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That's what the forums are for, asking for and finding help. Sometimes the answers may be found easily by searching, others aren't so easy - if you don't find it in the search bar, then make a topic. In this case, the answer was not obvious, but how grenades handle it is in the _exp (explosion) files. If you are just editing, this is the place to look.
Push = "10.0" //how hard the explosion will "push the player", this results in knocking them down
PushRadiusInner = "4.5" //inner radius (distance from center) of push, most powerful
PushRadiusOuter = "4.5" //outer radius of push, less powerful, but in this case it's the same.
You can see in haywiregrenade_exp (Republic) this is nulled out, which is why the Clone Trooper's EMP grenade doesn't knock anyone over.
If you are trying to add it to something else, you'll have to look and see how the game handles these things - weapon itself, ordinance (bullets/etc), then explosions.
some of serejas weapons have this i think tehy would be a good example to look at.
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