4C Model Research Articles

Body Composition Assessment in Male and Female Bodybuilders: A 4-Compartment Model Comparison of Dual-Energy X-Ray Absorptiometry and Impedance-Based Devices.

Graybeal, AJ, Moore, ML, Cruz, MR, and Tinsley, GM. Body composition assessment in male and female bodybuilders: a 4-compartment model comparison of dual-energy x-ray absorptiometry and impedance-based devices. J Strength Cond Res 34(6): 1676-1689, 2020-The purpose of this study was to examine the group and individual accuracy of body composition estimates obtained from multicompartment models, dual-energy x-ray absorptiometry (DXA), and several impedance-based devices in male and female bodybuilders. Twenty-seven male (n = 17; 4-compartment [4C] model fat-free mass index [FFMI]: 25.1 ± 1.8 kg·m; 4C body fat: 11.8 ± 4.4%) and female (n = 10; 4C FFMI: 18.3 ± 1.4 kg·m; 4C body fat: 19.7 ± 4.9%) bodybuilders underwent duplicate assessments using DXA, bioimpedance spectroscopy (BIS), electrical impedance myography (EIM), and 3 bioelectrical impedance analysis (BIA) devices. In addition to utilizing standard output, multicompartment models were generated. For each method, body fat %, FFM, and fat mass were compared with the reference 4C model for the evaluation of group and individual errors. The 3-compartment model with a BIS body water estimate produced the lowest standard error of the estimate, total error (TE), and 95% limits of agreement (LOA) for all variables, although some alternative methods had lower constant error (CE). In general, multicompartment models with BIS or multifrequency BIA body water estimates produced more accurate body composition estimates than single assessment techniques (i.e., DXA, BIS, EIM, and BIA). Single assessment techniques produced low CE and TE for some body composition variables. However, proportional bias was observed for DXA and BIS. All single assessment techniques produced LOA large enough to make the utility of these methods questionable in individual athletes. Appropriate caution should be used when interpreting and utilizing body composition estimates in muscular physique athletes, particularly at the individual level.

Determination of the remote-sensing reflectance from above-water measurements with the "3C model": a further assessment.

The Three-Component Reflectance Model (3C) was primarily developed to improve the determination of the remote-sensing reflectance (Rrs) from above-water radiometric hyperspectral measurements performed during sub-optimal conditions (i.e., cloudy sky, variable viewing geometry, high glint perturbations, low illumination conditions). In view of further validating the model and showing its broad range of uses, this work presents the application of 3C to above-water radiometry data collected in oceanic and coastal waters with a variety of measurement conditions. Rrs derived from measurements performed during optimal and slightly sub-optimal conditions exhibit equivalence with Rrs obtained with an established above-water method that is commonly used to support ocean color validation activities. Additionally, the study shows that 3C can still provide relevant Rrs retrievals from field data characterized by low-light illumination, high glint perturbations and variable measurement geometries, for which the established method cannot be confidently applied. Finally, it is shown that the optimization residual returned by the 3C full-spectrum inversion procedure can be a potential relative indicator to assess the quality of derived Rrs.

Le condizioni organizzative e professionali dello smart working dopo l'emergenza: progettare il lavoro ubiquo fatto di ruoli aperti e di professioni a larga banda

The Covid-19 lockdown generated an unprecedented experiment: extensive ubiquitous work (or working, home working, remote working, WFH-Working from Home, agile work, teleworking) involving almost 8 million people. This way of working has been well known for more than twenty years, but with limited pilot experiences. After the emergency, ubiquitous work may be consolidated and spreaded out only if it is designed and managed with rigor, method and appropriateness to different contexts, choosing the right proportion between on-site work and remote work. Action should be taken on rules, supporting technologies, way of managing work and life, mindset, but above all on the conception of offices and their organization and work, also inspired by success stories developed in these years. Ubiquitous work and blended offices between the physical and the virtual can work well under three socio-organizational conditions: a) going beyond the concept of the office-factory; b) favor organizations based on sociotechnical systems oriented towards measurable economic and social objectives and on 4C model (self-regulated cooperation, knowledge sharing, extended communication, performing community); c) redesigning the work based upon roles and professions, overcoming tasks, positions and levels. Our proposals concern first the methods and models for designing and managin working/ubiquitous work and second the launch of: a) a large multidisciplinary research program on the smart working experiment tooking place during and immediately after lockdown, a program to be conducted collaboratively by Italian research centers and universities, in strong relationship with Europe; b) a support program for SMEs and the Public Administration offered by universities, IT companies, consultancy, training, interior design with sustainable methods and costs. The recipients of the first proposal are companies and public administrations and their stakeholders; the recipients of the second proposal are the world of research and the world of public policies based upon pacts agreements among institutions and intermediate bodies like employers and workers agencies, education systems, media and the others .

