Article

Accuracy of the Omron HBF-500 Body Composition Monitor in Male and Female College Students

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Abstract

Int J Exerc Sci 4(1) : 93-101, 2011. The Omron HBF-500 is an inexpensive body composition monitor that incorporates both hand-to-hand and foot-to-foot electrical impedance technology. At this time, studies examining the accuracy of the HBF-500 when estimating percent body fat (%BF) are scarce and if this instrument gains popularity due to its claimed precision, comparisons against validated techniques should be conducted. The purpose of this study was to assess the accuracy of the Omron HBF-500 body composition monitor using the BOD POD as a criterion. Forty-eight men and 33 women participated in the study (24.3±6.9 years, 171.0±10.0 cm, 78.4±18.0 kg, 26.6±5.1 kg/m 2). Participants were asked to refrain from exercise and caffeine on the day of testing, not eat a heavy meal three hours prior to measurement (a meal that would typically constitute breakfast, lunch or dinner), and to remain normally hydrated. Participants removed all jewelry and garments down to skintight clothing such as swimsuits or cycling shorts and were assessed on the BOD POD and Omron according to manufacturer's guidelines. The Omron significantly overestimated %BF compared to the BOD POD in males (24.4±8.0 % and 22.9±9.1 %, respectively), and females (35.5±7.7 % and 30.1±7.9 %), p = .001. The Omron was significantly correlated with the BOD POD when assessing body fat, r= .95. The estimates of %BF produced by the BOD POD and HBF-500 differ considerably. Consequently, caution should be taken when using the Omron HBF-500 as a measure of body fat. However, given the difference of only 1.5% BF between the two methods, perhaps males could use the HBF-500 to gain a general idea of body composition status. For females, the degree of overestimation is too high to be suitable for this purpose and incorrect categorization of %BF status could result. In cases where an accurate estimate of %BF is crucial, using a more established method than the Omron is recommended.

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... The data were estimated using an Omron HBF-362 KaradaScan body composition monitor which measures w, is given h and reports BMR, BMI, body fat (BF) and skeletal muscle (SM), among other parameters. This instrument is fairly commonly used [14,15] and other models made by the same manufacturer are also in use [16][17][18][19][20][21][22][23][24]. There are some reports of comparative tests that indicate that these are reasonably reliable instruments [16,23,[25][26][27][28]. ...
... This instrument is fairly commonly used [14,15] and other models made by the same manufacturer are also in use [16][17][18][19][20][21][22][23][24]. There are some reports of comparative tests that indicate that these are reasonably reliable instruments [16,23,[25][26][27][28]. Despite all this work, it appears that the equation used by these instruments to calculate BMR or BF have not been released by the manufacturer [17], certainly none of the user manuals we have examined give any indication. ...
... Not only does that impede efforts to recover the data, but it makes it difficult to detect some errors in the instrument. No matter how much reliability testing is done [16,23,[25][26][27][28], manufacturers should be encouraged to provide researchers (and other users) with better access to the data stored in the microprocessor and explicit information about the calculations performed by the instrument. ...
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Many clinically significant parameters are estimated from height (h), weight (w) and age (y). Two important examples are body mass index (BMI) and basal metabolic rate (BMR). There are circumstances when it might be desirable to estimate h, w and y for a particular subject from BMI and BMR (or other similar combinations). While there is only one mathematical expression for BMI, there are many competing expressions for BMR which complicates this process.Here we describe methods for solving this problem for three different classes of BMR equation when the coefficients are known. We also provide means of identifying the coefficients of an unidentified BMR equation. We apply these technique to our own data, data published by others and in computer simulations, from which we conclude that in the most challenging case our method yields the correct result in more than 99% of cases and identifies the likelihood of error in about 0.96% of cases, leaving only about 0.03% of cases of unidentified error. Application of these techniques to data obtained using an Omron HBF-362 demonstrate some of the difficulties that can arise.
... The body composition methodology used in this study, foot-to-foot BIA, has questionable validity. Pribyl et al. (8) recently reported statistically significant inaccuracies in %BF estimations using the Omron HBF-500, the same model foot-to-foot BIA device used in the present study, compared to the Bod Pod in a sample of college students. Thus, there is some uncertainty about the precision of this method to detect small changes in fat and fat-free mass. ...
... Another limitation was the body composition assessment method used. Pribyl et al. (8) questioned the accuracy of the Omron HBF-500 device, and the variability in hydration status is thought to be a source of error with the BIA method (6). Fulco et al. (5) reported an inconsistent result from BIA compared to hydrostatic weighing in a group of soldiers that had spent 16 days between 3700 and 4300 m. ...
Article
Sojourns to high altitude have resulted in weight loss, but there is a lack of data from guided commercial expeditions. The purpose of this study was to determine the body mass and composition changes in mountaineers after a commercial climbing expedition on Denali (6194 m). Eleven mountaineers began the expedition, and 8 (5 clients, 3 guides; 7 males, 1 female; age: 37.4 ± 10.1 yrs) completed the study; all 8 reached the summit. Pre- and post-data, spanning 21 days, were collected in Talkeetna, AK (105 m). Body mass and body fat percentage (%BF) were obtained with a fullbody bioelectrical impedance scale. Every participant lost weight (-2.9 ± 1.4 kg, P = .001; -0.8 to -5.2 kg), and on average there was a significant drop in %BF (-3.0 ± 3.1% BF, P = .029). There was a tendency for the clients to lose more weight (-3.5 ± 1.1 kg vs. -2.0 ± 1.5 kg, P = .149) and %BF (-4.8 ± 1.4% BF vs. -0.1 ± 3.1% BF, P = .024) than the guides. Neither the pre-expedition mass nor %BF were significantly (P>0.05) correlated with the losses. Despite sleeping only 3 nights above 5000 m with no food restrictions, mountaineers lost a significant amount of mass and %BF during a 3-wk commercial expedition on Denali. Additional research is needed with a larger sample to make more definitive comparisons between groups of mountaineers (commercial vs. non-commercial expeditions, clients vs. guides, and males vs. females).
... Likewise, Gibson et al. (18) found that a hand-to-hand BIA device significantly underestimated %fat from hydrostatic weighting (HW) in men by 1.4% and in women nonsignificantly by 0.2%. Pribyl et al. (39) noted a hand-to-hand BIA device significantly overestimated ADP %fat in both men and women. Weaver et al. (50) also found a hand-tohand device significantly underestimated women's %fat by an average of 2.4% compared to ADP, with a moderate validity coefficient (r = 0.75). ...
... All participants were encouraged to be adequately hydrated. Although previous studies have discussed the effect of food and liquid intake prior to measurement and have noted trivial effects on body composition components (35), the current protocol may be more typical of procedures revolving around practical considerations of the schedule of college students and athletes (8,14,30,38,39,50). No participants under the age of 18 years were included in the study. ...
