Comparison of the Polar V800 and the Garmin Forerunner 230 to Predict V̇o2max.

ABSTRACT: Snyder, NC, Willoughby, CA, and Smith, BK. Comparison of the Polar V800 and the Garmin Forerunner 230 to predict V̇o2max. J Strength Cond Res 35(5): 1403-1409, 2021-The purpose of this study was to compare maximal oxygen consumption (V̇o2max) values (Amax) with predicted V̇o2max values obtained from the Polar V800 (PV800) and the Garmin Forerunner 230 (GF230) to determine whether the accuracy of these estimates differs between sexes. The PV800 predicts V̇o2max based on resting heart rate (HR). The GF230 predicts V̇o2max based on a 10-minute, self-paced outdoor run. Subjects consisted of 22 women and 22 men. After a 10-minute supine rest, predicted V̇o2max (Pmax) values from the PV800 were measured during a 5-minute supine rest. Subjects then completed a treadmill V̇o2max test to determine Amax. Within 48 hours of obtaining Amax, individuals completed a 10-minute, self-paced outdoor run using the GF230 to predict V̇o2max (Gmax). A 2-way (watch vs. sex) analysis of variance was used to determine whether there were differences between predicted V̇o2max and Amax between sexes. A significant interaction between HR monitors and sex was found (p = 0.007). Follow-up analysis showed that in men, Pmax was significantly overestimated compared with Gmax (3.87 ± 1.53 ml·kg-1·min-1, p = 0.013). Bland-Altman plots revealed large random errors that ranged from 6.6 to 16.4 ml·kg-1·min-1 with the PV800 having larger errors than the GF230. The results of this study indicate that the GF230 can provide an accurate estimate of V̇o2max in both sexes. The PV800 can provide an accurate estimate of V̇o2max for women but not men. Estimates of V̇o2max from the both devices should be used with caution because of the large random error associated with them.

Statins and almonds to lower lipoproteins (the STALL Study).

BACKGROUND: Dietary supplementation with almonds has demonstrated dose-dependent decreases in low-density lipoprotein cholesterol (LDL-C), likely because of their composition of beneficial nutrients including mono- and polyunsaturated fatty acids, fiber, and protein. OBJECTIVE: The primary objective of this study was to determine the changes in the lipid profile (LDL-C, high-density lipoprotein cholesterol [HDL-C], triglycerides, total cholesterol, non-HDL-C), LDL-C particle size, and lipoprotein (a) when 100 g of almonds daily were added to background statin therapy for 4 weeks. METHODS: Subjects (N = 48) receiving a consistent statin dose were randomized to 100 g of almonds daily and to The National Cholesterol Education Program Adult Treatment Panel's third report Therapeutic Lifestyle Changes Diet counseling (almond group; n = 22) or solely Adult Treatment Panel's third report Therapeutic Lifestyle Changes Diet counseling (non-almond group; n = 26), for 4 weeks. RESULTS: No significant changes in weight and weekly physical activity were noted between the 2 groups from baseline. However, the almond group consumed significantly more calories at 4 weeks compared with controls. The almond group experienced a 4.9% reduction in non-HDL-C compared with a 3.5% increase for the non-almond group (P = .02). Additionally, notable improvements were observed in LDL-C and triglycerides, but did not achieve statistical significance (P = .068 for both parameters). There was also a shift from LDL pattern A to pattern B particles (P = .003) in the almond group. No significant differences in total cholesterol (P = .1), HDL-C (P = .3), or lipoprotein (a) (P = .1) were observed. CONCLUSION: Adding 100 g of almonds daily to chronic statin therapy for 4 weeks significantly reduced non-HDL-C. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00603876.

Neuroimaging studies of factors related to exercise: rationale and design of a 9 month trial.

