Wayne Brewer

Validity of Fitbit’s active minutes as compared with a research-grade accelerometer and self-reported measures

Objectives The main purpose of the study was to assess the validity between the Fitbit and ActiGraph GT3X+ accelerometer. The specific aims were to determine the: (1) concurrent validity between the various models of the Fitbit and the GTX3+ accelerometer as the criterion measure for: number of steps and active minutes averaged over a single-day and 7-day period; (2) validity of the two devices with the International Physical Activity Questionnaire (IPAQ) for the number of daily active minutes performed. Methods Fifty-three subjects wore a Fitbit and ActiGraph concurrently for 7 days. Data were analysed using correlation coefficients, t-tests to assess mean comparisons and Bland-Altman plots to determine agreement between the Fitbit and the ActiGraph. Results The correlations between the Fitbit and ActiGraph for steps per day and per 7 days were r=0.862 and 0.820, respectively with significant mean differences between both devices. Bland-Altman analyses revealed agreement between the Fitbit and the ActiGraph for 7-day active minutes only. The correlations between the Fitbit and ActiGraph for active minutes per day and per 7 days were r=0.695 and r=0.658, respectively, with no significant mean differences between both devices. No significant correlations were found between the IPAQ and the other two devices. Conclusions The data produced by the Fitbit were consistent with the ActiGraph when the means of each device were compared over the 1-day and 7-day time periods. However, Bland-Altman analyses revealed that the Fitbit agreed with the ActiGraph when used to measure physical activity levels over a 7-day span only.

Are There Relationships between Perceived and Actual Measures of Physical Fitness and Health for Healthy Young Women

The purposes were to assess the bivariate and multivariate relationships among the subdomains of physical self-concept, self-esteem, and objective measures of physical fitness in young healthy fema...

A comparison of work-related physical activity levels between inpatient and outpatient physical therapists: an observational cohort trial.

BackgroundPhysical therapists (PTs) work in a variety of healthcare settings with varied levels of physical activity demands placed on them. The purpose of this study is to compare the physical activity (PA) levels between PTs in inpatient versus outpatient environments for one work week using a cross-sectional design.MethodsSixty-one PTs (30 inpatient, 31 outpatient) wore a tri-axial accelerometer and inclinometer for one work-week. The number steps-per-day, PA intensities, energy expenditures and postural positions adopted during the work day were recorded.ResultSignificantly longer amounts of time spent sitting was found for inpatient PTs regardless of the significantly higher number of steps-per-day. Outpatient PTs had a higher number of breaks from sedentary activity with those breaks being longer than the inpatient PTs. The percentage of time spent performing moderate-vigorous PA approached significance implying more time was spent performing these types of activities for outpatient PTs. The energy expenditures between the two groups of PTs were not different.ConclusionThis study compared the differences in physical activity levels between physical therapists who worked at inpatient versus outpatient environment as little is known about their activity levels. Inpatient physical therapists took more steps per day than outpatient physical therapists but the outpatient physical therapists were less sedentary and took more frequent and longer breaks from sedentary activities. The energy expenditures were similar between both types of therapists and this may be reflective of the gender and bodyweight differences between the groups that equalizes the energy expenditures. The findings of this study suggests that there are differences in the physical activity demands between inpatient and outpatient physical therapists. The results of this study may serve dual purposes: (1) employers may be able to more accurately describe the expected physical activity demands to future employees; (2) individuals tasked with preparing PTs to physically manage their work environment can outline training programs that are diverse based on the specific work environment of PTs.

Criterion Validity and Sensitivity to Change of a Pediatric Bioelectrical Impedance Analysis Scale in Adolescents

BACKGROUND BMI measures are often used to infer body composition. Bioelectrical impedance analysis (BIA) is a more accurate way to estimate percent body fat (%BF), particularly when screening children who may be overweight. The aim of this study was to determine the validity, sensitivity to change, and diagnostic value of a BIA scale designed specifically for adolescents. METHODS One hundred twelve adolescents had their body fat assessed using both BIA and dual-energy X-ray absorptiometry (DEXA). Mean difference and limits of agreement (LoA) were calculated for criterion validity. Intraclass correlation coefficients (ICCs) were calculated for sensitivity to change. Sensitivity/specificity for each classification was also assessed. Data from 46 returning adolescents (6-8 months later) were then used to assess sensitivity to change of BIA compared with DEXA. RESULTS ICC for absolute agreement (range) comparing BIA and DEXA was 0.78 (0.48-0.88). The mean difference between the BIA %BF reading and DEXA was -4.05% (LoA = [4.80%, -12.90%]). Sensitivity and specificity values for the underfat, healthy, overfat, and obese classifications were 0.0/0.89, 0.79/0.46, 0.28/0.92, and 0.5/1.00, respectively. ICC for absolute agreement over time between the BIA %BF and the DEXA %BF was 0.71 (0.242-0.866). CONCLUSIONS The Tanita BF-689 demonstrated poor-good agreement with DEXA when measuring %BF, poor-moderate agreement when measuring change in %BF over time, high sensitivity for classification into the healthy category and high specificity for classification into the underfat/overfat/obese categories. Compared to DEXA, the BF-689 is accurate, accessible, and efficient in classifying adolescents based on %BF.

