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Ann L. Gibson, Vivian H. Heyward and Christine M. Mermier

This study assessed the predictive accuracy of a new hand-held, segmental, bioimpedance (BI) analyzer in estimating the relative body fat (%BF) of a sample of 25 men and 23 women (18–55 years, 7.0 to 42.8%BFHW). The reference method was hydrostatic weighing (HW) at residual lung volume. The %BF estimates obtained from manufacturer’s (Omron) gender-specific equations were cross-validated. There were high validity coefficients (ry,y=.91 and .83, for men and women, respectively), moderate prediction errors (SEE = 3.46%, E = 3.64%BF for men; SEE = 4.04%, E = 3.87%BF for women), and no significant difference (p >.05) between the average %BFHW and %BFOmron for women (21.8% vs. 2I.6%BF, respectively). For men, there was a small but significant (p < .05) difference in %BFHW (18.7%) and %BFOmron (20.1 %). For both men and women, the line of identity did not differ significantly (p > .05) from the line of best fit. The Omron® BI equations accurately estimated the %BF of 72% of the men and 65% of the women in this sample within ±3.5%BF. Therefore, use of the Omron® BI analyzer is suitable for assessing the %BF of adults having demographic characteristics similar to those of this sample.

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Herculina S. Kruger, Lize Havemann-Nel, Chrisna Ravyse, Sarah J. Moss and Michael Tieland

Background:

Black women are believed to be genetically less predisposed to age-related sarcopenia. The objective of this study was to investigate lifestyle factors associated with sarcopenia in black South African (SA) urban women.

Methods:

In a cross-sectional study, 247 women (mean age 57 y) were randomly selected. Anthropometric and sociodemographic variables, dietary intakes, and physical activity were measured. Activity was also measured by combined accelerometery/heart rate monitoring (ActiHeart), and HIV status was tested. Dual energy x-ray absorptiometry was used to measure appendicular skeletal mass (ASM). Sarcopenia was defined according to a recently derived SA cutpoint of ASM index (ASM/height squared) < 4.94 kg/m2.

Results:

In total, 8.9% of the women were sarcopenic, decreasing to 8.1% after exclusion of participants who were HIV positive. In multiple regressions with ASM index, grip strength, and gait speed, respectively, as dependent variables, only activity energy expenditure (β = .27) was significantly associated with ASM index. Age (β = –.50) and activity energy expenditure (β = .17) were significantly associated with gait speed. Age (β = –.11) and lean mass (β = .21) were significantly associated with handgrip strength.

Conclusions:

Sarcopenia was prevalent among these SA women and was associated with low physical activity energy expenditure.

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Kerri L. Vasold, Andrew C. Parks, Deanna M.L. Phelan, Matthew B. Pontifex and James M. Pivarnik

Body composition is a key component of health-related fitness and often used as a tool for risk assessment or as a measure of change in physical activity or diet. A variety of situations require the use of accurate body composition measurement techniques. There are various methods used to assess

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Gregory Severino, Marcos Sanchez-Gonzalez, Michelle Walters-Edwards, Michael Nordvall, Oksana Chernykh, Jason Adames and Alexei Wong

that traditional exercise, such as aerobic and resistance training, improves HRV and body composition in several populations. However, due to perceived or actual barriers associated with traditional exercise (e.g., musculoskeletal discomfort, lack of motivation, reduced physical activity) many obese

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Grant M. Tinsley and Brett S. Nickerson

When estimating body composition, a pervasive recommendation is to perform assessments after a period of rest and fasting. This recommendation seeks to minimize biological error induced by daily activities, such as food and fluid ingestion or exercise. Overnight fasts are implemented for a variety

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Donna W. Lockner, Vivian H. Heyward, Sharon E. Griffin, Martim B. Marques, Lisa M. Stolarczyk and Dale R. Wagner

The Segal fatness-specific bioelectrical impedance (BIA) equations are useful for predicting fat-free mass (FFM). Stolarczyk et al, proposed a modified method of averaging the two equations for individuals who are neither lean nor obese, thus eliminating the need to know % BF a priori. To cross-validate this modification, we compared FFM determined using the averaging method versus hydrostatic weighing for 76 adults. Per the averaging method, accuracy for males was excellent (r = .91, SEE = 2.7kg, E = 2.7kg), with 78% of individuals within ± 3.5% BF predicted by hydrostatic weighing. Accuracy for females was lower (r = .88, SEE = 3.0kg, E = 3.1 kg), with %BF of 51% within ±3.5% of the reference method. The relative ease and practicality of the averaging method and the results of this study indicate this method may be useful with a diverse group.

