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David P. MacKinnon, Linn Goldberg, JeeWon Cheong, Diane Elliot, Greg Clarke and Esther Moe

This research examined the relationships among body attributes (i.e., body fat percent and bench press performance) and psychological esteem (i.e., perceived athletic competence, body image, and general self-esteem) in high school football players. Structural equation modeling was used to model the relationships among the constructs. Body fat was negatively related to athletic competence and body image, which in turn were positively related to general self-esteem. The role of bench press performance in predicting psychological esteem was inconsistent, however, suggesting that leanness may be more important than body strength for adolescent psychological esteem among high school football players.

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Jason C. Holmes, Ann L. Gibson, J. Gualberto Cremades and Constance M. Mier

Objective:

To compare estimates of body density (Db) from air-displacement plethysmography (ADP) with measured and predicted thoracic-gas-volume (TGV) measurements and those from hydrodensitometry (HD) in children.

Methods:

Seventeen participants (13 male and 4 female; 10.1 ± 2.20 yr, 42.0 ± 15.03 kg, 145.6 ± 17.41 cm, 30.0 ± 8.66 kg/m2) were tested using ADP and HD, with ADP always preceding HD. Db estimates were compared between ADP with measured TGV, ADP with predicted TGV, and the reference measure, HD. Regression analyses were used to assess the accuracy of the ADP methods, and potential bias between the ADP procedures and HD were evaluated using Bland–Altman analyses. The cross-validation criteria described by Lohman for estimating Db relative to HD were used to interpret the results of the study.

Results:

A significant difference was found between Db estimates from ADP with measured TGV (1.0453 ± 0.01934 g/cm3) and ADP with predicted TGV (1.0415 ± 0.01858 g/cm3); however, neither was significantly different from Db obtained by the reference HD procedure (1.0417 ± 0.02391 g/cm3). For both ADP procedures, regression analyses produced an r = .737–.738, r 2 = .543−.544, and SEE = 0.02 g/cm3, and the regression lines deviated significantly from the line of identity; however, no significant biases were indicated.

Conclusions:

Despite no significant mean differences between Db estimates from the ADP procedures and HD, more cross-validation research is needed before recommending the BOD POD for routine use with children in clinical and research settings.

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Nuno M. Pimenta, Helena Santa-Clara, Xavier Melo, Helena Cortez-Pinto, José Silva-Nunes and Luís B. Sardinha

Central accumulation and distribution of body fat (BF) is an important cardiometabolic risk factor. Waist-to-hip ratio (WHR), commonly elevated in nonalcoholic fatty liver disease (NAFLD) patients, has been endorsed as a risk related marker of central BF content and distribution, but no standardized waist circumference measurement protocol (WCmp) has been proposed. We aimed to investigate whether using different WCmp affects the strength of association between WHR and BF content and distribution in NAFLD patients. BF was assessed with dual energy X-ray absorptiometry (DXA) in 28 NAFLD patients (19 males, 51 ± 13 years, and 9 females, 47 ± 13 years). Waist circumference (WC) was measured using four different WCmp (WC1: minimal waist; WC2: iliac crest; WC3: mid-distance between iliac crest and lowest rib; WC4: at the umbilicus) and WHR was calculated accordingly (WHR1, WHR2, WHR3 and WHR4, respectively). High WHR was found in up to 84.6% of subjects, depending on the WHR considered. With the exception of WHR1, all WHR correlated well with abdominal BF (r = .47 for WHR1; r = .59 for WHR2 and WHR3; r = .58 for WHR4) and BF distribution (r = .45 for WHR1; r = .56 for WHR2 and WHR3; r = .51 for WHR4), controlling for age, sex and body mass index (BMI). WHR2 and WHR3 diagnosed exactly the same prevalence of high WHR (76.9%). The present study confirms the strong relation between WHR and central BF, regardless of WCmp used, in NAFLD patients. WHR2 and WHR3 seemed preferable for use in clinical practice, interchangeably, for the diagnosis of high WHR in NAFLD patients.

