Search Results

You are looking at 41 - 50 of 895 items for :

  • "body composition" x
Clear All
Restricted access

Marc K. Hellerstein

Changes in body composition and metabolism have been a central feature of HIV infection from the outset—initially, as the wasting syndrome and, more recently, as metabolic and body fat redistribution syndromes associated with antiretroviral (ARV) therapy. Here, advances in physiologic and biochemical understanding of these conditions are reviewed. First, the pathophysiology of wasting in HIV-1 infection is discussed, focusing on the failure of nutrients to increase lean tissue (“anabolic block”) and the role of hypogonadism. Results of anabolic interventions, including recombinant growth hormone, testosterone, and progressive resistance exercise, are presented. Next, ARV-associated disorders are reviewed, including lipoatrophy and an hypothesized “mitochondrial toxicity.” The possibility of establishing pathogenesis in vivo in humans, by direct measurement of mitochondrial DNA synthesis and adipocyte proliferation, is discussed. In summary, important advances have occurred toward the goal of explaining body composition and metabolic abnormalities associated with HIV disease.

Restricted access

Youn Soo Jung, Steven A. Hawkins and Robert A. Wiswell

The purpose of this study was to determine the contribution of body composition and muscle strength to racial differences in bone mineral density (BMD) in chronically active older adults. Participants were 49 men and 56 women grouped according to self-selected race (Black, Asian, or White). BMD, body composition, and knee strength were measured. Asian men had significantly lower body mass, strength, and BMD than White and Black men did (p < .05). Asian and White women had significantly lower body mass and BMD than Black women did (p < .05), with few strength differences between groups. When lean mass was controlled by ANCOVA. racial differences in BMD disappeared for all bone sites in both sexes. Controlling for body mass eliminated most racial differences in BMD. Controlling for strength did not alter racial differences in BMD for either sex. These results suggest that racial differences in BMD might in part result from differences in lean mass.

Restricted access

Paul Ford, Richard Bailey, Damian Coleman, Kate Woolf-May and Ian Swaine

Although differences in daily activity levels have been assessed in cross-sectional walk-to-school studies, no one has assessed differences in body composition and dietary energy intake at the same time. In this study of 239 primary school children, there were no significant differences in daily activity levels, body composition, or estimated dietary energy intake between those who walk to school (WALK) and those who travel by car (CAR; p < .05). WALK children were more active between 8 a.m. and 9 a.m. and 3 p.m. and 4 p.m. than CAR children (p < .05). In addition, there were no significant differences in the main analysis when participants were subgrouped by gender and age.

Restricted access

Kimberly M. White, Stephanie J. Bauer, Kristopher K. Hartz and Monika Baldridge

Introduction:

Resistance training is an effective method to decrease body fat (BF) and increase fat-free mass (FFM) and fat oxidation (FO). Dairy foods containing calcium and vitamin D might enhance these benefits. This study investigated the combined effects of habitual yogurt consumption and resistance training on body composition and metabolism.

Methods:

Untrained women (N = 35) participated in an 8-wk resistance-training program. The yogurt group (Y) consumed 3 servings of yogurt containing vitamin D per day, and the control groups maintained their baseline lowdairy-calcium diet. Postexercise, Y consumed 1 of the 3 servings/d fat-free yogurt, the protein group consumed an isocaloric product without calcium or vitamin D, and the carbohydrate group consumed an isocaloric product without protein. Strength, body composition, fasted resting metabolic rate (RMR) and FO, and serum 25-hydroxyvitamin D were measured before and after training.

Results:

Calories (kcal · kg−1 · d−1) and protein (g · kg−1 · d−1) significantly increased from baseline for Y. FFM increased (main effect p = .002) and %BF decreased (main effect .02) for all groups with training, but Group × Time interactions were not observed. RMR and FO did not change with training for any group.

Conclusion:

Habitual consumption of yogurt during resistance training did not augment changes in body composition compared with a low-dairy diet. Y decreased %BF as a result of training, however, even with increased calorie consumption.