The prevalence of obesity is high resulting from chronic imbalances between energy intake and expenditure. On the expenditure side, regular exercise is associated with health benefits, including enhanced brain function. The benefits of exercise are not immediate and require persistence to be realized. Brain regions associated with health-related decisions, such as whether or not to exercise or controlling the impulse to engage in immediately rewarding activities (e.g., sedentary behavior), include reward processing and cognitive control regions. A 9 month aerobic exercise study will be conducted in 180 sedentary adults (n = 90 healthy weight [BMI = 18.5 to 26.0 kg/m(2)]; n = 90 obese [BMI = 29.0 to 41.0 kg/m(2)) to examine the brain processes underlying reward processing and impulse control that may affect adherence in a new exercise regimen. The primary aim is to use functional magnetic resonance imaging (fMRI) to examine reward processing and impulse control among participants that adhere (exercise >80% of sessions) and those that do not adhere to a nine-month exercise intervention with secondary analyses comparing sedentary obese and sedentary healthy weight participants. Our results will provide valuable information characterizing brain activation underlying reward processing and impulse control in sedentary obese and healthy weight individuals. In addition, our results may identify brain activation predictors of adherence and success in the exercise program along with measuring the effects of exercise and improved fitness on brain activation.

Physical activity and academic achievement across the curriculum (A + PAAC): rationale and design of a 3-year, cluster-randomized trial.

BACKGROUND: Improving academic achievement and reducing the rates of obesity in elementary school students are both of considerable interest. Increased physical activity during academic instruction time during school offers a potential intervention to address both issues. A program titled "Physical Activity Across the Curriculum" (PAAC) was developed in which classroom teachers in 22 elementary schools were trained to deliver academic instruction using physical activity with a primary aim of preventing increased BMI. A secondary analysis of data assessed the impact of PAAC on academic achievement using the Weschler Individual Achievement Test-II and significant improvements were shown for reading, math and spelling in students who participated in PAAC. Based on the results from PAAC, an adequately powered trial will be conducted to assess differences in academic achievement between intervention and control schools called, "Academic Achievement and Physical Activity Across the Curriculum (A + PAAC)." METHODS/DESIGN: Seventeen elementary schools were cluster randomized to A + PAAC or control for a 3-year trial. Classroom teachers were trained to deliver academic instruction through moderate-to-vigorous physical activity with a target of 100+ minutes of A + PAAC activities per week. The primary outcome measure is academic achievement measured by the Weschler Individual Achievement Test-III, which was administered at baseline (Fall 2011) and will be repeated in the spring of each year by assessors blinded to condition. Potential mediators of any association between A + PAAC and academic achievement will be examined on the same schedule and include changes in cognitive function, cardiovascular fitness, daily physical activity, BMI, and attention-to-task. An extensive process analysis will be conducted to document the fidelity of the intervention. School and student recruitment/randomization, teacher training, and baseline testing for A + PAAC have been completed. Nine schools were randomized to the intervention and 8 to control. A random sample of students in each school, stratified by gender and grade (A + PAAC = 370, Control = 317), was selected for outcome assessments from those who provided parental consent/child assent. Baseline data by intervention group are presented. DISCUSSION: If successful, the A + PAAC approach could be easily and inexpensively scaled and disseminated across elementary schools to improve both educational quality and health. FUNDING SOURCE: R01- DK85317. TRIAL REGISTRATION: US NIH Clinical Trials, http://NCT01699295.

Improving weight maintenance using virtual reality (Second Life).

OBJECTIVE: Compare weight loss and maintenance between a face-to-face (FTF) weight management clinic and a clinic delivered via virtual reality (VR). METHODS: Participants were randomized to 3 months of weight loss with a weekly clinic delivered via FTF or VR and then 6 months' weight maintenance delivered with VR. Data were collected at baseline and 3 and 6 months for weight and process variables. Twenty overweight and obese individuals (31.1 ± 3.6 years of age; body mass index, 32.8 ± 5.1; 85% females; 20% minorities) responded to advertisement and met inclusion criteria. Diets (1,200-1,800 kcal/d) used prepackaged meals, fruits and vegetables, and physical activity (300 min/wk). RESULTS: Weight loss was significantly greater for FTF at 10.8% compared with 7.6% for VR (P < .05). However, weight maintenance was significantly greater for VR at 14.0% compared with 9.5% for FTF (P < .05). CONCLUSIONS AND IMPLICATIONS: Virtual reality compares favorably with FTF for weight loss and may facilitate greater weight maintenance.

Aerobic exercise alone results in clinically significant weight loss for men and women: midwest exercise trial 2.

