How do I change a player's animations for a limited time?

I'm trying to play an animation every time a player is running, in a limited time. I've already tried to use something like this

local humanoid = script.Parent:WaitForChild("Humanoid")
local anim = script.Animation
local animTrack = humanoid:LoadAnimation(anim)

humanoid.Running:Connect(function(speed)
	if speed > 0 then
		animTrack:Play()
	else
		animTrack:Stop()
	end
end)

in StarterCharacterScripts, and also altered it a bit to use in StarterPlayerScripts, but it didn't work. What's wrong?

Here

local humanoid = script.Parent:WaitForChild("Humanoid")
local anim = script.Animation
local animTrack = humanoid:LoadAnimation(anim)
while true do
wait(0.001) 
humanoid.Running:Connect(function(speed)
    if speed > 0 then
        animTrack:Play()
   else
        animTrack:Stop()
    end
   end
end)

its that work?