Levels and patterns of self-reported and objectively-measured free-living physical activity among prostate cancer survivors: A prospective cohort study.

BACKGROUND: No prior study has measured or compared self-reported and objectively measured physical activity trajectories in prostate cancer survivors before and after treatment. METHODS: Clinically localized prostate cancer patients treated with radical prostatectomy were recruited between 2011 and 2014. Of the 350 participants enrolled at the main site, 310 provided self-reported physical activity at baseline before radical prostatectomy, and 5 weeks, 6 months, and 12 months after radical prostatectomy. A subset of participants (n = 81) provided objectively measured physical activity at all study time points by wearing an accelerometer for 7 days each. Changes in activity over time were compared using Friedman's test. Agreement between self-reported and objective measures was evaluated using Spearman's rank correlation coefficient. RESULTS: Self-reported moderate-to-vigorous physical activity was high at baseline (median, 32.1 min/day), followed by a decline at 5 weeks (median, 15.0 min/day) and a recovery at 6 and 12 months (median, 32.1-47.1 min/day). In contrast, objectively measured moderate-to-vigorous physical activity was low at all 4 time points (median, 0.0-5.2 min/day), with no overall change across study assessments (global P = .29). Self-reported moderate-to-vigorous physical activity tended to be more closely related to objectively measured light-intensity physical activity (ρ = 0.29-0.42) than to objectively measured moderate-to-vigorous physical activity (ρ = 0.07-0.27, P = .009-.32). CONCLUSIONS: In our population of prostate cancer survivors with critically low moderate-to-vigorous physical activity levels, self-reported measures greatly overestimated moderate-to-vigorous physical activity and may have been more reflective of light-intensity physical activity. Because cancer survivor guidelines are derived from self-reported data, our findings may imply that intensities of physical activity below moderate, such as light intensity, still have health benefits.

Prediction of maximal oxygen consumption using the Young Men's Christian Association-step test in Korean adults.

PURPOSE: To develop accurate and practical prediction models of maximal oxygen consumption (VO2max) using the Young Men's Christian Association (YMCA)-step test in South Korean adults. METHODS: In total, 568 adults (20-66 years) were included in this study. To develop and cross-validate prediction models of VO2max, the total sample was divided into 80% training and 20% testing using a simple random sampling method. VO2max was measured using the maximal-graded exercise treadmill test. Sex, age, 1-min recovery heart rate, body weight, and height were measured as potential predictors. Each test was conducted within a 2- to 3-day interval, ensuring sufficient rest. Preliminary prediction models were developed from training datasets, which were cross-validated using regression analyses and/or repeated-measures analysis of variance. The accuracy of prediction models was evaluated using R2, standard error of estimate (SEE), and mean difference (MD) against a criterion-measured VO2max. RESULTS: The average age and VO2max were 43.5 ± 12.9 years and 39.1 ± 7.5 ml/kg/min, respectively. For model development, three practical models with acceptable accuracy were developed (R2 = 0.56-0.61; SEE = 4.74-5.01). For model cross-validation, significant relationships between the criterion-measured and predicted VO2max were observed in all three models (R2 = 0.56-0.61; SEE = 4.62-4.88). The difference between criterion-measured and predicted VO2max was not significant in the models (MD =- 0.03 to - 0.14). CONCLUSIONS: The prediction models included 3-5 variables as significant predictors of VO2max and had acceptable accuracy in a large sample of South Korean adults. The selected models provide a simple and practical method to estimate VO2max using the YMCA-step test for South Korean adults.

Association between objectively measured sedentary behavior and a criterion measure of obesity among adults.

OBJECTIVE: Results of published studies on the association between sedentary behavior (SB) and obesity are inconsistent, possibly due to reliance on subjective measures of SB and inappropriate measures of obesity. The aim of this study was to examine the relationship between objectively measured SB and criterion-measured obesity among adults. METHODS: A total of 2284 adults (≥18 years) from the 2003 to 2004 National Health and Nutrition Examination Survey were included in the analysis. The participants were categorized into tertiles of SB time measured by accelerometry. Obesity was determined using body fat percentage measured by dual-energy X-ray absorptiometry. RESULTS: Increased SB was significantly associated with obesity when controlling for covariates related to demographics, health behaviors, energy intake, and physical activity (P for trends = .025). CONCLUSIONS: This finding suggests that avoiding SB may be beneficial for lowering the risk of obesity in adults.

Motivational signage increases stair usage on a Hispanic serving institution.

Objective: Stair climbing is considered a good physical activity. Motivational signage has been successful in promoting stair usage in various settings. This study was to investigate the effects of motivational signage on stair usage in a Hispanic serving institution. Participants: A total of 31,067 pedestrians were observed from February to March 2013. Methods: Stair usage was monitored for 9 h per day each week at phase 1 (baseline), 2 (intervention), and 3 (post-intervention). Results: Overall, participants' stair usage was higher during phase 2 (49.0%) and phase 3 (48.0%), compared with phase 1 (39.7%). The participants during phase 2 and 3 were more likely to use the stairs compared to participants during phase 1, regardless of floor level (3-story or 4-story building), status (student or staff/faculty), and time of day (7:30-10:29, 10:30-13:29, or 13:30-16:30) (p < .001). Conclusion: Motivational signage can effectively encourage more stair usage, and hence promote healthy behavior in a predominantly Hispanic-serving institution.

Development and Cross-Validation of Equation for Estimating Percent Body Fat of Korean Adults According to Body Mass Index.

BACKGROUND: Using BMI as an independent variable is the easiest way to estimate percent body fat. Thus far, few studies have investigated the development and cross-validation of an equation for estimating the percent body fat of Korean adults according to the BMI. The goals of this study were the development and cross-validation of an equation for estimating the percent fat of representative Korean adults using the BMI. METHODS: Samples were obtained from the Korea National Health and Nutrition Examination Survey between 2008 and 2011. The samples from 2008-2009 and 2010-2011 were labeled as the validation group (n=10,624) and the cross-validation group (n=8,291), respectively. The percent fat was measured using dual-energy X-ray absorptiometry, and the body mass index, gender, and age were included as independent variables to estimate the measured percent fat. The coefficient of determination (R2), standard error of estimation (SEE), and total error (TE) were calculated to examine the accuracy of the developed equation. RESULTS: The cross-validated R2 was 0.731 for Model 1 and 0.735 for Model 2. The SEE was 3.978 for Model 1 and 3.951 for Model 2. The equations developed in this study are more accurate for estimating percent fat of the cross-validation group than those previously published by other researchers. CONCLUSION: The newly developed equations are comparatively accurate for the estimation of the percent fat of Korean adults.