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Kenneth H. Pitetti, James A. Jackson, Nancy B. Stubbs, Kathryn D. Campbell and Saraswathy S. Battar

Comparative and longitudinal studies were performed to determine the effect of Special Olympic activities on the physical fitness of participants. The comparative study compared cardiovascular fitness, percent body fat, and blood lipid profiles of non-Down, mildly mentally retarded adult Special Olympic participants (SOP) with those of nontraining, nonhandicapped (NTNH) and training nonhandicapped (TNH) adults. The results indicated that SOP displayed lower fitness profiles than TNH. Male SOP demonstrated fitness profiles similar to NTNH while female SOP showed lower cardiovascular fitness levels than both TNH and NTNH. The longitudinal study compared cardiovascular fitness and percent body fat of non-Down, mildly mentally retarded adult SOP before and after 4 to 18 months of Special Olympic activities. This latter study showed no significant change in body weight, percent body fat, or cardiovascular fitness during a time period that averaged over 13 months for each participant. The results indicated that the intensity level of activity for the SOP in this study failed to improve physical fitness.

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Cuisle O’Donovan, Fiona E. Lithander, Tara Raftery, John Gormley, Azra Mahmud and Juliette Hussey

Background:

Physical activity has beneficial effects on arterial stiffness among healthy adults. There is a lack of data on this relationship in adults with hypertension. The majority of studies which have examined physical activity and arterial stiffness have used subjective measures of activity. The aim of this study was to investigate the relationship between objectively measured habitual physical activity and arterial stiffness in individuals with newly diagnosed essential hypertension.

Methods:

Adults attending an outpatient hypertension clinic were recruited into this cross sectional study. Physical activity was measured using a triaxial accelerometer. Pulse wave velocity (PWV) and augmentation index (AIx) were measured using applanation tonometry. Participant’s full lipid profile and glucose were determined through the collection of a fasting blood sample.

Results:

Fifty-three adults [51(14) years, 26 male] participated, 16 of whom had the metabolic syndrome. Inactivity was positively correlated with PWV (r = .53, P < .001) and AIx (r = .48, P < .001). There were significant inverse associations between habitual physical activity of all intensities and both AIx and PWV. In stepwise regression, after adjusting for potential confounders, physical activity was a significant predictor of AIx and PWV.

Conclusion:

Habitual physical activity of all intensities is associated with reduced arterial stiffness among adults with hypertension.

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Humberto José Gomes Silva, Lars Bo Andersen, Mara Cristina Lofrano-Prado, Mauro V.G. Barros, Ismael Fortes Freitas Jr., James Hill and Wagner Luiz do Prado

Background:

It is unclear how different exercise intensities affect cardiovascular disease (CVD) risk factors in obese adolescents. The aim of this study was to compare the effects of high-intensity (HIT) vs. low-intensity (LIT) aerobic training on CVD risk factors in obese adolescents.

Methods:

Forty-three obese adolescents (age: 15.7 ± 1.3 years, BMI: 34.3 ± 4.1kg/m2) participated this study either HIT (corresponding to ventilatory threshold I; N = 20) or LIT (20% below ventilatory threshold I; N = 23) for 12 weeks. All sessions were isocaloric (350 kcal). All participants received the same nutritional, psychological, and clinical counseling. Subjects were assessed in fatness, fitness, lipid profile, and glucose at baseline and after 12 weeks. The CVD risk factors assessed were waist circumference (WC), total cholesterol (TC), high-density lipoprotein (HDL), glucose, and fitness, which were single and clustered analyzed (z scores sum).

Results:

Body mass, Body Mass Index, fatness, and WC were improved (P < .001) in both groups. The sum of z scores (WC + TC + glucose-fitness-HDL) improved in both HIT (12 weeks = −2.16 SD; Cohen’s d = .45) and LIT (12 weeks = −2.13 SD; Cohen’s d = .60) without groups differences. Changes in fitness were associated with changes in WC (r = −.48; P = .003).

Conclusion:

HIT does not promote any additional improvements in CVD risk factors than LIT in obese adolescents.

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Jamie Zoellner, Carol Connell, Alicia Powers, Amanda Avis-Williams, Kathy Yadrick and Margaret L. Bogle

Background:

Race/ethnic-specific physical activity patterns and biological responses to physical activity is one of the most understudied, yet critical aspects related to the development and adoption of physical activity recommendations.

Methods:

In this 6-month community walking intervention targeting African Americans, participants wore a pedometer and maintained a pedometer diary for the study duration. Outcome measures included height, weight, percent body fat, waist circumference, blood pressure, lipids and glucose. ANOVA, Pearson Correlations, and Kruskal-Wallis tests were used to examine changes in steps/day over each month of the intervention and explore associations among pedometer-determined physical activity and anthropometric/biological change scores from month 1 to 6.

