The purpose of this study was to determine the reliability of within-day and between-day measurements of body volume (BV), thoracic gas volume (Vtg), and body fat percentages (%fat) taken in the BOD POD. Fifty subjects (25 men, 25 women) of varying ages (20-81 yrs.), races, and body composition (2.2-51.1% fat) were tested under ideal conditions set forth by the manufacturer at the same time of day (± 3 hours) on three separate days within two weeks. On each day, testing was repeated in succession until three trials were obtained which met the manufacturer's criteria for acceptable BV and Vtg. Repeated measures ANOVA revealed no significant mean differences between the three within-day trials or for the first trial between each of the three days with the exception of between-day BV where day 1 was found to be 260 ml greater than days 2 and 3. Coefficient of variation (SD/mean* 100) and intra-class correlations were determined for each variable both within the three trials of each day and between the first trials of each of the days. For BV, the CV for the 150 cases of within-day measurements was.1 ± .01% while the between-day CV was .4 +.3%. For both within and between day BV, r = .99. The CV and correlations for Vtg was 2.8 ± 2.4% and .99 and 4.1 ± 2.6% and .98 for within-day and between-day measures, respectively. The mean absolute difference between measured Vtg and the predicted value (Vpred) from age, height, and weight was 0.471 ± 0.392 L which would result in body fat estimates that differ by 1.3 ± 0.3%. Estimates of body fat from Vpred were within +2% fat of those derived from measured Vtg values in 80% of the trials. Body fat percentage produced a within-day CV of 2.8 + 4.6% with an r = .99 and a between-day CV of 3.8 ± 5.9% with an r =.99. However, with the exclusion of 3 subjects with body fat <7%, the within-day and between-day CV decreased to 2.0 ± 1.8% and 2.7 ± 2.1%, respectively. The difference between the first two trials of each day was < 2% fat in 93% of the cases, and all 150 cases resulted in fat within + 2% in the three trials. In conclusion, these results support that BOD POD measurements of BV, Vtg, and % fat are reliable both within and between days for a wide range of adults. Also, to obtain the most reliable measurement of % fat in the BP, measuring thoracic gas volume and averaging the values obtained from two trials which agree within + 2 % fat is recommended. / School of Physical Education

No research has been performed comparing percent body fat measurements using dual energy x-ray absorptiometry (DEXA) and air plethysmography after weight loss. The purpose of this investigation was to compare body composition assessments using the Bod Pod® Body Composition System (BP) and the DEXA ProdigyTM before and after an 8-week weight loss diet and exercise program. Based on prior comparison studies, it was hypothesized that percent fat values would be significantly lower using the BP compared to the DEXA before and after weight loss. Also since both methods have been shown to be reliable, it was hypothesized that the BP and DEXA would detect similar changes in percent fat in response to a weight-loss intervention. Twelve women (42 ± 8 yrs) and ten men (40 + 11 yrs) had their percent body fat estimated using the BP and whole body DEXA ProdigyTM scanner. A similar significant (P < 0.05) decrease in percent body fat was observed using the BP and DEXA ProdigyTM (-2.2% and -1.8%, respectively) after weight loss. Percent body fat using the BP was significantly lower than the DEXA ProdigyTM before (36 ± 10.7% and 38.1 ± 9.4%, respectively) and after (33.8 ± 10.8% and 36.3 + 10.6%, respectively) the weight loss program. Significant Pearson correlation coefficients between the DEXA ProdigyTM and the BP were noted pre (r = 0.975) and post (r = 0.968) weight loss. These data indicate the BP provides significantly lower absolute %fat values within a range of body fat levels (20-56%) when compared to the DEXA. However, the BP and DEXA detect similar changes in %fat, fatfree mass, and fat mass from weight loss in men and women. Also, the BP consistently overestimated fat-free mass and underestimated %fat and fat mass compared to values obtained from DEXA. / School of Physical Education

