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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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Nathanael G. Mitchell, Justin B. Moore, Wendy S. Bibeau and Kathleen M. Rudasill

Background:

Levels of physical activity decline throughout childhood. Children’s physical self-perceptions have been found to relate to their physical activity. Understanding the relationships among physical self-perceptions, obesity, and physical activity could have important implications for interventions in children.

Methods:

The current study investigated the moderating effect of cardiovascular fitness (CVF, heart rate recovery from a 3-minute step test) on the relationship between obesity (BMI, waist circumference) and physical self-perceptions (athletic competence, physical appearance) in 104 fourth- and fifth-grade children from a small rural community.

Results:

Hierarchical regression analyses indicated that CVF moderated the relations between BMI and waist circumference on athletic competence. For children with lower fitness, higher waist circumference was associated with lower athletic competence, while for children with higher fitness levels, higher BMI was associated with higher athletic competence. Results also indicated that both BMI and waist circumference were negatively related to physical appearance. CVF moderated these relations such that only children with lower fitness, greater BMI and waist circumference was associated with poorer physical appearance scores.

Conclusions:

Implications include the need for support of fitness programs to promote psychological well-being and to investigate the relationship between obesity and physical self-perceptions within the context of fitness.

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James Dollman, Rebecca Stanley and Andrew Wilson

Valid measurement of youth physical activity is important and self-report methods provide convenient assessments at the population level. There is evidence that the validity of physical activity self-report varies by weight category. The aim of this study was to assess the validity of the 3-Day Physical Activity Recall (3DPAR), separately between normal weight and overweight/obese Australian youth. Accelerometer-derived physical activity variables were compared with 3DPAR variables in 155 (77 females) 11- to 14-year-olds from Adelaide, South Australia. In the whole sample, validity coefficients for self-reported moderate and moderate to vigorous physical activity were modest (rs = 0.12-0.31) and similar across gender and weight status categories. Validity coefficients for self-reported vigorous physical activity were much stronger (rs = 0.59-0.73) among overweight/obese than among normal weight participants. The validity of the 3DPAR in this study was low in the whole sample but varied according to physical activity intensity and the weight status of the child. Specifically, the 3DPAR may be appropriate for describing vigorous intensity physical activity among overweight and obese youth.

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Brett S. Nickerson, Michael R. Esco, Phillip A. Bishop, Brian M. Kliszczewicz, Kyung-Shin Park and Henry N. Williford

The purpose of this study was twofold: 1) compare body volume (BV) estimated from dual energy X-ray absorptiometry (DXA) to BV from a criterion underwater weighing (UWW) with simultaneous residual lung volume (RLV), and 2) compare four-compartment (4C) model body fat percentage (BF%) values when deriving BV via DXA (4CDXA) and UWW (4CUWW) in physically active men and women. One hundred twenty-two adults (62 men and 60 women) who self-reported physical activity levels of at least 1,000 MET·min·wk-1 volunteered to participate (age = 22 ± 5 years). DXA BV was determined with the recent equation from Smith-Ryan et al. while criterion BV was determined from UWW with simultaneous RLV. The mean BV values for DXA were not significant compared with UWW in women (p = .80; constant error [CE] = 0.0L), but were significantly higher in the entire sample and men (both p < .05; CE = 0.3 and 0.7L, respectively). The mean BF% values for 4CDXA were not significant for women (p = .56; CE = –0.3%), but were significantly higher in the entire sample and men (both p < .05; CE = 0.9 and 2.0%, respectively). The standard error of estimate (SEE) ranged from 0.6–1.2L and 3.9–4.2% for BV and BF%, respectively, while the 95% limits of agreement (LOA) ranged from ±1.8–2.5L for BV and ±7.9–8.2% for BF%. 4CDXA can be used for determining group mean BF% in physically active men and women. However, due to the SEEs and 95% LOAs, the current study recommends using UWW with simultaneous RLV for BV in a criterion 4C model when high individual accuracy is desired.

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Barbara Coiro Spessato, Carl Gabbard and Nadia C. Valentini

Our goal was to investigate the role of body mass index (BMI) and motor competence (MC) in children’s physical activity (PA) levels during physical education (PE) classes. We assessed PA levels of 5-to-10-year old children (n = 264) with pedometers in four PE classes. MC was assessed using the TGMD-2 and BMI values were classified according to CDC guidelines. We found small-to-moderate positive correlations between MC and PA; BMI was not significantly correlated with MC and PA. The linear regression model indicated that overall MC was a better predictor of PA than BMI. Our results suggest that children with higher MC find a way to be more active even in a structured setting such as a PE class. Our findings draw attention to the importance of promoting MC, especially for children with high BMI.

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Neha Singhal and Anupa Siddhu

Background:

The relationship between leisure-time physical activity (LTPA) and cardiorespiratory fitness (CRF) is not clearly understood in Indian men. It is important to elucidate whether the duration or intensity of LTPA is responsible for increasing CRF. This will help in designing better physical activity intervention strategies for improving CRF in Indian men.

Methods:

Healthy nondiabetic urban Indian men with no history of coronary heart disease (CHD) were selected (n = 603; aged 22–64 years) and their energy intake and physical activity was determined using a questionnaire. Body fat (percent) was determined by leg-to-leg bioelectrical impedance analysis while CRF was measured on multistage, continuous treadmill test using Bruce protocol.

