Figure 1. Relation between step counts per day and physical activity level (PAL). PAL = total energy expenditure / resting metabolic rate. TEE was measured by the doubly labeled water method. Filled circles: normal-weight boys, Opened circles: normal-weight girls. The association between steps/d and PAL was shown in Figure 1. Steps/d were positively associated with PAL among all subjects (r = 0.47, P < 0.01; PAL = 0.00003*steps/d + 1.236). When analyzing the data in boys and girls, respectively, steps/d were positively associated with PAL in boys (r = 0.68, P < 0.01), but not in girls (r = 0.27, P = 0.34). When adjusting the regression analysis by gender, r was 0.56 (P < 0.01; PAL = 0.00004015*Steps/d + 0.108*Gender + 0.954 [Gender: ‘boy=1, girl=2’; Steps/d: continuous variables]).