Bioelectrical Impedance Analysis System Research Articles

Effects of 16-week circuit training on physical fitness parameters, pulmonary function, and quality of life in healthy women.

Circuit training (CT) is an important type of training that can combine different types of exercises in a single form of training. This study aimed to investigate the effects of 16-week CT on physical fitness parameters, pulmonary function, and quality of life in healthy women. Twenty-nine healthy women (median age: 37.00 [31.50/39.50] years) were included in the study. CT was applied to the participants for a total of 16 weeks. Participants' body composition with the Bioelectrical Impedance Analysis System, knee flexor and extensor muscle strength with the Biodex System-4 Pro, flexibility with the sit-and-reach test, pulmonary function with a spirometer device, and quality of life with Short Form-36 were assessed. A significant difference was found between the participants' pretest and posttest median and interquartile range values of waist-hip ratio, body mass index, right/left knee flexor/extensor mean peak torque (60°/s,180°/s), right hamstring/quadriceps (H/Q) ratio (60°/s), flexibility, and SF-36 Mental Health Score (P˂0.050). There was no significant difference between the participants' pretest and posttest median and interquartile range values of total body fat, fat percentage, right H/Q ratio (180°/s), left H/Q ratio (60°/s,180°/s), pulmonary function, and Short Form-36 Physical Function Score (P˃0.050). CT decreased waist-hip ratio and body mass index, increased knee flexor/extensor strength and flexibility, and improved mental health. The 16-week CT may be an alternative approach to improve physical fitness parameters and mental health without any positive effects on body fat and pulmonary functions in healthy women.

Similarities and discrepancies between commercially available bioelectrical impedance analysis system and dual-energy X-ray absorptiometry for body composition assessment in 10–14-year-old children

A variety of easy-to-use commercial bioelectrical impedance appliances are available. The aim of this study was to examine the usefulness of a commercially available body composition meter using bioelectrical impedance analysis (BIA) by comparing its measurement results with those obtained from dual-energy X-ray absorptiometry (DXA). The participants were 443 children aged from 10 to 14 years (226 boys and 217 girls). Fat mass, fat-free mass, lean body mass, percentage of body fat, and bone mineral contents were evaluated for all participants using BIA and DXA. The agreement in the anthropometric data obtained from both devices was analyzed using correlation analysis, intraclass correlation coefficient (ICC), Lin’s concordance correlation coefficient (CCC), Bland–Altman plots, and ordinary least products regression analysis. Equivalence between both devices was tested by two one-sided t-test. All measured indicators showed strong linear correlations between the two measurement systems (r, 0.853–1.000). Fat mass, fat-free mass, and lean body mass showed absolute concordance (ICC, 0.902–0.972; Lin’s CCC, 0.902–0.972). BIA overestimated bone mineral content (62.7–66.5%) and underestimated percentage of body fat (− 8.9 to − 0.8%), lean body mass (− 3.5 to − 1.8%), and body mass (− 0.8 to − 0.5%). For fat mass and fat-free mass, the overestimate or underestimate varied according to the sex and statistical analysis test. Bland–Altman analysis and ordinary least products analysis showed fixed bias and proportional bias in all indicators. Results according to quartiles of body mass index showed poor agreement for fat mass and percentage of body fat in both boys and girls in the lowest body mass index quartile. The present results revealed strong linear correlations between BIA and DXA, which confirmed the validity of the present single-frequency BIA-derived parameters. Our results suggest that BIA cannot provide the exact same values as DXA for some body composition parameters, but that performance is sufficient for longitudinal use within an individual for daily health management and monitoring.

High precision but systematic offset in a standing bioelectrical impedance analysis (BIA) compared with dual-energy X-ray absorptiometry (DXA)

Bioelectrical impedance analysis (BIA) provides a practical method of body composition estimation for field research and weight management programmes, with devices and algorithms that have improved in recent years. We...