Restricted access

Jay R. Hoffman, Nicholas A. Ratamess, Christopher P. Tranchina, Stefanie L. Rashti, Jie Kang and Avery D. Faigenbaum

The effect of 10 wk of protein-supplement timing on strength, power, and body composition was examined in 33 resistance-trained men. Participants were randomly assigned to a protein supplement either provided in the morning and evening (n = 13) or provided immediately before and immediately after workouts (n = 13). In addition, 7 participants agreed to serve as a control group and did not use any protein or other nutritional supplement. During each testing session participants were assessed for strength (one-repetition-maximum [1RM] bench press and squat), power (5 repetitions performed at 80% of 1RM in both the bench press and the squat), and body composition. A significant main effect for all 3 groups in strength improvement was seen in 1RM bench press (120.6 ± 20.5 kg vs. 125.4 ± 16.7 at Week 0 and Week 10 testing, respectively) and 1RM squat (154.5 ± 28.4 kg vs. 169.0 ± 25.5 at Week 0 and Week 10 testing, respectively). However, no significant between-groups interactions were seen in 1RM squat or 1RM bench press. Significant main effects were also seen in both upper and lower body peak and mean power, but no significant differences were seen between groups. No changes in body mass or percent body fat were seen in any of the groups. Results indicate that the time of protein-supplement ingestion in resistance-trained athletes during a 10-wk training program does not provide any added benefit to strength, power, or body-composition changes.

Restricted access

Alan C. Utter, David C. Nieman, Elizabeth M. Shannonhouse, Diane E. Butterworth and Cathy N. Nieman

The purpose of this study was to measure the influence of diet, exercise, or both on body composition and cardiorespiratory fitness in obese women. Ninety-one obese subjects were randomized into one of four groups: diet (D) (4.19–5.44 MJ or 1,200–1,300 kcal/day), exercise (E) (five 45-min sessions at 78.5 ± 0.5% maximum heart rate), exercise and diet (ED), and controls (C). Maximal aerobic power and body composition were measured in all subjects before and after a 12-week diet intervention period. Subjects in D and ED lost 7.8 ± 0.7 and 8.1 ± 0.6 kg body mass, with no significant change for E relative to C. Losses of percent body fat and fat mass were significantly greater in D and ED but not in E relative to C. The change in VO2max was greater in ED and E but not D when compared to C. Results indicate that moderate aerobic exercise training during a 12-week period has no discernible effects on body composition but does improve cardiorespiratory fitness in dieting obese women.

Restricted access

Gerasimos Terzis, Thomas Kyriazis, Giorgos Karampatsos and Giorgos Georgiadis

Purpose:

Although muscle mass and strength are thought to be closely related to throwing performance, there are few scientific data about these parameters in elite shot-putters. The purpose of this case report was to present longitudinal data for muscle strength and body composition in relation to performance of an elite male shot-putter.

Methods:

A male national champion with the best rotational shot-put performance of 20.36 m (in 2010) was followed from 2003 to 2011 (current age: 29 y). Data regarding body composition (dual X-ray absorptiometry), as well as 1-repetition-maximum muscle strength (bench press, squat, snatch) and rotational shot-put performance, were collected every February for the last 9 y, 4 wk before the national indoor championship event.

Results:

The athlete’s personal-best performances in squat, bench press, and snatch were 175 kg, 210 kg, and 112.5 kg, respectively. His peak total lean body mass was 92.4 kg, bone mineral density 1.55 g/cm2, and lowest body fat 12.9%. His shot-put performance over these 9 years was significantly correlated with 1-repetition-maximum squat strength (r = .93, P < .01), bench press (r = .87, P < .01), and snatch (r = .92, P < .01). In contrast, shot-put performance was not significantly correlated with any of the body-composition parameters.

Conclusions:

The results of this case study suggest that elite rotational shot-put performance may not be directly correlated with lean body mass. Instead, it seems that it is closely related with measures of muscle strength.