UNLABELLED: Exercise is recommended by public health agencies for weight management; however, the role of exercise is generally considered secondary to energy restriction. Few studies exist that have verified completion of exercise, measured the energy expenditure of exercise, and prescribed exercise with equivalent energy expenditure across individuals and genders. OBJECTIVE: The objective of this study was to evaluate aerobic exercise, without energy restriction, on weight loss in sedentary overweight and obese men and women. DESIGN AND METHODS: This investigation was a randomized, controlled, efficacy trial in 141 overweight and obese participants (body mass index, 31.0 ± 4.6 kg/m(2) ; age 22.6 ± 3.9 years). Participants were randomized (2:2:1 ratio) to exercise at either 400 kcal/session or 600 kcal/session or to a nonexercise control. Exercise was supervised, 5 days/week, for 10 months. All participants were instructed to maintain usual ad libitum diets. Because of the efficacy design, completion of ≥90% of exercise sessions was an a priori definition of per protocol, and these participants were included in the analysis. RESULTS: Weight loss from baseline to 10 months for the 400 and 600 kcal/session groups was 3.9 ± 4.9 kg (4.3%) and 5.2 ± 5.6 kg (5.7%), respectively, compared with weight gain for controls of 0.5 ± 3.5 kg (0.5%) (P < 0.05). Differences for weight loss from baseline to 10 months between the exercise groups and differences between men and women within groups were not statistically significant. CONCLUSIONS: Supervised exercise, with equivalent energy expenditure, results in clinically significant weight loss with no significant difference between men and women.

Weight loss can lead to resolution of gastroesophageal reflux disease symptoms: a prospective intervention trial.

OBJECTIVE: Weight gain is an important risk factor for gastroesophageal reflux disease (GERD); however, whether weight loss can lead to resolution of GERD symptoms is not clear. Our aim was to measure the impact of weight loss on GERD symptoms. DESIGN AND METHODS: In a prospective cohort study at a tertiary referral center, overweight/obese subjects (BMI 25-39.9 kg/m2) were enrolled in a structured weight loss program. Weight loss strategies included dietary modifications, increased physical activity and behavioral changes. At baseline and at 6 months, BMI and waist circumference were measured and all participants completed a validated reflux disease questionnaire. RESULTS: A total of 332 adult subjects, mean age 46 years and 66% women were prospectively enrolled. At baseline, the mean body weight, BMI, and waist circumference were 101 (±18) kg, 35 (±5) kg/m2 and 103 (±13) cm. At 6 months, majority of the subjects (97%) lost weight (average weight loss: 13 ± 7.7 kg) and as compared with baseline, there was a significant decrease in the overall prevalence of GERD (15 vs. 37%; P < 0.01) and the mean GERD symptom score (1.8 vs. 5.5; P < 0.01). Overall, 81% of the subjects had reduction in GERD symptom scores; 65% had complete resolution and 15% had partial resolution of reflux symptoms. There was a significant correlation between % body weight loss and reduction in GERD symptom scores (r = 0.17, P < 0.05). CONCLUSIONS: In conclusion, the overall prevalence of GERD symptoms is high (37%) in overweight and obese subjects. A structured weight loss program can lead to complete resolution of GERD symptoms in the majority of these subjects.

Equivalent weight loss for weight management programs delivered by phone and clinic.

OBJECTIVE: Face-to-face (FTF) weight management is costly and presents barriers for individuals seeking treatment; thus, alternate delivery systems are needed. The objective of this study was to compare weight management delivered by FTF clinic or group conference calls (phone). DESIGN AND METHODS: Randomized equivalency trial in 295 overweight/obese men/women (BMI = 35.1±4.9, Age = 43.8±10.2, Minority = 39.8%). Weight loss (0-6 months) was achieved by reducing energy intake between 1,200 and 1,500 kcal/day and progressing physical activity (PA) to 300 min/week. Weight maintenance (7-18 months) provided adequate energy to maintain weight and continued 300 min/week of PA. Behavioral weight management strategies were delivered weekly for 6 months and gradually reduced during 7-18 months. A cost analysis provided a comparison of expenses between groups. RESULTS: Weight change from baseline to 6 months was -13.4 ± 6.7% and -12.3 ± 7.0% for FTF clinic and phone, respectively. Weight change from 6-18 months was 6.4 ± 7.0% and 6.4 ± 5.2%, for FTF clinic and phone, respectively. The cost to FTF participants was $789.58 more per person. CONCLUSIONS: Phone delivery provided equivalent weight loss and maintenance and reduced program cost. Ubiquitous access to phones provides a vast reach for this approach.

