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Gladys Block, Christopher D. Jensen, Torin J. Block, Jean Norris, Tapashi B. Dalvi and Ellen B. Fung

Background:

Understanding and increasing physical activity requires assessment of occupational, home, leisure and sedentary activities.

Methods:

A physical activity questionnaire was developed using data from a large representative U.S. sample; includes occupational, leisure and home-based domains; and produces estimates of energy expenditure, percent body fat, minutes in various domains, and meeting recommendations. It was tested in 396 persons, mean age 44 years. Estimates were evaluated in relation to percent body fat measured by dual-energy x-ray absorptiometry.

Results:

Median energy expenditure was 2,365 kcal (women) and 2,960 kcal (men). Women spent 35.1 minutes/day in moderate household activities, 13.0 minutes in moderate leisure and 4.0 minutes in vigorous activities. Men spent 18.0, 22.5 and 15.6 minutes/day in those activities, respectively. Men and women spent 276.4 and 257.0 minutes/day in sedentary activities. Respondents who met recommendations through vigorous activities had significantly lower percent body fat than those who did not, while meeting recommendations only through moderate activities was not associated with percent body fat. Predicted and observed percent body fat correlated at r = .73 and r = .82 for men and women respectively, P < .0001.

Conclusions:

This questionnaire may be useful for understanding health effects of different components of activity, and for interventions to increase activity levels.

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Luke E. Kelly and James H. Rimmer

The subjects were 170 moderately and severely mentally retarded men who were divided into two groups. The first group was used to formulate a new prediction equation and the second group was used to cross-validate and ascertain the stability of the derived equation. The prediction equation, employing waist and forearm circumferences, height and weight as predictors, and estimated percent body fat calculated by the generalized regression equation of Jackson and Pollock (1978) as the criterion measure, was formulated using a stepwise multiple regression analysis. A multiple R value of .86 was obtained for the derived equation with a standard error of estimate value of 3.35. The equation was cross-validated on the second sample to ascertain its stability. An r of .81 and a standard error of estimate of 4.41 was obtained between the subjects’ estimated percent body fat, using the new equation, and the criterion measure. This simplified equation provides practitioners with an accurate, reliable, and inexpensive method of estimating percent body fat for adult mentally retarded males.

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Terry J. Housh, Jeffrey R. Stout, Glen O. Johnson, Dona J. Housh and Joan M. Eckerson

The purpose of the present study was to determine the validity of near-infrared interactance (NIR) estimates of percent body fat (% fat) using Futrex-5000, Futrex-5000A, and Futrex-1000 instruments in youth wrestlers (age, M ± SD = 11.4 ± 1.5 years) by comparing them to % fat values from underwater weighing. Fifty-eight members of youth wrestling clubs (% fat, M ± SD = 10.7 ± 5.1% fat) volunteered to serve as subjects. The statistical analyses included examination of the constant error (CE), standard error of estimate (SEE), correlation coefficient (r), and total error (TE). The results indicated that the errors (TE = 8.0–16.2% fat) associated with the NIR instruments were too large to be of practical value for estimating % fat in young male athletes. It is recommended that (a) the instrument generated NIR % fat estimates be modified based on the CE values in the present investigation such that the CE = 0, and (b) the modified NIR % fat estimates be cross-validated on independent samples of young male athletes.

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Erin White, Jennifer D. Slane, Kelly L. Klump, S. Alexandra Burt and Jim Pivarnik

Background:

Knowing the extent to which genetic and environmental factors influence percent body fatness (%Fat) and physical activity (PA) would be beneficial, since both are tightly correlated with future health outcomes. Thus, the purpose was to evaluate sex differences in genetic and environmental influences on %Fat and physical activity behavior in male and female adolescent twins.

Methods:

Subjects were adolescent (age range 8.3 to 16.6 yr) twins. %Fat (n = 518 twins) was assessed by bioelectrical impedance analysis (BIA) and PA (n = 296 twins) was measured using 3-Day PA Recall. Each activity was converted to total MET-minutes. Univariate twin models were used to examine sex differences in genetic and environmental factors influencing %Fat and PA.

Results:

%Fat was influenced by genetic effects in both boys and girls (88% and 90%, respectively), with slightly higher heritability estimates for girls. PA was influenced solely by environmental effects for both sexes with higher shared environmental influences in boys (66%) and higher nonshared effects in girls (67%).

Conclusions:

When developing interventions to increase PA in adolescents, it is important to consider the environment in which it takes place as it is the primary contributor to PA levels.

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James H. Rimmer, Dave Braddock and Glenn Fujiura

Little data exist on the comparison of blood lipids and percent body fat between Down Syndrome and non-DS adults with mental retardation (MR). The following study was undertaken to determine if there were physiological and biochemical differences between these two groups. Subjects included 294 non-DS adults with MR (162 males and 132 females) and 31 adults with Down Syndrome (21 males and 10 females). Level of mental retardation was similar for both groups (males/females, Down vs. non-DS). A two-factor ANOVA with a regression approach was used to analyze the data. Results of the study found that there were no significant differences between the Down Syndrome and non-DS subjects on total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, or percent body fat. The present study suggests that the composition of lipoproteins and storage of body fat are similar in Down Syndrome and non-DS adults with mental retardation, and that the risk for developing coronary heart disease appears to be the same for both groups.

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Zan Gao and Ping Xiang

Background:

Exergaming has been considered a fun solution to promoting a physically active lifestyle. This study examined the impact of an exergaming-based program on urban children’s physical activity participation, body composition and perceptions of the program.

