Roblox Script Generated by ScripterAI

"also make sure it can run on local player, and make sure it remembers the last position and if the player is repositioned back then bypass it"

-- local script 
local UserInputService = game:GetService("UserInputService")
local player = game.Players.LocalPlayer
local character = player.Character or player.CharacterAdded:Wait()
local humanoid = character:FindFirstChildWhichIsA("Humanoid")

local lastPosition = character.HumanoidRootPart.Position
local isRunning = false

local function onKeyPress(input)
    if input.KeyCode == Enum.KeyCode.W then
        humanoid.WalkSpeed = 50
        isRunning = true
    end
end

local function onKeyRelease(input)
    if input.KeyCode == Enum.KeyCode.W then
        humanoid.WalkSpeed = 16
        isRunning = false
    end
end

local function onCharacterMoved()
    if isRunning and (character.HumanoidRootPart.Position - lastPosition).Magnitude > 5 then
        character.HumanoidRootPart.Position = lastPosition
    else
        lastPosition = character.HumanoidRootPart.Position
    end
end

UserInputService.InputBegan:Connect(onKeyPress)
UserInputService.InputEnded:Connect(onKeyRelease)
character.HumanoidRootPart.Changed:Connect(onCharacterMoved)