The prevalence of obesity has made it necessary to develop a convenient, reliable and safe tool for timely assessing and monitoring this condition in public health. We suggest that three-dimensional (3D) anthropometry can provide a convenient, accommodating and comprehensive means to body composition assessment. A 3D anthropometry system based on stereo vision technology is developed. To make it more portable and affordable, the system is reduced to a two-stance design and only uses off-the-shelf components. The system is calibrated in two separate stages: camera calibration and 3D registration. The first stage is relatively complicated, but there is no need to repeat frequently. Therefore, only 3D registration is required when the system is transported. This property contributes to the portability and also reduces cost of maintenance. In this system, image acquisition can be completed in 200 ms, which is important in reducing artifacts caused by slight body movement. However, the computation in stereo vision is complex and intensive, and is still a challenge. A two-phase stereo matching algorithm is developed. In the first phase, the foreground is accurately segmented with the help of a predefined virtual interface, and a coarse disparity map is generated with block matching. In the second phase, local least squares matching is performed in combination with global optimization within a regularization framework, so as to ensure both accuracy and reliability. To make the 3D data more interpretable and manageable, it is essential to convert the raw 3D data to a surface model. For our system, a unique challenge is that there are large gaps in the data caused by occlusions. An effective surface reconstruction algorithm based on subdivision surface representation is developed. It has been verified that the algorithm is reliable in gap closing, accurate in representation, and efficient in data compression. To make the 3D anthropometry system ready for practical use, a body measurement system dedicated to body composition assessment is developed based on an earlier system that was designed for applications in apparel fitting. The functions of 3D measurement are enhanced by taking advantage of modern graphics hardware. The overall performance of the presented system has been evaluated on mannequins and human subjects. It has been shown that the measurements are highly repeatable. The feasibility of 3D anthropometry in body fat assessment has been demonstrated in comparison to air displacement plethysmography and bioimpedance analysis. / text

Assessment of body fat percentage is desirable to identify health risks associated with obesity. There are few studies that have compared the assessment of body fat between air displacement plethysmography and dual-energy x-ray absorptiometry, particularly related to age and gender differences. The purpose of this study was to determine if body fat percent estimates differ depending on age and/or gender between air displacement plethysmography (Bod Pod, Life Measurements Instrument, Concord, CA) and dual-energy x-ray absorptiometry (DEXA, General Electric Medical Systems, Lunar Prodigy, Madison, WI). Sixty subjects were studied: 15 men and 15 women, 22-35 years and 15 men and 15 women, 55-80 years. Subjects were excluded if they competed in athletics or high-level exercise training in the last year. Standard calibration and testing procedures were used for both methods. Both methods were administered at least twice to evaluate reliability and were repeated a third time if the first two measures differed by >2%. Differences between methods for age groups and gender were analyzed using ANOVA and reliability comparisons between the body composition methods were evaluated with correlation coefficients and Bland-Altman plots. Using data for all subjects, DEXA (r = .996) and Bod Pod (r = .985) both showed good reliability. However, in younger females the reliability of the Bod Pod (r = .911) was lower. Sixteen of the 60 subjects required a third trial for the Bod Pod, whereas all repeated DEXA measures were consistent. The deviation between trial 1 and 2 for the DEXA (.6%) was significantly less than that in the Bod Pod (1.5%). Significant interactions between the body composition method and age group were found. Mean body fat percentage in the younger group was higher in the DEXA (24.1 + 1.1%) than the Bod Pod (23.0 + 1.3%) however, in the older group it was found to be lower in the DEXA (33.9 ± 1.1%) than the Bod Pod (37.2 ± 1.3%). Both the DEXA and the Bod Pod were reliable but repeated DEXA measures were more consistent than the Bod Pod measures. Bod Pod estimates of body fat percentage were lower for younger subjects, yet higher for older subjects compared to DEXA measurements. / School of Physical Education, Sport, and Exercise Science

