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Annie Fex, Jean-Philippe Leduc-Gaudet, Marie-Eve Filion, Antony D. Karelis and Mylène Aubertin-Leheudre

Objectives:

The purpose of the current study was to examine the impact of 12 weeks of elliptical high intensity interval training (HIIT) on metabolic risk factors and body composition in pre- and type 2 diabetes patients.

Methods:

Sixteen pre- (n = 8) and type 2 diabetes (n = 8) participants completed this study. Fasting blood glucose, HbA1c, anthropometric measurements, body composition (DXA), blood pressure, resting heart rate, VO2max, and dietary factors, as well as total and physical activity energy expenditure, were measured. The HIIT program on the elliptical was performed 3 times a week for 12 weeks.

Results:

After the intervention, we observed a significant improvement for fasting blood glucose, waist and hip circumference, appendicular fat mass, leg lean body mass and appendicular lean body mass, systolic blood pressure, resting heart rate, and VO2max (P < .05). In addition, we noted a lower tendency for leg fat mass (P = .06) and diastolic blood pressure (P = .05) as well as a higher tendency for total energy expenditure (P = .06) after the intervention.

Conclusions:

The current study indicates that elliptical HIIT seems to improve metabolic risk factors and body composition in pre- and type 2 diabetes patients.

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Helen T. Douda, Konstantina V. Kosmidou, Ilias Smilios, Konstantinos A. Volaklis and Savvas P. Tokmakidis

This five-year follow-up nonrandomized controlled study evaluated community-based training and detraining on body composition and functional ability in older women. Forty-two volunteers (64.3 ± 5.1 years) were divided into four groups: aerobic training, strength training, combined aerobic and strength, and control. Body composition and physical fitness were measured at baseline, after nine months of training and after three months of detraining every year. After five years of training, body fat decreased, and fat free mass, strength, and chair test performance increased (p < .05) in all training groups. Training-induced favorable adaptations were reversed during detraining but, eventually, training groups presented better values than the control group even after detraining. Thus, nine months of annual training, during a five-year period, induced favorable adaptations on body composition, muscular strength, and functional ability in older women. Three months of detraining, however, changed the favorable adaptations and underlined the need for uninterrupted exercise throughout life.

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Beau Kjerulf Greer, Kathleen M. Edsall and Anna E. Greer

The purpose of the current study was to determine whether expected changes in body weight via a 3-day low-carbohydrate (LC) diet will disrupt the reliability of air displacement plethysmography measurements via BOD POD. Twenty-four subjects recorded their typical diets for 3 days before BOD POD and 7-site skinfold analyses. Subjects were matched for lean body mass and divided into low-CHO (LC) and control (CON) groups. The LC group was given instruction intended to prevent more than 50 grams/day of carbohydrate consumption for 3 consecutive days, and the CON group replicated their previously recorded diet. Body composition measurements were repeated after dietary intervention. Test–retest reliability measures were significant (p < .01) and high for body fat percentage in both the LC and the CON groups (rs = .993 and .965, respectively). Likewise, skinfold analysis for body fat percentage reliability was high in both groups (rs = .996 and .997, respectively). There were significant differences between 1st and 2nd BOD POD measurements for body mass (72.9 ± 13.3 vs. 72.1 ± 13.0 kg [M ± SD]) and body volume (69.0 ± 12.7–68.1 ± 12.2 L) in the LC group (p < .05). However, there were no differences (p > .05) in BOD POD–determined body fat percentage, lean body mass, or fat mass between the 1st and 2nd trial in either group. Body composition measures via BOD POD and 7-site skinfolds remain reliable after 3 days of an LC diet despite significant decreases in body mass.

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Bruce Wayne Bailey, Pamela Borup, Larry Tucker, James LeCheminant, Matthew Allen and Whitney Hebbert

Background:

The aim of this study was to investigate the relationship between steps per day and adiposity among college women.

Methods:

This study was cross-sectional and included women ages 18–25. Participants wore a pedometer for 7 consecutive days. Body composition was assessed using air-displacement plethysmography. Height, weight, and waist and hip circumferences were assessed.

