Set a Force Threshold. Any force platform signal below this threshold will be set to zero.

Set_Force_Platform_Threshold
! /THRESHOLD=20
! /SET_AS_DEFAULT=FALSE
;

This value may also be set manually by going to Force → Modify Minimum Force Platform Value

If using this command in a pipeline script, do not forget to use the RECALC command (listed under File Management category in the pipeline workspace) to update force/kinetic signals.