From Viewpoint of 3C Model to Use Supply Chain Integrating to Create Competitive Advantage

While global environment is proceeding globalization and internationalization, traditional logistics management can not be coped with the change. Therefore, to be the winner, supply chain integrating is necessary. Domestic car manufacturers take supply chain integrating to cope with the pressure of the market in now and future, and they hope to keep the competitive advantage. In view of this, from viewpoint of 3C model, we use case study to discuss and analysis supply chain integrating on company C which is the benchmark of the car industry, and then we offer a good suggestion to car manufacturers and future study direction.

Novel body fat estimation using machine learning and 3-dimensional optical imaging.

Estimates of body composition have been derived using 3-dimensional optical imaging (3DO), but no equations to date have been calibrated using a 4-component (4C) model criterion. This investigation reports the development of a novel body fat prediction formula using anthropometric data from 3DO imaging and a 4C model. Anthropometric characteristics and body composition of 179 participants were measured via 3DO (Size Stream® SS20) and a 4C model. Machine learning was used to identify significant anthropometric predictors of body fat (BF%), and stepwise/lasso regression analyses were employed to develop new 3DO-derived BF% prediction equations. The combined equation was externally cross-validated using paired 3DO and DXA assessments (n=158), producing a R2 value of 0.78 and a constant error of (X±SD) 0.8±4.5%. 3DO BF% estimates demonstrated equivalence with DXA based on equivalence testing with no proportional bias in the Bland-Altman analysis. Machine learning methods may hold potential for enhancing 3DO-derived BF% estimates.

The Validity of Relative Fat Mass and Body Adiposity Index as Measures of Body Composition in Healthy Adults

ABSTRACTHigher relative adiposity is independently associated with adverse health consequences. As such, accurate estimates of body composition in field settings are of utmost importance. The aim of this study was to examine the validity of the Body Adiposity Index (BAI) and Relative Fat Mass (RFM) as measures of total body adiposity. BAI and RFM were assessed in young adults (n = 188, 48.4% female, 21.8 ± 4.8 years, 24.4 ± 4.6 kg/m2). Adiposity was assessed using the 4C model (%Fat4C) and derived from underwater weighing for body density, dual-energy X-ray absorptiometry for bone mineral content, and bioimpedance spectroscopy for total body water. Bivariate correlations between BAI, RFM, and %Fat4C were assessed using Pearson’s r. Differences between measures were assessed using a repeated-measures ANOVA. BAI and RFM were associated with %Fat4C (r = 0.668 and 0.827 respectively, both p < .001). BAI and RFM overestimated %Fat4C (+4.3 ± 6.1 versus +4.3 ± 4.6, respectively, p < .001). The large error limits the practical utility of these anthropometric indices.Abbreviation: ANOVA: Analysis of Variance; BAI: Body Adiposity Index; BM: Body Mass; BMI: Body Mass Index; CM: centimeter; DXA: Dual X-ray Absorptiometry; HC: Hip Circumference; KG: kilogram; RFM: Relative Fat Mass; SPSS: Statistical Package for the Social Sciencesp; WC: Waist Circumference; %Fat: Body Composition.

Development of a dual-energy X-ray absorptiometry-derived body volume equation in Hispanic adults for administering a four-compartment model.