Results:

The women took 10,119 ± 2836 steps per day. When divided into quartiles by steps, the top 2 quartiles of women in the study had significantly lower BMI, percent body fat, and waist and hip circumferences than the bottom quartile of women (P ≤ .05). Percent body fat was different between the bottom 2 quartiles and the top 2 quartiles (P ≤ .05). The odds of having a body fat of greater than 32% were reduced by 21.9% for every increase of 1,000 steps taken per day (P ≤ .05).

Conclusions:

Steps per day are related to body composition in young adult women, but this relationship weakens with progressively higher step counts. A reasonable recommendation for steps in young adult women that is associated with the lowest BMIs and body fat seems to be between 10,000–12,000 steps per day.

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Thomas B. Walker, Jessica Smith, Monica Herrera, Breck Lebegue, Andrea Pinchak and Joseph Fischer

The purpose of this study was to investigate the ability of whey-protein and leucine supplementation to enhance physical and cognitive performance and body composition. Thirty moderately fit participants completed a modified Air Force fitness test, a computer-based cognition test, and a dual-energy X-ray-absorptiometry scan for body composition before and after supplementing their daily diet for 8 wk with either 19.7 g of whey protein and 6.2 g leucine (WPL) or a calorie-equivalent placebo (P). Bench-press performance increased significantly from Week 1 to Week 8 in the WPL group, whereas the increase in the P group was not significant. Push-up performance increased significantly for WPL, and P showed a nonsignificant increase. Total mass, fat-free mass, and lean body mass all increased significantly in the WPL group but showed no change in the P group. No differences were observed within or between groups for crunches, chin-ups, 3-mile-run time, or cognition. The authors conclude that supplementing with whey protein and leucine may provide an advantage to people whose performance benefits from increased upper body strength and/or lean body mass.

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Lucy-Joy M. Wachira, Stella K. Muthuri, Mark S. Tremblay and Vincent O. Onywera

Background:

The report card presents available evidence on the physical activity (PA) and body weight status of Kenyan children and youth. It highlights areas where Kenya is succeeding and those in which more action is needed.

Methods:

Comprehensive review and analysis of available data on core indicators for Kenyan children and youth 5−17 years were conducted. The grading system used was based on a set of specific criteria and existing grading schemes from similar report cards in other countries.

Results:

Of the 10 core indicators discussed, body composition was favorable (grade B) while overall PA levels, organized sport participation, and active play were assigned grades of C. Active transportation and sedentary behaviors were also favorable (grade B). Family/peers, school, governmental and nongovernmental strategies were graded C.

Conclusions:

The majority of Kenyan children and youth have healthy body composition levels and acceptable sedentary time, but are not doing as well in attaining the World Health Organization (WHO) recommendation on PA. Although Kenya seems to be doing well in most indicators compared with some developed countries, there is a need for action to address existing trends toward unhealthy lifestyles. More robust and representative data for all indicators are required.

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Magnus Carlsson, Tomas Carlsson, Daniel Hammarström, Christer Malm and Michail Tonkonogi

Purpose:

To investigate the relationship between race performance and lean mass (LM) variables, as well as to examine sex differences in body composition in elite-standard cross-country skiers.

Methods:

Thirty-four elite cross-country skiers (18 men and 16 women) underwent a dual-emission X-ray-absorptiometry body-composition test to determine LM, fat mass, and bone mineral content. For both sexes, performance data were collected from a sprint prologue and a distance race.

Results:

The absolute expression of LM variables (whole-body [LMWB], upper body [LMUB], and lower body [LMLB]) was significantly correlated with finishing time in the sprint prologue independent of sex. Distance-race performance was significantly related to LMWB, LMUB, and LMLB in women; however, no correlation was found in men. Men had a significantly higher LM and lower fat mass, independent of expression (absolute or relative), for the whole body, arms, trunk, and legs, except for the absolute fat mass in the trunk.

