Death Ragdolls

If you don't want characters to rgdoll on death, you can use this function.

ragapi.setDeathRagdoll(character, false)

Limb Flop

If using AnimationConstraints, you can procedurally adjust how much strength a limb has.

ragapi.setConstraintFlop(character, part, torque, force, setcollide)
Example code
-- Make the character's legs go limp, but keep the torso stiff (r6) ragapi.setConstraintFlop(character, "LeftLeg", 0, 0, true) ragapi.setConstraintFlop(character, "RightLeg", 0, 0, true)