rib)
• “Mid-chest” may be more
appropriate
Describe the location of the circumference assessment Mid thigh
• Midpoint between greater
trochanter and tibial condyle
• ALSO: mid-point between inguinal
crease and superior patella
Describe the location of the circumference assessment thigh
• 1 cm below the gluteal
fold
Describe the location of the circumference assessment forearm
Maximal girth of forearm, distal
to humeral epicondyles
Describe the location of the circumference assessment calf
• Maximal girth of the calf
How to calculate the waist to hip ratio
Waist circumference ÷ hip circumference
What is the point of the waist to hip ratio
• An indicator of body fat distribution
Describe • High Waist:Hip ratio
greater adipose in the
abdomen
Describe • Low Waist:Hip ratio
greater adipose in the in
the hip/gluteal region
High risk measurements of men (obesity)
Waist measurements of >102 cm (men)
High risk measurements of women (obesity)
Waist measurements of >88 cm (men)
Describe assessing body composition using laboratory methods
• Require more specific and expensive
equipment
• Greater levels of reliability and validity
Name some laboratory methods to assessing body composition
- Dual Energy X-Ray Absorptiometry (DEXA)
- Hydrostatic Weighing
- Air Displacement
- Bioelectrical Impedance Analysis (BIA)
Describe DEXA
Low-radiation X-ray scan of the entire body which can
estimate BF% and bone density (the rest is ‘lean mass’)
Explain the purpose of the DEXA
Provides a measure of total body fat and the regional
distribution of fat
Describe hydrostatic weighing
Subject is weighed both on land and when fully
submerged in water
Explain the purpose of the hydrostatic weighing
Based on the density of various tissues:
- Lean mass: more dense than water
- Fat mass: less dense than water
• Therefore, more muscular individuals will weigh more
under water
Describe air displacement
Instead of being submerged, sensors in the
chamber estimate the amount of air displaced
by the subject
Describe the purpose of air displacement
Body fat can be calculated using the weight and
the amount of air displaced
Describe bioelectrical impedance analysis
A low-level current is passed through the body to estimate body
fat %
Describe the purpose of bioelectrical impedance analysis
Lean tissue contains more water than fat tissue
• Therefore, the level of resistance to the currents flow indicates the amount of lean and fat
mass
