Meta-Analysis of Workplace Physical Activity Interventions

The incidence of obesity is increasing rapidly. Research efforts for effective treatment strategies still focus on diet and exercise programmes, the individual components of which have been investigated in intervention trials in order to determine the most effective recommendations for sustained changes in bodyweight. The foremost objective of a weight-loss trial has to be the reduction in body fat leading to a decrease in risk factors for metabolic syndrome. However, a concomitant decline in lean tissue can frequently be observed. Given that fat-free mass (FFM) represents a key determinant of the magnitude of resting metabolic rate (RMR), it follows that a decrease in lean tissue could hinder the progress of weight loss. Therefore, with respect to long-term effectiveness of weight-loss programmes, the loss of fat mass while maintaining FFM and RMR seems desirable. Diet intervention studies suggest spontaneous losses in bodyweight following low-fat diets, and current data on a reduction of the carbohydrate-to-protein ratio of the diet show promising outcomes. Exercise training is associated with an increase in energy expenditure, thus promoting changes in body composition and bodyweight while keeping dietary intake constant. The advantages of strength training may have greater implications than initially proposed with respect to decreasing percentage body fat and sustaining FFM. Research to date suggests that the addition of exercise programmes to dietary restriction can promote more favourable changes in body composition than diet or physical activity on its own. Moreover, recent research indicates that the macronutrient content of the energy-restricted diet may influence body compositional alterations following exercise regimens. Protein emerges as an important factor for the maintenance of or increase in FFM induced by exercise training. Changes in RMR can only partly be accounted for by alterations in respiring tissues, and other yet-undefined mechanisms have to be explored. These outcomes provide the scientific rationale to justify further randomised intervention trials on the synergies between diet and exercise approaches to yield favourable modifications in body composition.

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The role of diet and exercise for the maintenance of fat-free mass and resting metabolic rate during weight loss.

https://aasldpubs.onlinelibrary.wiley.com/doi/pdf/10.1002/hep.22525

Role of leisure-time physical activity in nonalcoholic fatty liver disease: a population-based study.

Background. Caloric restriction (CR) increases maximal life span in short-lived organisms, and its effects are being explored in nonhuman primates. The objectives of this study were to determine the feasibility of prolonged CR in nonobese adults and to compare the effects of CR- and exercise-induced weight loss on body composition and abdominal adiposity. Methods. A randomized, controlled trial was conducted with 48 healthy, nonobese women and men, aged 57 6 1 (mean 6 standard error [SE]) years, with body mass index 27.3 6 0.3 kg/m 2 . Participants were randomly assigned to a 20% calorically-restricted diet (CR, n ¼ 19), exercise designed to produce a similar energy deficit (EX, n ¼ 19), or a healthy lifestyle control group (HL, n ¼ 10) for 1 year. Assessments included weight, body composition by dual-energy x-ray absorptiometry, abdominal adipose tissue by magnetic resonance imaging, and energy intake by doubly labeled water. Results. The average level of CR achieved by the CR group was 11.5 6 2.1%, and the EX group completed 59 6 6.7% of their prescribed exercise. Weight changes were greater (p � .0005) in the CR (� 8.0 6 0.9 kg) and EX (� 6.4 6 0.9) groups as compared to the HL group (� 1.3 6 0.9 kg), corresponding to reductions of 10.7%, 8.4%, and 1.7% of baseline weights, respectively. Whole-body fat mass and visceral and subcutaneous abdominal adipose tissue decreased significantly (p , .005) and comparably in the CR and EX groups, but did not change in the HL group. Conclusions. CR for 1 year was feasible, but the level of CR achieved was less than prescribed. CR and exercise were equally effective in reducing weight and adiposity.

