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Official Journal of the American College of Sports Medicine<br />

METhOds: Fifty-three women wore the SenseWear® Mini armband for 7-days at<br />

week 18 and 35 of pregnancy. All MVPA completed in at least 10-, 20-, or 30-minute<br />

bouts were summed. Total MET-minutes for the week were summed to reflect total PA<br />

including sedentary and light activity. GWG was calculated as the difference of prepregnancy<br />

weight from measured weight at week 35. A one-way ANOVA evaluated the<br />

differences in GWG for women meeting prenatal PA recommendations (sufficient PA;<br />

>150 min MVPA per week), those with insufficient PA (1-149 min), and none (0 min)<br />

for all 3 bout lengths. Total MET-minutes per week were compared with independent<br />

t-tests for women gaining within or in excess of the IOM guidelines.<br />

rEsuLTs: Twenty-six (49%) women gained in excess of IOM guidelines. A trend<br />

for MVPA completed in ≥ 10 min bouts was identified: sufficient PA (11.3 ± 4.3<br />

kg), insufficient PA (13.3 ± 5.1 kg), and none (18.9 ± 4.2 kg) (P = 0.056). GWG<br />

was not significantly different when PA was analyzed in at least 20 or 30 min bouts.<br />

Participants who gained within IOM guidelines had significantly higher MET-minutes<br />

at week 18 than women who gained in excess (11,068 vs. 10,414, respectively;<br />

P=0.032). PA at week 35 was not significantly related to weight gain.<br />

CONCLusION: Longer sustained activity (> 20 or 30 min bouts) did not significantly<br />

affect GWG, whereas moderate PA completed in ≥10-minute bouts may be a beneficial<br />

strategy to promote healthy GWG. Total activity (e.g. total MET-minutes per week)<br />

had a significant favorable relationship with GWG. Future work should address<br />

reducing sedentary time and increasing PA in at least 10-minute bouts.<br />

1429 Board #21 May 30, 2:00 PM - 3:30 PM<br />

Objectively Measured Total accelerometer Counts and<br />

MVPa: Contrasting relationships with Biomarkers using<br />

2003 - 2006 NhaNEs<br />

Dana L. Wolff1 , Eugene C. Fitzhugh1 , David R. Bassett,<br />

FACSM1 , James R. Churilla, FACSM2 . 1University of Tennessee,<br />

Knoxville, TN. 2University of North Florida, Jacksonville, FL.<br />

(No relationships reported)<br />

PurPOsE: To contrast the associations of objectively measured moderate-tovigorous<br />

physical activity (MVPA) and total accelerometer counts with biomarkers in<br />

a representative sample of U.S. adults.<br />

METhOds: Data from the 2003 – 2006 NHANES were used for this analysis. The<br />

sample included adults ≥ 20 y, not pregnant or lactating, who had self-reported PA and<br />

≥ 4 d of accelerometer data with ≥ 10 h wear time (N = 5668). MVPA was defined<br />

as the mean minutes with counts ≥ 2020 using a 10-min bout criterion on valid days.<br />

Total accelerometer counts represented the mean total counts acquired on valid days.<br />

Biomarkers included: blood pressure, body mass index (BMI), waist circumference,<br />

triceps and subscapular skinfolds, cholesterol, triglyceride, glycohemoglobin, plasma<br />

glucose, C-peptide, insulin, C-reactive protein, and homocysteine. Simultaneous<br />

regressions were conducted in which each biomarker was regressed on MVPA and total<br />

accelerometer counts per day independently while adjusting for relevant covariates.<br />

rEsuLTs: When compared to MVPA, total accelerometer counts per day displayed<br />

stronger associations with the following biomarkers: BMI, waist circumference, triceps<br />

skinfolds, subscapular skinfolds, HDL, triglycerides, plasma glucose, C-peptide,<br />

insulin, C-reactive protein, and homocysteine (adj. Wald F = 9.04 – 97.41, P <<br />