The purpose of the present study was: (1) to develop a new dual-energy X-ray absorptiometry (DXA)-derived body volume (BV) equation with the GE-Lunar prodigy while utilising underwater weighing (UWW) as a criterion and (2) to cross-validate the novel DXA-derived BV equation (4C-DXANickerson), Wilson DXA-derived BV equation (4C-DXAWilson) and air displacement plethysmography (ADP)-derived BV (4C-ADP) in Hispanic adults. A total of 191 Hispanic adults (18-45 years) participated in the present study. The development sample consisted of 120 females and males (50 % females), whereas the cross-validation sample comprised of forty-one females and thirty males (n 71). Criterion body fat percentage (BF %) and fat-free mass (FFM) were determined using a four-compartment (4C) model with UWW as a criterion for BV (4C-UWW). 4C-DXANickerson, 4C-DXAWilson and 4C-ADP were compared against 4C-UWW in the cross-validation sample. 4C-DXANickerson, 4C-DXAWilson and 4C-ADP all produced similar validity statistics when compared with 4C-UWW in Hispanic males (all P > 0·05). 4C-DXANickerson also yielded similar BF % and FFM values as 4C-UWW when evaluating the mean differences (constant error (CE)) in Hispanic females (CE = -0·79 % and 0·38 kg; P = 0·060 and 0·174, respectively). However, 4C-DXAWilson produced significantly different BF % and FFM values (CE = 3·22 % and -2·20 kg, respectively; both P < 0·001). Additionally, 4C-DXAWilson yielded significant proportional bias when estimating BF % (P < 0·001), whereas 4C-ADP produced significant proportional bias for BF % and FFM (both P < 0·05) when evaluated in Hispanic females. The present study findings demonstrate that 4C-DXANickerson is a valid measure of BV in Hispanics and is recommended for use in clinics, where DXA is the main body composition assessment technique.

Advances in understanding and intervening in teacher stress and coping: The Coping-Competence-Context Theory

Teacher stress and burnout are associated with many adverse outcomes for teachers, students, and the educational system. This paper describes the Coping-Competence-Context (3C) Theory of Teacher Stress. The theory is based on empirical research on teacher stress and coping highlighted within this special issue and attempts to more explicitly highlight three critical interconnected pathways to teacher stress development and intervention. The 3C model also highlights why teacher stress is important and should be the topic of future inquiry by showing clear links between teacher stress and adverse student and teacher outcomes. Lastly, this paper provides guidance for leverage points to intervene and describes a future research agenda in three domains: measurement, conceptual, and intervention issues and challenges.

Contact Sites of rDNA Clusters with FANK1 Gene Correspond to Repressed Chromatin

rDNA genes play an important role in epigenetic regulation and in differentiation of eukaryotic cells. Using the 4C (circular chromosome conformation capture) approach and model HEK293T cells, we analyzed the rDNA-contacting gene FANK1, using anchor located inside rDNA genes. At the 5' end of the FANK1 gene we detected frequent contacts with rDNA clusters. The contact sites coincide with the border where chromatin state changes and nucleosome positioning. The adjacent genes DHX32, BCCIP and UROS are located in the active chromatin and are transcribed, but do not contact with rDNA genes, while FANK1 gene is silenced, and is located in repressed chromatin. Heat shock treatment dramatically changes the pattern of rDNA contacts in the region and induces about 4-fold increase in activation of the FANK1 gene. We conclude that rDNA contacts may be involved in repression of the FANK1 gene.

External validation of the relative fat mass (RFM) index in adults from north-west Mexico using different reference methods.

