how do i add a animation on my shift to run script?

wait(2) local plr = game.Players.LocalPlayer local standardwalkspeed = plr.Character.Humanoid.WalkSpeed local base = plr.Character.Humanoid local standardjumppower = base.JumpPower local Xifiers =4 local Xifierj = 1.5 game:GetService("UserInputService").InputBegan:connect(function(Key, Gpe) if not Gpe then if Key.KeyCode == Enum.KeyCode.LeftShift then base.WalkSpeed = standardwalkspeed * Xifiers base.JumpPower = base.JumpPower * Xifierj end end end) game:GetService("UserInputService").InputEnded:connect(function(Key, Gpe) if not Gpe then if Key.KeyCode == Enum.KeyCode.LeftShift then base.WalkSpeed = 16 base.JumpPower = 50 end end end)~~~~~~~~~~~~~~~~~