Postprandial walking reduces glucose levels in women with gestational diabetes mellitus.

The purpose of this study was to investigate blood glucose changes, as measured by a continuous glucose monitoring system, that occur in women with gestational diabetes mellitus (GDM) following an acute bout of moderate-intensity walking after consuming a high-carbohydrate/low-fat meal. This study found that moderate-intensity walking induced greater postprandial glucose control compared with sedentary activity and it appears that moderate-intensity activity may be used to reduce postprandial glucose levels in women with GDM.

Effect of Adding Online Social Support Tools to an Adult Walking Program: A Pilot Randomized Controlled Trial.

This pilot study examined the efficacy of providing access to online social support tools on adults' step counts during a technology-mediated walking intervention. Sixty-three insufficiently active adults were randomized to a 12-week walking intervention with (SUPPORT) or without (NO SUPPORT) access to online social support tools. Both groups received a pedometer, step goals, and access to relevant websites. The SUPPORT group also received access to online social support tools. A mixed-factor analysis of variance was conducted to examine within- and between-group differences in measures of daily steps, psychosocial indicators, and health. Both groups significantly (p < .05) increased their daily steps over time from baseline by 1,401 (SUPPORT) and 2,461 (NO SUPPORT), with no significant differences between groups. Psychosocial and health improvements were no greater for SUPPORT versus NO SUPPORT. The SUPPORT group's use of the online social support tools was low. Results suggest that giving adults access to online social support tools during a technology-mediated walking program did not lead to an enhanced increase in daily steps versus an identical program without these tools; however, the low use of these tools may have weakened their effect. Future studies should examine SUPPORT versus NO SUPPORT among groups with preexisting social ties.

Physical Activity With and Without TV Viewing: Effects on Enjoyment of Physical Activity and TV, Exercise Self-Efficacy, and Barriers to Being Active in Overweight Adults.

BACKGROUND: Physical activity (PA) is enjoyable, but there are barriers to participation. TV viewing is highly enjoyable with limited barriers. Exercising while viewing TV may impact enjoyment, exercise self-efficacy, and barriers to PA, compared with exercising without TV. METHODS: 58 sedentary, overweight adults were randomized to 1 of 2 PA prescriptions: one that increased PA during TV viewing (TV Commercial Stepping), and another that focused solely on PA (Walking). Random effects models tested changes in enjoyment of TV and PA, exercise self-efficacy, and barriers to PA across time (baseline, 3, and 6 months) and PA prescription during a 6-month PA intervention. RESULTS: At baseline, TV was more enjoyable than PA. Over the 6-month intervention, enjoyment of TV viewing did not change, but enjoyment of PA and exercise self-efficacy significantly increased, while barriers to PA significantly decreased for both groups compared with baseline (P < .05). CONCLUSIONS: While enjoyment of TV viewing remained constant, PA became more enjoyable, confidence to exercise increased, and barriers to being active were reduced for previously sedentary adults participating in a behavioral PA intervention. These findings highlight the importance of encouraging inactive adults to engage in some form of PA, whether it occurs with or without TV viewing.

Validity of Physical Activity Monitors for Estimating Energy Expenditure During Wheelchair Propulsion.

BACKGROUND: It is unknown if activity monitors can detect the increased energy expenditure (EE) of wheelchair propulsion at different speeds or on different surfaces. METHODS: Individuals who used manual wheelchairs (n = 14) performed 5 wheeling activities: on a level surface at 3 speeds, on a rubberized track at 1 fixed speed and on a sidewalk course at a self-selected speed. EE was measured using a portable indirect calorimetry system and estimated by an Actical (AC) worn on the wrist and a SenseWear (SW) activity monitor worn on the upper arm. Repeated- measures ANOVA was used to compare measured EE to the estimates from the standard AC prediction equation and SW using 2 different equations. RESULTS: Repeated-measures ANOVA demonstrated a significant main effect between measured EE and estimated EE. There were no differences between the criterion method and the AC across the 5 activities. The SW overestimated EE when wheeling at 3 speeds on a level surface, and during sidewalk wheeling. The wheelchair-specific SW equation improved the EE prediction during low intensity activities, but error progressively increased during higher intensity activities. CONCLUSIONS: During manual wheelchair propulsion, the wrist-mounted AC provided valid estimates of EE, whereas the SW tended to overestimate EE.