Article
Bioelectric impedance analysis (BIA) devices are commonly used to estimate percent body fat (%fat), although validation of their accuracy varies widely. The purpose of this study was to assess the validity of four commonly used BIA devices compared to dual-energy X-ray absorptiometry (DXA). College-aged men (n = 29, age = 19.7 ± 1.2 y, weight = 76.9 ± 12.5 kg) and women (n = 31, age = 20.5 ± 0.8 y, weight = 61.5 ± 9.2 kg) were evaluated for %fat using four single-frequency (50 mHz) BIA devices and DXA. A gender × device repeated measures ANOVA indicated some less expensive BIA devices produced %fat values that were not significantly different from DXA. A thumb-to-thumb BIA device produced the closest values in men (21.9 ± 6.6%) and women (32.1 ± 5.3%) compared to DXA (20.6 ± 6.1% and 30.3 ± 5.4%, respectively). The two more expensive BIA devices significantly underestimated in men (14.7 ± 5.8% and 17.0 ± 5.6%) and women (23.3 ± 4.2% and 23.3 ± 4.2%) compared to DXA. Interclass correlation coefficients with DXA were higher for the more expensive devices in men (ICC = 0.899 and 0.958) than the less expensive devices (ICC = 0.681 and 0.730). In women, all BIA devices showed moderate correlations with DXA (ICC = 0.537 to 0.658). Despite the convenience of simple BIA devices, their use in estimating body composition in young men and women might be questionable due to large variations in the differences between DXA and each device in this study.
... It is a noninvasive and fast method for evaluating the body composition by emitting a low, safe dose of current that passes through the muscles without resistance. In contrast, some resistance exists when passing through fat (Omron BF511) (PRIBYL et al., 2011). ...
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Proper growth and development of young school children require mastering different skills, especially gross motor skills-basic locomotor and manipulative skills. It is essential to monitor the physical activity of nine-year-old children necessary for further proper development and healthy habits, which will continue into adulthood. This study aims to determine physical activity level, BMI, and gender differences in the performance of gross motor skills in children aged nine years (± six months). The study involved 40 participants (20 girls and 20 boys). Their body height, body weight, and body mass index were 140.46 ± 5.72 cm; 37.84 ± 8.21 cm; and 19.09 ± 3.56, respectively. All participants completed the Physical Activity Questionnaire for Children and performed the Test of Gross Motor Development, Second Edition (TGMD-2), and two sub-tests of BOT-2 (Speed and Agility and Upper-Limb Coordination). T-test for independent samples was used to compare groups according to physical activity level (physically active and inactive group) and explore interactions with gender and BMI, and gross motor skills variables. F-values, p-values, and partial eta squared (ɳ 2) values were reported as MANOVA outcomes. The results showed a significant difference between physical activity level and locomotor skills but not in manipulative skills. Further research should focus on various exercise programs that contribute to developing skills and participation in organized physical activity of children of different ages.
... This happened due to two reasons. Firstly, the male cadets were numerically a bigger sample and secondly, due to the fact that the device that we used to measure their BF % was reported to be more accurate for male subjects than for female [23]. The main challenge, however, comes in setting appropriate fat standards to support the full range of Army requirements [24]. ...
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The purpose of this study was twofold: Firstly, to examine the use of Body Mass Index (BMI) and Body Fat (BF %) measurements in order to monitor the cadets in the Hellenic Army Academy and secondly, to evaluate the aspects that enhance the performance of the cadets in specific physical activities, in order to help them to be more efficient in their duties as officers. More specifically, this study sets out to examine the advantage or disadvantage that cadets, with specific body composition have towards their peers and whether these characteristics can predict their performance in specific tests. Anthropometric measurements (height, body mass, BMI and BF %) and performance in specific physical tests were assessed for 868 male cadets with an average age of 19.9±1.6 years from all 4 undergraduate classes of the Academy. The results were extracted through odds ratios analysis for the different categories. It was shown that the cadets who belonged to groups with lower BMI and BF % had an advantage in their performance during the tests. BF % was presented as a more accurate predictor than BMI and the odds ratios for the tests revealed interesting associations, between the BF % of the cadets and their probability to accomplish specific tasks, which may help to enhance performance. In conclusion, it was recommended to use more than one anthropometric component for classification of the cadets and not to depend solely on BMI values, in order to have a more holistic picture of their physical condition and physical activity levels.
... beginning to use octopolar techniques at a significantly lower cost than laboratory measures. An Omron HBF-500 has been tested on college students with favorable results in male students (Pribyl, Smith, & Grimes, 2011) and female students (Peterson, Repovich, & Parascand, 2011) using the ADP (e.g., BOD POD) as the criterion measure. In the latter study, its accuracy was shown to be superior (less residual) to the Omron 306, which was also included in the comparison study. ...
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The purpose of this study was to test the convergent validity of Omron 306 using Biospace InBody 720. A total of 267 participants (145 boys; aged 10.4-17.9 years) completed testing during a single session. Each measure provided percent body fat (%BF), while the InBody 720 included fat-free mass (FFM). The validity was examined using the Pearson correlation. Limits of agreement (LOA) and multiple linear regression were also used to determine the impact of both age and FFM on the associations between the 2 measures. The 2 measures of %BF were correlated by .63 (p < .001) in boys and .89 (p < .001) in girls. The mean difference (i.e., InBody - Omron) for %BF in boys was - 4.7% with a lower LOA of - 20.5% and upper LOA of 11.2%. The same comparison for girls resulted in a difference of 3.0% with a lower LOA of - 10% and upper LOA of 4%. Examination of the residuals obtained from multiple linear regression indicated that FFM was the only statistically significant predictor of differences in boys (βFFM = - 0.25 ± 0.08%, p = .001). There were no significant associations for girls. Findings indicate that estimates of %BF obtained from Omron in boys exceed estimates from InBody 720. Disagreement was evident in younger boys with lower levels of FFM. Girls' %BF was closer between the 2 bioelectrical impedance analyzer measures (less residual) with age and FFM not explaining the disagreement. Overall, the 2 measures were not equivalent.
... Although the present study did not originally focus on the reliability of the employed analyzers, it can be concluded that both the analyzers are sufficiently precise and, as such, suitable for the study. The ICC values at all the observed parameters exceeded 0.9 and thus correspond with the results presented in the series of studies though the authors of those studies carried out the repeated measurements immediately one after another (in a "test-retest" manner) [21,23,[31][32][33][34][35][36][37]. Similar ICC values were detected in the study focused on the correlation of the values measured between 2 days by the Tanita TBF-350 analyzer [38]. ...
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Background The present study analyses changes in body composition over the course of a working week. The purpose of the study is to identify the size of the changes in the observed parameters by means of typical error of measurement (TE) as the initial value for the interpretation of the detected changes in the repeated measurement in diagnostic practice. Methods The researched group consisted of 86 males, aged 21.4 ± 1.0 years. All the participants were free of any medical conditions. The measurement of each participant took place over 1 week from Monday till Friday, in the morning hours. Parameters measured: body mass (BM), total body water (TBW), and body fat (BF). The measurement employed two devices using the bioelectric impedance analysis. These devices were the analyzers Tanita BC 418 MA and Nutriguard MS. In order to assess the differences between the average values, the analysis of repeated measurements was used. To assess the material significance, eta squared was used. TE was used to express the size of the changes in the observed parameters. Results A statistically significant difference between the average values of the observed parameters was only detected when using the Tanita BC 418 MA analyzer. Based on the post-hoc tests, these differences in the average values were always detected on Monday and Friday. No material significance was proved, however. The highest TE values were also detected in measurements carried out on Monday and Friday. For BM, the value of TE was 0.6 kg, for TBW 1.0–1.1 %, 0.8–0.9 kg, and for BF 1.2–1.6 %, 1.1–1.3 kg depending on the analyzer used. Conclusions The results of the present study demonstrate the stability of parameters of body composition throughout a working week, with the provision that standard measuring conditions are fulfilled. For the purpose of diagnostic practice, when interpreting the results of the repeated measurements, it is advisable to take as provable change caused by the observed factors only the ones whose values exceed the value of a weekly TE or the upper limit of the interval of the measurement reliability.