Wearable ring bioelectrical impedance analyzer for estimation and monitoring of body fat

The World Health Organization has declared obesity as one of the fastest growing global epidemics. People suffering from obesity are at an increased risk of serious health conditions including stroke, diabetes, high blood pressure, and other chronic diseases caused by excess fat in the body. To study and control this obesity epidemic, precise measurement of the body fat mass is necessary. Bioelectrical impedance analysis (BIA) is a common yet effective method for body composition, especially fat mass, measurement in which the electrical impedance of a human body is measured. Here we report a novel wireless BIA device, in the form of a wearable ring, for estimating the body fat as well as a smartphone application for users to manage and track their health data. The wearable analyzer was compared with an off-the-shelf body fat monitor in terms of performance for 40 healthy volunteers. In addition, the small, dry electrodes used in the ring analyzer are compared with traditional gel-based electrodes. Although the dry electrodes impose a larger skin-electrode contact impedance (5.18 ± 0.655 kΩ) than gel-based electrodes (933.37 ± 40.06 Ω), the designed system provides critical compensation for the higher electrode impedance and the parasitic effects for the dry electrodes. With the compensation implemented, these two types of electrodes are highly correlated with correlation coefficients r = 0.96 for resistance and r = 0.93 for reactance. Body fat estimation equations proposed by four different groups are analyzed and compared using the results from the wearable ring device. Our ring analyzer and the reference monitor demonstrate a linear regression with a strong correlation (r = 0.90) for estimating fat mass. Furthermore, the Bland-Altman plot shows that only 2 out of 40 subjects lie outside the 95% limit of agreement. All these findings show that the ring BIA system is highly portable, easy to use, and with comparable performance to large reference analyzers.

Changes in adipose tissue and biochemical parameters after aerobic exercise in overweight and obese women

Background/Aim: Obesity is a global epidemic, and it is more common in women due to physiological differences. Exercise programs are the cornerstones of obesity treatment. This retrospective study aimed to examine the effect of moderate-intensity continuous aerobic exercise (MICT) program on body composition, biochemical parameters, and cardiovascular risk in overweight and obese female. Methods: This retrospective cohort study analyzed the data of overweight and obese women who exercised for 12 weeks. The exercise program was maintained under the supervision of a physiotherapist three non-consecutive days a week. Each session was performed for 60 minutes at an intensity of 50% to 65% of maximum heart rate (HRmax). Body composition was evaluated by TANITA bioelectrical impedance analysis system, and aerobic capacity was assessed with 6-minute Walking Test (6-MWT). Biochemical parameters were analyzed in the laboratory. All results of the participants were obtained from the patient files. Results: Body Mass Index (BMI), Fat Mass (FM-kg), Fat-free Mass (FFM-kg), Total Body Water (TBW-kg), and aerobic capacity improved after the implementation of the exercise program (P<0.05 for all). There was no significant change in blood parameters except HDL (P=0.002). An 11% reduction was observed in cardiometabolic risk factors due to the increased HDL. Conclusion: The MICT program appears suitable for improving body composition and aerobic capacity with 50-65% intensity for 12 weeks. However, we think that exercise intensity should be increased for more biochemical benefits.

Relationships Between Estimated Hourly Energy Balance and Body Composition in Professional Cheerleaders