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Chia-Lin Li, Feng-Hsuan Liu and Jen-Der Lin

The purpose of this prospective study was to examine the effect of physical activity independent of obesity on metabolic risk factors. A total of 358 participants were recruited from the Department of Health Management of Chang Gung Medical Center. Physical activity was assessed using a 3-d activity record. Body-mass index (BMI) and metabolic risk factors were also assessed. Our findings demonstrate that an effect of obesity that was statistically independent of the levels of physical activity is associated with metabolic risk factors. Moreover, physical activity displayed inverse associations with triglycerides, and fasting plasma glucose and a positive association with HDL cholesterol. Those participants with time spent in moderate activity more than 0.5 h each day had significantly less risk of high fasting glucose. Significantly, these associations were independent of BMI.

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Katya Vargas-Ortiz, Victoriano Perez-Vazquez, Francisco J. Diaz-Cisneros, Arturo Figueroa, Lizbeth M. Jiménez-Flores, Gustavo Rodriguez-DelaRosa and Maciste H. Macias

Sirtuin 3 enzyme (SIRT3) is involved in the regulation of mitochondrial energy homeostasis by activating Peroxisome proliferator-activated receptor-gamma coactivator (PGC-1α). Murine models have shown that the protein SIRT3 was modified by exercise and diet, however, the effect of exercise without diet in humans has not been examined. Propose of this paper was to analyze the effect of aerobic training on SIRT3 and PGC-1α in skeletal muscle of overweight adolescents without change in caloric intake. Fourteen overweight or obese male adolescents (15.5 ± 0.8 years) trained 3 days-week/50 min x session, at 70-80% of maximal heart rate for 12 weeks. Anthropometrics and skeletal muscle biopsies from the vastus lateralis were taken before and after the exercise program to measure adiposity, SIRT3, and PGC-1α proteins. Peak aerobic capacity (VO2peak) was estimated before and after training. The participants did not change their eating habits during the intervention. SIRT3 (1.05 ± 0.11 vs. 1.25 ± 0.14 AU, p = .014) and PGC-1a (1.06 ± 0.15 Vs 1.39 ± 0.20 AU, p = .009) increased. Fat percentage and waist circumference decreased (p < .05). VO2peak increased after training (p < .001). There was a significant association between SIRT3 and PGC-1α after training program. These data suggest that aerobic training increased SIRT3 and PGC-1a expression levels in sedentary, overweight, or obese adolescents.

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Luisa Aires, Pedro Silva, Gustavo Silva, Maria Paula Santos, José Carlos Ribeiro and Jorge Mota

Background:

The purpose of this study was to analyze the relation between body mass index (BMI), Cardiorespiratory Fitness (CRF), and levels of physical activity (PA) from sedentary to very vigorous intensities, measured by accelerometry, in students from a middle and high school.

Methods:

This cross-sectional study included 111 children and adolescents, age 11 to 18 years. PA was assessed with an accelerometer for 7 consecutive days (1 minute epoch) using specific cut-points. PA components were derived using special written software (MAHUffe). CRF was assessed by maximal multistage 20m shuttle run. T-test was used to test differences between BMI groups, Pearson’s correlation, to analyze correlations between all variables and multinomial logistic regression, and to predict the value of BMI categories.

Results:

This paper provides evidence that BMI was inversely and significantly correlated with CRF. Only CRF was correlated with Vigorous and Very Vigorous PA levels and total amount of PA. Children with Overweight/Obesity were less likely to perform more laps than normal weight counterparts. The total amount or intensity level of PA did not show any influence on BMI level.

Conclusions:

Low CRF is strongly associated with obesity, which highlights the importance of increasing CRF for a protective effect even in youth. No associations were found for PA and BMI.

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Takashi Kamijo and Masami Murakami

Background:

Lifestyle-related diseases among middle-age and elderly people have become serious problems. Underlying causes might be related to the changes in the lifestyle including the absence of regular physical exercise.

Methods:

To clarify the significance of regular physical exercise to prevent lifestyle-related diseases, we studied motor functions and blood chemistry examinations in middle-age and elderly women (over 40 years old) who performed regular physical exercise for 2 years (exercise group) and those who initially did not (control group).