... The measured ICC values within the range from 0.983 to 0.997 are completely in accordance with the results presented in those studies. Authors most often state ICC values ranging from 0.932 to 1.000 for the BIA method in relation to the used device and the monitored group [21][22][23][24][25][26][27][28]. ...
... These monitors work on the principle of bio-impedance, are portable and easy to use within the confines of the submarine. [7], [8] The monitoring of weight and body composition should be supplemented by measurement of waist circumference, waist-to-hip ratio and skin fold thickness. ...
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Physical activity onboard the diesel-electric submarines is as it is restricted due to lack of space onboard. In the absence of physical activity, one would expect the weight of the submarine crew to increase during the period of deployment at sea. Submarine crew were seen to be consuming 3168±282 kCal/day while doing hard physical work but DIPAS, New Delhi designed ration scales for the submarine crew which were to provide 3640 kCal/day. In such a scenario, a high calorie intake with low physical activity at sea would be of grave concern for long term health status of the crew. Data from an Indian submarines during a 26 day sortie involving 42 crew members revealed that weight gain occurred in 29 crew members. When food remains an important motivator at sea to break the monotony, restriction of intake is important and that can be brought about only by motivation and individual awareness. Data from a US Navy study have shown that this is possible and implementable and the solution seems quite simple.
... Similar to whole-body SF-BIA devices, the validity of these devices for accurately and reliably predicting body composition has been questioned. In healthy populations, foot-to-foot devices can be considered as a useful alternative to whole-body devices, whereas the validity of hand-to-hand devices has been particularly questioned (115) , with one study of 81 healthy individuals demonstrating a significant overestimation of percentage body fat in women of approximately 5%, leading to potential misclassification of nutritional status (116) . Furthermore, anecdotally, the validity of any results obtained in the home setting may be questionable because individuals may not consistently adhere to a standardised measurement process. ...
Article
The accurate and valid assessment of body composition is essential for the diagnostic evaluation of nutritional status, identifying relevant outcome measures, and determining the effectiveness of current and future nutritional interventions. Developments in technology and our understanding of the influences of body composition on risk and outcome will provide practitioners with new opportunities to enhance current practice and to lead future improvements in practice. This is the second of a two-part narrative review that aims to critically evaluate body composition methodology in diverse adult populations, with a primary focus on its use in the assessment and monitoring of under-nutrition. Part one focused on anthropometric variables [Madden and Smith (2016) J Hum Nutr Diet 29: 7-25] and part two focuses on the use of imaging techniques, bioelectrical impedance analysis, markers of muscle strength and functional status, with particular reference to developments relevant to practice.
... Body composition (fat, muscle and visceral masses) was studied by bioelectrical impedance (Omron-HBF 500 system) according to manufacturer instructions (correlation with air displacement plethysmography in women, r= 0.85, p<0.01, % error=18.3) 19 . ...
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Purpose: The influence of regular exercise on bone properties is not well defined. Frail subjects have limitations to perform exercise with skeletal impact. This study aims to analyze whole-bone vibration treatment (WBV) as an enhancer of bisphosphonate effects in postmenopausal frail women with osteopenia/osteoporosis. Methods: Fiftythree postmenopausal sedentary osteopenic women were treated during 12 months with a drinkable alendronate (ALN) formulation. By randomization, 21 of them underwent a WBV (15-min sessions, 3 days per week) as an additional treatment. The serum C-terminal telopeptide of type I collagen (CTx) and total alkaline phosphatase (TAP) were determined at 0, 6 and 12 months of ALN therapy. In subgroups of 19/13 women, peripheral quantitative computerized tomography (pQCT) was applied at the tibia mid shaft to determine the volumetric BMD of cortical bone (CtBMDv) and the polar strain-strength index (SSIp). Results: CTx levels fell significantly deeper in the WBV subgroup (-39.3% and -30.3%, respectively, p<0.01), suggesting that in these women WBV promotes a greater effect of ALN on bone resorption inhibition. Basal CtBMDv and SSIp values were similar in both groups and were weakly (negatively) associated with basal CTx values. After treatment, the correlation between CtBMDv or SSIp values with CTx values were also weak and negative in the Sedentary subgroup but become positive and closer in the WBV subgroup. Conclusions: Vibration treatment enhanced the ALN-induced inhibition of bone resorption and may affect positively bone properties. Protracted treatments should show whether this trend is maintained as toeffectively reduce the incidence of falls and skeletal fractures in frail subjects.
... Hemoglobin A1c (HgA1c) measurements were also taken for participants using the A1cNow SELF-CHECK by Bayer Laboratories [12]; HgA1c measurements evaluate the average blood sugar levels over the previous 3 month period. Body mass index (BMI) and body fat percentage were both calculated using a handheld Omron body composition analyzer, that utilizes weight, height, age and sex to compute precise measurements [22]. Finally, resting metabolic rate (RMR) was assessed using the Metacheck by Korr Medical an instrument designed to use indirect calorimetry (a measurement of heat exchange) to calculate metabolic rate from the measured amount of oxygen consumed by the body [20]. ...
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A worsening epidemic of diabetes and its precursor, metabolic syndrome (MetS) is engulfing America. A healthy individual, with proper glucose regulation has an ability to switch between burning fat and carbohydrates. It has been suggested that signaling errors within this homeostatic system, characterized by impaired switching of substrate oxidation from glucose to fat in response to insulin, can contribute to the etiology of metabolic syndrome and occurs before the development of type II diabetes. Glucose regulation with restored insulin sensitivity facilitated through clinically regulated, benign dietary ketosis (BDK), may significantly reduce, regulate and reverse the adverse pathologies common to MetS and obesity. The study assessed if prolonged maintenance of induced and controlled physiological, dietary ketosis, would reverse pathological processes induced by MetS including a reduction in fasting triglycerides, BMI (body mass index) and body fat mass (BFM), weight, a significant decrease and/or normalization of hemoglobin A1c (HgA1c) and an increase in resting metabolic rate (RMR) and blood ketones. A group of 30 adults, previously diagnosed with MetS by their primary care physician, were randomly prescribed to one of three groups: a sustained ketogenic diet with no exercise, standard American diet (SAD) with no exercise or SAD with 3-5 days per week of exercise (30 min.). The results demonstrated that the change over time from week 0 to week 10 was significant (p=0.001) in the ketogenic group for weight, body fat percentage, BMI, HgA1c and ketones. All variables for the ketogenic group out-performed those of the exercise and non-exercise groups, with five of the seven demonstrating statistical significance.
... The validity of this device has been confirmed in previous studies. [16] All measures have been taken between morning and noon at the beginning and after 12 weeks of intervention. ...
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Background: Obesity in adolescence is the strongest risk factor for obesity in adulthood. This study aimed to evaluate the effects of a comprehensive lifestyle intervention on different anthropometric indices in 12.16.year.old boy adolescents after 12 Weeks of Intervention. Methods: A total of 96 male adolescents from two schools participated in this study. The schools were randomly assigned to intervention (53 students) and control school (43 students). Height and weight of students were measured and their body mass index (BMI) was calculated. Body fat percent (BF) and body muscle percent (BM) was assessed using a bioimpedance analyzer considering the age, gender, and height of students at baseline and after intervention. The obesity reduction intervention was implemented in the intervention school based on the Ottawa charter for health promotion. Results: Twelve weeks of intervention decreased BF percent in the intervention group in comparison with the control group (decreased by 1.81% in the intervention group and increased by 0.39% in the control group, P < 0.01). However, weight, BMI, and BM did not change significantly. Conclusions: The result of this study showed that a comprehensive lifestyle intervention decreased the body fat percent in obese adolescents, although these changes was not reflected in the BMI. It is possible that BMI is not a good indicator in assessment of the success of obesity management intervention.
