| The accurate and reliable assessment of physical activity is necessary
for any research study where physical activity is either an outcome
measure or an intervention. The aim of this review is to examine the
use of objective measurement techniques for the assessment and interpretation
of children's physical activity. Accurate measurement of children's
activity is challenging, as the activity is characteristically sporadic
and intermittent, consisting of frequent, short bouts. Objective measures
of physical activity include heart rate telemetry, pedometry and accelerometry,
and each of these methods has strengths and limitations. Heart rate
is suited to the measurement of sustained periods of moderate and
vigorous activity, pedometry provides a valid measure of total activity,
and accelerometry provides a valid measure of total activity as well
as the pattern and intensity of activity. As the weaknesses of heart
rate and accelerometry for the assessment of activity are not inter-correlated,
a combination of the two methods may be more accurate than either
method alone. Recent evidence suggests that the Actiheart, an integrated
accelerometer and heart rate unit, provides a more accurate prediction
of children's energy expenditure than either heart rate or accelerometry
alone. However, the cost of the Actiheart is prohibitive for large-scale
studies. The pedometer is recommended when only the total amount of
physical activity is of interest. When the intensity or the pattern
of activity is of interest, accelerometry is the recommended measurement
tool.
KEY
WORDS: Activity pattern, heart rate, pedometry, accelerometry.
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