Physical activity variety, energy expenditure, and body mass index.

OBJECTIVES: To examine if physical activity (PA) variety was associated with moderate- to vigorous-intensity PA (MVPA) energy expenditure and body mass index (BMI) at 18 months during an obesity intervention. METHODS: Participants with ≥ 10 minutes/week of MVPA at 6 months and complete PA data were included. Participants were classified into Variety (N = 30), ≥ 2 different activities/week, or Less Variety (N = 65), only 1 activity/week. RESULTS: Weekly MVPA-related energy expenditure was higher for Variety than Less Variety (3674.7 ± 1934.6 kcal/week vs 2197.3 ± 1841.4 kcal/week, p < .05) at 18 months, with no difference in BMI. CONCLUSIONS: Greater weekly PA variety during obesity treatment was related to greater 18-month MVPA energy expenditure.

Monitoring capabilities of the Omron HJ-720ITC pedometer.

PURPOSE: The purpose of our study was to examine the monitoring capabilities of the Omron HJ-720ITC pedometer and determine the feasibility of using it in physical activity interventions. METHODS: Using data from an 8-week lifestyle-intervention study, we tested the capabilities of the pedometer for recording physical activity data. Data from a total of 28 subjects were used in our analysis. The total number of patient steps per day was recorded over the duration of an intervention, as well as "aerobic steps per day" (ie, those taken at a cadence of > 60 steps per minute for ≥ 10 consecutive minutes). Daily wear time was computed in order to ascertain participant compliance in wearing the pedometer. In addition, aerobic steps per minute were computed, providing an assessment of activity intensity during continuous walking bouts. RESULTS: Total steps per day and aerobic steps per day increased from baseline assessment to Week 8. Participants exceeded 100 steps/minute for 89% of their aerobic minutes, suggesting that they were in the moderate-intensity range (3-6 metabolic equivalent tasks) when performing continuous bouts of walking (> 10 minutes). CONCLUSION: The new pedometer is a reasonably priced, wearable activity monitor that is feasible for use in clinical and research settings.

Reducing TV watching during adult obesity treatment: two pilot randomized controlled trials.

The more time adults spend being sedentary, the greater the risk of obesity. The effect of reducing television (TV) watching, a prominent sedentary behavior, on weight loss has not been tested in an adult standard behavioral obesity intervention, and the mechanisms by which reducing TV watching influences energy balance behaviors are not well understood. Two, 8-week, pilot, randomized controlled trials were conducted examining the effect of a reduced TV watching prescription on energy balance behaviors and weight loss within an adult standard behavioral obesity intervention. In the first study, participants (n=24) were randomized into one of two conditions: (a) reduce energy intake and increase moderate to vigorous physical activity (MVPA) (INCREASE PA); or (b) reduce energy intake and decrease TV watching (DECREASE TV). As findings from the first pilot study did not show an increase in MVPA in the DECREASE TV group, the second study was designed to examine the effect of adding a reduced TV prescription to a standard intervention to optimize outcomes. In Pilot Study 2, participants (n=28) were randomized to INCREASE PA or to INCREASE PA+DECREASE TV. Outcomes included objectively measured TV watching and MVPA, self-reported light physical activity (LPA-Pilot Study 2 only), self-reported dietary intake while watching TV, and weight. Conditions with TV watching prescriptions significantly reduced TV watching. Both studies showed medium to large effect sizes for conditions with TV watching prescriptions to show greater reductions in dietary intake while watching TV. Pilot Study 1 found a trend for an increase in MVPA in INCREASE PA and Pilot Study 2 found significant increases in MVPA in both conditions. Pilot Study 2 found a significant increase in LPA in the INCREASE PA+DECREASE TV. Results indicate adding a TV watching prescription to a standard obesity intervention did not enhance increases in MVPA, but may assist with reducing dietary intake while TV watching and increasing LPA. Future research should examine the effect of reducing TV watching during obesity treatment over a longer time frame in a larger sample.