We sought to describe and examine the interrelationships between energy intake, body composition, and estimated energy balance. Using self-reported hourly food intake and formula-based energy expenditure (EE) protocols, 19 female professional cheerleaders (mean age 25.4 years) were assessed to obtain energy balance (EB) for a typical training day. Energy intake (EI) was predicted using the USDA Food Composition Database SR27, and EE was predicted using the Harris-Benedict equation plus a MET-based relative intensity activity scale. Body composition was predicted using a multi-current, 8-mode segmental bioelectrical impedance analysis system. Hourly and daily EB was calculated from EI and EE data. Subjects reported a 24 h EI significantly below (P < 0.001) the unadjusted predicted energy requirement (1482 kcal vs. 2199 kcal, respectively), resulting in an average negative net EB of − 720 kcal. Carbohydrate intake was significantly below the minimum recommended level (3.1 g/kg vs. 6 g/kg, P < 0.001) while protein and fat intakes met the recommended levels. Higher fat intake (g/kg) was significantly associated with a higher EI kcal/kg (r = 0.726; P < 0.001), which was significantly associated (r = − 0.55; P = 0.01) with a lower body fat percent (BF%). Using the median of BF% (20.9) as the cut point, participants with fewer hours in a negative EB had lower BF% (P = 0.043) and those with lower BF% spent more time in an EB of ± 300 kcal (P = 0.013). These athletes reported low energy intakes that resulted in large EB deficits and/or more hours in a negative EB, which could be counterproductive for achieving a lean body composition overtime.

Validation of a bioelectrical impedance analysis system for body composition assessment in patients with COPD.

ABSTRACTObjective:To investigate the validity of an eight-contact electrode bioelectrical impedance analysis (BIA) system within a household scale for assessing whole body composition in COPD patients. Methods:Seventeen patients with COPD (mean age = 67 ± 8 years; mean FEV1 = 38.6 ± 16.1% of predicted; and mean body mass index = 24.7 ± 5.4 kg/m2) underwent dual-energy X-ray absorptiometry (DEXA) and an eight-contact electrode BIA system for body composition assessment. Results:There was a strong inter-method correlation for fat mass (r = 0.95), fat-free mass (r = 0.93), and lean mass (r = 0.93), but the correlation was moderate for bone mineral content (r = 0.73; p < 0.01 for all). In the agreement analysis, the values between DEXA and the BIA system differed by only 0.15 kg (−6.39 to 6.70 kg), 0.26 kg (−5.96 to 6.49 kg), −0.13 kg (−0.76 to 0.50 kg), and −0.55 kg (−6.71 to 5.61 kg) for fat-free mass, lean mass, bone mineral content, and fat mass, respectively. Conclusions:The eight-contact electrode BIA system showed to be a valid tool in the assessment of whole body composition in our sample of patients with COPD.

Phase angle and its determinants in healthy subjects: influence of body composition

AbstractBackground: The phase angle (PA) has been used as a prognostic marker in several clinical situations. Nevertheless, its biological meaning is not completely understood.Objective: We verified how body-composition components could explain the PA.Design: The trial was a cross-sectional study involving 1442 participants (women: 58.5%; Caucasian: 40.2%) from body-composition studies. Labeled tritium dilution and total-body potassium were used to estimate total-body water (TBW) and intracellular water (ICW), respectively. Extracellular water (ECW) and the ECW:ICW ratio were estimated from the difference and the ratio of these values. Fat-free mass (FFM) and fat mass (FM) were estimated with the use of dual-energy X-ray absorptiometry, underwater weighing (UWW), and TBW. The PA was estimated with the use of a single-frequency bioelectrical impedance analysis system. Correlations between the PA and all body-composition variables were evaluated. A multivariate linear regression analysis was performed to adjust for the effects of body-composition variables on the PA variability. All analyses were performed separately by sex.Results: Compared with men, women exhibited significantly larger ECW:ICW ratios and FM. The highest positive correlation was shown between the PA and FFM obtained with the use of UWW (both sexes). The highest negative correlation was shown between the PA and ECW:ICW ratios for both sexes. Age, race, height, ECW:ICW, and FFM from UWW were significant PA determinants in a multivariate linear regression model. Even after adjustment for all significant covariates, the explained PA variance was low (adjusted R2 = 0.539 and 0.421 in men and women, respectively). The greatest impact on the total PA prediction in both men and women were age, FFM, and height.Conclusions: Age is the most significant PA predictor in men and women followed by FFM and height. The ECW:ICW contribution may explain the association of the PA observed in the clinical setting and in people who are obese.

