Shift to Sprint

StarterPlayerScripts

LocalScript

local userInput = game:GetService("UserInputService")
local players = game:GetService("Players")

local sprintSpeed = 30 
local walkSpeed = 16 

local player = players.LocalPlayer

local function beginSprint(input, gameProcessed)
    if not gameProcessed then        
        if input.UserInputType == Enum.UserInputType.Keyboard then
            local keycode = input.KeyCode
            if keycode == Enum.KeyCode.LeftShift then 
                player.Character.Humanoid.WalkSpeed = sprintSpeed
            end
        end
    end
end

local function endSprint(input, gameProcessed)
    if not gameProcessed then
        if input.UserInputType == Enum.UserInputType.Keyboard then
            local keycode = input.KeyCode
            if keycode == Enum.KeyCode.LeftShift then
                player.Character.Humanoid.WalkSpeed = walkSpeed
            end
        end
    end
end

userInput.InputBegan:Connect(beginSprint)
userInput.InputEnded:Connect(endSprint)