Results:

The 83 participants were primarily African American (98%) women (94%). There was a significant increase in the average step/day beginning with 6665 (SD = 3,396) during month 1 and increasing to 9232 (SD = 3670) steps/day during month 6 (F = 4.5, P < .0001). Associations among step counts and anthropometric/biological change scores were not significant.

Conclusions:

While this intervention resulted in significant increases in steps/day; it exemplifies that physical activity standards may be unachievable for some vulnerable, minority communities. Methodological considerations for exploring associations between changes in pedometer-determined step counts and anthropometric/biological outcomes are emphasized through this study.

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Emily Read

Background:

Rural Canadians are at increased risk of metabolic syndrome. Physical inactivity is a primary target for preventing and reversing metabolic syndrome. Adherence to lifestyle interventions may be enhanced using cell phones and self-monitoring technologies. This study investigated the feasibility of a physical activity and self-monitoring intervention targeting high-risk adults in rural Ontario.

Methods:

Rural adults (n = 25, mean = 57.0 ± 8.7 years) with ≥ 2 criteria for metabolic syndrome participated in an 8-week stage-matched physical activity and self-monitoring intervention. Participants monitored blood glucose, blood pressure, weight, and physical activity using self-monitoring devices and Blackberry Smart phones. VO2max, stage of change, waist circumference, weight, blood lipids, and HbA1c were measured at weeks 1, 4, and 8.

Results:

Adherence to self-monitoring was > 94%. Participants’ experiences and perceptions of the technology were positive. Mean stage of change increased 1 stage, physical activity increased 26%, and predicted VO2max increased 17% (P < .05). Significant changes in weight, waist circumference, diastolic blood pressure, LDL cholesterol, and total cholesterol were found.

Conclusions:

This stage-matched technology intervention for increased physical activity was feasible and effective.

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Ya-Wen Hsu, Chih-Ping Chou, Britni R. Belcher, Selena T. Nguyen-Rodriguez, Marc J. Weigensberg, Arianna D. McClain and Donna Spruijt-Metz

While most studies have focused on investigating the preventive effects of physical activity on metabolic risk, the longitudinal impacts of metabolic syndrome (MetS) on activity levels is poorly understood. This study aims to examine the influence of MetS on initial activity levels and the trajectory of activity levels in Latina and African American female children over 12 months (n = 55, 9 ± 1 years). Metabolic measures, including fat and lean tissue mass by BodPod, fasting glucose, lipids, blood pressure, and waist circumference, were collected at baseline. Moderate-to-vigorous physical activity and sedentary behavior by accelerometry were collected on a quarterly basis. There were no significant differences in either initial activity levels by MetS status (Moderate-to-vigorous physical activity: 33 ± 12 mins/day for MetS, 48 ± 28 mins/day for Non-MetS, p = .12; sedentary behavior: 408 ± 57 mins/day for MetS, 421 ± 72 mins/day for Non-MetS, p = .67). Longitudinal declines in moderate-to-vigorous physical activity (p = .038) and increases in sedentary behavior (p = .003) were found. Daily sedentary behavior increased by 82.64 more minutes in youth with MetS than in those without over one year (p = .015). This study yields the first evidence of the adverse effect of MetS on sedentary behavior. Targeted intervention strategies to reduce progressive sedentariness evident in minority youth with MetS are warranted.

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Kamal Azizbeigi, Mohammad Ali Azarbayjani, Maghsoud Peeri, Hamid Agha-alinejad and Stephen Stannard

This study was undertaken to investigate the effects of progressive resistance-training (PRT) on plasma oxidative stress and antioxidant enzyme activity in erythrocytes. Twenty male volunteers were randomly assigned to 2 groups: PRT and control. Blood samples were collected before and after 8 wk of PRT and analyzed for enzymatic activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in erythrocytes, plasma total antioxidant capacity (TAC), and malondialdehyde concentration (MDA, an index of lipid per oxidation in plasma). Resistance training commenced with 8 exercises on nonconsecutive days for 8 wk at 50% of estimated 1-repetition maximum (E1RM) and reached 80% E1RM by Week 8. The results showed that PRT significantly increased erythrocyte SOD activity (1,323 ± 212.52 vs. 1,449.9 ± 173.8 U/g Hb, p = .014). Plasma concentration of MDA also decreased (5.39 ± 1.7 vs. 3.67.4 ± 0.7 nmol/ml, p = .030), although TAC (1.42 ± 0.21 vs. 1.61 ± 0.19 mmol/L, p = .1530) and GPx (39.87 ± 11.5 vs. 48.18 ± 14.48 U/g Hb, p = .883) activity did not undergo any considerable changes. Based on these data, the authors conclude that an 8-wk program of PRT strengthens the defensive system of erythrocytes against free-radical damage and therefore can be applied as a useful approach to alleviate oxidative stress.