... The validity of this device has been confirmed in previous studies. [16] All measures have been taken between morning and noon at the beginning and after 12 weeks of intervention. ...
... Estos factores pudieron ser fuente de error aleatorio en las mediciones antropométricas. Asimismo, las balanzas Omron® de la misma serie que el modelo utilizado en este estudio podrían sobreestimar los porcentajes de grasa corporal, especialmente en mujeres (37). Todos estos elementos implican que los valores antropométricos encontrados deben ser utilizados con cautela. ...
... Previous research on the validity of BIA has shown that while correlations are relatively strong (r = .81-.98), investigators have found a wide range of error (1.8-18.3%) (Fornetti et al., 1999;Gibson et al., 2000;Kelly & Metcalfe, 2012;Khaled et al., 1988;Pribyl et al., 2011). Thus, for a given individual, all instruments are not equal when it comes to predictive accuracy. ...
Article
Research comparing portable body composition methods, such as bioelectrical impedance analysis (BIA), to air displacement plethysmography (ADP) is limited. We assessed reliability and validity of predicting fat-free mass (FFM) by the RJL, Omron, and Tanita BIA machines using ADP via BodPod as a criterion. FFM (kg) was assessed twice in college students (N = 77, 31 males and 46 females; age = 19.1 ± 1.2 years) using ADP, RJL, Omron, and Tanita BIAs. Reliability was assessed using analysis of variance to obtain an intraclass correlation statistic (Rxx). Validity was assessed using Pearson correlation (r) coefficient. FFM averaged 75.6 ± 9.4 kg in men and 59.8 ± 7.6 kg in women. Reliability was high in both genders RJL (Rxx = .974-.994), Omron (Rxx = .933-.993), and Tanita (Rxx = .921-.991). Validity within males was also high: RJL (r = .935), Omron (r = .942), and Tanita (r = .934), and only slightly lower in females: RJL (r = .924), Omron (r = .897), and Tanita (r = .898). The RJL, Omron, and Tanita BIA machines appear to be both reliable and valid for predicting FFM of male and female college students. Therefore, any of these three BIA devices is appropriate to use for body composition assessment in a healthy adult population.
... On the day of the first study visit, participants reported to the laboratory and height and body mass were obtained on a wall-mounted stadiometer and calibrated digital scale, respectively. Body fat percentage was then assessed via bioelectrical impedance analysis using an Omron HBF-306CN portable device (Omron Healthcare, Osaka, Japan) (18) prior to familiarization with the isokinetic knee extensor performance test. The isokinetic knee extensor contractile function test was performed on a Biodex System 3 dynamometer (Biodex Medical Systems, Shirley, NY) ...
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International Journal of Exercise Science 13(2): 312-318, 2020. Capsaicin, the active pungent ingredient in chili peppers and various spicy foods, is demonstrated to influence a variety of physiological systems including skeletal muscle. The purpose of this study was to examine if a chewable capsaicin supplement (1.2 mg) could enhance isokinetic knee extensor contractile performance. Nine young, recreationally active individuals (5 females/4 males; 23.6 ± 1.5 yrs; 24.2 ± 3.3 kg/m 2) participated in this randomized, single-blind crossover study. Following a familiarization session, participants completed two isokinetic knee extensor contractile function assessments, 45 minutes after ingesting either a capsaicin fruit gummy or eucaloric placebo, the order of which was randomized. Knee extensor peak torque (strength), summed torque (endurance) and fatigue index (fatigue) were compared between trials. Knee extensor peak torque was significantly greater (p < 0.05; d = 0.80) in the capsaicin (126.0 ± 40.4 N⋅m-1) than the placebo (118.8 ± 41.3 N⋅m-1) trial. No significant differences (p > 0.05) were found for summed torque (8012 ± 2771 vs. 7823 ± 2611 N⋅m-1 ; d = 0.45) or fatigue index (56.0 ± 17.1 vs. 48.7 ± 21.0 %; d = 0.46) between capsaicin and placebo trials, respectively. These findings, in a relatively modest and mixed-gender sample, suggest that pre-exercise capsaicin ingestion may benefit knee extensor muscle strength but does not appear to affect parameters of skeletal muscle endurance or fatigue.
... Obesity was measured by body mass index (BMI) as division of body weight (kg) by the square of height (in meters) (18). Weight was measured to the nearest 100 IRANIAN JOURNAL OF DIABETES AND OBESITY, VOLUME 12, NUMBER 2, SUMMER 2020 g using digital scales (OMRON) (19). After a normal expiration, waist circumference was determined under the midline of the participant's armpit, at the midpoint between the top of the hip and the lower part of the last rib. ...
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Objective: Obesity is associated with inflammatory process and many different diseases. The objective of this study was to assess the impact of short term aerobic training on serum resistin and insulin resistance in adult obese women. Materials and Methods: In this quasi-experimental study, thirty untrained adult obese females matched for age 35-45 years old with body mass index (BMI) 30-36 kg/m2 were divided randomly into exercise (aerobic intervention; 6 weeks, 3 days/weekly, %55-70HRmax) and control (no training) groups. Pre and post-training of fasting blood samples were collected for measure serum resistin. Insulin resistance was calculated by HOMA-IR. Data were analyzed by the independent samples T-test. Results: Aerobic training resulted in significant decrease in BMI (32.1 (± 2.76) vs 31.6 (± 2.80) kg/m2, P-value: 0.023), body fat percentage (44.7 (± 4.55) vs 44 (± 4.33), P-value: 0.028) and fasting glucose (94 (± 8.9) vs 79 (± 5.8) mg/dl, P-value: 0.011) in exercise group. No changes were observed on insulin resistance (1.43 (± 1.11) vs 1.18 (± 0.57) HOMA-IR, P-value: 0.124) and serum resistin (2.20 (± 1.07) vs 1.58 (± 0.87) ng/ml P-value: 0.062) by training program. All variables remained unchanged in control subjects. Conclusion: Despite improving fasting glucose, a short-term aerobic training is not associated with anti-inflammatory property for obese females. Improved glucose could be likely attributed to other changes in metabolic markers in response to exercise training and further studies are necessary to clarify possible mechanisms.
... This device is a digital, mobile, and non-invasive device that has eight electrodes that sends an extremely weak electrical current of 50 kHz and less than 500 πA through the body to determine the amount of muscle tissue. The validity of this device has been confirmed in previous studies [26]. All data were classified according to the z-score guidelines defined by WHO recommendations (for weight and BMI). ...
Article
Introduction: The prevalence of both obesity and vitamin D deficiency has been dramatically increased worldwide. Aim: This study aimed to investigate the association between vitamin D serum level and anthropometric indices of overweight and obese male adolescents at baseline and after 18 weeks of a weight reduction intervention. Material and methods: This study was carried out on 90 male students aged 12 to 16 years who were randomly selected from two schools in Tehran, Iran. The participants were assigned to two groups with high and low vitamin D level based on their serum vitamin D levels at baseline. Five ml blood samples were collected at the baseline and after the 18 weeks of a weight reduction intervention. Height, weight, body mass index (BMI), body fat percent and body muscle percent were measured using a bio impedance analysis (BIA) scale. Results: Vitamin D level in non-obese adolescents was significantly higher than the obese participants (44.01 vs 37.67 ng/dl, p < 0.04). However, there was no significant correlation between changes of vitamin D level and anthropometric measurements after 18 weeks. Adjusting the effect of age did not alter the association. Further adjustments for physical activity, dietary intake of vitamin D, and fat and muscle percentage had no effect on the results. Conclusions: The serum level of vitamin D was negatively associated with obesity, but not with short-term changes of anthropometric measurements in male adolescents.