Results:

In study 1, VO2max significantly increased in the exercise group compared with the control group in the under 60 years old groups. In the over 60 years old groups, VO2max, foot balance, and HDL-cholesterol significantly increased. Plasma glucose at 120 minutes after the 75 g oral glucose tolerance test, fasting insulin, homeostasis model assessment (HOMA-R), and high sensitivity C-reactive protein (hsCRP) significantly decreased in the exercise group compared with the control group. In study 2, a 1-year exercise program significantly improved physical functions and biochemical markers in the control group.

Conclusion:

These results suggest that regular physical exercise might help to maintain sound motor functions and decrease insulin resistance and a risk for arteriosclerosis.

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Michael J. Davies, Gail P. Dalsky and Paul M. Vanderburgh

This study employed allometry to scale maximal oxygen uptake (V̇O2 max) by body mass (BM) and lean body mass (LBM) in healthy older men. Ratio standards (ml · kg−1 · min−1) derived by dividing absolute V̇O2 max (L · min−1) by BM or LBM often fail to control for the body size variable. The subjects were 73 older men (mean ± SD: age = 69.7 ± 4.3 yrs, BM = 80.2 ± 9.6 kg, height = 174.1 ± 6.9 cm). V̇O2 max was assessed on a treadmill with the modified Balke protocol (V̇O2 max = 2.2 ± 0.4 L · min−1). Body fat (27.7 ± 6.4%) was assessed with dual energy x-ray absorptiometry. Allometry applied to BM and V̇O2 max determined the BM exponent to be 0.43, suggesting that heavier older men are being penalized when ratio standards are used. Allometric scaling applied to LBM revealed the LBM exponent to be 1.05 (not different from the ratio standard exponent of 1.0). These data suggest that the use of ratio standards to evaluate aerobic fitness in older men penalized fatter older men but not those with higher LBM.

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Eric D.B. Goulet, Michel O. Mélançon, Mylène Aubertin Leheudre and Isabelle J. Dionne

It is unclear whether long-term aerobic (AT) or resistance (RT) training can improve insulin sensitivity (IS) beyond the residual effect of the last training bout in older women (54–78 years). Therefore, a group of nonobese, healthy older women underwent 6 months of AT (n = 8) or RT (n = 10), and the authors measured IS 4 days after the last training bouts using the hyperinsulinemic-euglycemic clamp technique. Women trained 3 days/week. AT consisted of 25- to 60-min sessions of walking/jogging at 60–95% of maximal heart rate. RT consisted of three sets of nine exercises repeated 10 times at 80% of 1 repetition maximum. AT decreased fat mass, whereas both AT and RT increased fat-free mass. Neither training program, however, improved absolute or relative rates of glucose disposal. The authors therefore concluded that nonobese, healthy older women should perform AT or RT on a daily basis in order to improve IS and maintain the improvement.

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Judith Jiménez, Maria Morera, Walter Salazar and Carl Gabbard

Purpose:

Motor skill competence has been associated with physical activity level, fitness, and other relevant health-related characteristics. Recent research has focused on understanding these relationships in children and adolescents, but little is known about subsequent years. The aim of this study was to examine the relationship between fundamental motor skill (FMS) ability and body mass index (BMI) in young adults.

Method:

Participants, 40 men and 40 women (M age = 19.25 yr, SD = 2.48), were assessed for BMI and motor competence with 10 fundamental motor skills (FMSs) using the Test for Fundamental Motor Skills in Adults (TFMSA).

Results:

BMI was negatively associated with total motor ability (r = –.257; p = .02) and object control skills (r = –.251; p = .02); the relationship with locomotor skills was marginally insignificant (r = –.204; p = .07). In regard to individual skills, a significant negative association was found for running, jumping, striking, and kicking (ps < .05). Multiple regression analysis indicated that BMI and gender predicted 42% of the variance in total FMS score; gender was the only significant predictor.

Conclusion:

Overall, these preliminary findings suggest that young adults with higher FMS ability are more likely to have lower BMI scores.