Robert Gorinski and Wendy Stuhldreher
Peter Pagels, Anders Raustorp, Trevor Archer, Ulf Lidman and Marie Alricsson
Health organizations suggest that adults ought to engage in at least 30 minutes of moderate-intensity daily physical activity. This study investigated the effects of a 30-minute single daily bout of brisk walking upon risk factors for coronary heart disease with blood lipid profile in particular.
Thirty-three (25–45 y) adults, were randomly assigned into an exercise group (EG; n = 16, 9w) and a control group (CG; n = 17, 6w). The EG walked briskly 30 minutes daily during the 3-week test period. Compliance/adherence was maximal throughout the 3-week intervention due to stringent daily monitoring.
The EG showed a significant decrease in concentrations of low density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) during the intervention period. A significant inverse correlation between Δ energy expenditure/day and Δ LDL-C (r = –0.39, P < .05) and an improvement in weight and BMI in the EG was found. Average steps during 30 minutes brisk walking bout was 3669 steps/bout generating a mean energy expenditure of 191 kcal/ bout.
The most unique findings were that daily single bouts of moderate-intensity physical activity for 30 minutes, during 3 weeks, induced favorable effects upon body weight, BMI, and blood concentration of LDL-C and TC in healthy adults.
Ezzedine Bouhlel, Myriam Denguezli, Monia Zaouali, Zouhair Tabka and Roy J. Shephard
To evaluate the effect of Ramadan fasting on parameters of insulin resistance in trained athletes at rest and after aerobic exercise.
Nine male rugby players (age 19 ± 2 yr, height 1.78 ± 0.74 m) were tested 3 times: 1 week before observance of Ramadan (C), at the end of the first week (R1), and during the fourth week (R2). They performed a progressive cycle-ergometer test at each visit. Data collected at rest and at the end of aerobic exercise included simple anthropometry (body mass, body-mass index, body fat, fat-free mass), biochemical parameters (serum glucose, cholesterol, HDL cholesterol, triglycerides, creatinine, and serum proteins), and selected hormone concentrations (plasma insulin, leptin, and adiponectin).
Ramadan fasting was associated with a reduction of body mass and body fat (R2 vs. C, p < .01) without significant change in leptin or adiponectin levels.
Lipolysis might have occurred because of increased plasma triglycerides and HDL cholesterol concentrations.
Kenneth H. Pitetti, Daniel A. Yarmer and Bo Fernhall
The purpose of this study was to compare the aerobic fitness and body mass index (BMI) of children and adolescents (8-18 yr) with and without mild mental retardation (MR). Sample size of participants with MR but without Down syndrome was 169 males and 99 females. Sample size of participants without MR was 289 males and 317 females. Analysis was made by gender and age: children (8-10 yr); early adolescents (11-14 yr); and late adolescents (15-18 yr). The 20-m shuttle run test (20 MST) was used to assess field test performance and predicted aerobic fitness. For all age groups, females and males without MR ran significantly more laps and had a significantly higher predicted aerobic fitness (V̇O2peak: ml $$ kg-1 $$ min-1) than their peers with MR. Additionally, participants with MR tended to have higher BMI than their peers without MR. The results of this study indicate that children and adolescents with MR have lower exercise capacity, lower aerobic fitness, and higher BMIs than their peers without MR.
Stuart J. Fairclough
This study assessed the physical activity levels of 20 high school girls (age 13 years, SD = 1.1) during physical education classes, over an 8-month period. Physical activity was measured by heart rate telemetry and accelerometry. Skinfold measurements were used to estimate percent body fat, and peak VO2 was assessed by maximal treadmill running. Girls engaged in moderate-to-vigorous intensity physical activity (MVPA) for 38.5% of class time and produced 961.8 vector magnitude (Vmag) counts · min−1. Body fat was inversely correlated with Vmag counts · min−1 (r = −.65, p < .01) and peak VO2 (r = −.65, p < .01). Girls’ MVPA in physical education did not meet the Healthy People 2010 50% of class time criterion. Body fat significantly predicted 42% of the variance in Vmag counts · min−1. Cardiorespiratory fitness appeared not to influence physical activity during physical education, regardless of measurement method. Girls’ physical activity in physical education may be improved if schools advocate planned lesson outcomes that aim to maximize opportunities for physical activity.
Lee E.F. Graves, Nicola D. Ridgers, Greg Atkinson and Gareth Stratton
Active video game interventions typically provide children a single game that may become unappealing. A peripheral device (jOG) encourages step-powered gaming on multiple games. This trial evaluated the effect of jOG on children’s objectively measured PA, body fat and self-reported behaviors. 42 of 58 eligible children (8–10 y) randomly assigned to an intervention (jOG) or control (CON) completed the trial. Intervention children received two jOG devices for home use. Analyses of covariance compared the intervention effect at 6 and 12 weeks from baseline. No differences were found between groups for counts per minute (CPM; primary outcome) at 6 and 12 weeks (p > .05). Active video gaming increased (adjusted change 0.95 (95% CI 0.25, 1.65) h·d−1, p<.01) and sedentary video gaming decreased (-0.34 (-1.24, 0.56) h·d−1, p > .05) at 6 weeks relative to CON. No body fat changes were observed between groups. Targeted changes in video game use did not positively affect PA. Larger trials are needed to verify the impact of active video games on children’s PA and health.