Conclusions:

The absolute expressions of LMWB, LMUB, and LMLB were significant predictors of sprint-prologue performance in both sexes, as well as of distance-race performance in women only. Compared with women, male skiers have a higher LM in the body segments that are major contributors to propelling forces. These results suggest that muscle mass in the lower and upper body is equally important for race performance; thus, more focus of elite skiers’ training should be directed to increasing whole-body muscle mass to improve their competitive performance capability.

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Pavle Mikulic

Purpose:

To examine variations in physical, physiological, and performance parameters over an annual training cycle in a world champion rowing crew.

Methods:

Four world-class rowers, all of them members of the men’s heavyweight quadruple sculls squad who are current world rowing champions, were assessed 3 times at regular 4-mo intervals during the 2011 season (November 2010, March 2011, and July 2011). Physical assessments included stature, body mass, body composition, whereas physiological and performance assessments obtained during an incremental rowing ergometer test to exhaustion included maximum oxygen uptake and anaerobic gas-exchange threshold with corresponding power output values.

Results:

Body mass (∼95 kg) and body composition (∼12% body fat) remained stable over the annual training cycle. Power output at anaerobic gas-exchange threshold increased +16% from November to July, whereas the corresponding oxygen uptake, expressed as a percentage of maximum oxygen uptake, increased from 83% to 90%. Maximum oxygen uptake decreased from 6.68 L/min in November to 6.10 L/min in March before rising to 6.51 L/min in July. The corresponding power output increased steadily from 450 W to 481 W.

Conclusion:

Seasonal variation in body mass and body composition of 4 examined world-class rowers was minimal. Oxygen uptake and power output corresponding to anaerobic threshold continuously increased from off-season to peak competition season. Seasonal variation in maximum oxygen uptake reached ∼10%; however, it remained above 6 L/min, that is, the value consistently observed in top caliber heavyweight rowers regardless of the time of the assessment.

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Jennifer W. Bea, Robert M. Blew, Carol Howe, Megan Hetherington-Rauth and Scott B. Going

Purpose:

This systematic review evaluates the relationship between resistance training and metabolic function in youth.

Methods:

PubMed, Embase, Cochrane Library, Web of Science, CINAHL, and ClinicalTrials. gov were searched for articles that (1): studied children (2); included resistance training (3); were randomized interventions; and (4) reported markers of metabolic function. The selected studies were analyzed using the Cochrane Risk-of-Bias Tool.

Results:

Thirteen articles met inclusion criteria. Mean age ranged from 12.2 to 16.9 years, but most were limited to high school (n = 11) and overweight/obese (n = 12). Sample sizes (n = 22–304), session duration (40–60min), and intervention length (8–52 wks) varied. Exercise frequency was typically 2–3 d/wk. Resistance training was metabolically beneficial compared with control or resistance plus aerobic training in 5 studies overall and 3 out of the 4 studies with the fewest threats to bias (p ≤ .05); each was accompanied by beneficial changes in body composition, but only one study adjusted for change in body composition.

Conclusions:

Limited evidence suggests that resistance training may positively affect metabolic parameters in youth. Well-controlled resistance training interventions of varying doses are needed to definitively determine whether resistance training can mitigate metabolic dysfunction in youth and whether training benefits on metabolic parameters are independent of body composition changes.

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Eric T. Poehlman and Christopher Melby

In this brief review we examine the effects of resistance training on energy expenditure. The components of daily energy expenditure are described, and methods of measuring daily energy expenditure are discussed. Cross-sectional and exercise intervention studies are examined with respect to their effects on resting metabolic rate, physical activity energy expenditure, postexercise oxygen consumption, and substrate oxidation in younger and older individuals. Evidence is presented to suggest that although resistance training may elevate resting metabolic rate, il does not substantially enhance daily energy expenditure in free-living individuals. Several studies indicate that intense resistance exercise increases postexercise oxygen consumption and shifts substrate oxidation toward a greater reliance on fat oxidation. Preliminary evidence suggests that although resistance training increases muscular strength and endurance, its effects on energy balance and regulation of body weight appear to be primarily mediated by its effects on body composition (e.g., increasing fat-free mass) rather than by the direct energy costs of the resistance exercise.