Mobile evaluation of human energy balance and weight control: Potential for future developments.

Quantification of energy storage is essential in understanding energy balance and can be determined by bioelectrical impedance analysis (BIA). Here, we have developed a smartphone form factor multi-frequency BIA device that incorporates an analog front end for body composition measurements. The device was compared against a reference gel-electrode based BIA system in a clinical trial of 311 subjects for predicting BIA equations by calibrating the impedance index to body composition data from dual energy X-ray absorptiometry (DXA). Strong correlations were observed between DXA-based lean soft tissue and the impedance index generated at 50 KHz (R(2)=0.87; p<;0.001). A similar trend was also evident at higher frequencies which matched results from the reference gel-electrode BIA device. The findings support the role of our consumer-oriented mobile Health initiative for multi-frequency BIA assessments to aid weight management.

Skeletal Muscle Quality: Concordant Findings from Two Practical Non‐Invasive Approaches

Phase angle (θ), derived from bioelectrical impedance analysis (BIA) resistance and reactance, decreases with adult age and is associated with changes in nutritional status and skeletal muscle (SM) function. Another measure of SM quality is the light fraction (LF) measured with ultrasound (US) followed by image processing; echogenic light SM is produced with fat and fibrous tissue infiltration of normally dark SM. While the BIA system automatically measures θ, technical training is needed for operation of the US system and subsequent image analysis. The aim of this study was to examine the associations between these two age-related measures of SM quality: θ at 50 KHz using an 8-electrode multifrequency BIA system (MC980, Tanita Corp., Tokyo, Japan); US (GE LOGIC e, Milwaukee, Wisconsin; Nikon NIS Elements Advanced Research 3.22.11, Melville, NY). Subjects were 165 males and females, ages 5-80 yrs, with US measures of biceps, triceps, calf, and thigh muscles; and θ measures of each arm and leg. Significant correlations (p<0.05) were present for key associations, including: bicep LF and arm θ; triceps LF and arm θ; thigh LF and leg θ; age and biceps and thigh LF, and leg θ. Our findings thus show concordant relations between the two different measures of SM quality, θ and LF. Measurement of θ may be a simple, practical, and clinically-useful measure of age-related changes in SM quality.

A best practice fall prevention exercise program to improve balance, strength / power, and psychosocial health in older adults: study protocol for a randomized controlled trial

BackgroundWith increasing age neuromuscular deficits (e.g., sarcopenia) may result in impaired physical performance and an increased risk for falls. Prominent intrinsic fall-risk factors are age-related decreases in balance and strength / power performance as well as cognitive decline. Additional studies are needed to develop specifically tailored exercise programs for older adults that can easily be implemented into clinical practice. Thus, the objective of the present trial is to assess the effects of a fall prevention program that was developed by an interdisciplinary expert panel on measures of balance, strength / power, body composition, cognition, psychosocial well-being, and falls self-efficacy in healthy older adults. Additionally, the time-related effects of detraining are tested.Methods/DesignHealthy old people (n = 54) between the age of 65 to 80 years will participate in this trial. The testing protocol comprises tests for the assessment of static / dynamic steady-state balance (i.e., Sharpened Romberg Test, instrumented gait analysis), proactive balance (i.e., Functional Reach Test; Timed Up and Go Test), reactive balance (i.e., perturbation test during bipedal stance; Push and Release Test), strength (i.e., hand grip strength test; Chair Stand Test), and power (i.e., Stair Climb Power Test; countermovement jump). Further, body composition will be analysed using a bioelectrical impedance analysis system. In addition, questionnaires for the assessment of psychosocial (i.e., World Health Organisation Quality of Life Assessment-Bref), cognitive (i.e., Mini Mental State Examination), and fall risk determinants (i.e., Fall Efficacy Scale – International) will be included in the study protocol. Participants will be randomized into two intervention groups or the control / waiting group. After baseline measures, participants in the intervention groups will conduct a 12-week balance and strength / power exercise intervention 3 times per week, with each training session lasting 30 min. (actual training time). One intervention group will complete an extensive supervised training program, while the other intervention group will complete a short version ('3 times 3’) that is home-based and controlled by weekly phone calls. Post-tests will be conducted right after the intervention period. Additionally, detraining effects will be measured 12 weeks after program cessation. The control group / waiting group will not participate in any specific intervention during the experimental period, but will receive the extensive supervised program after the experimental period.DiscussionIt is expected that particularly the supervised combination of balance and strength / power training will improve performance in variables of balance, strength / power, body composition, cognitive function, psychosocial well-being, and falls self-efficacy of older adults. In addition, information regarding fall risk assessment, dose–response-relations, detraining effects, and supervision of training will be provided. Further, training-induced health-relevant changes, such as improved performance in activities of daily living, cognitive function, and quality of life, as well as a reduced risk for falls may help to lower costs in the health care system. Finally, practitioners, therapists, and instructors will be provided with a scientifically evaluated feasible, safe, and easy-to-administer exercise program for fall prevention.Trial registrationClinicalTrials.gov Identifier: NCT01906034