One Year of Caloric Restriction in Humans: Feasibility and Effects on Body Composition and Abdominal Adipose Tissue

Effects of Pilates exercise on trunk strength, endurance and flexibility in sedentary adult females

Purpose: To investigate whether abdominal fat is reduced in response to substantial weight loss induced by exercise in young obese men. Methods: Thirty obese men (mean age 19.8 +/- 0.6 yr) were evaluated before (pretraining) and after (posuraining) 4 months of regimented training in the Singapore Armed Forces. There were 30 obese male subjects (mean age 19.2 +/- 1.3 yr) without training who were monitored as control subjects. Fat free mass (FFM), fat mass, and percent body fat were determined from skinfold measurements. Differences between pre- and posuraining responses were analyzed with a paired t-test. Results: Subjects lost 12.0 +/- 3.6 kg (P < 0.001) from pre- to posuraining, which was attributable to a reduction in fat mass (P < 0.001), as FFM was unchanged. Both waist circumference (WC) and hip circumference (HC) decreased (P < 0.01), the reduction in WC (13.7%) being greater than the reduction in HC (7.7%) as reflected by the decrease in waist-to-hip ratio (WHR; P < 0.001). These data reveal that large exercise-induced weight losses are associated with maintenance of FFM. The significant reduction in WHR indicates a greater mobilization of abdominal fat and a preferential loss of fat from this region. Conclusions: Large exercise-induced weight loss is associated with a preferential reduction in abdominal fat and a corresponding maintenance of FFM. Such an effect on body composition should reduce disease risk and the eventual weight regain that typically follows diet-induced weight losses with obese subjects.

Exercise-induced weight loss preferentially reduces abdominal fat.

AIM\nThe Children's OMNI scale of perceived exertion (OMNI Scale) has been validated with children. However, the scale's validity to assess exertional perceptions in obese (OB) adolescents has not been investigated. The aim of this paper was to validate and compare exertional perceptions using the OMNI Scale between OB and normal weight (NW) adolescent males.\n\n\nMETHODS\nEighteen OB and 23 NW adolescent males (age: 12-14) participated in a perceptual estimation paradigm with a load incremented cycle ergometer protocol. Heart rate (HR;beats·min-1), oxygen uptake (VO2 mL·min-1 and mL·kg-1·min-1) and rating of perceived exertion (RPE) for the overall body (RPE-O), legs (RPE-L), and chest (RPE-C) were determined at the end of each continuously administered 3-min power output stage as subjects cycled stage-wise incrementally to exhaustion beginning with 4 sub-maximal stages.\n\n\nRESULTS\nFor OB, 17 completed 4 stages and 3 attained maximal stage 7. For NW, all 18 completed stage 5, and 8 reached maximal stage 7. RPE ranges (i.e. stage 1 to stage 7) for OB and NW were: Stage 1: RPE-O (1.0±1.6, 1.2±0.6), RPE-L (0.9±1.4, 0.9±0.8) and RPE-C (0.9±1.1, 0.9±0.7). Stage 7: RPE-O (7.3±2.3, 8.8±1.4), RPE-L (8.0±2.0, 8.8±1.4) and RPE-C (7.7±2.1, 7.6±3.0). Linear regression for all three RPEs correlated significantly (P<0.001) with HR and VO2 (0.61 to 0.79) for both cohorts. ANOVA indicated no differences between RPE-O and differentiated RPE (RPE-C and RPE-L) at each stage. The RPE responses between OB and NW adolescent males were analyzed by the Bland Altman plot, which indicated significant agreement (95% CI) between the two groups.\n\n\nCONCLUSION\nThe OMNI Scale is valid for use with 12-14 year-old OB and NW adolescent males. The scale seems to be robust and RPE remained similar for the two cohorts with the same fat free mass but with different fat mass. Hence OMNI scale RPE seems to be able to reflect effort delivered by metabolically active muscle during cycle exercise.

Omni Scale Perceived Exertion Responses In Obese And Normal Weight Male Adolescents During Cycle Exercise: 70 10:15 AM - 10:30 AM

Concurrent validity of the omni perceived scale using cross modal pictorial descriptors

Omni scale perceived exertion responses in obese and normal weight male adolescents during cycle exercise

The aim of this study was to investigate the effect of fat distribution and metabolic risk factors in young obese males following the cessation of training.

Melissa J. Mayo

Papers

Exercise-induced weight loss preferentially reduces abdominal fat.

Omni Scale Perceived Exertion Responses In Obese And Normal Weight Male Adolescents During Cycle Exercise: 70 10:15 AM - 10:30 AM

Concurrent validity of the omni perceived scale using cross modal pictorial descriptors

Omni scale perceived exertion responses in obese and normal weight male adolescents during cycle exercise

Fat distribution and metabolic risk factors of young obese males following the cessation of training: A follow‐up