Shift to Sprint

-- Put LocalScript in StarterPlayerScripts

local Player = game:GetService("Players").LocalPlayer
local Humanoid = nil

local UserInputService = game:GetService("UserInputService")

local isRunning = false
local triggerKey = Enum.KeyCode.LeftShift

local REGULAR_SPEED = 16
local RUN_SPEED = 30


local function connectToHumanoid(character)
    Humanoid = character:WaitForChild("Humanoid")

    UserInputService.InputBegan:Connect(function(input)
        if input and input.KeyCode == triggerKey then
            Humanoid.WalkSpeed = RUN_SPEED
            isRunning = true
        end
    end)

    UserInputService.InputEnded:Connect(function(input)
        if input and input.KeyCode == triggerKey then
            Humanoid.WalkSpeed = REGULAR_SPEED
            isRunning = false
        end
    end)
end


connectToHumanoid(Player.Character or Player.CharacterAdded:Wait())


Player.CharacterAdded:Connect(function(character)
    if Humanoid then
        Humanoid:Destroy()
    end

    connectToHumanoid(character)
end)