Jennifer Gornall and Rudolph G. Villani
The primary aim was to investigate whether the reduction in resting metabolic rate (RMR) and fat free mass (FFM) associated with a short-term very low kilojoule diet (VLKD) is altered by concurrent resistance exercise. Twenty overweight, premenopausal women were pair matched on body surface area and randomly assigned to either diet only (3,400 kJ/day) or diet combined with resistance training. Before and after 4 weeks of treatment, RMR was assessed by indirect calorimetry; total body mass (TBM), FFM, and fat mass (FM) by dual energy x-ray absorptiometry; total body water (TBW) by bioelectrical impedance; and strength by a weight-lifting test. Both groups had significantly lower TBM, FFM, FM, TBW, absolute RMR, and RMR, with FFM as the covariate, in the posttests than the pretests with no significant differences between groups. It was concluded that 4 weeks of resistance training did not prevent or reduce the decline in FFM and RMR observed with a VLKD.
Eric T. Trexler, Katie R. Hirsch, Bill I. Campbell and Abbie E. Smith-Ryan
The purpose of the current study was to evaluate changes in body composition, metabolic rate, and hormones during postcompetition recovery. Data were collected from natural physique athletes (7 male/8 female) within one week before (T1) competition, within one week after (T2), and 4–6 weeks after (T3) competition. Measures included body composition (fat mass [FM] and lean mass [LM] from ultrasongraphy), resting metabolic rate (RMR; indirect calorimetry), and salivary leptin, testosterone, cortisol, ghrelin, and insulin. Total body water (TBW; bioelectrical impedance spectroscopy) was measured at T1 and T2 in a subsample (n = 8) of athletes. Significant (p < .05) changes were observed for weight (T1 = 65.4 ± 12.2 kg, T2 = 67.4 ± 12.6, T3 = 69.3 ± 13.4; T3 > T2 > T1), LM (T1 = 57.6 ± 13.9 kg, T2 = 59.4 ± 14.2, T3 = 59.3 ± 14.2; T2 and T3 > T1), and FM (T1 = 7.7 ± 4.4 kg, T2 = 8.0 ± 4.4, T3 = 10.0 ± 6.2; T3 > T1 and T2). TBW increased from T1 to T2 (Δ=1.9 ± 1.3 L, p < .01). RMR increased from baseline (1612 ± 266 kcal/day; 92.0% of predicted) to T2 (1881 ± 329, 105.3%; p < .01) and T3 (1778 ± 257, 99.6%; p < .001). Cortisol was higher (p < .05) at T2 (0.41 ± 0.31 μg/dL) than T1 (0.34 ± 0.31) and T3 (0.35 ± 0.27). Male testosterone at T3 (186.6 ± 41.3 pg/mL) was greater than T2 (148.0 ± 44.6, p = .04). RMR changes were associated (p ≤ .05) with change in body fat percent (ΔBF%; r = .59) and T3 protein intake (r= .60); male testosterone changes were inversely associated (p≤ .05) with ΔBF%, ΔFM, and Δweight (r=-0.81–-0.88). TBW increased within days of competition. Precompetition RMR suppression appeared to be variable and markedly reversed by overfeeding, and reverted toward normal levels following competition. RMR and male testosterone increased while FM was preferentially gained 4–6 weeks postcompetition.
Patricia A. Hageman, Susan Noble Walker, Carol H. Pullen, Linda S. Boeckner and Maureen K. Oberdorfer
This study investigated physical activity and fitness of midlife and older rural women. Random-digit dialing was used to recruit 225 women (57.9 ± 5.6 years old). Self-reported activity (moderate activity, flexibility, and strength) and fitness (body composition, flexibility, strength, and estimated VO2max) were assessed. The women demonstrated low daily energy expenditure (30.74 ± 10.63 kcal · kg−1 · day−1) and estimated VO2max (20.12 ± 7.81 ml · kg−1 · min−1), with 51.5% reporting fair or poor health. Few women reported meeting Healthy People 2010 targets for moderate activity (43.1%), flexibility (28.9%), or strength (14.2%). When classified by estimated VO2max into three categories, differences were observed for body-mass index, percent body fat, sit and reach, and timed chair stands, with the poorest performance by those with low cardiorespiratory fitness. Adherence to Healthy People 2010 targets for moderate activity and strengthening was associated with higher cardiorespiratory fitness. These rural women are targets for physical activity interventions because of their sedentary behaviors and low cardiorespiratory fitness.