The American College of Sports Medicine advocates the use of a percentage of maximal oxygen uptake reserve (%VO2R) for exercise prescription purposes because it's thought to provide a close match with percentage of heart rate reserve (%HRR) than a given percentage of maximal oxygen uptake (%VO2max). However, some recent studies have challenged the validity of this matching. The purpose of this study was to assess the association of body mass index (BMI) with the matching of %HRR and %VO2R during graded exercise testing. The study sample included 626 subjects (281 men; 345 women); mean age of 45.5+11.7 years; mean BMI of 27.9+5.4 kg .m-2) who completed a maximal treadmill test to volitional fatigue using the BSU/Bruce Ramp protocol. The distribution of BMI measures within the sample was 31.4% <25; 38% between 25.0 and 29.9; 17.9% between 30 and 34.9%; 8.8% between 35 and 39.9%; and 3.1% were > 40 kg•m"2. Subjects were excluded from the analysis if they failed to achieve a peak RER > LO during the maximal exercise test, possessed pulmonary or cardiovascular disease (excluding hypertension), or incomplete/erroneous submaximal heart rate and/or V02 data that was unable to be retrieved from subject's existing file. Heart rate and VO2 data from minutes 3, 6, and 9 were converted into %HRR and %VO2R, with 3.5 ml•kg-'•min' serving to represent resting VO2. The relative exercise intensity for minutes 3, 6, and 9 represented 39.7 +12.2, 62.9 ± 15.6, and 80.8 ± 12.5% of VO2R, respectively and 43.1 f 12.6, 64.7 ± 14.9, and 83.5 + 10.6% of HRR. %HRR significantly overestimated %VO2R at each measurement point during the exercise test with mean differences 3.3, 2.0, and 3.8%, respectively (p<0.05). The association of BMI with the matching of %HRR and %VO2R was assessed by correlation with the difference the scores (AHRRVO2R) at each specified time during exercise test. Correlations for BMI and AHRRVO2R were -0.102, -0.175, and -0.231 for minutes 3,6, and 9, respectively (p<0.05). These results demonstrate a low association between BMI and the matching of HRR and VO2R. / School of Physical Education, Sport, and Exercise Science

1. ABSTRACT This diploma thesis refers to human body composition and its alterations by physiological and pathological processes that occur during different stages of life. Fat mass, fat free mass and total body water represent the major components of the human body which are modified during infancy, childhood, puberty, pregnancy and adulthood. Bioelectrical Impedance Analysis (BIA), Dual Energy Absorptiometry (DEXA), Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) are some methods which are utilized for the qualitative and quantitative assessment of the body composition according to nutritional and pathological state of each individual, targeting the optimal clinical outcome. During growth, the amount of total body water elevates through infancy but it gradually declines in the next stages of life. Fat mass or total body fat possesses higher values during infancy, pregnancy and aging whereas it increases preferentially in female population at puberty. Muscle mass is elevated significantly in males during puberty and declines gradually due to aging. Osteoporosis, obesity and wasting diseases such as anorexia, cachexia and sarcopenia provoke severe disturbances in body composition compartments resulting in high rates of morbidity and mortality of the population.

The purpose of this thesis was to monitor body composition and energy expenditure changes during weight loss in subjects encouraged to maintain a diet equal to 90% of resting energy expenditure (REE). Over six months, 69 female subjects had REE measured at baseline and weeks 13 and 25 with fortnightly body composition measurements. Subjects lost significant total body mass (17.2 lb) and fat mass (16.7 lb) (p≤.000). Fat-free mass remained stable during the six month period. REE was significantly higher at baseline (1701.1 kcal) than weeks 13 (1576.3 kcal) and 25 (1579.4) (p≤.000); REE at weeks 13 and 25 were similar (p≥.05). Predicted REE at weeks 13 (1671.3 ± 254.7 kcal) and 25 (1658.5 ± 252.4 kcal), compared to measured REE, was significantly lower, 1576.3 kcal and 1579.4 kcal, respectively (p≤.000). Results of this study illustrate that individuals can lose significant amounts of total body mass while preserving fat-free mass and that during active weight loss, there is a metabolic adaptation to reduced caloric intake. / Department of Family and Consumer Sciences

The purpose of this study was to determine the effect of 100% cotton underwear worn beneath a swimsuit on the accuracy and reliability of percent body fat measurements in the BOD POD. Sixty adults (30 males, 30 females) of various ages (1887 years) and body composition (1.95-57.15%) were tested four times in one day. Subjects wore a swimsuit and swimcap for two trials and 100% cotton underwear beneath the swimsuit and a swimcap for the remaining trials. The clothing order was randomized. Thoracic gas volume was predicted. ANOVA found no significant difference between the swimsuit only trials (25.4+12.4%) and swimsuit with underwear trials (25.1+12.3%) for all subjects. Intra-class correlation coefficients were 0.994 and 0.995 for the swimsuit only and swimsuit with underwear trials, respectively. In conclusion, these results suggest that wearing 100% cotton underwear beneath a swimsuit is an acceptable practice for fitness laboratories and the reliability was very good. / School of Physical Education

