How do i detect a distance between player's torso and a ground?

How do i detect a distance between player's torso and a ground

local FallTrack = nil



function PlayTrack()

FallTrack = FallAnim

FallTrack:Play()

end



function StopTrack()

if FallTrack then

FallTrack:Stop()

end

FallTrack = nil

end

function OnFallDown()
    PlayTrack()
end


Player.Humanoid.FallingDown:Connect(OnFallDown)

When i just jump and then fall the anim plays. I wanna make when i jump and falls like 5 studs freefall anim plays