BackgroundAnalysis of body composition is becoming increasingly important for the assessment, understanding and monitoring of multiple health issues. The body mass index (BMI) has been questioned as a tool to estimate whole-body fat percentage (FM%). Recently, a simple equation described as relative fat mass (RFM) was proposed by Woolcott & Bergman. This equation estimates FM% using two anthropometric measurements: height and waist circumference (WC). The authors state that due to its simplicity and better performance than BMI, RFM could be used in daily clinical practice as a tool for the evaluation of body composition. The aim of this study was to externally validate the equation of Woolcott & Bergman to estimate FM% among adults from north-west Mexico compared with Dual-energy X-ray absorptiometry (DXA) as an alternative to BMI and secondly, to make the same comparison using air displacement plethysmography (ADP), Bioelectrical Impedance Analysis (BIA) and a 4-compartment model (4C model).MethodsWeight, height and WC were measured following standard procedures. The RFM index was calculated for each of the 61 participating subjects (29 females and 32 males, ages 20–37 years). The RFM was then regressed against each of the four body composition methods for estimating FM%.ResultsCompared with BMI, RFM was a better predictor of FM% determined by each of the body composition methods. In terms of precision the best equation was RFM regressed against DXA (y = 1.12 + 0.99 x; R2 = 0.84 p<0.001). Accuracy (represented by the closeness to the zero-intercept) was 1.12 (95% CI: -2.44, to 4.68) and thus, not significantly different from zero. For the rest of the methods, precision in the prediction of FM% was improved compared to BMI, with significant increases in the R2 and reduction of the root mean squared error (RMSE). However, the intercepts of each regression did not show accuracy since they were different from zero, for ADP: -9.95 (95%CI: -15.7 to -4.14), for BIA: -12.6 (95%CI: -17.5 to -7.74) and for the 4C model: -13.6 (95%CI: -18.6 to -8.60). Irrespectively, FM% measured by each of the body composition methods was higher for DXA than the other three methods (p<0.001).ConclusionsThis external validation proved that the performance of the RFM equation used in this study to estimate FM% was more consistent than BMI in this Mexican population, showing a stronger correlation with DXA than with the other body composition methods.

A Culturally Competent Phenotypic Evaluation/Obesity Assessment in African and African American Populations: Pilot Study

BMI, a ratio of weight over height, is a culturally-biased tool imposed upon the scientific, academic and medical communities as an errant measure of obesity across ethnicity. Body Mass Index (BMI) relates mass (g) to a relative fat distribution with regards to height. Its genesis is from the actuarially derived and ethnically exclusive height and weight tables that promote the fictional notion of inter-ethnic ideal weights that would be later adopted by the National Institutes of Health (NIH) as a competent measure of adiposity. Best practice, movement towards individualized medicine and deployment of effective models that impact the diabetes epidemic and its related precursors like insulin resistance and the metabolic syndrome, requires terminal use of BMI, a biologically meaningless and crude indicator of obesity, in favor of effective and culturally competent non-relative body composition evaluation of genetically determined adiposity that untenably compares values among groups. African Americans are among the increasingly affected groups for diabetes and posses unique composition variation requiring proper intra-cultural evaluation independent of inter-ethnic Eurocentric assumptions that over assesses obesity risk. Incorporating use of 4C models to evaluate adiposity and assess risk for diabetic predisposition and onset provides an effective unbiased assessment of the cultural components inherent within body composition variation among ethnicity, age, gender. Obesity and type II diabetes onset and pre-disposition is assessed phenotypically, in creation of a body mass profile among African and African American groups, using 4C model, photography, anthropometry, somatotype and genetic evaluation. Environmental obeseogenic cultural factors are also explored.

Body fat gain and loss differentially influence validity of dual-energy x-ray absorptiometry and multifrequency bioelectrical impedance analysis during simultaneous fat-free mass accretion

The validity of dual-energy x-ray absorptiometry (DXA) and multifrequency bioelectrical impedance analysis (MFBIA) for detecting changes in fat mass (FM), fat-free mass (FFM), and body fat percentage (BF%) was evaluated, as compared to a rapid 4-component (4C) model, in 31 females completing 8 weeks of resistance training. Analyses were performed in all participants (ALL) and in subgroups that gained FFM but lost FM (R subgroup) or gained both FFM and FM (G subgroup). It was hypothesized that methods would comparably detect changes in ALL, but discrepancies would occur in subgroup analysis. Changes in body composition did not significantly differ between 4C, DXA, and MFBIA. Equivalence testing indicated that similar changes were detected by DXA and MFBIA, compared to 4C, for ΔFFM in all analyses and ΔBF% in ALL and R subgroup. ΔFM was equivalent to 4C only in R subgroup for DXA and G subgroup for MFBIA. For ΔFM and ΔBF%, DXA and MFBIA produced similar magnitude errors in ALL. However, DXA exhibited lower error in R subgroup, whereas MFBIA exhibited lower error in G subgroup. For ΔFFM, DXA and MFBIA exhibited relatively similar errors in ALL and R subgroup, although MFBIA displayed proportional bias and weaker correlations with 4C than DXA. In G subgroup, MFBIA exhibited lower errors and a higher correlation with 4C ΔFFM than DXA. Although both DXA and MFBIA may have utility for estimating body composition changes during FFM accretion, DXA may be superior during simultaneous FM loss, whereas MFBIA may produce lower error during simultaneous FM gain.