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Pedro Curi Hallal, Felipe Fossati Reichert, Fernando Vinholes Siqueira, Samuel Carvalho Dumith, Juliano Peixoto Bastos, Marcelo Cozzensa da Silva, Marlos Rodrigues Domingues, Mario Renato Azevedo and Ulf Ekelund

Objectives:

The objective of this study was to evaluate physical activity (PA) levels in adults and their association with sex, age, and education level across categories of body mass index (BMI).

Methods:

We conducted a population-based, cross-sectional study including 3100 individuals age ≥20 years living in Pelotas, Brazil. PA was assessed using the leisure-time section of the long International Physical Activity Questionnaire. “No PA” was defined as zero minutes of activity/week; “insuffcient PA” was defined as <150 minutes of activity/week; “high PA” was defined as ≥500 minutes of activity/week. BMI was categorized into normal (<25 kg/m2), overweight (25–29.9 kg/m2), and obesity (≥30 kg/m2).

Results:

The prevalence of insufficient PA was 71.6% among normal BMI subjects, 71.3% among overweight individuals, and 73.7% among obese ones (P = .67). No PA and high PA were also not associated with BMI. The associations between sex, age, and education level and PA levels tended to be stronger among normal-weight individuals compared with overweight and obese individuals. Among the obese, most associations were not significant. Among normal-weight individuals, higher PA levels were observed in men, young adults, and those with higher education.

Conclusions:

Variables associated with leisure-time PA differed between normal-weight, overweight, and obese individuals. Studies on PA correlates might benefit from stratifying by BMI.

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Eric Joseph Rosario, Rudolph Gino Villani, Jeff Harris and Rudi Klein

Aging generally results in muscle and bone atrophy, with accelerated loss in the first few years after menopause contributing to decline in strength, balance, and mobility. This investigation compared the effects of 1 of year periodized high-intensity strength training on a group of less-than-5-years (LF) postmenopausal women (n = 10, mean age 51 years) with its effects on a more-than-10-years (MT) postmenopausal group (n = 11, mean age 60 years). Mean lean body mass, strength, and balance increased over the intervention period for both groups, with no significant intergroup differences. Mean total fat mass significantly decreased for both groups, with no significant difference between groups. Total and regional bone density and mineral content did not significantly change in either group. These results indicate that even during the accelerated muscle-loss period after menopause, women can gain muscle and strength with resistance training to a similar extent as older women.

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David A. Rowe and Matthew T. Mahar

Background:

The purpose of the study was to evaluate race-specific FITNESSGRAM® body mass index (BMI) standards in comparison to the recommended standards, i.e., percent fat (%BF) ≥25 in boys and %BF ≥32 in girls.

Methods:

BMI and %BF were estimated in 1,968 Black and White children ages 6-14 years, using methods similar to those used to develop the current FITNESSGRAM standards. Multiple regression was employed to develop age-, sex-, and race-specific BMI standards. Percent agreement and modified kappa (κq) were used to evaluate agreement with the %BF standards, and sensitivity and specificity were used to evaluate classification accuracy.

Results:

Race significantly (p < .05) and meaningfully (β = 2.3% fat) added to the relationship between BMI and %BF. Agreement of the race-specific BMI standards with %BF standards was moderate to high (κq = .73–.88), and classification accuracy improved on the current FITNESSGRAM BMI standards.

Conclusions:

Race-specific BMI standards appear to be a more accurate representation of unhealthy %BF levels than the current FITNESSGRAM BMI standards.

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Miguel Camões, Andreia Oliveira and Carla Lopes

Objective:

Evaluate the role of different types of physical activity (PA) and diet on overall and central obesity incidence.

Methods:

A cohort study with 1621 adults was conducted in an urban Portuguese population. Anthropometrics were objectively obtained during 1999−2003 and 2005−2008. Overall, obesity was defined by a body mass index (BMI) ≥ 30.0 kg/m2 and central obesity by a waist circumference (WC) > 88.0 cm in women and >102.0 cm in men. Usual PA and dietary intake were assessed using validated questionnaires. Analyses of obesity incidence were conducted through different types of PA and a “healthy” dietary score.

Results:

Significant inverse associations were found between leisure-time PA and obesity incidence, namely among subjects classified into the last tertile of energy expenditure, who had approximately a 40% lower risk of developing the disease. Despite higher energy intakes, individuals with a high Physical Activity Level (PAL > 1.60) were significantly protected against obesity incidence, relative risks (RR) = 0.25 (0.09−0.72) and RR = 0.47(0.27−0.94), for overall and central obesity, respectively. No significant associations were found between dietary score and obesity incidence rates.

Conclusions:

In our population, leisure-time PA played a significant role in preventing obesity. In both overall and central obesity, PAL above 60% of the resting metabolic rate and moderate energy intake seem to strike the right balance to prevent obesity.