Classification accuracy of the wrist-worn gravity estimator of normal everyday activity accelerometer.

PURPOSE: The purpose of this study was to determine whether the published left-wrist cut points for the triaxial Gravity Estimator of Normal Everyday Activity (GENEA) accelerometer are accurate for predicting intensity categories during structured activity bouts. METHODS: A convenience sample of 130 adults wore a GENEA accelerometer on their left wrist while performing 14 different lifestyle activities. During each activity, oxygen consumption was continuously measured using the Oxycon mobile. Statistical analysis used Spearman's rank correlations to determine the relationship between measured and estimated intensity classifications. Cross tabulations were constructed to show the under- or overestimation of misclassified intensities. One-way χ2 tests were used to determine whether the intensity classification accuracy for each activity differed from 80%. RESULTS: For all activities, the GENEA accelerometer-based physical activity monitor explained 41.1% of the variance in energy expenditure. The intensity classification accuracy was 69.8% for sedentary activities, 44.9% for light activities, 46.2% for moderate activities, and 77.7% for vigorous activities. The GENEA correctly classified intensity for 52.9% of observations when all activities were examined; this increased to 61.5% with stationary cycling removed. CONCLUSIONS: A wrist-worn triaxial accelerometer has modest-intensity classification accuracy across a broad range of activities when using the cut points of Esliger et al. Although the sensitivity and the specificity are less than those reported by Esliger et al., they are generally in the same range as those reported for waist-worn, uniaxial accelerometer cut points.

The influence of commercially-available carbohydrate and carbohydrate-protein supplements on endurance running performance in recreational athletes during a field trial.

BACKGROUND: It is recommended that endurance athletes consume carbohydrate (CHO) supplements, providing 6-8% CHO concentration, during exercise > 60 minutes to improve athletic performance. Recently research has compared carbohydrate-protein (CHO-P) supplementation to the traditionally used CHO supplementation during endurance exercise, following these supplementation recommendations, in controlled settings, but not under simulated applied conditions such as a field trial. Therefore, the purpose of the present investigation was to test CHO and CHO-P supplementation under applied conditions such that commercially-available isocaloric (CHO-P & double-carbohydrate [CHO-CHO]) and isocarbohydrate (CHO-P & CHO) supplements were compared to a placebo (PLA), within an outdoor running field trial > 60 minutes in order to asses their influence on endurance performance. METHODS: Twelve male recreational runners completed four, 19.2 km runs, where they were instructed to run at a pace similar to race pace including a final sprint to the finish, which in this case was the final two laps of the course (1.92 km). Supplementation was provided before the start and in 4 km increments. Performance was measured by time to complete the 19.2 km run and last 1.92 km sprint. RESULTS: Analyses found no difference between supplements in time to complete the 19.2 km run (PLA = 88.6 ± 11.6 min, CHO = 89.1 ± 11.3 min, CHO-P = 89.1 ± 11.8 min, CHO-CHO = 89.6 ± 11.9 min) or last 1.92 km sprint to the finish (PLA = 8.3 ± 1.2 min, CHO = 8.2 ± 1.2 min, CHO-P = 8.2 ± 1.2 min, CHO-CHO = 8.4 ± 1.5 min). CONCLUSIONS: When following recommendation for supplementation within a field trial, commercially available CHO and CHO-P supplements do not appear to enhance performance in male recreational runners.

The ability of the PACER to elicit peak exercise response in youth [corrected].

PURPOSE: A graded exercise test (GXT) is the standard laboratory method of determining peak aerobic fitness (V˙O2peak). The FITNESSGRAM's Progressive Aerobic Cardiovascular Endurance Run (PACER) test is commonly used to estimate the peak oxygen consumption in the youth in the field.The objective of this study is to compare the peak physiological variables and RPEpeak during a treadmill GXT and the PACER test in 10- to 15-yr-old youths. METHODS: Participants (20 boys and 25 girls, 12.7 ± 1.7 yr) completed the PACER and treadmill GXT in a randomized order, separated by at least 24 h. HRpeak was measured via telemetry, V˙O2peak and RERpeak were measured using a portable metabolic system, and participants reported RPEpeak at the end of each test. RESULTS: No significant differences were found between the GXT and PACER HRpeak (197 vs 197 beats·min), RERpeak (1.13 vs 1.12), V˙O2peak (45.0 vs 45.9 mL·kg·min), and RPEpeak (8.4 vs 8.3). The SE of the measurement between the GXT V˙O2peak and PACER V˙O2peak was 1.4 mL·kg·min. CONCLUSIONS: It appears that the PACER elicits similar peak exercise responses compared with a treadmill GXT. The PACER can also be administered for fitness and functional capacity assessments in healthy and clinical populations.