A 6-month trial of resistance training with milk supplementation in adolescents: effects on body composition.

Fluid milk consumed in conjunction with resistance training (RT) provides additional protein and calcium, which may enhance the effect of RT on body composition. However, the literature on this topic is inconsistent with limited data in adolescents. Therefore, we examined the effects of a supervised RT program (6 mo, 3 d/ wk, 7 exercises, 40-85% 1-repetition maximum) with daily milk supplementation (24 oz/day, one 16-oz dose immediately post-RT) on weight, fat mass (FM), and fat-free mass (FFM) assessed via dual-energy X-ray absorptiometry (baseline, 3 mo, 6 mo) in a sample of middle-school students who were randomly assigned to 1 of 3 supplement groups: milk, isocaloric carbohydrate (100% fruit juice), or water (control). Thirty-nine boys and 69 girls (mean age = 13.6 yr, mean BMI percentile = 85th) completed the study: milk n = 36, juice n = 34, water n = 38. The results showed no significant differences between groups for change in body weight (milk = 3.4 ± 3.7 kg, juice = 4.2 ± 3.1 kg, water = 2.3 ±2.9 kg), FM (milk = 1.1 ±2.8 kg, juice = 1.6 ± 2.5 kg, water = 0.4 ±3.6 kg), or FFM (milk = 2.2 ± 1.9 kg, juice = 2.7 ± 1.9 kg, water = 1.7 ± 2.9 kg) over 6 mo. FFM accounted for a high proportion of the increased weight (milk = 62%, juice = 64%, water = 74%). These results from a sample of predominantly overweight adolescents do not support the hypothesis that RT with milk supplementation enhances changes in body composition compared with RT alone.

Weight management by phone conference call: a comparison with a traditional face-to-face clinic. Rationale and design for a randomized equivalence trial.

State-of-the-art treatment for weight management consists of a behavioral intervention to facilitate decreased energy intake and increased physical activity. These interventions are typically delivered face-to-face (FTF) by a health educator to a small group of participants. There are numerous barriers to participation in FTF clinics including availability, scheduling, the expense and time required to travel to the clinic site, and possible need for dependent care. Weight management clinics delivered by conference call have the potential to diminish or eliminate these barriers. The conference call approach may also reduce burden on providers, who could conduct clinic groups from almost any location without the expenses associated with maintaining FTF clinic space. A randomized trial will be conducted in 395 overweight/obese adults (BMI 25-39.9 kg/m(2)) to determine if weight loss (6 months) and weight maintenance (12 months) are equivalent between weight management interventions utilizing behavioral strategies and pre-packaged meals delivered by either a conference call or the traditional FTF approach. The primary outcome, body weight, will be assessed at baseline, 6, 12 and 18 months. Secondary outcomes including waist circumference, energy and macronutrient intake, and physical activity and will be assessed on the same schedule. In addition, a cost analysis and extensive process evaluation will be completed.

A randomized, controlled, supervised, exercise trial in young overweight men and women: the Midwest Exercise Trial II (MET2).

We evaluated weight loss response to 16 months of supervised exercise (45 min/day, 5 days/week, 75% heart-rate-reserve) in sedentary, overweight/obese participants without energy restriction in the Midwest Exercise Trial (MET1). Results indicated men lost weight, women did not. The gender differences were associated with differences in the energy expenditure of exercise (EEEx) (men=667±116; women=439±88 kcal/session) when exercise was prescribed by frequency, intensity and duration. MET2 is a randomized control trial designed and powered to examine differences in weight loss and gender in response to EEEx for men and women of 400 or 600 kcal/session, 5 days/week, for 10 months without energy restriction. One hundred forty-one participants will be randomized to 1 of 2 exercise groups or a non-exercise control. EEEx will be verified by indirect calorimetry monthly during the intervention. This study will evaluate: (1) the weight change response to two levels of EEEx versus non-exercise control; (2) gender differences in weight response to two levels of EEEx; (3) potential compensatory changes in energy intake and/or daily physical activity that may explain the observed weight changes. Results from this study may impact how exercise is prescribed for weight loss and prevention of weight regain and may clarify if men and women differ in response to exercise.

Resistance training volume, energy balance and weight management: rationale and design of a 9 month trial.

