Thursday-Abstracts

Thursday, May 30, 2013
S262 Vol. 45 No. 5 Supplement
METhOds: Activity data were collected during a longitudinal bone growth study,
contrasting gymnasts (GYM: non-seasonal OPA) vs. non-gymnasts (NON: seasonal
OPA). Activity-specific OPA for each calendar month was recorded using semi-annual
questionnaires. Total OPA monthly means (MOPA) and annual means (AOPA) were
calculated. For individual subjects, MOPA and AOPA means, standard deviations (sd)
and coefficients of variation (CV, sd/mean) were calculated; similar group statistics
were calculated for GYM, NON and ALL (GYM + NON).
rEsuLTs: OPA data were analyzed for 59 girls (27 GYM, 32 NON), aged 8-17 yrs.
AOPA group means were as follows: ALL 8.5 h/wk (sd 5.3); GYM 12.6 h/wk (sd 4.3);
NON 5.1 h/wk (sd 3.4). For MOPA, mean intra-subject CVs (INTRACV) were: ALL
52%, GYM 35% and NON 66%. For AOPA, mean inter-subject CVs (INTERCV)
were: ALL 63%, GYM 34%, NON 66%. Thus, monthly intra-individual variability
(MOPA INTRACV) was high and similar to annual inter-individual variability (AOPA
INTERCV).
suMMary: For females in late childhood and adolescence, MOPA differs widely
from month-to-month and may not reflect annual VPA exposure. Thus, use of
“snapshot” activity sampling may weaken associations with biological properties of
interest, as intra-individual variation across time rivals inter-individual differences. For
growing females, use of general AOPA records may be more appropriate for studies of
skeletal adaptation and maintenance than extrapolation from more specific “snapshot”
sampling.
1380 May 30, 2:00 PM - 2:15 PM
assessment of Light-Intensity activities and sedentary
Behaviors using Multiple Measurement devices
Nathanael Meckes, Laura R. Brittain, Barbara E. Ainsworth,
FACSM. Arizona State University, Phoenix, AZ.
(No relationships reported)
PurPOsE: To examine the accuracy of three measurement devices (ActiGraph
GT3x+, ActivPAL, and Sensewear Armband) in assessing sedentary behavior and
light-intensity physical activity (PA) against a referent measure of oxygen uptake
(Oxycon Mobile).
METhOds: 16 adults (8 males, 8 females) wore the four measurement devices
while performing 7 activities (walking at 1.0 mph, 1.5 mph, 2.0 mph, cleaning a
kitchen, standing and reading, typing at a computer, and playing board games)
classified in the 2011 Compendium of Physical Activities between 1.2 and 1.8 METs
or were unmeasured activities that were light-intensity in nature. Activities were
classified as either sedentary or light-intensity according to the oxygen uptake, and
the other measurement devices were compared against oxygen uptake for accuracy
in measurement. Mean absolute percent error (MAPE) was used to calculate
measurement accuracy.
rEsuLTs: The Sensewear Armband measured treadmill walking accurately (0%
MAPE), but activities requiring arm movement were less accurate (typing - 50.00%
MAPE). The ActivPAL also measured treadmill walking accurately (1.88% MAPE)
but misclassified standing activities (reading - 86.88% MAPE). The ActiGraph GT3X+
misclassified activities with slow (