# BODY COMPOSITION SKINFOLD METHOD

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```					                    BODY COMPOSITION: SKINFOLD METHOD
NTRS 417L NUTRITIONAL ASSESSMENT

INTRODUCTION

There are several field techniques to predict body density or percent body fat (BF).
These are less time consuming to use and usually required inexpensive equipment such as
skinfold calipers and anthropometric tape measures. When you use skinfold (SKF) prediction
equations to estimate body density (BD), several assumptions are made:
1. Because there is a relationship between total subcutaneous fat and total body fat,
the sum of several skinfolds can be used to estimate total body fat
2. The distribution of fat subcutaneously and internally is similar for all individuals
within each gender
3. The sums of SKFs are a good measure of subcutaneous fat
4. There is a relationship between the sum of SKFs and body density
5. Age is an independent predictor of body density for both men and women

Following are some SKF prediction equations:

Age           Equations for Males
18 – 26       BD = 1.1043 – (0.001327 * thigh SKF) – 0.00131 * subscapular SKF)
18 – 61       BD = 1.10938 – (0.0008267 * sum of chest, abdominal, and thigh SKFs) +
2
(0.0000016 [sum of chest, abdominal, and thigh SKFs] ) – (0.0002574 * age)
Athletes      BD = 1.10647 – (0.00162 * subscapular SKF) – (0.00144 * abdominal
SKF) – (0.00077 * triceps SKF) + 0.00071 * midaxillary SKF

Age           Equations for Females
17 – 25       BD = 1.0764 – (0.00081 * suprailiac SKF) – (0.00088 * triceps SKF)
18 – 55       BD = 1.09949 – (0.00099 * sum of triceps, thigh, and suprailiac SKFs) +
(0.0000023 * [sum of triceps, thigh, and suprailiac SKFs]2) – (0.0001392 *
age)
Athletes      BD = 1.0960 – (0.00069 * sum of triceps, suprailiac, abdominal, and thigh
SKFs) + (0.0000011 * [sum of triceps, suprailiac, abdominal, and thigh
SKFs]2 – (0.0000714 * age)

Nomograms exist to use with skinfold measurements. When using nomograms, each
variable, such as the sum of SKFs or age, it plotted in the appropriate column and a ruler is
used to connect these two points. The corresponding BD or percent BF is read at the point
where the connecting line intersects these columns on the nomogram.

OBJECTIVES

 Assess body fat composition using the skinfold method.
 Assess body density using diameter and circumferential measurements.
 Use equations to predict body density.
PROCEDURE
Skinfold Measurements

The accuracy and precision of SKF measurements are affected by the type of caliper,
the training of the technician, and the proper identification of the SKF site. When selecting a
caliper for use in the clinical setting, you should consider cost, durability and degree of
precision. Plastic calipers have:
Less scale precision (2mm)
Irregular pressure throughout the range of measurements
Smaller measurement scale (40mm)
Less reliability

