Different Methods of body composition

Different Methods of body composition

1. Surface Anthropometry
A. Matiegka’s Method:
Jindrich Matiegka (1921) felt the need of developing a method to determine the physical efficiency of a given subject just as psychologists test the mental faculties of a person.
The physical efficiency of a person depends on various factors such as quantities or amounts of various tissues (bone, muscle and subcutaneous fat), the physiological qualities of various organs like the reaction time, fatigue, and the state of health. Matiegke concentrated on body measurements of extremities and thought that these represent the whole of the body well, just as the brain is a representative of the mentality of a person. The method which he developed is called somatotechnique by which quantitative analysis of various compartments of the body is made. His method of finding the amount of various body masses is given below:
W=O+D+M+R
Where
W= Body Weight
O= Weight of Bones
D= Weight of Derma or Fat
M= Weight of Skeletal Muscles
R= Remainder Weight
The above components masses can be calculated by using the following equations:
1. Weight of bones or Ossa
Ossa=O2xLxK1
Where L is height of the subject
K1=1.2 (Constant)
O= (o1+o2-o3+o4)/4
o1 is the maximum diameter of humerus bicondylar (cm)
o2 is the maximum diameter of femur bicondylar (cm)
o3 is the maximum diameter of wrist (cm)
o4 is the maximum diameter of Ankle (cm)

