How Can I obtain the velocity of the player (such as distance that he fell down)?

I just want to use this to create a ragdoll effect. The only way I can think of is using a loop to check the player’s position change.

I don’t quite understand.
There is BodyVelocity.
You can use this function to create a ragdoll, if I’m right.

I only used it like tweenservice, I don’t fully get what it does and the Roblox Developer Resources doesn’t explain it well for me.

Edit: Got it confused with BodyPosition

It also seems that the player’s velocity cannot be changed with movement once a ‘bodyvelocity’ has been added, it can only be changed. I’m not really sure if I want to write a full player movement script…

You can access the character’s velocity with BasePart | Roblox Creator Documentation. This might look like this:

local velocity = character.HumanoidRootPart.AssemblyLinearVelocity

To access the vector distance I’m pretty sure you can do

velocity.Magnitude
-- OR
character.HumanoidRootPart.AssemblyLinearVelocity.Magnitude