Access to abstract permanently restricted to Ball State community only / Access to thesis permanently restricted to Ball State community only / School of Physical Education, Sport, and Exercise Science

Als Resultat überhöhter Energieaufnahme und zu geringen Energieverbrauchs beobachten wir eine über das normale Maß hinausgehende Akkumulation von Fettgewebe, die sich als Adipositas manifestiert. Sie gilt als einer der Hauptrisikofaktoren für Krankheiten des metabolischen Syndroms. Im Rahmen von Prävention, Diagnose und Therapie der Adipositas, muss ihr wesentliches Charakteristikum; der individuelle Körperfettanteil; einer Messung zugänglich gemacht werden. Eine direkte Bestimmung der Körperzusammensetzung erlauben die Neutronenaktivierungsanalyse und die chemische Analyse. Beide Verfahren sind sehr genau, aber aufwendig und kostenintensiv und darüber hinaus die chemische Analyse nur am menschlichen Cadaver praktizierbar. Um dennoch die Körperzusammensetzung hinreichend genau bestimmen zu können, wurden zahlreiche indirekte Messverfahren entwickelt. Man kann sie in Labor- und Feldmethoden untergliedern. Die Labormethoden bestechen durch hohe Genauigkeit und Reproduzierbarkeit, sind aber zumeist aufwendig und teuer. Feldmethoden sind im Gegensatz dazu leicht anwendbar, transportabel und preiswert, weisen aber eine weniger hohe Genauigkeit und Reproduzierbarkeit auf.<br><br> In der vorgestellten Arbeit wird über eine jüngere Entwicklung, die das Prinzip der unterschiedlichen Leitfähigkeit für den elektrischen Strom durch die verschiedenen Gewebe des Körpers nutzt, berichtet. Der Prototyp eines Gerätes wurde innerhalb eines von der EU geförderten multizentrischen Projekts entwickelt und auf seine Einsatzfähigkeit und Qualität hin geprüft. Der Schwerpunkt der Arbeit liegt auf der Einschätzung der Körperzusammensetzung normal- und übergewichtiger Probanden mit der neu entwickelten Technik. Das vorliegende Studiendesign diente nicht nur der Beurteilung der neuen Technik die Körperzusammensetzung und Veränderungen dieser zu erfassen, sondern darüber hinaus, etablierte Methoden hinsichtlich ihrer Genauigkeit zu bewerten. Bezüglich ihrer Anwendbarkeit und Reproduzierbarkeit hat die neue Methode Hoffnung geweckt, sich als eine Feldmethode zu etablieren. Auf der anderen Seite zeigte sich in Abhängigkeit der Gesamtkörperfettmasse eine Überschätzung der Zielgröße im Vergleich zur Referenzmethode (dual energy x ray absorptiometry (DXA)). Die Abweichungen waren dabei gerade für das einzelne Individuum sehr groß. Technische Verbesserungen und die Entwicklung spezifischer Regressionsgleichungen könnten in Zukunft zu einer wesentlichen Verbesserung der neuen Methode beitragen.<br><br> Die Labormethode "Air Displacement Plethysmography" konnte durch die guten Übereinstimmungen der Ergebnisse mit denen der Referenzmethode DXA und die einfache Anwendung überzeugen. Sie stellt eine durchaus konkurrenzfähige Alternative zur Hydrodensitometrie dar, die noch heute als "goldener Standard" zur Erfassung der Körperzusammensetzung akzeptiert wird. Im Verlauf der durchgeführten Studie stellte sich heraus, dass die Hydrodensitometrie sehr hohe Anforderungen an den Probanden stellt. Das Untertauchen des gesamten Körpers unter Wasser in Kombination mit einer maximalen Ausatmung erwies sich als sehr problematisch. Die dabei auftretenden Fehler schlugen sich in der Berechnung der Gesamtkörperfettmasse des einzelnen Individuums wieder und führten zu zum Teil erheblichen Abweichungen der Ergebnisse von denen der Referenzmethode.<br><br> Die Feldmethoden bioelektrische Impedanzanalyse und Hautfaltendickenmessung erwiesen sich als kostengünstige und leicht anwendbare Methoden. Die Ergebnisse beider Methoden stimmten im Mittel gut mit den Ergebnissen der Referenzmethoden überein. Dennoch zeigte die BIA größere Abstriche in der Beurteilung der Gesamtkörperfettmasse des einzelnen Individuums und bei der Dokumentation von Veränderungen der Gesamtkörperfettmasse. Die Hautfaltendickenmessung stellt – wendet man sie korrekt an – eine Methode dar, die sowohl die Gesamtkörperfettmasse als auch Veränderungen dieser gut erfassen kann. In Abhängigkeit der geforderten Genauigkeit kann diese Methode für die Erfassung der Körperzusammensetzung empfohlen werden.