Direct Segmental Multi-Frequency Bioelectrical Impedance Analysis Is Useful to Evaluate Sarcopenia

To the Editor:We are grateful to Safer et al. (1) for commenting on themethodology used in our recent study (2), and for definingsarcopenia. The validity of segmental bioelectrical imped-anceanalysis(BIA)forassessingskeletalmusclemassandthe significance of low muscle function in the diagnosis ofsarcopenia are important issues.Safer et al. argued that segmental BIA might not beappropriate for measuring muscle mass, referring to twoprevious papers from Japan and Europe. The BIA systemused in these studies is different from that used in ourrecent study (2). We used multifrequency BIA with atetrapolar eight-point tactile electrode system (InBody 720;Biospace, Tokyo, Japan), a newly developed directsegmental multifrequency BIA (DSM-BIA) system. Unlikeconventional BIA equipment, whichoften takes only partialmeasurements and therefore relies upon formulas toestimate whole body composition, this technique employsthe assumption that the human body is composed of fiveinterconnecting cylinders and takes direct impedancemeasurements from the various body compartments. Ofthe BIA devices developed over the years, the DSM-BIAsystem has been thus shown to be superior in theestimation of body composition (3). Ling et al. recentlydemonstratedexcellentagreementbetweenDSM-BIAanddualenergyX-rayabsorptiometry(DEXA)fortheestimationof lean body mass in both sexes in a large general middle-aged population (n ¼ 484) (4).In our recent report, no significant correlations wereobserved between the skeletal muscle mass and Child-Pugh classification (p ¼ 0.278). To rule out the possibilitythat BIA overestimated muscle mass in patients withoverhydration, including massive ascites and edema,which are often found in patients with Child-Pugh C liverdisease, we further divided 74 Child-Pugh C patients intothree groups according to the degree of ascites fluidretention (no ascites; 24, mild to moderate ascites; 24,massive ascites; 26), and compared skeletal muscle massamong them. Consequently, skeletal muscle mass in themassive ascites group (92.2 12.2) was significantlylower than that in the no ascites group (102.9 15.5;p ¼ 0.0286; Figure 1). Therefore, the effect of over-hydration on overestimation of BIA might be, if any,minimum in using this device, andthe deterioration of liverfunction caused by liver cirrhosis accompanied thedecreaseinskeletalmusclemassinChild-PughCpatients.A recent report demonstrating that lean body mass washighly correlated with good method agreement usingDEXAasthereferencetestin104stableperitonealdialysispatients (r ¼ 0.95, p < 0.0001) strongly supports theaccuracy of DSM-BIA, even in overhydrated patients (5).DSM-BIA is superior to DEXA in its simplicity, portability,lower cost, and absence of radiation exposure. Takingthese findings into consideration, DSM-BIA can be viewedas the gold standard for assessing sarcopenia.Evaluation of muscle function, in addition to muscle mass,would indeed be important for diagnosing sarcopenia. Asfor muscle function in patients undergoing liver transplan-tation, we are now conducting a prospective study, asdescribed in our recent paper. The interim analysis showsthat skeletal muscle mass is strongly correlated with gripstrength (data not shown); therefore, misclassification ofsubjects in our recent report would be, if any, almostnegligible.T. Kaido* and S. UemotoDivision of Hepato-Biliary-Pancreatic and TransplantSurgery, Department of Surgery, Graduate School ofMedicine, Kyoto University, Kyoto, Japan*Corresponding author: Toshimi Kaido,kaido@kuhp.kyoto-u.ac.jp