Restricted access

Jose Antonio, John Uelmen, Ramsey Rodriguez and Conrad Earnest

The purpose of this study was to determine the effects of the herbal preparation Tribulus terrestris (tribulus) on body composition and exercise performance in resistance-trained males. Fifteen subjects were randomly assigned to a placebo or tribulus (3.21 mg per kg body weight daily) group. Body weight, body composition, maximal strength, dietary intake, and mood states were determined before and after an 8-week exercise (periodized resistance training) and supplementation period. There were no changes in body weight, percentage fat, total body water, dietary intake, or mood states in either group. Muscle endurance (determined by the maximal number of repetitions at 100—200% of body weight) increased for the bench and leg press exercises in the placebo group (p < .05; bench press ±28.4%. leg press ±28.6%), while the tribulus group experienced an increase in leg press strength only (bench press ±3.1 %, not significant; leg press ±28.6%, p < .05). Supplementation with tribulus does not enhance body composition or exercise performance in resistance-trained males.

Restricted access

Ricardo A. Tanhoffer, Aldre I. P. Tanhoffer, Jacqueline Raymond, Andrew P. Hills and Glen M Davis

Background:

The objective of this study was to verify the long-term effects of exercise on energy expenditure and body composition in individuals with spinal cord injury (SCI), as very little information is available on this population under free-living conditions.

Methods:

Free-living energy expenditure and body composition using doubly labeled water (DLW) was measured in 13 individuals with SCI, subdivided in 2 groups: (1) sedentary (SED; N = 7) and (2) regularly engaged in any exercise program, for at least 150 min·wk−1 (EXE; N = 6).

Results:

The total daily energy expenditure (TDEE) was significantly higher in the EXE group (33 ± 4.5 kcal·kg−1·day−1) if compared with SED group (27 ± 4.3 kcal·kg−1·day−1). The percentage of body fat was significantly higher in SED group than in EXE group (38 ± 6% and 28 ± 9%).

Conclusion:

Our findings revealed that, despite the severity of SCI, the actual ACSM’s guidelines for weight management for healthy adults exercise could significantly increase TDEE and BMR and improve body composition in individuals who regularly perform exercise. However, the EXE group still showed a high percentage of body fat, suggesting that a more specific approach might be considered (ie, increased intensity or volume, or combining with a diet program).

Restricted access

Kevin Till, Ben Jones, John O’Hara, Matthew Barlow, Amy Brightmore, Matthew Lees and Karen Hind

Purpose:

To compare the body size and 3-compartment body composition between academy and senior professional rugby league players using dual-energy X-ray absorptiometry (DXA).

Methods:

Academy (age 18.1 ± 1.1 y, n = 34) and senior (age 26.2 ± 4.6 y, n = 63) rugby league players received 1 total-body DXA scan. Height, body mass, and body-fat percentage alongside total and regional fat mass, lean mass, and bone mineral content (BMC) were compared. Independent t tests with Cohen d effect sizes and multivariate analysis of covariance (MANCOVA), controlling for height and body mass, with partial eta-squared (η2) effect sizes, were used to compare total and regional body composition.

Results:

Senior players were taller (183.2 ± 5.8 vs 179.2 ± 5.7 cm, P = .001, d = 0.70) and heavier (96.5 ± 9.3 vs 86.5 ± 9.0 kg, P < .001, d = 1.09) with lower body-fat percentage (16.3 ± 3.7 vs 18.0 ± 3.7%, P = .032, d = 0.46) than academy players. MANCOVA identified significant overall main effects for total and regional body composition between academy and senior players. Senior players had lower total fat mass (P < .001, η 2 = 0.15), greater total lean mass (P < .001, η 2 = 0.14), and greater total BMC (P = .001, η 2 = 0.12) than academy players. For regional sites, academy players had significantly greater fat mass at the legs (P < .001, η 2 = 0.29) than senior players.

Conclusions:

The lower age, height, body mass, and BMC of academy players suggest that these players are still developing musculoskeletal characteristics. Gradual increases in lean mass and BMC while controlling fat mass is an important consideration for practitioners working with academy rugby league players, especially in the lower body.