A review of Islamic perspectives on leadership.

Islamic culture encourages and supports a rich and complete way of life, with guidance, both spiritual and secular, provided for every facet of the devotee’s life.&#x0D; The Qur’an and the Sunnah are the two sources for the Islamic concept of the role of the leader. The Qur’an is the holy book of the religion of Islam, and the Sunnah describes the exemplary life of Prophet Mohammad, largely understood through narration of his words and deeds – the Hadeeth.&#x0D; The Holy Qur’an is universally honoured by Muslims, who identify passages that are pertinent and influential to their lives.&#x0D; Leadership is a tenet that is highly emphasized in Islamic life and is embodied in the pillar of accountability. Indeed, the Prophet Mohammad in the Hadeeth states: ‘each of you is a guardian and is responsible for his subjects’ (Saheeh al Bukhari: 212).&#x0D; This form of multi-level leadership is highly encouraged in Islam.&#x0D; The operational principles that should be applied by Muslim leaders include the exercise of justice, fulfilment of trust, observance of righteousness, perseverance in doing what is right, and honouring promises (Beekum, 1999).&#x0D; The model of Islamic leadership has four dimensions: Consciousness of God, Competency, Consultation, and Consideration (The 4C model).

Relative accuracy of anthropometric-based body fat equations in males and females with varying BMI classifications

BMI based body fat equations developed from Womersley and Durnin (BMIWO), Jackson etal. (BMIJA), Deurenberg etal. (BMIDE), and Gallagher etal. (BMIGA) are commonly used to quantify body fat percentage (BF%). However, relative fat mass (RFM) is a new anthropometric-based method that has been proposed as an alternative. The purpose of this study was to examine the independent and interactive effects of sex and BMI classification on the relative accuracy of BMI-based body fat equations and RFM. Males (n=75) and females (n=75) were stratified and classified into three different groups; 1) normal weight (n=50 [NW: 50% males]; BMI<25.0kg/m2); 2) overweight (n=50 [OW: 50% males]; BMI≥25.0-29.9kg/m2); 3) obese (n=50 [OB: 50% males]; BMI≥30.0kg/m2). A criterion three-compartment model (3C model) was determined with air displacement plethysmography for body volume and multi-frequency bioimpedance analysis for total body water. Data were stratified by sex and BMI classification. Difference scores were created by subtracting estimated BF% from 3C model BF%. A significant SEX×BMI interaction was detected for all comparisons (all p<0.05). Post hoc analysis indicated the differences in BF% were statistically significant between OW females and males for all equations (BMIWO:-2.99±4.79% vs. 4.71±5.86%, p=0.003; BMIJA:-1.77±4.83% vs. 5.77±5.85%, p<0.001; BMIDE:-3.09±4.80% vs. 4.97±5.98%, p<0.001; BMIGA:0.36±4.51% vs. 4.56±5.55%, p=0.018; RFM:-2.17±4.84% vs. 3.01±5.34%, p=0.004, respectively). In addition, there were significant differences between females and males classified as NW (BMIJA:-2.11±4.15% vs. 2.61±5.98%, p=0.008) and OB (BMIGA:2.40±3.36% vs.-1.09±6.40%, p=0.006). The current findings highlight that RFM does not appear to overcome error commonly associated with BMI-based body fat equations when stratifying by sex and BMI classification. Nonetheless, practitioners can use BMIWO, BMIDE, and RFM in males and females classified as NW or OB, but should employ caution prior to use in OW persons.