The increased prevalence of obesity and the lack of treatment success both argue for the design and evaluation of strategies to prevent the development of overweight and obesity. To date, the role of resistance training (RT) in this regard is largely unexplored. RT may be effective for weight management as a result of increased fat-free mass (FFM), which may result in increased resting metabolic rate and increased physical activity energy expenditure. However, the literature relative to the efficacy of RT protocols recommended for healthy adults to alter the aforementioned parameters is inconsistent or inadequately evaluated. We will conduct a 9 month randomized controlled efficacy trial to compare changes in body composition (fat mass, FFM, % body fat) and energy balance in response to 2 volumes of RT (1 vs. 3 sets vs. non-exercise control) both at the completion of training (9 months) and 1 year later (body composition). This investigation will be conducted in a sample of healthy, normal and overweight, sedentary, young adult men and women; a group at high risk for development of overweight and obesity. Our results will provide information relative to the minimum volume of RT that may be associated with body weight/fat gain which may inform the development of guidelines for RT to prevent weight gain or to alter body composition.

Evaluation of an approach to weight loss in adults with intellectual or developmental disabilities.

Of 79 overweight adults with intellectual or developmental disabilities who participated in a weight loss intervention, 73 completed the 6-month diet phase. The emphasis in the intervention was consumption of high volume, low calorie foods and beverages, including meal-replacement shakes. Lower calorie frozen entrees were recommended to control portion size. A walking activity was encouraged. Participants attended monthly meetings in which a small amount of cash was exchanged for self-recorded intake and exercise records completed on picture-based forms. Average weight loss was 13.2 pounds (6.3%) of baseline weight at 6 months, with weight loss shown by 64 of the 73 individuals enrolled. Those completing a 6-month follow-up phase showed weight loss of 9.4% of baseline. Increased choice and control are discussed as possible contributors to individual success.

Comparison of a reduced carbohydrate and reduced fat diet for LDL, HDL, and VLDL subclasses during 9-months of weight maintenance subsequent to weight loss.

OBJECTIVES: This study compared LDL, HDL, and VLDL subclasses in overweight or obese adults consuming either a reduced carbohydrate (RC) or reduced fat (RF) weight maintenance diet for 9 months following significant weight loss. METHODS: Thirty-five (21 RC; 14 RF) overweight or obese middle-aged adults completed a 1-year weight management clinic. Participants met weekly for the first six months and bi-weekly thereafter. Meetings included instruction for diet, physical activity, and behavior change related to weight management. Additionally, participants followed a liquid very low-energy diet of approximately 2092 kJ per day for the first three months of the study. Subsequently, participants followed a dietary plan for nine months that targeted a reduced percentage of carbohydrate (approximately 20%) or fat (approximately 30%) intake and an energy intake level calculated to maintain weight loss. Lipid subclasses using NMR spectroscopy were analyzed prior to weight loss and at multiple intervals during weight maintenance. RESULTS: Body weight change was not significantly different within or between groups during weight maintenance (p>0.05). The RC group showed significant increases in mean LDL size, large LDL, total HDL, large and small HDL, mean VLDL size, and large VLDL during weight maintenance while the RF group showed increases in total HDL, large and small HDL, total VLDL, and large, medium, and small VLDL (p<0.05). Group*time interactions were significant for large and medium VLDL (p>0.05). CONCLUSION: Some individual lipid subclasses improved in both dietary groups. Large and medium VLDL subclasses increased to a greater extent across weight maintenance in the RF group.

Construct validity of a continuous metabolic syndrome score in children.

OBJECTIVE: The primary purpose of this study was to examine the construct validity of a continuous metabolic syndrome score (cMetS) in children. The secondary purpose was to identify a cutpoint value(s) for an adverse cMetS based on receiver operating characteristic (ROC) curve analysis. METHODS: 378 children aged 7 to 9 years were assessed for the metabolic syndrome which was determined by age-modified cutpoints. High-density-lipoprotein cholesterol, triglycerides, the homeostasis assessment model of insulin resistance, mean arterial pressure, and waist circumference were used to create a cMetS for each subject. RESULTS: About half of the subjects did not possess any risk factors while about 5% possessed the metabolic syndrome. There was a graded relationship between the cMetS and the number of adverse risk factors. The cMetS was lowest in the group with no adverse risk factors (-1.59 +/- 1.76) and highest in those possessing the metabolic syndrome (> or =3 risk factors) (7.05 +/- 2.73). The cutoff level yielding the maximal sensitivity and specificity for predicting the presence of the metabolic syndrome was a cMetS of 3.72 (sensitivity = 100%, specificity = 93.9%, and the area of the curve = 0.978 (0.957-0.990, 95% confidence intervals). CONCLUSION: The results demonstrate the construct validity for the cMetS in children. Since there are several drawbacks to identifying a single cut-point value for the cMetS based on this sample, we urge researchers to use the approach herein to validate and create a cMetS that is specific to their study population.

