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Comparative study of anthropometric measurements of the same subjects in two different institutes.

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Comparative Study of Anthropometric Measurements of
the Same Subjects in Two Different Institutes
H. C. G. KEMPER AND J. J. L. PIETERS
Coronel Laboratory and Labortitory of Psychophysiology, J a n S w a m m e r d a m
Institute, University of A m s t e r d a m , t h e Netherlands and Central
Institute f o r Nutrition and Food Research ( C I V O , T N O ) ,
Zeist, t h e Netherlnnds
K E Y W O R D S Comparability . Objectivity . Anthropometry
Measurements.
ABSTRACT
The objectivity of several anthropometric measurements were
tested in two institutes on the same subjects.
In many cases systematic differences are to be expected: 1. Girth measurements tend to differences in the same direction. 2. The comparability of skeletal
measurements is often uncertain; some measurements tend to give lower, other
ones higher figures. Biacromial diameter and radio-ulnar epicondylar width do
not reveal systematic differences. 3. Skinfold thicknesses measured do not reveal
systematic differences.
Some 50 different procedures described
in Human Biology, a Guide to Field Methods (Weiner and Lourie, '69) cover a wide
range of investigations essential to the biological study of human populations. By
following these procedures investigators
could achieve one of the major aims of
the International Biological Programme
(I.B.P.), a high degree of comparability
between studies of different populations.
All methods, even when described in
great detail, demand a thorough acquaintance with their underlying principles.
Even such a simple technique as anthropometry cannot give reliable results unless
the observer has practiced the methods
extensively (Meredith, '36; Steggerda, '42).
The purpose of the present study was
to test the objectivity of several routine
anthropometric measurements from the
recommended IBP full list (Barrow and
McGee, '68).
It is essential that very small differences
occur between the same sets of scores
measured by different investigators (Marshall, '37). The correlation coefficient of
objectivity, derived from paired measurements, should be high.
MET H 0DS
In March 1970, 50 boys 12 and 13 years
old from a secondary school in Amsterdam
AM. J. PHYS. ANTHROP., 40: 341-344.
(St. Ignatius College), were measured independently by experienced workers in
two institutes:
-Central Institute for Nutrition and Food
Research (CIVO-TNO) in Zeist, and
-Coronel Laboratory and Laboratory for
Psychophysiology, Jan Swammerdam
Institute (University of Amsterdam) in
Amsterdam.
The principal reason for accumulating
these anthropometric data was different
for each institute. Afterwards we decided
to compare the two sets of data taken on
the same subjects. All measurements were
taken in normal conditions and not under
unusually favorable ones as in the case
of Marshall ('37).
In each institute all measurements were
taken by a team of workers previously
trained according to the techniques described by Tanner ('64). There was no
preliminary training to minimize the interobserver differences. All measurements
were, wherever possible, taken on the left
side of the body. Measurements are listed
in a convenient working order: weight,
stature, biacromial diameter (shoulder
width), bi-iliocristal diameter (pelvic
width), radio-ulnar epicondylar width
(wrist breadth), femoral bicondylar width
(knee breadth), upper arm circumference,
thigh circumference, calf circumference,
34 1
342
H . C. G. KEMPER AND J. J. L. PIETERS
tricipital-, subscapular- and supra-iliaca1
skinfold thickness.
The same measuring instruments were
used in both institutes (except for stature
and weight): a steel measuring tape (Black
and Decker) for circumferences; a sliding
caliper for knee and wrist breadth; spreading caliper for shoulder and pelvic width
and skinfold caliper (Harpenden) for
skinfolds.
In both institutes the accuracy of the
instruments was checked periodically for
proper scale calibration.
RESULTS
For each measurement the me% values
of Zeist (x,) and for Amsterdam (x,) were
calculated. In table 1 column (1) the mean
differences and standard deviations of
these data are listed (de Jonge, '64). In
9 out of 12 measurements the mean differences could not be attributed to change
(,=0.05). No differences were found for
biacromial diameter, subscapular- and
supra-iliacal skinfolds.
In table 1 column (2) the correlation
coefficients of the data collected at the
two institutes are given. All are high and
significant at the 1% level.
These figures, however, have a limited
value without more information on the
extent of the differences €or each measure-
ment along the whole range of values of
the group. Therefore we calculated also
the correlation coefficient between the
differences (x - x,) and the mean absolute values
and summarized them
in table 1 column (3). In 4 out of 12 comparisons, the coefficients are significant
at a 5% level: bi-iliocristal diameter, thigh
circumference, subscapular skinfold and
supra-iliacal skinfold. Further analysis reveals that in subscapular skinfold differences for high values were larger than for
low values and in thigh circumferences
and supra-iliacal skinfold differences for
high values were smaller than for low
values.
(v)
DISCUSSION
The comparison of test results involves
consideration of systematic and non-systematic differences (Clarke and Clarke,
'70).
