|Year : 2017 | Volume
| Issue : 3 | Page : 153-157
Applicability of video-based training program on inter- and intra-observer variation in common anthropometric parameters measurement in adults
Shaikat Mondal1, Himel Mondal2, Chayan Baidya3
1 Department of Physiology, Medical College and Hospital, Kolkata, West Bengal, India
2 Department of Physiology, M. K. C. G. Medical College, Ganjam, Odisha, India
3 JB Roy State Ayurvedic Medical College, Kolkata, West Bengal, India
|Date of Web Publication||4-Oct-2017|
Department of Physiology, M. K. C. G. Medical College, Ganjam - 760 004, Odisha
Background: Measurement of simple anthropometric parameters (e.g., weight, height) helps in estimation of degree of obesity in clinical and outdoor settings. However, inter- and intra-observer variation in measurement may contribute to bias in measured parameters. These should be minimized to get reliable data for patient management and researches.
Aim: The aim of the study was to find out inter- and intra-observer variation in measurement of common anthropometric parameters by fitness trainer and to check the applicability of a video-based training program on change in variation.
Materials and Methods: Two observers measured weight, height, waist circumference (WC), and hip circumference (HC) in 32 adult males on two occasions in forenoon. After a video based training, observers measured same parameters in same sample on two occasions. Inter- and intra-observer variations were expressed in terms of technical error of measurement (TEM), %TEM, and reliability by coefficient of reliability (R).
Results: Interobserver variation was higher than intraobserver variation in all measurements expressed in %TEM. Before the training, measurement of waist-to-hip ratio (WHR) showed highest %TEM (2.437) followed by HC (1.716 %TEM). Weight measurement showed lowest %TEM (0.075). After the training, all measurements showed a decrease in %TEM. Waist-to-hip ratio showed highest error (1.598%TEM) followed by HC (1.396%TEM). All measurements showed reliability coefficient >0.98 both before and after the training.
Conclusion: In measurement of weight, height, WC, and HC, interobserver variation is higher than intraobserver variation. Variation in circumference measurement is more than length measurement. Simple video-based training program helps in lowering both inter- and intra-observer variation.
Keywords: Body mass index, fitness trainer, interobserver variation, intraobserver variation, technical error of measurement
|How to cite this article:|
Mondal S, Mondal H, Baidya C. Applicability of video-based training program on inter- and intra-observer variation in common anthropometric parameters measurement in adults. Saudi J Sports Med 2017;17:153-7
|How to cite this URL:|
Mondal S, Mondal H, Baidya C. Applicability of video-based training program on inter- and intra-observer variation in common anthropometric parameters measurement in adults. Saudi J Sports Med [serial online] 2017 [cited 2019 May 21];17:153-7. Available from: http://www.sjosm.org/text.asp?2017/17/3/153/215921
| Introduction|| |
Obesity is a trending global epidemic. Considering its footprint worldwide, the World Health Organization (WHO) designated the problem as “globesity.” The WHO also indicated that it is the most neglected public health problem. Body mass index (BMI) is a simple parameter to estimate the level of obesity in clinical settings which is calculated from weight and height. According to the WHO, a person with BMI >25 is overweight and 30 is obese. Waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR) are also easily measurable parameters which reflect the level of central obesity. Even a person with normal BMI with high WC is predisposed to more health risks.,, Hence, measuring these parameters helps clinician, nutritionist, and fitness professionals to stratify population with health risk and then to provide appropriate exercise guidance.
Field surveyors or health professionals can easily measure weight, height, WC, and hip circumference (HC) in outdoor without any sophisticated instrument. However, there may be variation in measurement when different person measures the same subject and when same person measures the subject in different time. The former is known as interobserver variation and later is known as intraobserver variation. These should be kept at minimum level for the reliability of data. The level of inter- and intra-observer variation is also important for research purpose to estimate the level of bias in measured parameters. Training about standard anthropometric procedure helps in reducing the variation and improves reliability. However, providing training for a larger audience is limited by logistics in many cases.
Carefully designed educational video is an effective way to disperse information to large audience. A video clip can be stored and used to educate learners in the future without the instructor. It can be used to train learners in multiple centers at the same time. However, the effectiveness of a video-based training program is unknown in reducing inter- and intra-observer variation.