Results:

Intensity of physical activity (METs) emerged as the best independent predictor of CRF (β = 0.217; P < .001). Using univariate General Linear Model, it was found that CRF is more a function of LTPA intensity than LTPA duration, since LTPA duration was not related to CRF when controlled for LTPA intensity. However, LTPA intensity remained significantly associated with CRF even after adjustment for LTPA duration.

Conclusion:

LTPA of preferably higher intensity should be incorporated in the lifestyle to improve CRF and prevent CHD in Indian men.

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Gregory R. Cox, Iñigo Mujika and Cees-Rein van den Hoogenband

Water polo is an aquatic team sport that requires endurance, strength, power, swimming speed, agility, tactical awareness, and specific technical skills, including ball control. Unlike other team sports, few researchers have examined the nutritional habits of water polo athletes or potential dietary strategies that improve performance in water polo match play. Water polo players are typically well muscled, taller athletes; female players display higher levels of adiposity compared with their male counterparts. Positional differences exist: Center players are heavier and have higher body fat levels compared with perimeter players. Knowledge of the physical differences that exist among water polo players offers the advantage of player identification as well as individualizing nutrition strategies to optimize desired physique goals. Individual dietary counseling is warranted to ensure dietary adequacy, and in cases of physique manipulation. Performance in games and during quality workouts is likely to improve by adopting strategies that promote high carbohydrate availability, although research specific to water polo is lacking. A planned approach incorporating strategies to facilitate muscle glycogen refueling and muscle protein synthesis should be implemented following intensified training sessions and matches, particularly when short recovery times are scheduled. Although sweat losses of water polo players are less than what is reported for land-based athletes, specific knowledge allows for appropriate planning of carbohydrate intake strategies for match play and training. Postgame strategies to manage alcohol intake should be developed with input from the senior player group to minimize the negative consequences on recovery and player welfare.

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Alistair R. Mallard, Rebecca T. McLay-Cooke and Nancy J. Rehrer

Effects of protein versus mixed macronutrient supplementation on total energy intake (TEI) and protein intake during an ad libitum diet were examined. Trained males undertook two, 2-week dietary interventions which were randomized, double blinded, and separated by 2 weeks. These were high-protein supplementation (HP: 1034.5 kJ energy, 29.6 g protein, 8.7 g fat and 12.3 g CHO) and standard meal supplementation (SM: 1039 kJ energy, 9.9 g protein, 9.5 g fat, and 29.4 g CHO) consumed daily following a week of baseline measures. Eighteen participants finished both interventions and one only completed HP. TEI (mean ± SD) was not different between baseline (11148 ± 3347 kJ) and HP (10705 ± 3143 kJ) nor between baseline and SM (12381 ± 3877 kJ), however, TEI was greater with SM than HP (923 ± 4015 kJ p = .043). Protein intake (%TEI) was greater with HP (22.4 ±6.2%) than baseline (19.4 ± 5.4%; p = .008) but not SM (20.0 ± 5.0%). No differences in absolute daily protein intake were found. Absolute CHO intake was greater with SM than HP (52.0 ± 89.5 g, p = .006). No differences in fat intake were found. Body mass did not change between baseline (82.7 ± 11.2 kg) and either HP (83.1 ± 11.7 kg) or SM (82.9 ± 11.0 kg). Protein supplementation increases the relative proportion of protein in the diet, but doesn’t increase the absolute amount of total protein or energy consumed. Thus some compensation by a reduction in other foods occurs. This is in contrast to a mixed nutrient supplement, which does not alter the proportion of protein consumed but does increase TEI.

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Kayla W. Carrigan, Trent A. Petrie and Carlin M. Anderson

Female athletes have been identified as a subpopulation at heightened risk for disordered eating attitudes and behaviors, particularly due to weight pressures in their environment. Using a sample of 414 NCAA Division-I female collegiate athletes, we examined the relations of required team weigh-ins or self-weighing on disordered eating attitudes and behaviors. Through a series of multivariate analyses, we determined that team weighs were significantly unrelated to all outcome measures. Self-weighing, however, differentiated the athletes’ scores on internalization, body satisfaction, dietary restraint, negative affect, and bulimic symptomatology; athletes who self-weighed three or more times a week reported significantly higher levels of pathology across all measures. Mandatory team-conducted weigh-ins appear to not be a salient pressure for female gymnasts and swimmer/divers, although the frequency of their self-weighing may represent a level of self-monitoring that is associated with greater endorsement of disordered eating attitudes and behaviors.

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Melinda M. Manore, Janice Thompson and Marcy Russo

This study presents the diet and exercise strategies of a world-class bodybuilder during an 8-week precompetition period. Weighed food records were kept daily, and body fat, resting metabolic rate (RMR), VO2max, blood lipids, and liver enzymes were measured. Two hrs of aerobic exercise and 3 hrs of weight training were done daily 6 daystweek. Mean energy intake was 4,952 kcallday (54 kcallkg) and included 1,278 kcallday from mediumchain triglycerides (MCT). Diet without MCT provided 76% of energy from carbohydrate, 19% from protein (1.9 g proteiag), and 5% from fat. Micronutrients were consumed at ≥ 100% of the RDA, except for zinc and calcium, without supplementation. Mean RMR was 2,098 kcallday and represented 43% of energy intake. VO2max was 53 ml.kg−1.min−1. Underwater weighing showed that body fat decreased from 9% to 7%. Blood lipids were normal, but two liver enzymes were elevated (alanine and aspartate aminotransferase). This world-class bodybuilder achieved body fat goals by following a nutrient dense, high energy, high carbohydrate diet and an exercise program that emphasized both aerobic and anaerobic metabolism.