I'm just guessing here, hopefully someone else will know instead of guess how that is controlled.
Search your Mods directory for filename "physicsbodies.xml". If there is one, note in which mod it is and either remove the mod or ask the author if it is safe to delete just this one file or how to edit it.
If there is no such file, look for filename "buffs.xml" and look for lines that have the word "Ragdoll" in them. Again, either remove that mod completely or ask the author if it is safe to only delete the lines with "Ragdoll" in it or the whole file.
Or guess which mod may do this. Total Conversion mods might do it. Hint: If you use a Total Conversion, don't add further mods unless the author explicitly states that those are compatible. If you added a weapon mod, that's likely the one. Check the mod description, maybe it is listed as a feature. Ask the author.