Association of physical activity, fitness, and race: NHANES 1999­2004.

PURPOSE: Regular physical activity (PA) can be used to improve cardiorespiratory fitness (CRF). Previous research has shown differences in CRF (VO2max) among racial groups, but it is unclear how much of these differences can be explained by PA. Thus, we sought to examine the association between PA and CRF in different racial groups. METHODS: As a part of the National Health and Nutrition Examination Survey (1999­2004), 3115 adults (18­49 yr) completed a submaximal graded treadmill exercise test to estimate VO2max. Independent variables were demographics (race, education, sex, partner status, and waist circumference), behavioral measures (smoking and alcohol consumption), self-reported PA from three domains (leisure-time, domestic, and transportational PA (MET x min x wk(-1)), and the proportion of PA at a vigorous intensity (VMET). CRF was the dependent variable. Multiple linear regression was performed using SUDAAN statistical software. RESULTS: Results indicated that VO2max was significantly higher for Mexican Americans (40.9 T 0.5 mL x kg(-1) x min(-1)) and non-Hispanic whites (40.2 +/- 0.3 mL x kg(-1) x min(-1)) compared with non-Hispanic blacks (37.9 +/- 0.6 mL x kg(-1) x min(-1)) (P = 0.01). Demographics including race explained 18.5% of the variance in VO2max, with race being significant (P < 0.01) in the model. When PA was added to the model, the explained variance in VO2max increased to 19.3% (P = 0.001). VMET was more predictive of VO2max than total PA, and the model including VMET explained 20.4% of the variance in VO2max. Race remained a significant, independent predictor of VO2max after VMET and overall PA were added to the model. CONCLUSION: Race, PA, and exercise intensity are important factors in explaining differences in CRF. After accounting for demographics, PA, and VMET, a large proportion of the variance in CRF remains unexplained. Thus, other factors should also be considered when examining racial/ethnic differences in CRF.

Effect of BMI on pedometers in early adolescents under free-living conditions.

PURPOSE: Pedometers may provide valuable information regarding the ambulatory patterns of adolescents, but the effects of body mass index (BMI) on pedometer accuracy in this population are unknown.The purpose of this study was twofold: 1) to determine whether the New Lifestyles NL-2000 (NL) and the Digi-Walker SW-200 (DW) (New Lifestyles, Inc., Lees Summit, MO) yield similar step counts as compared with an ankle-mounted criterion, StepWatch 3, when worn by early adolescents in a free-living environment and 2) to study whether BMI percentile affects the accuracy of waist-mounted pedometers in adolescents. METHODS: Seventy-four early adolescents (13.0 ± 1.1 yr) wore the devices during one weekday. The study population included 33 normal weight, 21 overweight, and 20 obese participants. Two-way repeated-measures ANOVA was used to determine whether the BMI and the device were related to the number of steps per day and percentage of actual steps. RESULTS: The NL and DW recorded fewer steps than the StepWatch 3 in each BMI category (P < 0.05). In the obese group, the DW underestimated the steps more than the NL (P < 0.001). For the normal weight, overweight, and obese groups, the NL counted 89.1%, 89.1%, and 91.6% of the steps, respectively, whereas the DW counted 86.7%, 84.6%, and 72.7%, respectively. CONCLUSION: Researchers must be cognizant of the limitations of waist-mounted pedometers and carefully choose a device that suits the needs of their investigations. Because of the inaccuracies of the DW when measuring steps in obese adolescents, careful consideration must be given before choosing this device for research and interventions. The NL is a better device for assessment of adolescents' steps than the DW, especially for those who are obese.