The data of table 1 demonstrate that
9 out of 12 anthropometric measures show
systematic differences between the two
laboratories: in the mean of 3 out of 12
measurements values of Amsterdam are
systematically lower than those of Zeist
(weight, bi-iliocristal diameter and femoral
bicondylar width); it appears from the
table that all three skinfolds as well as
the other measurements given, are higher
in Amsterdam.
TABLE I
Dtrtn collected i n t h e t w o i n s t i t u t e s o n the, s a m e szibjects: ( I ) M e a n differences nnd stnndnrd
deviations (S.D.); ( 2 ) Coefficients of correlation ( r ) b e t w e e n x z a n d x,: (3) Coefficients
of correltrtion ( r ) b e t w e e n (x, -x(,) and
(2)
Anthropometric
measureinen t s
Weight
Stature
Biacromial diameter
Bi-iliocristal diameter
Radio-ulnar epicondylar
width
Femoral bicondylar width
Upper arm circumference
Thigh circumference
Calf circumference
Tricipital skinfold
Subscapular skinfold
Supra-iliacal skinfold
1
p S 0.05.
2
pso.01.
r
between
xz-xa
Mean (S.D.)
xz and x,
kg
cm
cm
cm
+0.466 '(0.465)
-0.624 l(0.501)
-0.004 (0.603)
+0.271 1 (0.355)
0.995 2
0.996 2
0.872 2
0.948 2
cm
cm
cm
cm
cm
mm
mm
mm
-0.092 l(O.192)
+0.470 1 (0.355)
- 1.659 1 (0.600)
- 3.1 14 1 (0.929)
- 1.045 1 (0.348)
- 0.480 1 (1.080)
- 0.046 (0.654)
-0.002 (1.483)
0.903 2
0.940 2
0.971 2
0.982 2
0.992 2
0.952 2
0.973 2
0.951 2
(3)
r
between
-xa) and
(xz
xz i x ,
2
+0.089
- 0.039
f0.189
0.274 1
+
+0.189
+0.189
- 0.148
- 0.357 1
- 0.207
- 0.058
0.395 2
- 0.306 1
+
OBJECTIVITY OF ANTHROPOMETRY
In as much as the instruments themselves remain constant, differences probably refer to any personal influence of the
examiner. In Zeist for instance, all three
circumferences were consistently lower
than those in Amsterdam. When dealing
with girth measurements care must be
taken to exert the same tension on the
ends of the tape at each reading. According to Weiner and Lourie (‘69: 7) “contact
with the skin should be continuous along
the tape, but the skin should not be
pressed inwards.” The systematic lower
values of Zeist could be explained by a
difference in tightening the steel tape
around the limbs.
No systematic difference could be found
in mean biacromial diameter. This particular skeletal measurement, however,
shows a relatively low coefficient of objectivity (r = 0.87), which is an indication of
poor reproducibility. Similarly the correlation coefficient for the radio-ulna epicondylar width is not as high as in others
(r = 0.90). All other correlation coefficients
exceed 0.90 indicating satisfactory correlation between the two institutes according to Barrow and McGee’s arbitrary standards (‘68).
We have to consider, however, that for
four of these measurements the differences
in the low and high values between the two
institutes are not equal (table 1, column
( 3 ) >.
A certain amount of error, the variable
error, is inevitable in the testing process
no matter how much care is taken to ensure that the instruments are calibrated
and the testing procedures are standardized. Such variability especially in the
343
measurement of biacromial diameter is
likely. This measurement has to be taken
on the subject “with his shoulder relaxed
to the point of slumping forward” (Tanner,
’64: 25), resulting in a maximum shoulder
width. Squaring the shoulders backward
invariably decreases biacromial diameter.
For the radio-ulnar epicondylar width the
rotation of the lower arm may be different
in separate measurements. Such an intraindividual variability of the subject in
holding his shoulder more or less relaxed
and his wrist more or less rotated could
contribute to the rather low objectivity
coefficient of biacromial diameter and radio-ulnar epicondylar width.
LITERATURE CITED
Barrow, H. M., and R. McGee 1968 A Practical
Approach to Measurement in Physical Education. Lea and Febiger, Philadelphia.
Clarke, D. H., and H. H. Clarke 1970 Research
Processes in Physical Education, Recreation and
Health. Prentice Hall, Englewood Cliffs, New
Jersey.
Jonge, H. de 1964 Inleiding tot de medische
statistiek I en I1 (Introduction to medical statistics). Nederlands Instituut voor Praeventieve
Geneeskunde (NIPG), Leiden.
Marshall, E. L. 1937 The objectivity of anthropometric measurements taken on eight- and
nine-year-old white males. Child Develop., 8:
249-256.
Meredith, H. V. 1936 The reliability of anthropometric measurements taken on eight- and
nine-year-old white males. Child Develop., 7:
262-2 72.
Steggerda, M. 1942 Anthropometry of the living: A study on checking of techniques. Anthrop.
Briefs, 2: 7-15.
Tanner, J. M. 1964 The Physique of the Olympique Athlete. Allen and Unwin, London.
Weiner, J . S.,and J. A. Lourie 1969 IBP Handbook, no. 9. Human Biology, a Guide to Field
Methods. Blackwell, Oxford.
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