Standardized sites for skinfold measurements

SITE         DIRECTION OF           ANATOMICAL                 MEASUREMENT
FOLD                REFERENCE
Chest                 Diagonal               Axilla and nipple     Fold is taken between axilla
and nipple as high as
possible with measurement
taken 1 cm below fingers
Subscapular           Diagonal               Inferior angle of Fold is along natural
scapula               cleavage line of skin
Midaxillary           Horizontal             Xiphisternal junction Fold is taken on midaxillary
line at level of xiphisternal
junction
Suprailiac            Oblique                Iliac crest           Fold is grasped posteriorly
to midaxillary line and
superiorly to iliac crest
along natural cleavage
Abdominal             Horizontal             Umbilicus             Fold is taken 3 cm lateral
and 1 cm inferior to center
of the umbilicus
Triceps               Vertical               Scapula and ulna      Distance between lateral
projection      of   acromial
process and inferior margin
of olecranon process. Fold is
lifted 1 cm above marked
line on posterior aspect of
arm
Biceps                Vertical               Biceps brachii        Fold is lifted over belly of
the biceps brachii. Caliper is
applied 1 cm below fingers
Thigh                 Vertical               Inguinal crease and Fold is lifted on anterior
patella               aspect of thigh midway
between inguinal crease and
proximal border of the
patella. Body weight is
shifted to left foot
Skinfold Technique
Procedure
 Take all SKF measurements on the right side of the body
 Carefully identify, measure, and mark all SKF site
 Grasp the SKF firmly between the thumb and index finger on your left hand. The fold
is lifted 1 cm above the site to be measured
 Lift the fold by placing the thumb and index finger approximately 8 cm apart on a
line that is perpendicular to the long axis of the skinfold
 Keep the fold elevated while the measurement is taken
 Place the jaws of the caliper perpendicular to the fold, approximately 1 cm below the
thumb and index finger, and release the jaw pressure slowly
 Take the SKF measurement 4 seconds after the pressure is released

Measurement Errors

   Read the dial of the caliper to the nearest 0.1 mm, 0.5 mm or 1 mm depending on the
   Two minimum measurements
   Skin should be dry and lotion-free
   Do not measure after exercise
   Skills of technician
   Avoid plastic calipers

Diameter Measurements (Skeletal)

   Shoulder width – distance between the lateral borders of the acromial processes and
the scapulae with arms hanging vertically, and measured from the rear while the
subject is standing
   Elbow width – distance between the epicondyles of the humerus with the forearm
flexed to 90o and the are horizontal
   Wrist width – distance between the styloid processes of the radius and ulna with the
forearm probated and elbow flexed to 90o
   Hip width – distance between the lateral-most aspects of the iliac crest, measured
from the rear while the subject stands, feet 5 cm apart
   Knee width – distance between the lateral and medial epicondyles of the tibia with
the knee flexed to 90o and the subject seated
   Ankle width – distance between the malleoli of the tibia and fibula, measured from
the rear of the subjects

Circumferential Measurements

   Chest – measured at the fourth costosternal joints at the end of a normal expiration
   Abdominal – measured a the greatest anterior protuberance of the abdomen, usually
at the umbilicus
   Hips – measured at the maximum posterior protrusion of the buttocks
   Thigh (proximal) – measured just below the gluteal fold
    Thigh (mid) – measured midway between the inguinal crease and proximal border of
the patella
    Thigh (distal) – measured just proximal to the femoral epicondyles
    Calf – measured at the maximum circumference of the calf with the subject standing,
feet spread 20 cm apart and weight evenly distributed
    Ankle – measured at the minimum circumference if the calf just proximal to the
melleoli
    Arm – measured midway between the olecranon process of the ulna and the acromial
process of the scapula
    Forearm – measured at the maximum circumference of the midforearm with elbow
extended and foreare supinated
    Wrist – measured just distal to the styloid processes of the radius and ulna

Equations to predict body density from circumferences and skeletal diameters

Sex            Age           Equation
Male           College       BD = 1.15114 + (0.00068 * BW) + (0.00146 * hip W) +
(0.00057 * chest C) - (0.00192 * abdominal C) – (0.00124 *
thigh C)
Male           18 – 22       BD = 1.12691 – (0.00357 * arm C) – (0.00127 * abdominal C) +
(0.00524 * forearm C)
Female         College       BD = 1.065551 + (0.0112 * wrist D) – (0.00055 * abdominal C)
– (0.00082 * hip C) – (0.00159 * arm C) + (0.00362 * forearm
C)
Female         20 –70        BD = 1.168297 – (0.002824 * abdominal C) + (0.000733128 *
hip C) + (0.000510477 * HT) – (0.000216161 * Age)
BW = body weight
C = circumference
D = diameter (cm)
HT = height (cm)
W = width (cm)

CALCULATIONS

RESULTS

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