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Background Over 50% of adults in Latin America and the Caribbean have a body mass index (BMI) ≥ 25 suggesting excess energy intakes relative to energy expenditure. Accurate estimation of resting metabolic rate (RMR), the largest component of total energy requirements, is crucial to strategies aimed at reducing the prevalence and incidence of overweight and obesity. Aim We evaluated the accuracies of established and locally developed RMR prediction equations (RMR P ) among adults. Methods Four hundred adult volunteers ages 20 to 65 years had RMR measured (RMR M ) with a MedGem® indirect calorimeter according to recommended procedures. RMR P were compared to RMR M with values ± 10% of RMR M deemed accurate. Anthropometry was measured using standard procedure. Linear regression with bootstrap analyses was used to develop local RMR P equations based on anthropometric and demographic variables. The University of the West Indies Ethics Committee approved the study. Results Males had higher mean absolute RMR ( p < 0.001) but similar mean age-adjusted measured RMR per kg of body (20.9 vs. 21.5 kcals/day; p = 0.1) to females. The top performing established anthropometry-based RMR P among participants by sex, physical activity (PA) level and BMI status subgroups were Mifflin-St Jeor, Owen, Korth, Harris–Benedict, and Livingston, while Johnstone, Cunningham, Müller (body composition (BC)), Katch and McArdle, Mifflin-St Jeor (BC) were the most accurate BC-based RMR P . Locally developed RMR P had accuracies comparable to their top-ranked established RMR P counterparts. Conclusions Accuracies of established RMR P depended on habitual PA level, BMI status, BC and sex. Furthermore, locally developed RMR P provide useful alternatives to established RMR P .
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The purpose of this study was to determine the validity of the BOD POD® when compared to the DXA and if placement on a percentile chart and standard table is affected by any differences between the two measures. A total of 244 (27.7 ± 10.8 yrs, 77.3 ± 16.1 kg, 171.4 ± 10.1 cm, 26.31 ± 5.42 BMI) males and females between the ages of 18 and 52 were recruited to participate in this study. The participant’s body fat percentage (%BF) was tested in random order on the BOD POD® and DXA during a 30-minute session following manufacturer’s guidelines and procedures. Dependent t-test indicated the %BF measured by the BOD POD® (23.4% ± 12.8) was significantly lower when compared to the DXA (29.5% ± 12.1), p = .001. The Pearson’s Product moment correlation was .95 (p = .001), indicating a very strong relationship between the two instruments. Using estimates of %BF from the BOD POD® also resulted in more favorable shifts on a percentile chart and standard table. Since a high correlation was evident between the two, the BOD POD® can be used as an instrument to track %BF changes over time during a diet and/or exercise intervention. However, caution should be made when classifying %BF with percentile charts or standard tables using the BOD POD® %BF estimates.
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Air displacement plethysmography (ADP) may provide a partial alternative to body density (Bd) and therefore body composition measurement compared to conventional hydrodensitometry (Hd) in children. As there are no evaluation studies of ADP in children, this study had a two-fold objective: to compare Bd estimates by ADP and Hd; and to compare fat estimates by both ADP and Hd to fat estimates by another reference method, dual energy X-ray absorptiometry (DXA). Obesity Research Center, St. Luke's/Roosevelt Hospital, New York, USA. One hundred and twenty subjects (66 females/54 males) who ranged in age from 6-86 y and in body mass index (BMI, kg/m2) from 14.1-40.0 kg/m2 met study entry criteria. Cross-sectional study of healthy children (age < or = 19 y) and adult group for comparison to earlier studies. Each subject completed ADP, Hd, and DXA studies on the same day. Only subjects with subjectively-judged successful Hd studies were entered into the study cohort. There was a high correlation between Bd by ADP and Hd (Bd Hd = 0.11 + 0.896 x Bd ADP; r = 0.93, SEE = 0.008 g/cm3, P < 0.0001), although the regression line slope and intercept differed significantly from 1 and 0, respectively. Additional analyses localized a small-magnitude Bd bias in the child (n = 48) subgroup. Both ADP and Hd %fat estimates were highly correlated (r > 0.9, P < 0.0001) with %fat by DXA in child and adult subgroups. Bland-Altman analyses revealed no significant %fat bias by either ADP or Hd vs DXA in either children or adults, although a bias trend (P = 0.11) was detected in the child subgroup. With additional refinements, the air displacement plethysmography system has the potential of providing an accurate and practical method of quantifying body fat in children as it now does in adults.
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This study compared air displacement plethysmography (ADP), which relies on measurements of body density to estimate body fat, with three other techniques that measure body composition: (1) hydrostatic weighing (HW), which also measures body density; (2) bioelectrical impedance (BIA), which determines electrical resistance and total body water to estimate fat-free mass; and (3) dual-energy x-ray absorptiometry (DXA), which measures bone, fat, and fat-free soft tissue masses. ADP, HW, BIA, and DXA were performed on 20 healthy volunteers (10 males and 10 females). The subjects were within 20% of ideal body weight, 31.1 +/- 1.8 years of age, and 75.4 +/- 2.7 kg with body mass index values of 25.2 +/- 0.9 (kg/m2) and percent body fat by ADP ranging from 6.0% to 41.0%. Percent body fat measurements by the four methods were highly correlated (r > .90, p < .0001). Mean body fat as determined by ADP, HW, BIA, and DXA were 23.4% +/- 2.3%, 23.9% +/-1.8%, 23.1% +/- 1.9%, and 26.4% +/- 2.4%, respectively (* p < .05 vs ADP). There was a significantly positive slope (+0.23) for the individual differences vs the average of ADP and HW percent body fat, demonstrating a slightly negative difference at lower body fat levels and a slightly positive difference at greater body fat levels. Although the average percent body fat determined by ADP was similar to that by HW for the entire population, there was a significant gender difference with the average body fat measured by ADP being 16% less in males and 7% greater in females than that determined by HW. Body fat measurements using ADP were highly correlated with those using HW, BIA, and DXA across a relatively wide range of body fat levels in healthy adults. These results support the utility of ADP as a relatively new technique in the estimation of percent body fat in healthy adults. However, the error associated with gender and the level of body fat is not negligible and requires further investigation.
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To assess the acceptability and feasibility of whole body air displacement plethysmography in children and to determine its precision and agreement with hydrodensitometry, an appropriate reference method. Age specific two component model equations were used to predict fat mass from body density in 22 children aged 8-12 years and in 10 adults for comparison of methods. Precision for each method was established from duplicate measurements. Plethysmography was accepted more readily than hydrodensitometry (100% v 69% provided duplicate measurements). Precision for fat mass in children was 0.38 kg by plethysmography and 0.68 kg by hydrodensitometry, and results were similar in adults. The mean (SD) fat mass in children was 6.9 kg (4.0) and 6.7 kg (4. 2) by plethysmography and hydrodensitometry, respectively, but 95% limits of agreement between methods were large (-4.1 kg to 3.5 kg fat). Plethysmography was more readily accepted and had better precision than hydrodensitometry. It also provided similar body composition results for the group but not for all individual children.
