Hello, I'm looking for a way to implement the following in my script: Make the player overloaded (move slower, not able to fast-travel and so on) even if he is not carrying too much weight. And of course making him stop beeing overloaded when some conditions are no longer met.
The normal weight system should still be in place and the script should just be an addition to it.
Could anyone help with this?

Kind of a hack, but you could add an item that weighs a lot to the player and turn off the "playable" flag so it cannot be seen in the inventory. Use the additem function to add it to the player.

The problem ist that I want to use the normal weight system beside my one. So the actual weight needs to be unmodified by my script.

Look at this article
http://www.creationkit.com/Stats_Tab

The speed is a stat of the player. You should be able to deal with it with script.
http://www.creationkit.com/Actor_Value

The Actor Value seems to be "SpeedMult"

Game.GetPlayer().SetAV("SpeedMult", 50) ;that should o the hack, but i didn't test it myself

Confirmed by that post from PoopusMaximus
http://www.gamesas.com/topic/1368587-increase-starting-health-magicka-stamina/

Well right, this way it can not conflict with the normal weight system (as it doesn't use it). Thanks for your help and the useful links!

Edit: Well, changing the SpeedMult only kicks in after the player has run, which is not usable this way. And the animations look pretty weired, as they are the normal ones, just slowed down, which look... well, stupid (especially when you run (with 20% of the normal speed)).
Is there any other way to slow the player down? Or a way to tweak the SpeedMult change?