Bioelectrical impedance analysis, hydrometry and hydrodensitometry for body composition assessment in adult Colombian women

Bioelectrical impedance analysis (BIA) is a noninvasive method for assessment of body composition with better accuracy, and less inter-observer error than anthropometry. Despite these advantages, reported BIA equations may not be suitable for populations other than where they were developed. The aim of this study was to develop equations for single-frequency (SF) BIA and bioelectrical impedance spectroscopy (BIS) using a three compartment (3C) model as the criterion method to predict total body water (TBW) and fat-free mass (FFM) in South-American adult women. A cross-sectional observational study was conducted using a convenience sample (n=40). SF-BIA and BIS prediction equations were developed using forward-stepwise multiple regression with TBW by D2O and FFM by 3C model as dependent variables; and weight, resistance and impedance index (stature2/resistance) as independent variables. A cross-validation was conducted in a randomly split subsample (n=20). Four final equations were developed. There were no differences between SF-BIA and BIS equations for TBW (p=0.68) and FFM (p=0.66). The cross-validation showed a strong association and broadly meets the limits of agreement with the 3C reference method. The equations have an excellent goodness-of-fit to predict TBW and FFM. Validation of these equations in populations of different ages and ethnicities is warranted.

VACCINE CONFIDENCE IN KHYBER PAKHTUNKHWA IN LIGHT OF RECENT UPSURGE IN POLIO CASES: A VIEW BY PUBLIC HEALTH ASSOCIATION- KHYBER PAKHTUNKHWA, PAKISTAN

Vaccine hesitancy as defined by World Health Organization (WHO) refers to “delay in acceptance or refusal of vaccines despite availability of vaccination services. Vaccine hesitancy is complex and context specific, varying across time, place and vaccines. It is influenced by factors such as complacency, convenience and confidence.”1 Vaccine hesitancy is a multidimensional complex phenomenon with many determinants.2,3 It is usually seen amongst specific subgroups of population within a country and have certain context. Vaccine hesitancy is not always related to one specific vaccine. Sometimes it is against immunization in general. It is important to understand who is hesitant towards vaccines or the immunization program and why.4 Many models are available to understand and help elucidate this phenomenon. WHO has adopted “the 3C model” as it is readily understandable and has incorporated the themes in its definition as well i.e. complacency, convenience and confidence.5 Complacency and convenience are important determinants of vaccine hesitancy, in this write up we will keep ourselves limited to discussion on vaccine confidence. Vaccine confidence implies “trust in the vaccine (the product), trust in the vaccinator or other health professional (the provider), and trust in those who make the decisions about vaccine provision (the policy-maker).” It is the trust of the public not only on the vaccine itself but also the healthcare workers and the government that leads to vaccine confidence.

Single ionization of helium by fast proton impact in different kinematical regimes

We present ultrahigh-resolution data on fully differential cross sections for single ionization of helium induced by 1 MeV proton impact. In the present work we explore a different regime of kinematic conditions in terms of momentum transfer and electron energies than previously published data. These data are compared with different theoretical calculations. Reasonable agreement between the first Born approximation and experiment is obtained in the kinematic regime close to the Bethe ridge. Far from this region the calculated binary peak is shifted with respect to experiment. In order to resolve this problem, we analyze several theoretical mechanisms beyond the customary first Born approximation theory. These mechanisms include the 3C model (three Coulomb functions), effective charges, off-shell pair $T$ matrices instead of pair potentials, and semiclassical postcollision interaction. We find that a combination of the 3C model with a semiclassical postcollision interaction effect may explain the observed discrepancy.