This triggered the necessity of the current study. The aim of the study was to determine intra- and inter-observer variation in measurement of common anthropometric parameters before and after a video-based training program to find out the effectiveness of the program in reducing the inter- and intra-observer variability.
| Materials and Methods|| |
This observational study was aimed to measure noninvasive anthropometric parameters which common people measure in day-to-day life. Hence, formal clearance from the Institutional Ethics Committee was not obtained, but the study was conducted according to the WMA Declaration of Helsinki after taking written informed consent from the observers and subjects. This study was conducted in March 2017 in Kolkata, India.
Recruitment of observers
Two adult fitness trainers with >2 years' experience in their field were contacted personally. They had experience in measurements of common anthropometric parameters. However, their competency in those measurement techniques was not checked. The study protocol was described to them with detailed purpose of the study. Both of them provided written consent for participation and further use of the study data by the authors. From then onward, they were designated as observer 1 and 2. They were instructed not to refer any literature except which they would be provided during the study.
Recruitment of subjects
Forty apparently healthy adult male subjects were approached from two fitness training centers in Kolkata. They were informed about the aim and procedure of the study. After the briefing, all of them signed the informed consent form for their willingness in the study. However, on the test day, 32 subjects participated in the study. The sampling technique was “convenience sample” where inclusion criteria were male sex and age above 18 years with apparently healthy physique. Person with any limb or skeletal deformity, amputated limb where height measurement is difficult were excluded from the study. Female subjects were not included in the study as both the observers were male.
In a morning, all the participating subjects were measured for weight, height, WC, and HC. Weight was measured by digital weighing scale with 0.1 kg sensitivity. Height was measured by stadiometer in centimeter. Circumferences were measured by fiberglass measuring tape in centimeter. One observer measured the parameters in 32 subjects continuously when other observer was not present in the room. After completion of measurement by observer 1, observer 2 measured anthropometric parameters in all subjects without the presence of observer 1. After completion of measurement by observer 2, observer 1 again measured all the parameters again on the same set of subjects. After that, observer 2 again measured the parameters on the subjects. After measurement, BMI was calculated from weight and height (BMI = weight [kg]/height [m] 2), WHtR was calculated from WC and height (WHtR = WC [cm]/height [cm]), and WHR was calculated from WC and HC (WHR = WC [cm]/HC [cm]). First set of measurements by any observer was considered for interobserver variation test. All these parameters were measured before lunch and food or fluid intake or any exercise were not allowed for the subjects during the time span of 4 rounds of measurement.
After the lunch, on the pretraining day of anthropometry, observers were shown a video clip about standard procedure of anthropometric measurement according to guidelines by the International Society for the Advancement of Kinanthropometry. The same video clip was also provided for their mobile phone. The video was comprised of 5 components. First component described the general precaution during anthropometry. Following 4 components were about specific measurements. Procedure of weight measurement was shown on digital weighing scale. Standing height measurement by stadiometer to nearest 0.1 cm was shown with proper position of the subject. WC measurement by fiberglass measuring tape to nearest 0.1 was shown and the position of the subject and proper placement of the tape was shown at the level between lower palpable rib and upper border of iliac crest. HC measurement by same tape to nearest 0.1 cm at the maximum girth of hip was shown and adequate privacy measures were described.
On the next day morning, four rounds of anthropometric measurements by 2 observers were conducted with the same order as pretraining day. Observers used the same instruments which were calibrated after the 1st day use.
Collected data were entered into spreadsheet software and all the statistical analysis were done manually in that spread sheet computer program.
Technical error of measurement (TEM) carries the same unit that of the anthropometric parameter (e.g., centimeters for WC). For the current study, we measured interobserver variability with 2 observers and intraobserver variability with 2 measurements. The formula used for calculation of absolute TEM was:
Where D = difference between two measurements (deviation) (e.g., for interobserver variability, observer 1 measured WC of a subject as 90 cm, observer 2 measured WC of same subject as 89.5 cm. Then, D = 90 − 89.5 = 0.5 cm. Similarly, for intraobserver variability, one observer measures WC of a subject as 80 cm and again after a time gap, same observer measures WC of the same subject as 81.8 cm. Then, D = 80 − 81.8 = −0.8).
N = number of subjects measured.
