STRAND: Number
TOPIC:
Percentages
Body fat analysis
To complete this task you must have a pair of skin fold calipers. The Physical Education Department at your school may have a pair.
LITERACY TASK • Find the meanings of these key terms:
1. skin fold calipers: ..............................................................................................................................................................
2. suprailiac: ..........................................................................................................................................................................
3. triceps:................................................................................................................................................................................
4. subscapula: ........................................................................................................................................................................
5. thigh: ..................................................................................................................................................................................
6. density:...............................................................................................................................................................................
7. lean: ....................................................................................................................................................................................
A percentage of every person’s body mass is made up of fat tissue. In fact, it is healthy to have a reasonable amount of fat tissue
in your body. To calculate the percentage of your body mass that is fat tissue, you will need to take some measurements with
the calipers.
1. Taking the necessary body measurements:
Females
(a) Females — Take the measurements of the triceps and
suprailiac with the skin fold calipers as shown.
(b) Males — Take the measurements of the thigh and
subscapula with the skin fold calipers as shown.
NB: You will need to take three measurements at each
point and average the results.
suprailiac
triceps
Males
thigh
subscapula
 John Wiley & Sons Australia, Ltd 2001
STRAND: Number
TOPIC:
Percentages
INVESTIGATION: Body fat analysis
If you are unable to take these measurements accurately, please use the following data taken from a female (mass 64 kg) for the
remainder of this investigation:
Trial 1
Trial 2
Trial 3
Tricep
12.2
12.1
11.9
Suprailiac
12.8
12.9
13.0
Average
Or use the following data taken from a male (mass 71 kg) for the rest of the investigation:
Trial 1
Trial 2
Trial 3
Subscapula
12.2
12.1
11.9
Thigh
12.8
12.9
13.0
Average
2. Calculating body density:
The formula to calculate body density is:
Females — Body Density = a – (b × tricep) – (c × suprailiac)
Males — Body Density = a – (b × subscapula) × (c × thigh)
The values of a, b and c are shown below:
a
b
c
Females
1.076 4
0.000 88
0.000 81
Males
1.104 3
0.001 31
0.001 327
3. Calculating the percentage of body fat:
The percentage of body fat is calculated using the formula:
4.57
Percentage body fat =  ------------------------------ × 4.142 × 100%
 body density

4. Assessing your body fat percentage:
Look up your percentage body fat in the table below to see which category you belong to:
Category
Females
Males
Very low fat
14.0 – 16.9
7.0 – 9.9
Low fat
17.0 – 19.9
10.0 – 12.9
Average fat — normal
20.0 – 23.9
13.0 – 16.9
Above normal fat
24.0 – 26.9
17.0 – 19.9
Very high fat
27.0 – 29.9
20.0 – 24.9
Obese
30.0 and over
25.0 and over
5. Calculating the desired body mass:
Once you’ve calculated your body fat percentage, your mass can be divided into a fat mass and a lean mass (your mass
without any body fat).
(a) Find your mass.
(b) Use the body fat percentage to find the mass of fat on your body.
(c) Subtract your fat mass from your body mass to find your lean mass.
It is desirable that a female has 18% of body fat tissue and that a male has 11%. To calculate your desirable body mass:
--------Females: multiply your lean mass by 100
82
100
Males: multiply your lean mass by --------89
 John Wiley & Sons Australia, Ltd 2001