A systematic literature review of reported challenges in health care delivery to migrants and refugees in high-income countries - the 3C model

BackgroundMigrants and refugees have important health needs and face inequalities in their health status. Health care delivery to this patient group has become a challenging public health focus in high income countries. This paper summarizes current knowledge on health care delivery to migrants and refugees in high-income countries from multiple perspectives.MethodsWe performed a systematic literature review including primary source qualitative and quantitative studies between 2000 and 2017. Articles were excluded if the study setting was in low- or middle-income countries or focused on skilled migration. Quality assessment was done for qualitative and quantitative studies separately. Predefined variables were extracted in a standardized form. Authors were approached to provide missing information.ResultsOf 185 identified articles, 35 were included in the final analysis. We identified three main topics of challenges in health care delivery: communication, continuity of care and confidence. All but one study included at least one of the three main topics and in 21/35 (60%) all three topics were mentioned. We further developed the 3C model and elaborated the interrelatedness of the three topics. Additional topics identified showed that the specific regional context with legal, financial, geographical and cultural aspects is important and further influences the 3C model.ConclusionsThe 3C model gives a simple and comprehensive, patient-centered summary of key challenges in health care delivery for refugees and migrants. This concept is relevant to support clinicians in their day to day practice and in guiding stakeholders in priority setting for refugee and migrant health policies.

The Prevalence of Body Composition Criterion Methods for Validation Studies in Humans

PURPOSE: To determine the recent prevalence of body composition criterion methods in validation studies of total body percent fat or fat free mass. METHODS: A literature search was performed to identify studies between 2013 - 2018 using the following key words: four component model, validation, body composition, and fat using Medline. Only human studies published in English were included. One person (L. Milliken) screened all articles and coded the results to identify the criterion and comparison methods used. For all studies where multi component models were used, a further note was made regarding what methods comprised those models. All methods were summarized to capture the prevalence of methods used in the literature for body composition validation studies. RESULTS: A total of 176 articles were identified; 128 measured total body composition or body volume articles and were included. Some studies used more than one criterion method. 10.9% of studies used a 2 component (2C) model, 67.2% used a 3C model and 10.9% used a 4C model as a criterion method. The most common 2C, 3C, and 4C models respectively were air displacement plethysmography (ADP)(9.3%), dual-energy x-ray absorptiometry (DXA) (62.5%) and ADP/DXA/total body water (TBW) (7.8%). 3.9% of studies used an inappropriate 3C or 4C model by using bioimpedance spectroscopy (BIS) in place of TBW by isotope dilution. The criterion methods used in order of prevalence were DXA (62.5%), 4C (10.9%), ADP (9.4%), isotope dilution (7.0%), magnetic resonance imaging (4.7%), 3C not including DXA (4.7%), bioelectrical impedance analysis (3.9%), and underwater weighing (1.6%). CONCLUSIONS: Body composition validation studies are dominated by DXA as a criterion method which may not be appropriate in all situations. Also, researchers are incorrectly using field methods rather than laboratory methods (most commonly using BIS for TBW) as part of the 4C model in validation studies. The gold standard for body composition validation studies remains the 4C model with TBW determined by isotope dilution.

Comparing a 3-Compartment Model to Criterion Measures for Estimating Body Composition in Athletes

Multi-compartment models are emerging as a criterion method of analyzing body composition, thereby reducing the error associated with standalone laboratory measures. PURPOSE: The purpose of this study was to compare a 3-compartment model (3-C) with two gold standard lab measures (i.e., air displacement plethysmography (ADP) and dual-energy x-ray absorptiometry (DEXA)). METHODS: Sixty-nine male and forty-eight female athletes completed three body composition measures (i.e., DEXA, ADP, and bioelectrical impedance spectroscopy (BIS)). Body fat percentage (BF%) was calculated using a 3-compartment (3C) model, consisting of total body water (via BIS), body volume (via ADP), and body weight. For statistical analysis, a repeated measures ANOVA was used to compare ADP and DEXA against a 3-C model for all within gender comparisons. RESULTS: For males, results showed a significant mean difference when comparing 3-C (13.2±7.0%) and DXA (16.5±9.5%; p<0.01), but no difference between 3-C and ADP (12.0±8.0%; p=0.09). For females, a significant mean difference was seen with 3-C (23.5±7.2%) and DXA (28.5±6.6%; p<0.01); however, there was no difference between 3-C and ADP (22.2±7.1%; p=0.34). CONCLUSION: DEXA may provide overestimates of BF% for both male and female athletes, while ADP provided no significant differences when compared to a multi-compartment model.