Predicting postprandial lipemia in healthy adults and in at-risk individuals with components of the cardiometabolic syndrome.

To determine whether a single-point triglyceride (TG) concentration could estimate the 8-hour postprandial lipemic (PPL) response, men and women performed baseline PPL (n=188) and postexercise PPL (n=92) trials. Correlations were generated between TG concentrations at baseline and at various time points after a high-fat meal vs 8-hour area under the TG curve (TG-AUC) and peak TG level. Stepwise multiple regression and bootstrap simulations using TG level and additional predictor variables of sex, age, percentage of body fat, training status, and maximal oxygen consumption indicated that the 4-hour TG concentrations accounted for >90% of the variance in TG-AUC and peak TG responses during the PPL trials. Equations were confirmed by cross-validation in healthy as well as at-risk individuals with components of the cardiometabolic syndrome. Our data suggest that the 4-hour TG value is highly related to the total 8-hour PPL response and can be used for accurate estimation of PPL in a clinical or research setting.

Physical Activity Across the Curriculum (PAAC): a randomized controlled trial to promote physical activity and diminish overweight and obesity in elementary school children.

BACKGROUND: Physical Activity Across the Curriculum (PAAC) was a three-year cluster randomized controlled trial to promote physical activity and diminish increases in overweight and obesity in elementary school children. METHODS: Twenty-four elementary schools were cluster randomized to the Physical Activity Across the Curriculum intervention or served as control. All children in grades two and three were followed to grades four and five. Physical Activity Across the Curriculum promoted 90 min/wk of moderate to vigorous intensity physically active academic lessons delivered by classroom teachers. Body Mass Index was the primary outcome, daily Physical activity and academic achievement were secondary outcomes. RESULTS: The three-year change in Body Mass Index for Physical Activity Across the Curriculum was 2.0+/-1.9 and control 1.9+/-1.9, respectively (NS). However, change in Body Mass Index from baseline to 3 years was significantly influenced by exposure to Physical Activity Across the Curriculum. Schools with > or =75 min of Physical Activity Across the Curriculum/wk showed significantly less increase in Body Mass Index at 3 years compared to schools that had <75 min of Physical Activity Across the Curriculum (1.8+/-1.8 vs. 2.4+/-2.0, p=0.02). Physical Activity Across the Curriculum schools had significantly greater changes in daily Physical activity and academic achievement scores. CONCLUSIONS: The Physical Activity Across the Curriculum approach may promote daily Physical activity and academic achievement in elementary school children. Additionally, 75 min of Physical Activity Across the Curriculum activities may attenuate increases in Body Mass Index.

Minimal resistance training improves daily energy expenditure and fat oxidation.

UNLABELLED: Long-term resistance training (RT) may result in a chronic increase in 24-h energy expenditure (EE) and fat oxidation to a level sufficient to assist in maintaining energy balance and preventing weight gain. However, the impact of a minimal RT program on these parameters in an overweight college-aged population, a group at high risk for developing obesity, is unknown. PURPOSE: We aimed to evaluate the effect of 6 months of supervised minimal RT in previously sedentary, overweight (mean +/- SEM, BMI = 27.7 +/- 0.5 kg x m(-2)) young adults (21.0 +/- 0.5 yr) on 24-h EE, resting metabolic rate (RMR), sleep metabolic rate (SMR), and substrate oxidation using whole-room indirect calorimetry 72 h after the last RT session. METHODS: Participants were randomized to RT (one set, 3 d x wk(-1), three to six repetition maximums, nine exercises; N = 22) or control (C, N = 17) groups and completed all assessments at baseline and at 6 months. RESULTS: There was a significant (P < 0.05) increase in 24-h EE in the RT (527 +/- 220 kJ x d(-1)) and C (270 +/- 168 kJ x d(-1)) groups; however, the difference between groups was not significant (P = 0.30). Twenty-four hours of fat oxidation (g x d(-1)) was not altered after RT; however, reductions in RT assessed during both rest (P < 0.05) and sleep (P < 0.05) suggested increased fat oxidation in RT compared with C during these periods. SMR (8.4 +/- 8.6%) and RMR (7.4 +/- 8.7%) increased significantly in RT (P < 0.001) but not in C, resulting in significant (P < 0.001) between-group differences for SMR with a trend for significant (P = 0.07) between-group differences for RMR. CONCLUSION: A minimal RT program that required little time to complete (11min per session) resulted in a chronic increase in energy expenditure. This adaptation in energy expenditure may have a favorable impact on energy balance and fat oxidation sufficient to assist with the prevention of obesity in sedentary, overweight young adults, a group at high risk for developing obesity.