Can sedentary behavior be made more active? A randomized pilot study of TV commercial stepping versus walking.

BACKGROUND: There is a growing problem of physical inactivity in America, and approximately a quarter of the population report being completely sedentary during their leisure time. In the U.S., TV viewing is the most common leisure-time activity. Stepping in place during TV commercials (TV Commercial Stepping) could increase physical activity. The purpose of this study was to examine the feasibility of incorporating physical activity (PA) into a traditionally sedentary activity, by comparing TV Commercial Stepping during 90 min/d of TV programming to traditional exercise (Walking). METHODS: A randomized controlled pilot study of the impact of 6 months of TV Commercial Stepping versus Walking 30 min/day in adults was conducted. 58 sedentary, overweight (body mass index 33.5 ± 4.8 kg/m2) adults (age 52.0 ± 8.6 y) were randomly assigned to one of two 6-mo behavioral PA programs: 1) TV Commercial Stepping; or 2) Walking 30 min/day. To help facilitate behavior changes participants received 6 monthly phone calls, attended monthly meetings for the first 3 months, and received monthly newsletters for the last 3 months. Using intent-to-treat analysis, changes in daily steps, TV viewing, diet, body weight, waist and hip circumference, and percent fat were compared at baseline, 3, and 6 mo. Data were collected in 2010-2011, and analyzed in 2011. RESULTS: Of the 58 subjects, 47 (81%) were retained for follow-up at the completion of the 6-mo program. From baseline to 6-mo, both groups significantly increased their daily steps [4611 ± 1553 steps/d vs. 7605 ± 2471 steps/d (TV Commercial Stepping); 4909 ± 1335 steps/d vs. 7865 ± 1939 steps/d (Walking); P < 0.05] with no significant difference between groups. TV viewing and dietary intake decreased significantly in both groups. Body weight did not change, but both groups had significant decreases in percent body fat (3-mo to 6-mo), and waist and hip circumference (baseline to 6-mo) over time. CONCLUSIONS: Participants in both the TV Commercial Stepping and Walking groups had favorable changes in daily steps, TV viewing, diet, and anthropometrics. PA can be performed while viewing TV commercials and this may be a feasible alternative to traditional approaches for increasing daily steps in overweight and obese adults. TRIAL REGISTRATION: This study is registered at ClinicalTrials.gov, NCT01342471.

Effects of body mass index on step count accuracy of physical activity monitors.

BACKGROUND: Activity monitors are widely used in research, and are currently being used to study physical activity (PA) trends in the US and Canada. The purpose of this study was to determine if body mass index (BMI) affects the step count accuracy of commonly used accelerometer-based activity monitors during treadmill walking. METHODS: Participants were classified into BMI categories and instructed to walk on a treadmill at 3 different speeds (40, 67, and 94 m·min(-1)) while wearing 4 accelerometer-based activity monitors (ActiGraph GT1M, ActiCal, NL-2000, and StepWatch). RESULTS: There was no significant main effect of BMI on pedometer accuracy. At the slowest speed, all waist-mounted devices significantly underestimated actual steps (P < .001), with the NL-2000 recording the greatest percentage (72%). At the intermediate speed, the ActiGraph was the least accurate, recording only 80% of actual steps. At the fastest speed, all of the activity monitors demonstrated a high level of accuracy. CONCLUSION: Our data suggest that BMI does not greatly affect the step-counting accuracy of accelerometer-based activity monitors. However, the accuracy of the ActiGraph, ActiCal, and NL-2000 decreases at slower speeds. The ankle-mounted StepWatch was the most accurate device across a wide range of walking speeds.

Evaluation of activity monitors in controlled and free-living environments.