0.05 – 0.0001). Only one biomarker, glycohemoglobin, had stronger associations<br />

with MVPA (F = 6.67, P ≤ 0.05) than total accelerometer counts (F= 0.87, P > 0.05).<br />

After adjusting for BMI and other relevant covariates, total accelerometer counts<br />

remained more strongly associated with cardiometabolic biomarkers than MVPA, with<br />

glycohemoglobin found to have no relationship with either PA variable.<br />

CONCLusIONs: Total accelerometer counts per day were more robustly associated<br />

with various cardiobiomarkers than MVPA. Thus, using total accelerometer counts per<br />

day may provide a better estimate of the strength of the relationship between PA and<br />

biomarkers.<br />

1430 Board #22 May 30, 2:00 PM - 3:30 PM<br />

reliability of Peak stepping Cadences using Generalizability<br />

Theory<br />

Minsoo Kang, FACSM1 , Youngdeok Kim1 , David A. Rowe,<br />

FACSM2 . 1Middle Tennessee State University, Murfreesboro, TN.<br />

2University of Strathclyde, Glasgow, United Kingdom.<br />

(No relationships reported)<br />

Recent studies have introduced the concept of using peak stepping cadences to<br />

quantify the intensity of ambulatory physical activity using step-count data. Although<br />

this is a novel approach and has demonstrated evidence of validity (Tudor-Locke<br />

et al., 2011), the reliability of peak stepping cadences associated with measurement<br />

conditions (e.g., a number of monitoring days) has not been addressed.<br />

PurPOsE: The purpose of this study was to establish the minimum number of days<br />

required for reliably estimating peak stepping cadence among adults.<br />

METhOds: Data from the 2005-2006 National Health and Nutrition Examination<br />

Survey were analyzed. A total of 1,300 adults (> 17 yr) with valid accelerometer<br />

step-count data (defined as 7 days with ≥ 10 hr wear time) were included. One-min,<br />

30-min, and 60-min peak cadences were obtained across 7 days. Generalizability (G)<br />

theory with unbalanced two-facet nested design [i.e., person x (days: type of days)]<br />

was applied for each peak stepping cadence, with days nested within weekend or week<br />

Vol. 45 No. 5 Supplement S273<br />

days. G-studies were performed to quantify the percentage of variance associated<br />

with each facet and interaction in the model. Follow-up D-studies were performed to<br />

determine the optimal combinations of number of days for weekend and week days to<br />

achieve a desirable reliability coefficient (G ≥ .80).<br />

rEsuLTs: The G-study showed that the relative magnitudes of variances attributed<br />

to differences between weekend and week days were relatively low (i.e., < 10%) for<br />

all peak stepping cadence measures; however, the D-study indicated that at least 1<br />

weekend day should be included in the monitoring period in addition to 4 week days<br />

for 1-min peak cadence. For 30-min and 60-min peak cadences, at least 5 week days,<br />

or the combinations of 1 weekend day and 3 week days, or 2 weekend days and 2 week<br />

days would be necessary for reliable measures of peak stepping cadences.<br />

CONCLusIONs: This study provides empirical evidence of the number of required<br />

monitoring days to obtain reliable measures of peak stepping cadences based on a<br />

large, nationally-representative sample of US adults. The guidelines suggested in<br />

this study could be applied in future research as a reference for monitoring periods to<br />

obtain a reliable measure of peak stepping cadences.<br />

1431 Board #23 May 30, 2:00 PM - 3:30 PM<br />

Physical activity and Energy Expenditure Measurements<br />

using sensewear armband, actiheart and actigraph in<br />

adults<br />

Dharini M. Bhammar, Brandon J. Sawyer, Wesley J. Tucker,<br />

Julian C. Baez, Glenn A. Gaesser, FACSM. Arizona State<br />

University, Phoenix, AZ.<br />

(No relationships reported)<br />

PurPOsE: Our aim was to estimate validity and reliability of the Sensewear<br />

Armband (SWA), Actiheart (AH) and Actigraph GT3X+ (AG) monitors for assessing<br />

