We calculated the mean trajectory of the COM of the forearm along the mediolateral and craniocaudal axis for each LOD.
We defined the reference curve as the mean trajectory of the COM of the forearm for the L0 level of detail.
This kinematics analysis was based on the mean trajectory of limb movement (Figure 4).
For the mean trajectory, after careful consideration, we chose the middle projection of the Social Security Actuary, with an ultimate total fertility rate (TFR) of 1.
The historical gap series can provide useful information about the variability from year to year in the gap, but not necessarily about the long-run mean trajectory of the gap for the future.