UNLABELLED: Numerous studies have established the usefulness of pedometers and accelerometers as objective activity monitors. Under laboratory conditions, some of these devices have been shown to provide accurate and reliable measures of steps. However, limited data exist on the performance of these devices under free-living conditions. PURPOSE: This study aimed 1) to compare the effects of speed and body mass index (BMI) on the step count accuracy of five different accelerometer-based activity monitors and a pedometer during treadmill walking, 2) to compare the performance of these devices in a free-living environment, and 3) to compare the step counts of three generations of a single device (ActiGraph) against a criterion method. METHODS: Fifty-six individuals wore six activity monitors while performing treadmill walking (40, 54, 67, 80, and 94 m·min⁻¹) and during 1 d of free-living activity. The criterion measure of steps during treadmill walking was investigator-determined steps, whereas the criterion measure of steps during the free-living condition was the StepWatch. RESULTS: BMI had no effect on step count accuracy during treadmill walking. The StepWatch, activPAL™, and the AG7164 were the most accurate across all speeds, whereas the remaining devices were only accurate at 67 m·min⁻¹ and faster. In the free-living environment, the AG7164 recorded 99.5% ± 27% (mean ± SD) of StepWatch-determined steps. CONCLUSIONS: We demonstrated that BMI does not affect the step output of commonly used activity monitors during walking. In addition, 67 m·min⁻¹ seems to be the minimum speed required for accurate step counting, at least for most waist-mounted activity monitors. Finally, the StepWatch, AG7164, and activPAL™ were the most accurate devices on the TM, but only the AG7164 yielded comparable step counts to the StepWatch in the free-living environment.

Adiponectin is associated with risk of the metabolic syndrome and insulin resistance in women.

The purpose of this study was to examine insulin resistance, markers of the metabolic syndrome, cardiovascular disease (CVD) risk, and serum adiponectin concentrations in pre-menopausal Hispanic and non-Hispanic White (NHW) women. This cross-sectional study examined 119 pre-menopausal women (76 Hispanic, 45 NHW) for markers of the metabolic syndrome (ATP III criteria), level of insulin resistance (HOMA-IR), CVD risk factors, and serum total adiponectin concentrations. Relationships between variables were assessed using Student's t-tests, Pearson's and Spearman's Rho correlations, and stepwise multiple regression analysis. Hispanic women had significantly lower adiponectin concentrations than NHW women, even after controlling for body fat (%) (P < 0.01). Number of markers of the metabolic syndrome was inversely related to total adiponectin concentration for all women combined and for NHW women (P ≤ 0.04), but not for Hispanic women. Insulin resistance was inversely related to adiponectin for all women and for NHW women (P < 0.01), but not significantly associated in Hispanic women. Adiponectin concentration was not significantly associated with number of CVD risk factors for these women. While adiponectin was associated with markers of metabolic syndrome and insulin resistance for all women of this study and despite lower adiponectin concentrations for Hispanic women than NHW women, the role of adiponectin to these conditions among Hispanics remains unclear. There was no significant association between adiponectin and CVD risk for these women. Future research should focus on understanding mechanisms for up-regulating adiponectin secretion and if ethnicity affects adiponectin gene expression and secretion given the beneficial effects derived from elevated adiponectin levels.

Energy cost of stepping in place while watching television commercials.

INTRODUCTION: Modifying sedentary television (TV) watching behaviors by stepping in place during commercials (TV commercial stepping) could increase physical activity and energy expenditure. PURPOSE: The study's purpose was to determine the energy cost of TV commercial stepping and to quantify the amount of activity (number of steps and minutes) performed during 1 h of TV commercial stepping. METHODS: In part 1, 23 adults (27.8 ± 7.0 yr) had their energy expenditure measured at rest, sitting, standing, stepping in place, and walking at 3.0 mph on the treadmill. The second part of this study involved 1 h of sedentary TV viewing and 1 h of TV commercial stepping. Actual steps were counted with a hand tally counter. RESULTS: There were no differences (P = 0.76) between the caloric requirements of reclining rest (79 ± 16 kcal·h(-1)) and sedentary TV viewing (81 ± 19 kcal·h(-1)). However, stepping in place (258 ± 76 kcal·h(-1)), walking at 3.0 mph on the treadmill (304 ± 71 kcal·h(-1)), and 1 h of TV commercial stepping (148 ± 40 kcal·h(-1)) had a higher caloric requirement than either reclining rest or sedentary TV viewing (P < 0.001). One hour of TV commercial stepping resulted in an average of 25.2 ± 2.6 min of physical activity and 2111 ± 253 steps. CONCLUSIONS: Stepping in place during commercials can increase the energy cost and amount of activity performed during TV viewing.

