Table 6. Pearson interclass correlation coefficient (ICC) and the corresponding 95% confidence interval (95% CI) between energy expenditure either during school, vacation and whole year periods and both the indirect and direct peak VO measurements, by gender and group ages. Indirect VO2 Direct VO2 ICC 95% CI ICC 95% CI All (N =36) School period (280 days) (kJ·kg-1·day-1) .54 ** .26-.74 .67 ** .43-.82 Vacations period (85 days) (kJ·kg-1·day-1) .52 ** .23-.72 .64 ** .40-.80 12- month period (kJ·kg-1·day-1) .56 ** .28-.75 .69 ** .40-.80 Males (N =18) School period (280 days) (kJ·kg-1·day-1) .43 * -.04 -.75 .59 ** .18-.83 Vacations period (85 days) (kJ·kg-1·day-1) .46 * -.01-.76 .63 ** .23-.85 12- month period (kJ·kg-1·day-1) .45 * -.01-.76 .63 ** .22-.84 Females (N =18) School period (280 days) (kJ·kg-1·day-1) .34 -.15-.69 .57 ** .14-.82 Vacations period (85 days) (kJ·kg-1·day-1) .37 -.11-.71 .55 ** .11-.81 12- month period (kJ·kg-1·day-1) .37 -.12-.71 .61 ** .18-.83 (8-10 years) (N =12) School period (280 days) (kJ·kg-1·day-1) .44 * -.18-.81 .64 ** .10-.89 Vacations period (85 days) (kJ·kg-1·day-1) .39 ** -.23-.79 .57 * .00-.86 12- month period (kJ·kg-1·day-1) .44* -.18-.81 .64 ** .10-.89 (11-13 years) (N =12) School period (280 days) (kJ·kg-1·day-1) .71 ** .23-.91 .69 ** .20-.91 Vacations period (85 days) (kJ·kg-1·day-1) .78 * .36-.93 .78 ** .38-.94 12- month period (kJ·kg-1·day-1) .78 ** .36-.93 .76 ** .34-.93 (14-16 years) (N =12) School period (280 days) (kJ·kg-1·day-1) .82 ** .46-.95 .89 ** .64-.97 Vacations period (85 days) (kJ·kg-1·day-1) .73 ** .28-.95 .78 ** .38-.94 12- month period (kJ·kg-1·day-1) .82 ** .47-.95 .89 ** .64-.97 * p < 0.05 ** p < 0.01