American College of Sports Medicine Position Stand. Appropriate physical activity intervention strategies for weight loss and prevention of weight regain for adults.

Overweight and obesity affects more than 66% of the adult population and is associated with a variety of chronic diseases. Weight reduction reduces health risks associated with chronic diseases and is therefore encouraged by major health agencies. Guidelines of the National Heart, Lung, and Blood Institute (NHLBI) encourage a 10% reduction in weight, although considerable literature indicates reduction in health risk with 3% to 5% reduction in weight. Physical activity (PA) is recommended as a component of weight management for prevention of weight gain, for weight loss, and for prevention of weight regain after weight loss. In 2001, the American College of Sports Medicine (ACSM) published a Position Stand that recommended a minimum of 150 min wk(-1) of moderate-intensity PA for overweight and obese adults to improve health; however, 200-300 min wk(-1) was recommended for long-term weight loss. More recent evidence has supported this recommendation and has indicated more PA may be necessary to prevent weight regain after weight loss. To this end, we have reexamined the evidence from 1999 to determine whether there is a level at which PA is effective for prevention of weight gain, for weight loss, and prevention of weight regain. Evidence supports moderate-intensity PA between 150 and 250 min wk(-1) to be effective to prevent weight gain. Moderate-intensity PA between 150 and 250 min wk(-1) will provide only modest weight loss. Greater amounts of PA (>250 min wk(-1)) have been associated with clinically significant weight loss. Moderate-intensity PA between 150 and 250 min wk(-1) will improve weight loss in studies that use moderate diet restriction but not severe diet restriction. Cross-sectional and prospective studies indicate that after weight loss, weight maintenance is improved with PA >250 min wk(-1). However, no evidence from well-designed randomized controlled trials exists to judge the effectiveness of PA for prevention of weight regain after weight loss. Resistance training does not enhance weight loss but may increase fat-free mass and increase loss of fat mass and is associated with reductions in health risk. Existing evidence indicates that endurance PA or resistance training without weight loss improves health risk. There is inadequate evidence to determine whether PA prevents or attenuates detrimental changes in chronic disease risk during weight gain.

Comparison of two self-directed weight loss interventions: Limited weekly support vs. no outside support.

OBJECTIVE: The purpose of this study was to compare the efficacy of two home-based weight loss interventions that differ only in the amount of outside support provided. METHODS: This was a 12-week, randomized, controlled trial. One group received limited support (LWS, n = 35) via a single 10 min phone call each week while another group received no weekly support (NWS, n = 28). Both the LWS and NWS received pre-packaged meals (PM) and shakes. A third group served as control (CON, n = 30) and received no components of the intervention. Weight loss at 12 weeks was the primary outcome. Diet (PM, shake, and fruit/vegetable (F/V) intake) and physical activity (PA) were self-monitored, recorded daily and reported weekly. An exit survey was completed by participants in the intervention groups upon completion of the study. RESULTS: Weight loss and percent weight loss in the LWS, NWS, and CON groups were 7.7 ± 4.4 kg (8.5 ± 4.2%), 5.9 ± 4.1 kg (6.0 ± 4.2%), and 0.3 ± 1.9 kg (0.4 ± 1.2%), respectively. The decrease in body weight and percent weight loss was significantly greater in the LWS and NWS groups when compared to the CON group and the percent weight loss was significantly greater in the LWS when compared to both the NWS and CON groups. CONCLUSION: A home-based weight loss program utilizing PM and shakes results in clinically significant percent weight loss and the addition of a brief weekly call promotes additional percent weight loss.