Can metabolic function and physical fitness improve without weight loss for inactive, obese, Hispanic adolescents? A feasibility study

ABSTRACT Introduction: A case series that examines the effects of a 12-week combined resistance and aerobic training program for four sedentary obese, Hispanic adolescents without weight loss. Subjects/Methods: Baseline and post-intervention anthropometric, metabolic and physical fitness measures were obtained. Body composition, hepatic, visceral, and intramuscular fat contents were analyzed via imaging. Fasting levels of alanine transaminase (ALT), insulin, glucose, free fatty acids, triglycerides, high- and low-density lipoproteins (LDL), and C-reactive protein were obtained via blood samples. Results: Two subjects decreased their glucose levels by 1.86% and 4.06%. Subjects 1, 3, and 4 increased their lean body mass by 4.12%, 9.70%, and 5.48%. ALT was reduced 13.0%, 16.0%, and 35.7% for subjects 2, 3, and 4, respectively. LDLs were reduced by 37.7%, 4.5%, and 7.5% for subjects 1, 2, and 3. Triglycerides were reduced by 25.4%, 37.8%, and 4.6% for subjects 1, 2, and 3. Visceral fat reductions by 16.5%, 14.2%, and 13.0% occurred for subjects 1, 2, and 3. C-reactive protein was reduced for subjects 1, 2, and 3 by 19.4%, 16.3%, and 32.0%. Conclusion: Expected directions of change were made for most indicators of metabolic function and body composition, but measures of physical fitness improved for all four subjects.

Muscular and Cardiorespiratory Fitness in Homeschool versus Public School Children

PURPOSE The growth and unregulated structure of homeschooling creates an unknown population in regard to muscular and cardiorespiratory fitness. The purpose of this research was to compare muscular and cardiorespiratory fitness between elementary school aged homeschool and public school children. METHOD Homeschool children ages 8-11 years old (n = 75) completed the curl-up, 90° push-up, and Progressive Aerobic Capacity Endurance Run (PACER) portions of the FitnessGram to assess abdominal and upper body strength and endurance as well as cardiorespiratory fitness. Comparisons to public school children (n = 75) were made using t tests and chi-square tests. RESULTS Homeschool children showed significantly lower abdominal (t(148) = -11.441, p < .001; χ2 (1) = 35.503, p < .001) and upper body (t(148) = -3.610, p < .001; χ2 (1) = 4.881, p = .027) strength and endurance. There were no significant differences in cardiorespiratory fitness by total PACER laps (t(108) = 0.879, p = .381) or estimated VO2max (t(70) = 1.187, p = .239; χ2 (1) = 1.444, p = .486). CONCLUSION Homeschool children showed significantly lower levels of both abdominal and upper body muscular fitness compared with their age and gender matched public school peers but no difference in cardiorespiratory fitness.

The Effects of a Group Exercise Program on the Weight Management of Obese Women in a Publicly Funded Healthcare System

Women from minority backgrounds have the highest prevalence rates of obesity and physical inactivity. A prospective cohort pilot study was conducted to investigate the effectiveness of a 12-week intervention that consisted of a group exercise program with educational reinforcement to enhance physical activity, physical fitness and physical self-worth. Twenty-three minority women completed the intervention. The participants were obese, had a neuromusculoskeletal impairment, chronic medical condition or disability that required outpatient physical therapy services. The results of this study revealed no significant reduction in body-weight but improvement was made for functional cardiovascular endurance (p < .005), lower and upper body strength (p < .006 and .042, respectively), physical self-worth (p < .0005) and moderate physical activity (p < .009). Despite the absence of weight-loss for these participants, the exercise and education intervention provided improvements in levels of physical fitness, physical self-worth and engagement in health enhancing physical activity.