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Sonia Vega-López, Giselle A.P. Pignotti, Colleen Keller, Michael Todd, Barbara Ainsworth, Allison Nagle Williams, Kathie Records, Dean Coonrod and Paska Permana

Background:

The effects of moderate intensity walking on lipoprotein remodeling in postpartum Hispanic women are unknown.

Methods:

Sedentary postpartum Hispanic women (28.2 ± 5.6 y; BMI = 29.3 ± 3.3 kg/m2) participating in a social support physical activity (PA) intervention, were randomly assigned to a 12-month walking program (walkers; n = 22; target 150 min/wk, moderate intensity) or a control group (nonwalkers; n = 22). Fasting lipids and cholesterol distribution within low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particles were measured at baseline (BL), 6 months, and 12 months.

Results:

Walkers had an 11% increase and nonwalkers a 7% decrease in HDL cholesterol from 6 to 12 months (P = .0367) without an effect on LDL cholesterol. Whereas nonwalkers had virtually no change in mean LDL particle size, walkers had a borderline reduction in LDL size from BL (268.7 ± 4.1 Å) to 6 months (266.9 ± 4.9 Å), followed by a significant increase in size by 12 months (269.7 ± 4.1 Å; P = .011). The proportion of cholesterol in large LDL particles decreased by 15% from BL to 6 months, but subsequently increased 25% by 12 months among walkers; changes among nonwalkers were smaller and in opposite direction (4% and –3%, respectively; P = .0004).

Conclusions:

Participation in the social-support PA intervention resulted in slightly increased HDL cholesterol concentrations and a modest and beneficial shift toward larger, less atherogenic LDL particles.

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Marco Malaguti, Marta Baldini, Cristina Angeloni, Pierluigi Biagi and Silvana Hrelia

The authors evaluated the role of a high-protein, low-calorie, polyunsaturated fatty-acid (PUFA) -supplemented diet on anthropometric parameters, erythrocytemembrane fatty-acid composition, and plasma antioxidant defenses of nonprofessional volleyball athletes. The athletes were divided in two groups: One (n = 5) followed the Mediterranean diet, and the other (n = 6) followed a high-protein, low-calorie diet with a 3-g/day fish-oil supplementation. All the athletes had anthropometric measurements taken, both at the beginning and at the end of the study, which lasted for 2 months. Body-mass index and total body fat were significantly diminished in the second group, while they remained unchanged in the first. Plasma total antioxidant activity (TAA) was significantly increased in the plasma of both groups, with no differences between the groups, suggesting that physical activity, not the different diets, is the main contributor to the increase of plasma TAA. The second group showed a significant increase in erythrocytemembrane PUFA content and in the unsaturation index value (UI) because of the fish-oil supplementation. A high-protein, low-carbohydrate, fish-oil-supplemented diet seems to be useful only when the aim of the diet is to obtain weight loss in a short-term period. The significant increase in the UI of erythrocyte membranes indicates the potential for harm, because a high intake of PUFA might increase susceptibility to lipid peroxidation not counterbalanced by a higher increase in TAA. Adherence to the Mediterranean diet seems to be the better choice.

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Ildus I. Ahmetov, Olga L. Vinogradova and Alun G. Williams

The ability to perform aerobic or anaerobic exercise varies widely among individuals, partially depending on their muscle-fiber composition. Variability in the proportion of skeletal-muscle fiber types may also explain marked differences in aspects of certain chronic disease states including obesity, insulin resistance, and hypertension. In untrained individuals, the proportion of slow-twitch (Type I) fibers in the vastus lateralis muscle is typically around 50% (range 5–90%), and it is unusual for them to undergo conversion to fast-twitch fibers. It has been suggested that the genetic component for the observed variability in the proportion of Type I fibers in human muscles is on the order of 40–50%, indicating that muscle fiber-type composition is determined by both genotype and environment. This article briefly reviews current progress in the understanding of genetic determinism of fiber-type proportion in human skeletal muscle. Several polymorphisms of genes involved in the calcineurin–NFAT pathway, mitochondrial biogenesis, glucose and lipid metabolism, cytoskeletal function, hypoxia and angiogenesis, and circulatory homeostasis have been associated with fiber-type composition. As muscle is a major contributor to metabolism and physical strength and can readily adapt, it is not surprising that many of these gene variants have been associated with physical performance and athlete status, as well as metabolic and cardiovascular diseases. Genetic variants associated with fiber-type proportions have important implications for our understanding of muscle function in both health and disease.