A review of different behavior modification strategies designed to reduce sedentary screen behaviors in children.

Previous research suggests that reducing sedentary screen behaviors may be a strategy for preventing and treating obesity in children. This systematic review describes strategies used in interventions designed to either solely target sedentary screen behaviors or multiple health behaviors, including sedentary screen behaviors. Eighteen studies were included in this paper; eight targeting sedentary screen behaviors only, and ten targeting multiple health behaviors. All studies used behavior modification strategies for reducing sedentary screen behaviors in children (aged 1-12 years). Nine studies only used behavior modification strategies, and nine studies supplemented behavior modification strategies with an electronic device to enhance sedentary screen behaviors reductions. Many interventions (50%) significantly reduced sedentary screen behaviors; however the magnitude of the significant reductions varied greatly (-0.44 to -3.1 h/day) and may have been influenced by the primary focus of the intervention, number of behavior modification strategies used, and other tools used to limit sedentary screen behaviors.

Treadmill workstations: a worksite physical activity intervention in overweight and obese office workers.

PURPOSE: To determine if a treadmill-workstation (TMWS) increases physical activity (PA) and influences anthropometric, body composition, cardiovascular, and metabolic variables in overweight and obese office-workers. METHODS: Twelve (mean age= 46.2 ± 9.2 years) overweight/obese sedentary office-workers (mean BMI= 33.9 ± 5.0 kg·m-2) volunteered to participate in this 9-month study. After baseline measurements of postural allocation, steps per day, anthropometric variables, body composition, cardiovascular, and metabolic variables, TMWS were installed in the participants' offices for their use. Baseline measurements were repeated after 3 and 9 months. Comparisons of the outcome variables were made using repeated-measures ANOVAs or nonparametric Friedman's Rank Tests. RESULTS: Between baseline and 9 months, significant increases were seen in the median standing (146-203 min·day-1) and stepping time (52-90 min·day-1) and total steps/day (4351-7080 steps/day; P < .05). Correspondingly, the median time spent sitting/lying decreased (1238-1150 min·day-1; P < .05). Using the TMWS significantly reduced waist (by 5.5 cm) and hip circumference (by 4.8 cm), low-density lipoproteins (LDL) (by 16 mg·dL-1), and total cholesterol (by 15 mg·dL-1) during the study (P < .05). CONCLUSION: The additional PA energy expenditure from using the TMWS favorably influenced waist and hip circumferences and lipid and metabolic profiles in overweight and obese office-workers.

Validation of the Cosmed Fitmate for prediction of maximal oxygen consumption.

The main purpose of this study was to assess the validity of the Cosmed Fitmate (FM) for the prediction of maximal oxygen consumption (VO(2)max). In addition, this study examined whether measuring submaximal VO(2), rather than predicting it, can improve upon the prediction of VO(2)max. Participants for the study were 48 young to middle-age adults (32 men, 16 women), with a mean age of 31 yr. Each participant completed a submaximal and maximal treadmill test on 2 separate occasions. During the submaximal test, VO(2)max was predicted using the FM. This device extrapolates the linear regression relating heart rate (HR) and measured VO(2) at submaximal work rates to age-predicted maximum HR (HR = 220 - age). The criterion measure was obtained using a graded, maximal treadmill test, with VO(2) measured by the Douglas bag (DB) method. There was no significant difference between VO(2)max predicted by the FM and VO(2)max measured by the DB method. The results of this study showed that a strong positive correlation (r = 0.897) existed between VO(2)max predicted by the FM and VO(2)max measured by the DB method, with a standard error of the estimate (SEE) = 3.97 ml·kg(-1)·min(-1). There was a significant difference in VO(2)max predicted by the American College of Sports Medicine (ACSM) metabolic equations and VO(2)max measured by the DB method (p = 0.01). The correlation between these variables was r = 0.758 (SEE = 5.26 ml·kg(-1)·min(-1)). These findings indicate that a small, portable, and easy-to-use metabolic system provides valid estimates of VO(2)max, and improves upon predictive accuracy, compared to using generalized ACSM metabolic equations.