Methods:

A sample of 185 children’s physical activity was measured in August 2009 (pretest), and percent body fat was used as index of body composition. Fourth graders were assigned to intervention group engaging in 30 minutes exergaming-based activities 3 times per week, while third and fifth graders were in comparison group. Measurements were repeated 9 months later (posttest). Interviews were conducted among 12 intervention children.

Results:

ANCOVA with repeated measures revealed a significant main effect for intervention, F(1, 179) = 10.69, P < .01. Specifically, intervention children had significantly greater increased physical activity levels than comparison children. Logistic regression for body composition indicated intervention children did not differ significantly in percent body fat change from comparison children, Chi square = 5.42, P = .14. Children interviewed reported positive attitudes toward the intervention.

Conclusions:

The implementation of exergaming-based program could have a significantly positive effect on children’s physical activity participation and attitudes. Meanwhile, long-term effect of the program on children’s body composition deserves further investigation.

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Linda B. Houtkooper

Body composition assessment techniques provide estimates of percent body fat (%BF), fat mass (FM), and fat-free mass (FFM) based on indirect assessment models and methods. Prediction equations for %BF developed using a two-component model based on adult body composition constants will overestimate %BF in youths, especially prepubescent youths. Body composition prediction equations that have been validated and cross-validated using multiple-component criterion models which include measurements of body density and the water and mineral components of FFM provide the most accurate means for assessment of body composition in youths. Use of appropriate prediction equations and proper measurement techniques, for either bioelectrical impedance or skinfolds, results in body composition estimates with standard errors of estimate (prediction errors) of 3 to 4% BF and 2.0 to 2.5 kg of FFM. Poor measurement technique and inappropriate prediction equations will result in much larger prediction errors.

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Bailey Peck, Timothy Renzi, Hannah Peach, Jane Gaultney and Joseph S. Marino

. *Significant effect of sport ( P  < .05). Dual-Energy X-ray Absorptiometry A whole-body and regional dual-energy X-ray absorptiometry (DEXA; GE Lunar Primo Prodigy, Madison, WI; enCORE™ 2011 software, version 15) scan was performed to measure percent body fat. 14 Color mapping indicated areas of high and low

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Khaled Trabelsi, Stephen R. Stannard, Ronald J. Maughan, Kamel Jammoussi, Khaled Zeghal and Ahmed Hakim

The aim of this study was to evaluate the effects of a hypertrophic training program during Ramadan on body composition and selected metabolic markers in trained bodybuilders. Sixteen male recreational bodybuilders (9 Ramadan fasters and 7 nonfasters) participated in the study. All visited the laboratory 2 d before the start of Ramadan (Bef-R) and on the 29th day of Ramadan (End-R). In the morning of each session, subjects underwent anthropometric measurement, completed a dietary questionnaire, and provided fasting blood and urine samples. Body mass and body-mass index in nonfasters increased by 2.4% (p = .05 and p = .04, respectively) from Bef-R to End-R but remained unchanged in fasters over the period of the investigation. Fasters experienced an increase in the following parameters from Bef-R to End-R: urine specific gravity (1%, p = .022) and serum concentrations of urea (5%, p = .008), creatinine (5%, p = .007), uric acid (17%, p < .001), sodium (2%, p = .019), potassium (6%, p = .006), chloride (2%, p = .028), and high-density lipoprotein cholesterol (10%, p = .005). However, only serum creatinine and low-density lipoprotein cholesterol increased in nonfasters (3%, p < .001 and 14%, p = .007, respectively) during the same period. Creatinine clearance values of fasters decreased by 3% (p = .03) from Bef-R to End-R. Continuance of hypertrophic training through Ramadan had no effect on body mass and body composition of bodybuilders, but a state of dehydration and reduced renal function were apparent, perhaps because of the restricted opportunity for fluid intake imposed by the study design.

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Michelle Walsh, Laura Cartwright, Clare Corish, Sheila Sugrue and Ruth Wood-Martin

Purpose:

This study examined the body composition, nutritional knowledge, behaviors, attitudes, and educational needs of senior schoolboy rugby players in Ireland.

Methods:

Participants included 203 male rugby players age 15–18 yr competing at Senior School’s Cup level in Leinster, Ireland. Estimation of body composition included measurement of height, weight, and percentage body fat (PBF; using bioelectrical impedance analysis, Tanita BC-418). Nutritional knowledge, behaviors, attitudes, and education needs were assessed by questionnaire.

Results:

The range of PBF was 5.1–25.3%. Sixty-eight percent of the players in this study had a healthy PBF (10–20%), 32 (22%) were classified as underweight (<10% body fat), and 9.7% (n = 14) were overweight. Assessment of nutritional knowledge demonstrated poor knowledge of the foods required for refueling, appropriate use of sports drinks, and the role of protein in muscle formation. Alcohol consumption and dietary supplement use were reported by 87.7% and 64.5%, respectively. A perception that greater body size enhances sport performance did not predict dietary supplement use. Nutritional advice had been previously sought by 121 players from coaches (66.9%), magazines (42.1%), Web sites (38.8%), peers (35.5%), family (28.1%), sport organizations (16.5%), and health professionals (8.2%). Nutritional knowledge was no better in these players, nor did better nutritional knowledge correlate with positive dietary behaviors or attitudes.

Conclusions:

Most players had a healthy PBF. Despite a positive attitude toward nutrition, poor nutritional knowledge and dietary practices were observed in many players. Young athletes’ nutritional knowledge and dietary practices may benefit from appropriate nutritional education.