Nadwaga i otyłość kobiet w okresie okołomenopauzalnym mierzone metodą bioimpedancji elektrycznej

Nadwaga i otyłość kobiet w okresie okołomenopauzalnym mierzone metodą bioimpedancji elektrycznej

신체 성분 분석을 위한 다 주파수 생체전기 임피던스 분석 시스템 구현

In this paper, we introduce the multiple frequency bio-electrical impedance analysis method for body composition analysis. And then we implement the multiple frequency bio-electrical impedance analysis system. Overall system consists of: multiple frequency alternating current signal generator contained alternating current signal, phase signal detector, voltage signal detector, micro controller, in-out device(key-pad LCD), conductivity electrodes, system power. We explain the architecture of the system and required theory to implement the system. In order to investigate the clinical significance of the body composition data, compare to the data measured by the expert body composition analyzer which provide high reproduction and precision. Finally, experimental results which are the correlation between the measured data show the very high reproduction performance of the body composition analysis in the proposed system.

Effects of a Short-Term Resistance Program Using Elastic Bands Versus Weight Machines for Sedentary Middle-Aged Women

This study was designed to determine whether different effects on functional capacity and body composition were produced by using different devices (elastic bands (EBs) versus weight machines (WMs)) with the same resistance training program. Forty-five healthy sedentary middle-aged women volunteers were chosen and randomly assigned to 1 of 3 groups: 21 subjects trained using EBs (EBG), 14 in trained using WMs (WMG), and 10 were controls (CG). Both exercise groups trained with a periodized muscular endurance program twice a week for 10 weeks, with a total of 6 exercises per session for the major muscle groups. Exercise intensity was equalized by jointly monitoring the same targeted number of repetitions (TNRs) and rate of perceived exertion in active muscles (RPE-AM). Functional capacity was assessed by using knee push-up (KPU) and 60-second squat (S) tests. Body composition was measured using an 8-polar bioelectrical impedance analyzer. The results for both the EBG and WMG show a decrease in fat mass (p = 0.05 and p < 0.01, respectively) and an increase in both the fat-free mass (p < 0.05 and p < 0.01, respectively) and the number of repetitions in the KPU (p < 0.05 and p < 0.01, respectively) and S tests (p < 0.01 in both). None of the variables measured for the CG varied significantly. It can be concluded that, independently of the device used, the combined monitoring of TNRs and RPE-AM can be a valid tool for controlling the resistance exercise intensity and can lead to healthy adaptations. EBs can thus offer significant physiological benefits that are comparable to those obtained from WMs in the early phase of strength training of sedentary middle-aged women.