<br><br> Demnach bleibt die Frage unbeantwortet, inwieweit die indirekten Methoden in der Lage sind, die "wahre" Körperzusammensetzung adäquat zu erfassen. Jede neu entwickelte Methode – die möglichst viele Vorteile in sich vereint – wird wieder vor dem Problem stehen: eine geeignete und dabei praktikable Referenzmethode zu finden, die die wahre Körperzusammensetzung zu bestimmen in der Lage ist. Daher sollte neben dem Streben nach der Entwicklung einer Methode, die genau und leicht anwendbar ist, das Hauptaugenmerk auf die Überarbeitung der zugrunde liegenden Modellvorstellungen und die Verbesserung von Regressionsgleichungen gelegt werden. / Western industrial countries are characterized by sedentary lifestyle and a high-fat and simple carbohydrate diet. Decrease physical activity and increase energy intake are leading to an epidemic increase of overweight and obesity. Obesity is defined as the presence of excess adipose tissue and has been associated with an increased risk for diseases of the metabolic syndrome. Thus, the importance of obtaining reliable and accurate body fat estimates is essential not only for the prevention, but also for the diagnosis and therapy of obesity. Direct chemical analysis is the most definitive method for determining human body composition. The few data obtained on the composition of adult bodies stemmed from cadaver analyses, dated back to 1945 and 1956. These results contributed greatly to the actual fundamental knowledge about human body composition. Obviously, the method is limited by the precondition of needing the human cadaver and the high complexity of the analyses. Because of this limitation, indirect methods have been developed during the last decades. To date more than ten methods to estimate body composition in vivo are available. The methods can be generally organized into two groups: laboratory and fields methods. Laboratory methods have high accuracy and reproducibility, but are complex and very expensive, whereas field methods are easy to use and economically priced, but less accurate. A new device that combines the positive features of both, laboratory and field methods is needed . An already existing method - Total Body Electrical Conductivity (TOBEC) - meets the requirements for such new device. The technique is based on the principle, that lean tissue is far more electrically conductive than fat, due to the higher content of electrolytes in the fat-free mass. The difference between impedance when a subject is inside and outside of the generated field is an index of the total electrical conductivity of the body, which, in turn is proportional to the lean body mass of the subject.<br><br> Within the European Project BodyLife (IST - 2000 - 25410) a new field method for estimation the human body composition was developed. To assess the suitability of the new technique the present study aimed to evaluate the reliability of nTOBEC and to validate it against established laboratory and field methods.<br><br> Within the project the development of the new method (nTOBEC) succeeded to combine the TOBEC-principle, and additionally, to be transportable and easy to use.<br><br> The high reliability coefficients found in this investigation indicate that nTOBEC is an extremely reliable instrument. By application the new technique we observed a significant overestimation of total body fat mass compared the reference method dual energy x ray absorptiometry (DXA) in both, males and females. However, nTOBEC could document changes in total body fat mass during a weight loss intervention trial.<br> Our data suggest nTOBEC deserves further investigation with the intention of establishing nTOBEC as a non-invasive method for accurately quantifying total body fat mass.<br> Aside from these results we observed accurate results for the easy to use laboratory method "air displacement plethysmography" compared to the results measured by DXA. Furthermore, the field methods - bioelectrical impedance analysis and skinfold thickness measurement – produced good results compared to the reference method.