Objective measurement of posture and posture transitions in the pre-school child

Recent evidence suggests that between-individual variation in posture and
posture transitions may have important health consequences in adults. The
early life development of between-individual variation in posture and posture
transitions has not been studied, and the physiological consequences of such
variations in childhood are unknown, largely because of the absence of objective
methods for measuring posture and posture transitions in young children. This
study aimed to examine the objectivemeasurement of posture transitions in preschool
children with the activPALTM monitor (PAL Technologies, Glasgow).
Single-unit activity monitors such as the activPALTM have a limited output,
with data categorized as ‘sit/lie’, ‘stand’ or ‘walk’ and the consequences of
this for measurement of posture transitions in young children are unknown.
Thirty children (mean age 4.1 years) were videoed for 1 h in nursery while
wearing an activPALTM. Video was analysed on a second-by-second basis, with
all postures categorized. From direct observation, time spent was sit/lie 46%;
stand 35%; walk/run 16%; 3% was spent in heterogeneous non-sit/lie/upright
postures (crawl, crouch, and kneel up). Despite these ‘non-standard’ postures
being responsible for a low proportion of time, posture transitions involving
them contributed to 34% of total transitions. There was a significant rank–
order correlation (r = 0.79, p < 0.0001) between the number of posture
transitions measured by activPALTM and by direct observation. ‘Non-standard’
postures in young children are probably not a problem if the aim is to measure
total time sedentary or active, and the activPALTM may measure betweenindividual
variation in transitions adequately in young children. However,non-standard postures may present problems for the detailed characterization
of posture transitions in early childhood