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The objective of this study was to determine the effect of body hair (scalp and facial) on air displacement plethysmography (BOD POD) estimates of percentage of body fat. A total of 25 men (31.4 +/- 8.0 years, 83.4 +/- 12.2 kg, 181.8 +/- 6.9 cm) agreed to grow a beard for 3 weeks to participate in the study. Total body density (g/cm(3)) and percentage of body fat were evaluated by BOD POD. To observe the effect of trapped isothermal air in body hair, BOD POD measures were performed in four conditions: criterion method (the beard was shaven and a swimcap was worn), facial hair and swimcap, facial hair and no swimcap, and no facial hair and no swimcap(.) The presence of only a beard (facial hair and swimcap) resulted in a significant underestimation of percentage of body fat (16.2%, 1.0618 g/cm(3)) vs. the criterion method (17.1%, 1.0597 g/cm(3), p < 0.001). The effect of scalp hair (no swim cap worn) resulted in a significant underestimation in percentage of body fat relative to the criterion method, either with facial hair (facial hair and no swimcap; 14.8%, 1.0649 g/cm(3)) or without facial hair (no facial hair and no swimcap; 14.8%, 1.0650 g/cm(3), p < 0.001 for both). A significant underestimation of percentage of body fat was observed with the presence of facial hair ( approximately 1%) and scalp hair ( approximately 2.3%). This underestimation in percentage of body fat may be caused by the effect of trapped isothermal air in body hair on body-volume estimates. Thus, excess facial hair should be kept to a minimum and a swimcap should be worn at all times to ensure accurate estimates of body fat when using the BOD POD.
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Laboratory-based body-composition techniques include hydrostatic weighing (HW), dual-energy X-ray absorptiometry (DXA), measurement of total body water (TBW) by isotope dilution, measurement of total body potassium, and multicompartment models. Although these reference methods are used routinely, each has inherent practical limitations. Whole-body air-displacement plethysmography is a new practical alternative to these more traditional body-composition methods. We reviewed the principal findings from studies published between December 1995 and August 2001 that compared the BOD POD method (Life Measurement, Inc, Concord, CA) with reference methods and summarized factors contributing to the different study findings. The average of the study means indicates that the BOD POD and HW agree within 1% body fat (BF) for adults and children, whereas the BOD POD and DXA agree within 1% BF for adults and 2% BF for children. Few studies have compared the BOD POD with multicompartment models; those that have suggest a similar average underestimation of approximate 2-3% BF by both the BOD POD and HW. Individual variations between 2-compartment models compared with DXA and 4 -compartment models are partly attributable to deviations from the assumed chemical composition of the body. Wide variations among study means, -4.0% to 1.9% BF for BOD POD - HW and -3.0% to 1.7% BF for BOD POD - DXA, are likely due in part to differences in laboratory equipment, study design, and subject characteristics and in some cases to failure to follow the manufacturer's recommended protocol. Wide intersubject variations between methods are partly attributed to technical precision and biological error but to a large extent remain unexplained. On the basis of this review, future research goals are suggested.
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The purpose of the study was to compare estimates of body density and percentage body fat from air displacement plethysmography (ADP) to those from hydrodensitometry (HD) in adults and children and to provide a review of similar recent studies. Body density and percentage body fat (% BF) were assessed by ADP and HD on the same day in 87 adults aged 18-69 y (41 males and 46 females) and 39 children aged 8-17 y (19 males and 20 females). Differences between measured and predicted thoracic gas volumes determined during the ADP procedure and the resultant effects of those differences on body composition estimates were also compared. In a subset of 50 individuals (31 adults and 19 children), reliability of ADP was measured and the relative ease or difficulty of ADP and HD were probed with a questionnaire. The coefficient of reliability between %BF on day 1 and day 2 was 96.4 in adults and 90.1 in children, and the technical error of measurement of 1.6% in adults and 1.8% in children. Using a predicted rather than a measured thoracic gas volume did not significantly affect percentage body fat estimates in adults, but resulted in overestimates of percentage body fat in children. Mean percentage body fat from ADP was higher than percentage body fat from HD, although this was statistically significant only in adults (29.3 vs 27.7%, P<0.05). The 95% confidence interval of the between-method differences for all subjects was -7 to +9% body fat, and the root mean square error (r.m.s.e.) was approximately 4% body fat. In the subset of individuals who were asked to compare the two methods, 46 out of 50 (92%) indicated that they preferred the ADP to HD. ADP is a reliable method of measuring body composition that subjects found preferable to underwater weighing. However, as shown here and in most other studies, there are differences in percentage body fat estimates assessed by the two methods, perhaps related to body size, age or other factors, that are sufficient to preclude ADP from being used interchangeably with underwater weighing on an individual basis.
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To compare percentage body fat (percentage fat) estimates from DXA and air displacement plethysmography (ADP) in overweight and obese children. Sixty-nine children (49 boys and 20 girls) 14.0+/-1.65 years of age, with a BMI of 31.3+/-5.6 kg/m2 and a percentage fat (DXA) of 42.5+/-8.4%, participated in the study. ADP body fat content was estimated from body density (Db) using equations devised by Siri (ADP(Siri)) and Lohman (ADP(Loh)). ADP estimates of percentage fat were highly correlated with those of DXA in both male and female subjects (r=0.90 to 0.93, all p<0.001; standard error of estimate=2.50% to 3.39%). Compared with DXA estimates, ADP(Siri) and ADP(Loh) produced significantly (p<0.01) lower estimates of mean body fat content in boys (-2.85% and -4.64%, respectively) and girls (-2.95% and -5.15%, respectively). Agreement between ADP and DXA methods was further examined using the total error and methods of Bland and Altman. Total error ranged from 4.46% to 6.38% in both male and female subjects. The 95% limits of agreement were relatively similar for all percentage fat estimates, ranging from +/-6.73% to +/-7.94%. In this study, conversion of Db using the Siri equation led to mean percentage fat estimates that agreed better with those determined by DXA compared with the Lohman equations. However, relatively high limits of agreement using either equation resulted in percentage fat estimates that were not interchangeable with percentage fat determined by DXA.
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The aims of this study were to validate BOD POD in a wide sample of healthy and independent Mexican elderly men and women subjects using the 4 compartment (4C) model as the reference method, and to evaluate the assumptions of the densitometric two-compartment (2C) model. Cross-sectional study designed to assess body composition and validation of a method based on 2C model (BOD POD). Urban and rural regions of Sonora, Mexico. Two hundred and two free-living subjects >or=60 years old were completed in this study. Body density and body fat were measured by the BOD POD, total body water by deuterium dilution and total body bone ash by dual energy X-ray absorptiometry. Body composition was determined using Baumgartner's equation. Percent body fat by the 4C model was 31.2 and 42.5% in men and women, respectively (P<0.001). Group mean accuracy of body fat by BOD POD against that of the 4C model showed an effect of sex (P<0.001), but not the method (P=0.27). Results of individual accuracy showed no significant difference with the identity line and the slope was significantly different from zero or a slope similar to one. Precision assessed by model R (2) was high for all subjects and for men and women by separate. The standard error of the estimate was low for all and for men and women by separate. Bland and Altman analysis showed no significant bias. The BOD POD technique is a valid and reliable method compared to the 4C model and it could be applied in subjects with similar physical and anthropometric characteristics to subjects of this study.
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In clinical measurement comparison of a new measurement technique with an established one is often needed to see whether they agree sufficiently for the new to replace the old. Such investigations are often analysed inappropriately, notably by using correlation coefficients. The use of correlation is misleading. An alternative approach, based on graphical techniques and simple calculations, is described, together with the relation between this analysis and the assessment of repeatability.
