Title: Digital photogrammetry versus ISAK anthropometry in determining body segment lengths of powerlifters. Running title: Digital photogrammetric method for body segment lengths of powerlifters. Authors: Peter Mellow, Patria A. Hume, Justin Keogh, Simon Pearson Institutional affiliations: Sport Performance Research Centre, Division of Sport and Recreation, Faculty of Health, Auckland University of Technology, New Zealand Acknowledgments: AUT funded this study. Thanks are given to the New Zealand Powerlifting Association and the Australian Powerlifting Association for their support of the project, the organisers of the Oceania Powerlifting and New Zealand Bench Press competitions for access to the powerlifters and performance scores, to the powerlifters who participated in the study, and to the ten anthropometrists who helped with data collection. Category: Sport Anthropometry: Original research. Date of submission to Journal of Sport Biomechanics: 19 th May 2003
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Digital photogrammetry versus ISAK anthropometry in determining body segment lengths of powerlifters
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Title: Digital photogrammetry versus ISAK anthropometry in determining body segment
lengths of powerlifters.
Running title: Digital photogrammetric method for body segment lengths of powerlifters.
Authors: Peter Mellow, Patria A. Hume, Justin Keogh, Simon Pearson
Institutional affiliations:
Sport Performance Research Centre, Division of Sport and Recreation, Faculty of Health,
Auckland University of Technology, New Zealand
Acknowledgments: AUT funded this study. Thanks are given to the New Zealand
Powerlifting Association and the Australian Powerlifting Association for their support of the
project, the organisers of the Oceania Powerlifting and New Zealand Bench Press
competitions for access to the powerlifters and performance scores, to the powerlifters
who participated in the study, and to the ten anthropometrists who helped with data
collection.
Category: Sport Anthropometry: Original research.
Date of submission to Journal of Sport Biomechanics: 19th May 2003
ABSTRACT
The validity and reliability of digital photogrammetry and International Society for the
Advancement of Kinanthropometry (ISAK) anthropometry in determining body segment
lengths were determined. Sixty-eight Australasian and Pacific powerlifters (54 males and
14 females) were measured for 42 anthropometric dimensions (using ISAK protocols) and
had six digital photos taken in the front and back, left sagittal, right medial leg, right sagittal
arm and right sagittal leg planes.
The mean intra-tester reliability for the seven sites, as assessed by the technical error of
measurement (TEM) was 0.31% for digital photogrammetry and 0.90% for the ISAK
method. Both of these mean TEM were within acceptable ISAK limits (1.0%). However,
the inter-tester TEM for digital photogrammetry (1.64%) was greater than the ISAK
acceptable error level of 1.5%. A mean difference of 3.8% existed between the limb
segments lengths measured with digital photogrammetry compared to the ISAK values.
Greater error was found in the upper limb compared to the lower limb segments.
Therefore, digital photogrammetry does not yet appear as valid as ISAK anthropometry in
determining body segment lengths. Several potential sources of error have been identified
and with future development may reduce the error to acceptable levels.
Key words: Anthropometry, digital photogrammetry, ISAK anthropometry, body segment
lengths.
INTRODUCTION
An athlete’s anthropometric dimensions, reflecting body shape, proportionality and
composition, are variables that play a role in determining the potential for success in a
chosen sport (Norton et al., 1996). Athlete’s anthropometric characteristics are usually
physically measured according to the guidelines of The International Society for the
Advancement of Kinanthropometry (ISAK), a society that implements worldwide standards
in anthropometry via an accreditation system. The visual photoscopic somatotype rating of
an athlete (see Figure 1) is often used in conjunction with anthropometry. Technical errors
of measurement (TEM)1 are established for each anthropometrist with the limits for
acceptable error reducing with the increasing accreditation level of the anthropometrist
(Level 1 being a newly accredited anthropometrist, with level 4 being a criterion or expert
anthropometrist). “This is an objective method of maintaining quality control of all persons
who are accredited” (Norton et al., 1996 p. 397).
1 Technical Error of Measurement (TEM) is the square root of the sum of the differences squared divided by
the number of pairs of scores doubled.
