Validation of methods of measuring physical activity using The Observer
and actiwatch in young children
C.P. Khokhar3, R. Juyall3, U. Dhingra2, A. Dutta2 M. Osmany1, R.E. Black2,
A. Sarkar1, P. Dhingra 1,
P. Verma1, M. Black4, R.M. Angulo-Kinzler5, V.P. Menon1, J. Kumar1, G.S.
Hiremath2 and
S. Sazawal1,2
1Center for Micronutrient Research, Annamalai
University, India
2Department of International Health, Johns Hopkins Bloomberg School
of Public Health, Baltimore USA
3Department of Psychology, Gurukul Kangri University, Haridwar,
India
4University of Maryland, School of Medicine, Baltimore, USA
5Division of Kinesiology, Center for Human Motor Research, University
of Michigan, Michigan, USA
Physical activity and active exploration play an important intermediary
role in a childs developmental processes. Assessing the levels of
physical activity of young children in free living conditions with non-invasive
techniques remains a challenge and studies have used direct observation
of the activity. Direct observation is costly, tedious and accuracy may
decrease as the observation period lengthens. With the advent of smaller
watches using motion sensors, measurement of physical activity has gained
popularity. Validation studies in young children of active watch are lacking.
We validated the Actiwatch activity monitor (Mini- Mitter Company Inc.)
against direct observation using The
Observer® (Noldus Information Technology bv, The Netherlands).
Among 100 children aged 13-76 months from peri urban population in Delhi,
one hour of direct observation of activity at home while wearing an omni
directional sensory monitor on wrist (W) as well as ankle (A) was undertaken.
From direct observation, an overall activity score was estimated using
proportion of time spent in each of the 5 activity levels (gross and .ne
motor), and scoring using Childrens Activity Rating Scale (CARS).
The activity counts from watch were correlated well with the CARS scoring
W: ß 0.18, R2 0.03 (p=0.07), A: ß 0.30, R2 0.09 (p=0.003),
C: ß 0.31, R2 0.099 (p=0.001)] and were not affected by age [W:
ß -0.04, R2: 0.03 (p=0.68), A: ß -0.04, R2 0.09 (p=0.72),
C: ß -0.05, R2 0.10 (p=0.63)]. When children were categorized into
4 quartiles based on CARS score, mean scores with watch across four categories
showed a significant rising trend. Our results indicate that 1 hour observation
CARS score for activity correlates with 1 hour activity counts of W and
A, however, combined scores (W+A) reflected better association, validating
the use of the activity monitors in assessing physical activity in young
children.
Paper presented
at Measuring Behavior 2005
, 5th International Conference on Methods and Techniques
in Behavioral Research, 30 August - 2 September 2005, Wageningen, The
Netherlands.
© 2005 Noldus
Information Technology bv
|