Relative TEM (%TEM) is used to compare TEM of two variables as it is expressed in percentage only. For calculation of %TEM, variable average value (VAV) was calculated from the available data. For VAV calculation, first, mean was calculated between two measured values for each individual. Then, mean values of all the subjects were added and divided by the number of subjects (i.e., mean of all means). After calculation of VAV, %TEM was calculated from the following formula:
Coefficient of reliability (R), ranges from 0 to 1, denotes consistency in measurement by two observers in interobserver reliability and consistency in measurement on same subject by same observer in intraobserver variability. For getting R value, first, total TEM was calculated from the following formula:
Where intra1TEM = intraobserver TEM for observer 1,
intra2TEM = intraobserver TEM for observer 2,
and interTEM = interobserver TEM.
After that, R was calculated from the following formula:
where total standard deviation 2 (SD 2) is the total intersubject variance. For calculation of total SD 2, first, variance of each pair of measurements was calculated; then, they were added together.
Calculated data were presented in tabular form for comparison.
| Results|| |
Mean age of subjects participated in the study was 27.3 ± 5.6 years. Result of interobserver variation before and after training, and reliability is shown in [Table 1]. Intraobserver variation of 2 observers in pretraining day and posttraining day is shown in [Table 2].
|Table 1: Interobserver variation in anthropometric measurement by two observers in 32 adult male before and after video-based training|
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|Table 2: Intraobserver variation in anthropometric measurement by two observers in 32 adult male before and after video-based training expressed in technical error of measurement and percentage technical error of measurement|
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| Discussion|| |
Interobserver variation and reliability in practicing faintness professionals before the training program showed higher %TEM for circumference (1.716%TEM for HC and 1.597%TEM for WC) when compared to length measurement (0.174%TEM for height). Among measured parameters, weight measurement showed minimum %TEM (0.075). All the measured parameters showed almost similar level of reliability (R > 0.98). Although the absolute TEM for WHtR was least (TEM = 0.004) among calculated parameters, BMI showed least %TEM (0.376).
In the training program, observers gained knowledge about precise measurement about height, weight, WC, and HC. Assimilation of this knowledge is reflected by the posttraining anthropometry. Relative TEM for all measured parameters was reduced after the training with similar level of reliability as of pretraining anthropometry. As %TEM of measured parameters was reduced, hence, the %TEM of calculated parameters were also reduced. There are several advantages of video-based training program. When a video is recorded, it can be used multiple times in training programs. If it is necessary to conduct training simultaneously in different centers, it can be done effectively with the video. Even a video can be shared online for the targeted audience. However, there are few limitations also. Interaction with the speaker is one of the important parts which is not possible with video-based training.
Intraobserver variation before training was lower than interobserver variation. Measurement technique used by an observer may differ from another observer. This may be the reason behind lower variation in intraobserver variation test. After the training program, intraobserver variation was also reduced.
The study conducted by Sebo et al. from Switzerland found that circumference measurement has higher interobserver variability when compared with length and weight measurement. Authors also showed that training program can reduce the variation in circumference measurement. Nádas et al. from Hungary also reported that there is higher inter- and intra-observer variability in measurement of WC when compared with that of BMI. Stomfi et al. from Hungary found higher interobserver technical error in circumference measurement than that of height measurement in children. These findings are supported by our study.
Higher interobserver variation in WC measurement may be attributed to difficulty in placement of measuring tape in proper horizontal plane and variation in respiratory movements of abdomen. HC measurement difficulty may be due to difference in assumption or palpation of maximum girth of hip and control of tensile strength of measurement of tape as there is gap in front of pubic area. These difficulties are not faced during height measurement. Weight measurement showed least variation in measurement. Hence, BMI is still a reliable parameter to estimate obesity from measurement point of view. In addition, for measurement of central obesity, WHtR is better than WC and WHR.
Limitations of the study
Observers measured anthropometric parameters on male subjects only. Difference in thickness of hair may contribute to measurement bias in height which was beyond control. We did not measure the competency of observers in anthropometric measurements before the training. After the training program, theoretical knowledge gained from the program was not assessed.
| Conclusion|| |
Interobserver variation is higher than intraobserver variation in measurement of weight, height, WC, and HC. Inter- and intra-observer variation is more in circumference measurement than length measurement. Simple video clip-based training program helps in decreasing both inter- and intra-observer variation in measurement. Weight by digital weighing scale and height by stadiometer showed minimum technical error; thus, BMI showed least variation in inter- and intra-observer measurement. WHtR is better than WHR for measurement of central obesity.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]