Prediction of visceral fat area at the umbilicus level using fat mass of the trunk: The validity of bioelectrical impedance analysis

The aims of this study were to determine the validity of fat mass of the trunk as a predictor for visceral fat area at the umbilicus level and to develop equations to predict visceral fat mass at the umbilicus level using fat mass of the trunk measured by dual-energy X-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA). The participants were 121 normal Japanese adults (69 males, 52 females). Another 60 volunteer adults (34 males, 26 females) were recruited for examination of cross-validity. Altogether, 41 adults (15 males, 26 females) in the original group and 19 adults (7 males, 12 females) in the cross-validity group received BIA measurement. We measured fat mass by DXA and the BIA system, which was a single-frequency BIA with 8-point contact electrodes, and visceral fat area by computed tomography. We observed significant correlations for visceral fat area in waist circumference (0.56) and fat mass of the trunk measured by DXA (0.64). There was no significant difference in fat mass of the trunk between the DXA and BIA systems, but the BIA system tended to provide an underestimate compared with DXA. With combined fat mass of the trunk measured by DXA and waist circumference as predictors, visceral fat area was estimated byequation (1) (R = 0.87, R 2 = 0.76, standard error of the estimate = 20.9 cm2). When substituting fat mass of the trunk measured by BIA into equation (1), there was no significant difference in visceral fat area between the reference and predicted values. An equation using fat mass of the trunk measured by BIA (equation 2) was obtained (R = 0.89, R 2 = 0.78, standard error of the estimate = 20.7 cm2), but a systematic error was found for the males. There was cross-validity in both equations. In conclusion, fat mass of the trunk is an effective predictor for the visceral fat area at the umbilicus level. Fat mass of the trunk measured by BIA might be a valid method to predict visceral fat, although further studies with larger samples taking into account the extent and type of obesity are required.

Evaluation of a Foot-to-Foot Bioelectrical Impedance Analyzer in Pre-Menopausal Hispanic and Caucasian Women

The prevalence of obesity and overweight continues to increase among adults and adolescents lending to the development of many chronic diseases including cardiovascular disease, diabetes, and high blood pressure. The accuracy of a foot-to-foot bioelectrical impedance analysis (BIA) system for estimating body composition has been previously reported. However, the validity of a foot-to-foot BIA system for assessing body fatness in Hispanic women has not been determined. PURPOSE: To determine the efficacy of a foot-to-foot bioelectrical impedance analyzer in pre-menopausal Hispanic and Caucasian women. METHODS: The body composition of 76 Hispanic [mean (SD) age: 42.7 (4.6) y; height: 161.3 (5.7) cm; body mass: 70.1 (15.1) kg] and 47 Caucasian [age: 43.8 (4.3) y; height: 165.5 (6.2) cm; body mass: 66.4 (12.1) kg] women was assessed by BIA, dual energy x-ray absorptiometry, and hydrostatic densitometry. Percentage of body fat (%BF) values measured by BIA were compared to %BF values derived from a 2-compartment (2-C) (Brozek, 1963) and a 3-compartment (3-C) (Lohman, 1986) model using a one-way ANOVA with repeated measures. RESULTS: There was no significant difference in body mass (P = 0.15) or age (P = 0.17) between the Hispanic and Caucasian women; although Caucasian women were significantly taller than Hispanic women (P <0.001). Mean (SD) %BF was significantly greater for Hispanic women than Caucasian women (P <0.001) but, no significant interaction was observed for race and %BF (P = 0.09). For Hispanic women, mean (SD) %BF values measured by BIA [36.3 (7.3) %] were similar to %BF derived from the 2-C model [35.3 (8.0) %] (P = 0.07) and BIA %BF values were significantly different than %BF derived from the 3-C model [38.2 (8.6) %] (P = 0.005). For Caucasian women, BIA measured %BF values [33.1 (7.9) %] were similar to those derived from the 2-C [32.1 (6.3) %] and 3-C [34.0 (7.5) %] model (P >0.40). CONCLUSION: For these data, BIA provided similar %BF values as the 2-C and 3-C models for Caucasian women. However, BIA %BF values were significantly different from 2-C and 3-C values for Hispanic women. These data may suggest the need to develop race specific equations for estimating body composition using foot-to-foot BIA. This study was supported by funds from NIH (P20-MD000548-01).

