*3.2. Free-Living Study*

The results from the free-living study shows that when applying the VO2net calibration, there was a considerable increase in the time being physically active in children and adolescents compared with application of the standard MET calibration (Table 2). For example, the time spent in moderate-and-vigorous PA (MVPA = MPA + VPA + VVPA) accounted for 13.8% of the wear-time in children and 8.1% in adolescents with the MET calibration, but increased to 21.2% and 11.2%, respectively, with the VO2net calibration. Consequently, the difference in MVPA between children and adolescents versus adults increases. As an example, with the standard MET calibration the difference

in MVPA between children and younger adults is 6.5% units, while with the VO2net calibration it is 13.9% units. In daily minutes, the difference corresponds to 66 min and 142 min, respectively.


**Table 2.** Time spent daily (min and % of wear time) in different intensity levels by age-group and calibration method for the hip placement.

As the VO2net cut-points are determined from the MET-values for the different intensity levels in adults (i.e., 1.5, 3.0, 6.0 and 9.0), there will be no difference in the accelerometer cut-points in adults applying VO2net calibration vs. MET calibration. Consequently, the time spent in the different intensity levels does not differ between VO2net calibration vs. MET calibration in adults. Children include the age-range 4–12 years, adolescents 13–16 years, and the adult group was divided into younger adults (<50 years, range 21–49 years) and older adults (≥50 years, range 50–67 years).