2. D or Derma
D=dxSxk2
d=1/2 (d1+d2+d3+d4+d5+d6) (mm)
Where
d1= skin fold at the biceps muscles
d2= skin fold of forearm, at maximum development, over the plantar side.
d3= skin fold of thigh over quadriceps muscles in the middle of inguinal and knee.
d4= skin fold over the calf muscle
d5= skin fold over the thorax in the middle of the mammary gland and umbilicus
d6= skin fold over the abdomen, in the middle of the naval and the anterior superior iliac spine
The science of anthropometry was in infancy in the time of Matiegke and there was no instrument for measuring skin fold thickness. So, the skin fold measurements were taken with a sliding caliper by picking up the fat fold with mild pressure. The readers can make out how inaccurate the measurements can be if there is no way of checking the pressure with which to measure the skinfold of thickness.
S= surface area in cm2
=Wt0.425 x Ht0.725 x 71.84
Weight in kg and height in cm should be taken.
K2=0.13 (Constant)
3. M or skeletal muscle
M=r2 L x k3
r= (r1 + r2 + r3 + r4)/4
where L = height (cm)
r1= corrected radius of upper arm (flexed)
r2= corrected radius of upper arm (maximum)
r3= corrected radius of thigh between trochanter and lateral epicondyle.
r4= corrected radius of calf
k3= 6.5 (constant)
The correct radii can be calculated as following assuming the limb as a cylindrical entity:
Circumference= 2 x (22/7) x r
Or r=c/2 (22/7)
Corrected r=[c/2 (22/7) – ½ skinfold]
The unit of skin folds is the same as for circumference or radius while subtracting it.
4. R or remainder mass
R= W—(O +D +M)
In the process of development of this method, Matiegka studied the corpses of 12 boys of 16-17 years of age, all in good health. The constants were calculated, however, he felt that these constants must be finely tuned by conducting further studies on large groups of cadavers.
Concerning the physical efficiency, he found a good co-relation between the amount of muscles and the dynamometric strengths of persons; however, the correlation was not complete.
Further improvements in the method can help forming basis for comparison of various subjects from which it may be easily determined whether a person having an average skeleton has feeble, medium or bulky muscles and insufficient, normal or excessive quantity of fat.
Metiegka suggested that the constants for the above equations be carefully calculated which can be age, sex and height specific, on the basis of controls and cadavers. The qualities of different tissues and the results of physiological test must be carefully studied. Mental influence on muscular work also needs to be studied. Muscular work also depends on the state of mental health. Other things like test of strength, influence of exercise, training, experience and mental tone, all should be determined for a better understanding of a person’s physical efficiency. A deeper understanding of a person’s physical and mental faculties and efficiencies can be highly useful in the choice of a suitable profession. A person can feel happy and will be more satisfied if he finds a profession to which he is mentally and physically most suitable.
Example:
Height = 150 cm
Weight = 50 kg
Humerus bicondylar breadth = 6.8 cm
Femur bicondylar breadth = 8.5 cm
Wrist Breadth = 6.0 cm
Ankle Breadth = 6.5 cm
Biceps Skinfold = 5 mm
Forearm Skinfold = 6 mm
Thigh Skinfold = 10 mm
Calf Skinfold = 8 mm
Thoracic = 12 mm
Abdominal = 11 mm
Upper arm girth (Flexed) = 27.0 cm
Forearm girth = 25.0 cm
Thigh girth = 45.0 cm
Calf girth = 32 cm
A. Weight of Bones
Ossa=O2 x L x K1
= (6.95)2 x 150.0 x1.2
= 8694 grams
= 8.694 kg
B. Weight of derma or adipose tissue
D= d x S x k2
d= ½ [(5+6+10+8+12+11)/6]
= 4.33 mm
S= 500.425 x 1500.725 x 71.84 cm2
= 14320 cm2
D = 4.33 x 14320 x 0.13
= 8060.7 grams
= 8.061 kg
C. Weight of skeletal muscles
r1= corrected radius of upper arm
= [Circumference of upper arm/2 (22/7)—1/2 Skinfold]
= [27/2 (22/7) –0.25]
= 4.045 cm
r2= 3.677
r3= 6.659
r4= 4.691
Mean radius or r=(r1 + r2 +r3 +r4)/4
= (4.045 +3.677 +6.659 + 4.691)/4
= 4.768 cm
M= r2 x L x k3
= (4.768)2 150.0 x 6.5
= 22165 grams
= 22.165 kg
D. Remainder mass
R = Body weight – (O + M + D)
= 50 – (8.6940 + 8.061 + 22.1650)
= 50.0 – 38.920
= 11.080 kg
Fat mass calculation
z(triceps) =1/4.47[10(170.18/150.0)-15.4] = -0.907
z(subscapular) = 1/5.07[12(170.18/150)-17.2] = -0.707
z(suprailiac) =1/4.47[12(170.18/150.0)- 15.4] = -0.399
z(abdominal) = 1/7.78[20(170.18/150.0)- 25.4] = -0.348
z(thigh) =1/8.33[20(170.18/150.0)- 27.0] = -0.507
z(calf) = ¼.67 = [15(170.18/150.0)- 16.0] = -0.218
Mean z- value = -0.4433
The subject fat mass is 0.4433 SD less than that of the phantom’s fat mass of 12.13 kg. A z – value of 0.4433 for fat mass corresponds to a value of 1.4407 kg (0.4433x phantom SD for fat mass which is 3.25 = 1.4407), so, the subject fat mass = 12.13 – 1.4407 kg =10.6893 kg.
The above fat mass of the subject is so when his height is 170.18 cm. It is necessary to rescale this fat to its actual size which is 150.0 cm which can be done in the following manner:
Actual fat mass = Obtained fat mass/[170.18/height]3
=10.6893/[170.18/150.0]3
=7.3198 kg
Utilizing the mean score, the fractional masses can be directly calculated with the following formula:
M = [(z x s) + p]/170.18/h)3
Where M is the fractional mass
z is mean phantom z-values for the subset off the variables
p is the phantom value for the given fractional mass
s is the standard deviation
h is the subject’s height
d is the dimensional constant
The fat mass of the subject can be calculated with the above formula.
Fat mass =[(-0.4433 x 3.25) + 12.13]/(170.18/150.0)3
= 7.3198 kg
Skeletal mass
z(humerus) – 1/0.35[6.0(170.18/150.0) – 6.48] =0.9349
z(femur) = 1/0.48[8.9(170.18/150.0) – 9.52] = 1.2028
z(wrist) = 1/0.72[15.0(170.18/150.0) – 16.35] = 0.9278
z(ankle) = 1/1.33[20.2(170.18/150.0) – 21.71] = 0.9079
The mean z – value = 0.9934
M = [(0.9934 x 1.57) + 10.49]/(170.18/150.0)3
= 8.2513 kg
So, the skeletal mass = 8.2513 kg
Muscle mass
For the calculation of the muscle mass, four body girths, viz, upper arm (relaxed), chest, thigh and calf are necessary. All these girths must be corrected for the subcutaneous tissue overlying the body, in the following manner:
Corrected arm girth = Arm girth – [(22/7) x triceps skinfold]/10 = 22.0 – [(22/7) x 10]/10 = 18.86 cm
Corrected chest girth = Chest girth –[(22/7) x subscapular skinfold]/10 = 75.0 – [(22/7) x 12]/10 = 71.29 cm
Corrected thigh girth = Thigh girth – [(22/7) x front thigh skin fold]/10 = 40.0 – [(22/7) x 20]/10 = 33.71 cm
Corrected calf girth = Calf girth – [(22/7) medical calf skin fold]/10 =28.0 – [(22/7) x 15]/10 = 23.29 cm
These corrected body girths are utilized for the calculation of z – values. Since the body girths are taken in the centimeters and the skin fold in the millimeters, so, while making the above corrections, the entire skin fold must be divided by a factor of 10 so as to convert them into centimeters, as has been done in the above calculations.
z (arm) = 1/1.91 [18.86(170.18/150.0) – 22.05] = -0.3417
z (chest) = 1/4.86[71.29(170.18/150.0) - 82.46] = -0.3249
z (thigh) = 1/3.59 =[33.71(170.18/150.0) – 47.34] = - 2.5334
z (calf) = 1/1.97 =[23.29(170.18/150.0) – 30.22] = - 1.9273
Mean z – value= -1.2818
Muscle mass = [(-1.2818 x 2.99) + 25.55]/170.18/150.0)3