physical activity (PA) levels and energy expenditure (EE) in adults.<br />

METhOds: Twenty-four adults (ages 29 ± 9 years; BMI: 23.9 ± 3.7 kg/m 2 )<br />

underwent two identical 96-min exercise sessions, at least 24 h apart, including<br />

walking, cycling, arm cranking, and simulated activities of daily living. Each activity<br />

lasted 8 min with a 4-min seated rest period between activities. EE and PA levels were<br />

measured by indirect calorimetry using the Oxycon Mobile TM (OM) and estimated by<br />

four activity monitors: SWA (version 7.0), AH software versions 2.0 (AH 2.0) and 4.0<br />

(AH 4.0) and AG. Linear mixed models and intraclass correlation coefficients (ICC)<br />

were used for statistical analysis.<br />

rEsuLTs: Total EE for 96-min was not significantly different between SWA and OM<br />

(P = 0.084). Total EE for AH 4.0, AH 2.0 and AG was significantly lower than OM<br />

by 62 ± 63 kcal (P = 0.015), 110 ± 47 kcal (P < 0.001) and 129 ± 60 kcal (P < 0.001)<br />

respectively. During steady-state periods (min 4 to 7 of each activity), only AH 4.0<br />

accurately predicted walking EE (P = 1.000) and only AH 2.0 accurately predicted<br />

jogging EE (P = 0.704). AH 2.0 and AH 4.0 accurately estimated time spent in light<br />

and moderate PA, while only AH 2.0 accurately tracked time spent in vigorous PA.<br />

ICC analysis for OM and the four activity monitors showed high test-retest reliability<br />

for total EE (0.847 to 0.911) and for time spent in moderate to vigorous PA (MVPA;<br />

0.888 to 0.999). ICC analysis for individual activities showed high test-retest reliability<br />

for walking at 3 mph (0.824 to 0.943), moderate-to-high reliability for walking at 4<br />

mph, jogging at 5 mph, sweeping, and loading and unloading boxes (0.506 to 0.989),<br />

and low to moderate reliability for cycling, arm cranking and seated rest (0.005 to<br />

0.738).<br />

CONCLusIONs: The SWA provides valid estimates for total EE, while the AH<br />

provides valid estimates for walking and jogging EE. All devices were unreliable<br />

for estimating EE for activities with minimal or variable accelerometer input such<br />

as cycling, arm cranking and activities of daily living. Additionally, only AH 2.0<br />

accurately tracked time spent in MVPA suggesting that it may be the best device for<br />

tracking PA levels.<br />

supported by NIh grant r01 hL091006<br />

1432 Board #24 May 30, 2:00 PM - 3:30 PM<br />

The Context of Physical activity in a representative sample<br />

of adults: Physical activity Measurement survey<br />

Bradley P. Peters, Youngwon Kim, Gregory J. Welk, FACSM,<br />

Sarah M. Nusser, Alicia L. Carriquiry, Miguel A. Calabro,<br />

Jungmin Lee. Iowa State University, Ames, IA.<br />

(No relationships reported)<br />

Numerous studies have sought to assess and evaluate levels of participation in physical<br />

activity (PA) in the population but few studies have provided contextual information<br />

about PA behaviors. This information is needed to better understand and promote PA<br />

in the population. PURPOSE: The purpose of this study was to provide insights on the<br />

purpose and location of accumulating PA in a representative sample of adults ages 21<br />

to 70.<br />

METhOds: Data were obtained from the Physical Activity Measurement Survey<br />

(PAMS), a large field-based study of PA behavior conducted in Iowa. As part of the<br />

study, a representative sample of 1459 Iowa adults from four counties completed a<br />

telephone-administered 24hour PA recall (PAR). Participants were asked to report<br />

participation in different types of PA and to categorize each activity by both purpose<br />

(work, home/family, leisure, sports, education/volunteering) and location (work, home/<br />

<strong>Abstracts</strong> were prepared by the authors and printed as submitted.<br />

<strong>Thursday</strong>, May 30, 2013

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