Tanita Foot-to-Foot Bioelectrical Impedance Analysis System Validated in Older Adults

Simple, accurate, and noninvasive methods for assessing body composition are needed in many clinical, community, and research settings. The foot-to-foot bioelectrical impedance analysis (BIA) system may be one method of addressing those needs. The objective of this study was to determine the validity of a foot-to-foot BIA system for body-composition assessment of older adults. Subjects 55 years of age or older without functional limitations or cognitive impairments (N=50) were measured using both the Tanita foot-to-foot system (Tanita Corporation of America, Inc, Arlington Heights, IL) and traditional hand-to-foot BIA. The correlation for percent body fat measurements between the Tanita and traditional BIA was r=0.84 ( P<.001). Percent body fat estimates from both BIA measures were significantly correlated with waist circumference, body mass index, and age (all P<.01). The Tanita BIA system provides a valid measure of percent body fat in older adults, and could be a convenient and practical approach for assessment in public health settings.

Assessment of Body Composition Change in a Community-Based Weight Management Program

Objective: The purpose of this study was to validate the use of the leg-to-leg bioelectrical impedance analysis (BIA) system in assessing change in body composition over 32 weeks in overweight and obese women participating in a community weight management program.Design: Intervention, with subjects prescribed an energy-restriction diet and exercise program for 32 weeks and body composition measured pre-study and after 12 and 32 weeks.Subjects and Setting: Overweight and obese premenopausal women (n=201) with no overt disease were recruited at six sites into community-based weight loss programs. One hundred and twenty-four women completed all aspects of the study.Intervention: Energy intake was set at 0.8 × resting metabolic rate (RMR) for weeks 1 through 12, 1.0 × RMR for weeks 13 through 20 and 1.2 × RMR for weeks 21 through 32. Energy intake was based on a food exchange table, with the number of food exchanges adjusted to encourage a percent distribution of 55% carbohydrate, 30% fat and 15% protein. Subjects increased their daily walking distance by 3.2 km above pre-study levels.Measures of Outcome: Underwater weighing, seven skinfolds, and leg-to-leg BIA tests were used to assess body composition.Results: A 3 × 3 repeated measures ANOVA revealed no significant difference in detecting change in FFM at 12 and 32 weeks among underwater weighing, BIA and skinfold, (F(4,492)=1.73, p=0.141) (decrease in FFM of 1.0±3.3 kg, 1.7±2.2 kg, and 1.4±3.3 kg respectively, 32 weeks).Conclusions: The leg-to-leg BIA system provides a valid measure of body composition change in overweight premenopausal women during a 32-week community-based weight loss program.

A comparison of leg‐to‐leg bioelectrical impedance and underwater weighing methods in measuring body composition in Caucasian and African American football athletes

The purpose of this study was to validate leg‐to‐leg bioelectrical impedance analysis (BIA) methodology for estimating body composition in ethnically mixed football athletes. Sixty‐four Caucasian and 36 African American Division 1AA football athletes took part in this study. Their mean age ± SD was 20.2 ± 1.9 yr and their body mass index was 29.2 ± 4.8 kg/m2. Age, body mass index, and percent body fat did not differ significantly between ethnic groups. Fat free mass (FFM) and percent body fat was also estimated from underwater weighing (UW), seven‐site skinfold measurement (SK), and B1A. A significant correlation in estimating FFM was found between underwater weighing and BIA (r = 0.94, p< 0.001; SEE 3.7 kg), and between underwater weighing and skinfold thickness measurement (r = 0.97, p < 0.001; SEE 2.6 kg). The mean difference in estimation of FFM between underwater weighing and BIA was — 0.46±3.8kg. No significant correlation (r = 0.10, p = .166) was found between the estimation of FFM from underwater weighing and the difference in estimation of FFM between underwater weighing and BIA. This indicated there was no systematic underestimation or overestimation of FFM in either Caucasian or African American athletes. In conclusion, the leg‐to‐leg BIA system provided a quick and accurate method of determining body composition in football athletes compared to conventional underwater weighing.