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Over the past decade, considerable attention has been paid to accurately measuring body composition in diverse populations. Recently, the use of air-displacement plethysmography (AP) was proposed as an accurate, comfortable, and accessible method of body-composition analysis. The purpose of this study was to compare measurements of percentage body fat (%BF) by AP and 2 other established techniques, hydrostatic weighing (HW) and bioelectrical impedance analysis (BIA), in adults. The sample consisted of healthy men (n = 23) and women (n = 24). %BF was measured by AP, HW, and BIA. In the total group, %BF(AP) (25.0+/-8.9%) was not significantly different from %BF(HW) (25.1+/-7.7%) or %BF(BIA) (23.9+/-7.7%), and %BF(AP) was significantly correlated with %BF(HW) (r = 0.944, P < 0.001) and with %BF(BIA) (r = 0.859, P < 0.01). Compared with HW, AP underestimated %BF in men (by -1.24+/-3.12%) but overestimated %BF in women (by 1.02+/-2.48%), indicating a significant sex effect (P < 0.05). The differences in estimation between AP and BIA and between BIA and HW were not significantly different between the sexes. AP is an accurate method for assessing body composition in healthy adults. Future studies should assess further the cause of the individual variations with this new method.
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The purpose of this investigation was to evaluate the accuracy of a new air displacement plethysmograph, BOD POD Body Composition System, for determining %fat in collegiate football players. Body fatness was estimated from body density (Db), which was measured on the same day using the BOD POD and hydrostatic weighing (HW) in 69 Division IA football players. In addition, 20 subjects were whole body scanned using dual-energy x-ray absorptiometry, DXA (Lunar DPX-L) to assess total body mineral content and %fat. Mineral content and HW determined Db were used to compute %fat from a three-component model (3C; fat, mineral, and residual). Test-retest reliability for assessing %fat using the BOD POD (N = 15) was 0.994 with a technical error of measurement of 0.448%. Mean (+/- SEM) Db measured with the BOD POD (1.064 +/- 0.002 g x cc(-1) was significantly greater (P < 0.05) than HW (1.060 +/- 0.002 g x cc(-1)), thus resulting in a lower %fat for the BOD POD (15.1 +/- 0.8%) compared with HW (17.0 +/- 0.8%). Similar results (N = 20) were found for DXA (12.9 +/- 1.2%) and the 3C (12.7 +/- 0.8%) where %fat scores were significantly higher (P < 0.05) than scores determined using the BOD POD (10.9 +/- 1.0%). Db measured with the BOD POD was higher than the criterion HW, thus yielding lower %fat scores for the BOD POD. In addition, BOD POD determined %fat was lower than DXA and 3C determined values in a subgroup of subjects. Assessment of %fat using the BOD POD is reliable and requires minimal technical expertise; however, in this study of collegiate football players, %fat values were underpredicted when compared to HW, DXA, and the 3C model.
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The purpose of this study was to verify the validity of an air displacement plethysmography device (Bod Pod) for estimating body density (Db). The Db from the Bod Pod (DbBP) was compared with the Db from hydrostatic weighing (DbHW) at residual lung volume in a heterogeneous sample of 30 black men who varied in age (32.0 +/- 7.7 yr), height (180.3 +/- 7.5 cm), body mass (84.2 +/- 15.0 kg), body fatness (16.1 +/- 7.5%), and self-reported physical activity level and socioeconomic status. The Db for each method was converted to relative body fat (%BF) using race-specific conversion formulas and subsequently compared with %BF obtained from dual-energy x-ray absorptiometry (%BFDXA). Linear regression, using DbHW as the dependent variable and DbBP as the predictor, produced an R2 = 0.84 and SEE = 0.00721 g x cc(-1). However, the mean difference between the two methods (0.00450 +/- 0.00718 g x cc(-1) was significant (P < 0.01). The Bod Pod underestimated the Db of 73% of the sample. The %BF estimates from the Bod Pod, HW, and DXA differed significantly (P < 0.01). The average %BFBP (17.7 +/- 7.4%) was significantly greater than %BFHW (15.8 +/- 7.5%) and %BFDXA (16.1 +/- 7.5%); however, there was no significant difference between %BFHW and %BFDXA. The Bod Pod significantly and systematically underestimated Db, resulting in an overestimation of %BF. More cross-validation research is needed before recommending the Bod Pod as a reference method.
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A new device based on the plethysmographic measurement of body volume, named the BOD POD Body Composition System, was developed for the purpose of estimating body composition. The performance, reliability, validity, and clinical application of this system were evaluated in Japanese subjects. The coefficient variation (CV:%) in same-day tests was 2.48, in three separate-day tests it was 2.27, and for independent operators it was 4.53, respectively. There was a clear correlation between the results from BOD POD and those from dual energy X-ray absorptiometry (DEXA) (r = 0.910, p < 0.01). Finally, the fat body composition of 4489 subjects (1499 men, 2990 women) was clinically measured by BOD POD. The findings indicate that the BOD POD is a highly reliable and valid method for determining body fat percentage. This new method has several advantages, e.g. it is quick, simple to operate and may accommodate wide populations.
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To compare measurements of body density (D(b)) obtained from air displacement plethysmography (AP) and hydrostatic weighing (HW) and to determine the accuracy of substituting D(b) via AP (D(b)-AP) for D(b) via HW (D(b)-HW) in estimating body fatness (%Fat(4C)) and the composition and density of the fat-free mass (Dffm) from a four-component model (fat, mineral, water, and protein). D(b) was measured in 50 young adults using AP and HW. Total body water via deuterium dilution, bone mineral content via dual-energy x-ray absorptiometry, and D(b) were used to estimate %Fat(4C). D(b)-AP and D(b)-HW were highly correlated (r = 0.89, SEE = 0.008 g x mL(-1)), but D(b)-AP (1.065 +/- 0.003 g x mL(-1)) was significantly higher (P < 0.05) than D(b)-HW (1.058 +/- 0.003 g x mL(-1)), resulting in a mean difference of 2.8%fat. Differences between %Fat(4C-AP) (17.8 +/- 1.2%) and %Fat(4C-HW) (19.3 +/- 1.2%) were significant (P < 0.05), but the SD of the differences (2.3%) was low. When D(b)-AP was used in a four-component model in place of D(b)-HW, the calculated Dffm was significantly higher (1.109 +/- 0.002 vs 1.105 +/- 0.002 g x mL(-1)) based on a higher (P < 0.05) protein fraction (22.0 +/- 0.4% vs 20.6 +/- 0.4%) and lower (P < 0.05) water (71.1 +/- 0.4% vs 72.4 +/- 0.4%) and mineral fractions (7.0 +/- 0.1% vs 7.1 +/- 0.1%). AP yields a higher D(b) than HW and may not be a valid method for measuring D(b) or estimating %fat using densitometry. However, due to relatively small bias and low individual error, D(b)-AP is an acceptable substitute for D(b)-HW when estimating %fat with a four-component model in young adults.
