Inf stamina open source

local Players = game:GetService("Players")
local RS = game:GetService("RunService")

local lp = Players.LocalPlayer
local playerGui = lp:WaitForChild("PlayerGui")
local sprintButton = playerGui:WaitForChild("MainUI"):WaitForChild("SprintingButton")

local anim = Instance.new("Animation")
anim.AnimationId = "rbxassetid://136252471123500"
local animTrack

local isRunning = false
local SPEED_ON = 29
local SPEED_OFF = nil

local function setupCharacter(char)
    local hum = char:WaitForChild("Humanoid")
    SPEED_OFF = hum.WalkSpeed
    animTrack = hum:LoadAnimation(anim)
    animTrack.Priority = Enum.AnimationPriority.Action
end

if lp.Character then
    setupCharacter(lp.Character)
end
lp.CharacterAdded:Connect(setupCharacter)

sprintButton.Activated:Connect(function()
    isRunning = not isRunning
end)

RS.RenderStepped:Connect(function()
    local char = lp.Character
    if not char then return end
    local hum = char:FindFirstChildOfClass("Humanoid")
    if not hum then return end

    if isRunning then
        if hum.WalkSpeed ~= SPEED_ON then
            hum.WalkSpeed = SPEED_ON
        end
        if animTrack and not animTrack.IsPlaying then
            animTrack:Play()
        end
    else
        if hum.WalkSpeed ~= SPEED_OFF then
            hum.WalkSpeed = SPEED_OFF
        end
        if animTrack and animTrack.IsPlaying then
            animTrack:Stop()
        end
    end
end)