The accuracy of a uniaxial accelerometer for assessing physical activity in preschool-aged children was assessed by using an indirect calorimeter which provides the physical activity ratio (PAR) for free living activities. Subjects were 5- to 6-yr-old Japanese girls and boys (n=24, 6.1±0.3 years). PAR was assessed for nine activities (lying down, watching a video while sitting and standing, line drawing for coloring-in, playing with blocks, walking, stair climbing, ball toss, and running) using the Douglas bag method. “Exercise intensities” were recorded with the uniaxial accelerometer (Lifecorder EX ; Suzuken Co. Ltd, Nagoya, Japan). PARs were also predicted by using the equations presented by Higuchi et al. (2003) and Kumahara et al. (2004). Significant correlation was observed between “exercise intensities” as measured by the uniaxial accelerometer and PAR for all activities (r=0.827). Predicted PAR values for walking and running were overestimated according to the equations. On the other hand, PAR values for stair climbing and ball toss were underestimated. These findings indicate that although the uniaxial accelerometer may help in evaluating daily physical activity in preschool-aged children, its use as a proxy measure of PAR based on the above equations may be limited.

In this study, we examined applicability of existing equations to predicting the body surface area (BSA) of children, and newly developed prediction equations for the BSA of children. BSA of 87 children of both genders (7∼12 yr) was determined by the three-dimensional photonic image scanning (3DPS), which was used as reference. BSA predicted using existing equations yielded overestimation or underestimation and/or a systematic error with respect to the reference. BSA prediction equations for boys and girls were developed using height and body mass as independent variables for the validation group and cross-validated for another group. The standard errors of estimation of the prediction equations were 105 cm² (0.9 %) for boys and 158 cm²(1.4 %) for girls. In the cross-validation group, there was no significant difference between the predicted and measured values without systematic errors. These findings indicate that existing equations cannot accurately predict BSA of children, and that the newly developed prediction equations are capable of predicting BSA of children with adequate accuracy.