Article
This study was designed to compare the accuracy and bias in estimates of total body density (Db) by hydrostatic weighing (HW) and the BOD POD, and percent body fat (%fat) by the BOD POD with the four-compartment model (4C model) in 42 adult females. Furthermore, the role of the aqueous and mineral fractions in the estimation of body fat by the BOD POD was examined. Total body water was determined by isotope dilution ((2)H(2)0) and bone mineral was determined by dual-energy x-ray absorptiometry. Db and %fat were determined by the BOD POD and HW. The 4C model of Baumgartner was used as the criterion measure of body fat. HW Db (1.0352 g x cm(-3)) was not statistically different (P = 0.35) from BOD POD Db (1.0349 g x cm(-3)). The regression between Db by HW and the BOD POD significantly deviated from the line of identity (Db by HW = 0.90 x Db by BOD POD + 0.099; R(2) = 0.94). BOD POD %fat (28.8%) was significantly lower (P < 0.01) than %fat by the 4C model (30.6%). The regression between %fat by the 4C model and the BOD POD significantly deviated from the line of identity (%fat by 4C model = 0.88 x %fat by BOD POD + 5.41%; R(2) = 0.92). BOD POD Db and %fat showed no bias across the range of fatness. Only the aqueous fraction of the fat-free mass (FFM) had a significant correlation with the difference in %fat between the 4C model and the BOD POD. These data indicate that the BOD POD underpredicted body fat as compared with the 4C model, and the aqueous fraction of the FFM had a significant effect on estimates of %fat by the BOD POD.
Article
The purpose of this study was to determine the concurrent validity of the BOD POD (BP) (Life Measurement Instruments) and Dual Energy X-Ray Absorptiometry (DXA) Elite 4500A (Hologic, Inc.) techniques for assessing the body fat percentage of young women. The participants were forty-three white college-aged women (19.4 +/- 1.4 years) with a BMI of 23.4 +/- 2.3. Both body composition analyses were completed on the same day and were taken within 10 minutes of each other. Body fat percentage was estimated to be 24.3 (SE = 1.1) and 23.8 (SE = 0.8) using the BP and DXA techniques, respectively. Exact matches, in terms of body fat percentage, were obtained for 10 of the 43 participants (23.3%). In conclusion, our data supports the concurrent validity of the BP and DXA techniques for assessing body fat in young women.
Article
Objectives: To investigate methodological precision of air displacement plethysmography for assessment of body composition in a heterogenous sample of adults. Design: Accuracy of volume measurements by air displacement plethysmography (ADP) for a range of known volumes was ascertained. Repeated measurements of body volume, lung volume, and derived body composition using the BODPOD measurement system were performed. Influence of surface area estimation on ADP measurement was investigated as a possible source of variation. Setting: Clinical Nutrition Laboratory, School of Health & Sports Science, University of North London, London, UK. Subjects: One hundred and two healthy subjects (57 women, 45 men) who ranged in age between 16 and 55 y and in BMI (kg/m(2)) between 17.8 and 41.9. Study design: Cross-sectional study of healthy adults for comparison with previous studies. Repeat measurements of raw body volume, lung volume and % body fat (BF) by ADP were all performed on the same day. Results: From the range of known volumes a marked increase in the CV and a significantly greater measurement error were found at volumes below 40 l (P=0.04). Repeat measurements of raw body volume in human subjects resulted in a technical error equivalent to 0.8% BF. There was no significant difference found between measured and predicted lung volume and the 95% confidence interval for difference was only 0.3% BF. Repeat measurements of lung volume in our subset resulted in a technical error equivalent to 0.5% BF. Although body surface area estimation only accounted for variation in % BF of 0.1%, the extent of variation appeared to be governed by leanness (P<0.001). Conclusions: Although ADP retains excellent precision, in practice, repeat measurements of ADP should be performed whenever possible to allow for erroneous volume measurement within one procedure. Protocols for ADP measurement should be created with an awareness of those factors, which may affect measurements. Sponsorships: This study was supported by the University of North London Diversity & Development Fund.
Article
This study was designed to evaluate the reliability and validity of air displacement plethysmography (ADP) compared with dual energy x-ray absorptiometry (DXA) Hologic QDR 4500A (Waltham, MA) in female collegiate athletes. Forty-seven females representing various Division II collegiate sports and 24 controls participated in the current study. All women underwent both methods of testing within a 30-min period. Comparison of means indicated that the ADP and DXA are not different when measuring body fat (BF%) in the athletes (ADP = 22.5 +/- 5.5%, DXA = 22.0 +/- 4.7%P = 1.0). Furthermore, this study determined that ADP is a reliable measure of body fat (BF%; r = 0.96, P < 0.001; 0.97, P < 0.001) in collegiate female athletes and nonathletes, respectively. The results from this study indicate that ADP is a valid measure of body composition in female athletes and nonathletes when compared with DXA.
Article
The majority of studies investigating the accuracy of the Bod Pod have compared it to hydrostatic weighing (HW), the long held, and perhaps outdated 'gold standard' method of body composition analysis. Much less research has compared the Bod Pod to dual energy x-ray absorptiometry (DXA), a technique that is becoming popular as an alternative reference method. The purpose of this study was to compare per cent fat estimates by the Bod Pod to those of DXA in a large number of men. Participants were 160 men (32 +/- 11 years). Per cent body fat was estimated to be 19.4 +/- 6.8 and 21.6 +/- 8.4 for DXA and the Bod Pod, respectively. Although the two methods were highly correlated (0.94), the mean difference of 2.2% was significant (p < 0.01). The amount of difference increased as body fatness increased (p < 0.0001). The results of this study indicate that a difference between methods existed for our sample of men. It is uncertain exactly where the difference lies. Practitioners should be aware that even with the use of technologically sophisticated methods (i.e., Bod Pod, DXA), differences between methods exist and the determination of body composition is at best, an estimation.
Article
To compare bioelectrical impedance analysis (BIA) of body composition using three different methods against DXA in overweight and obese men. Forty-three healthy overweight or obese men (ages 25 to 60 years; BMI, 28 to 43 kg/m(2)) underwent BIA assessment of body composition using the ImpediMed SFB7 (version 6; ImpediMed, Ltd., Eight Mile Plains, Queensland, Australia) in multifrequency mode (Imp-MF) and DF50 single-frequency mode (Imp-SF) and the Tanita UltimateScale (Tanita Corp., Tokyo, Japan). Validity was assessed by comparison against DXA using linear regression and limits of agreement analysis. All three BIA methods showed good relative agreement with DXA [Imp-MF: fat mass (FM), r(2) = 0.81; fat-free mass (FFM), r(2) = 0.81; percentage body fat (BF%), r(2) = 0.69; Imp-SF: FM, r(2) = 0.65; FFM, r(2) = 0.76; BF%, r(2) = 0.40; Tanita: BF%, r(2) = 0.44; all p < 0.001]. Absolute agreement between DXA and Imp-MF was poor, as indicated by a large bias and wide limits of agreement (bias, +/-1.96 standard deviation; FM, -6.6 +/- 7.7 kg; FFM, 8.0 +/- 7.1 kg; BF%, -7.0 +/- 6.6%). Imp-SF and Tanita exhibited a smaller bias but wide limits of agreement (Imp-SF: FM, -1.1 +/- 8.5 kg; FFM, 2.5 +/- 7.9 kg; BF%, -1.7 +/- 7.3%; Tanita: BF%, 1.2 +/- 9.5%). Compared with DXA, Imp-MF produced large bias and wide limits of agreement, and its accuracy estimating body composition in overweight or obese men was poor. Imp-SF and Tanita demonstrated little bias and may be useful for group comparisons, but their utility for assessment of body composition in individuals is limited.
ACSM's exercise management for persons with chronic diseases and disabilities
  • J L Durstine
  • E M Moore
  • P L Painter
  • S O Roberts
Durstine JL, Moore EM, Painter PL, Roberts SO. ACSM's exercise management for persons with chronic diseases and disabilities (3 rd ed.). U.S.: Human Kinetics, 2009.
Exercise testing and prescription: a health-related approach
  • D C Nieman
Nieman DC. Exercise testing and prescription: a health-related approach (6 th ed.). U.S.: McGraw-Hill, 2007.