Figure 1: Traditional somatotype photos. The athlete is 77.5 kg and 158 cm with an
anthropometric somatotype of 3.1 - 9.5 - 0.1.
Knowing the expected normal variation between repeated anthropometric measures is
essential for monitoring performance and/or studying the effect of an intervention. To
conclude that an intervention has had a real effect on performance, the change due to the
intervention must be greater than what would normally be expected with repeated
measurements under the same conditions. Examination of repeated trials under the same
conditions provides the reliability or repeatability of the measurements. A reliable test is
one that has small changes in the mean, small within-individual variation (coefficient of
variation) and a high test-retest correlation between the repeated tests (Hopkins, 2000;
Hopkins et al., 2001).
Digital photogrammetry is a relatively new method for measuring limb segments that holds
some advantages when measuring athletes (Blade, 1993; Crawford, 1990). Taking photos
of the athlete with the bony landmarks marked with a pen, allows the anthropometrist to
measure specific body segment lengths using their computer. This method is less invasive
for the athlete and allows a greater number of athletes to be tested in a given time
compared to manually measuring the athletes.
With the recent advancement in digital imaging technology we now have access to photo
images that are as high quality as film. Thus, the present study aimed to determine the
validity and reliability of using digital photogrammetry to determine body segment lengths
compared to the traditional ISAK anthropometric method for 53 powerlifters.
METHODS
Sixty-eight Australasian and Pacific powerlifters (54 males and 14 females) were
measured for 42 anthropometric dimensions (using ISAK protocols). Fifty-three of the
powerlifters agreed to have digital photos taken of them in six planes during the Oceania
Powerlifting Championships and the New Zealand Bench Press Championships.
The Auckland University of Technology Ethics Committee approved this study. All athletes
received verbal and written information about the study and gave written informed consent
prior to anthropometric measurement and being photographed.
Double measures for each of the 42 anthropometric dimensions (triple measures for
skinfolds) were obtained on the right side of the body using the ISAK protocols (Norton et
al., 1996). Measures included eight skinfolds (using a Slimguide calliper with 10 g.mm-2
constant pressure; Creative Health Products, Michigan), 13 limb/body girths (Lufkin
606PM, Cooper Tools, Ohio), 11 limb/body lengths (Rosscraft Segmometer, British
Colombia), four breadths and widths (Rosscraft Anthropometer, British Colombia), height
(Mentone Stadiometer, Victoria) and body mass (Secca scales). All anthropometrists were
ISAK level 2 or 3 accredited.
Digital photos (see Figure 2) were taken in the front and back, left sagittal, right medial leg,
right sagittal arm and right sagittal leg planes using a turntable (Rosscraft, British
Colombia) to rotate the powerlifter. Three of the photos (frontal, back and left sagittal) are
the traditional photoscopic somatotype photos, using the standard somatotype pose. The
other three (right medial leg, right sagittal arm and right sagittal leg) were chosen as they
displayed pen marks on the bony landmarks that were used for the anthropometry.
Figure 2: Digital photogrammetric poses. A) Right sagittal arm; B) Right sagittal leg; C)
Right medial leg. Bony landmarks are marked and visible.
A Fuji FinePix4700 digital camera (Fuji Photo Film, Tokyo), with a resolution of 2400 by
1800 pixels, was mounted on a tripod to record the digital photos of the powerlifters. The
lens to subject distance was 4.5 metres, following guidelines for film somatotype
photographs (Carter & Heath, 1990). Photos were managed by digital asset management
(DAM) software (iPhoto, Apple Computer) and measured using Photoshop 6.0 (Adobe
Systems). The “measure tool” within the Photoshop application was used to measure the
250 mm calibration line drawn on the support box (see Figure 3) to indicate the calibration
correction factor. Using the zoom function in Photoshop, the images on the computer
screen were magnified to 200% of their usual size.
Figure 3: A screenshot of the digital measurement of the Tibale laterale to floor body
segment length using the measure tool in Photoshop. The 250 mm calibration scale is
seen on the support box.
The digital method used the seven standard ISAK body segment lengths (1: Acromiale-