So... Here is my sprint script it is somehow working buti feel like that it can be better?

local mouse = game.Players.LocalPlayer:GetMouse()
local running = false

function getTool()	
	for _, kid in ipairs(script.Parent:GetChildren()) do
		if kid.className == "Tool" then return kid end
	end
	return nil
end


mouse.KeyDown:connect(function (key) -- Run function
	key = string.lower(key)
	if string.byte(key) == 48 then
		running = true
		local keyConnection = mouse.KeyUp:connect(function (key)
			if string.byte(key) == 48 then
				running = false
			end
		end)
		game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = game.Players.LocalPlayer.Stats.Agility.Value + 30
		repeat wait () until running == false or game.Players.LocalPlayer.Stamina.Value <= 0
		keyConnection:disconnect()
		game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = 16
	end
end)

mouse.KeyDown:connect(function (key)
	key = string.lower(key)
	if string.byte(key) == 48 then
		running = true
		while running == true and game.Players.LocalPlayer.Stamina.Value > 0 do
			game.Players.LocalPlayer.Stamina.Value = game.Players.LocalPlayer.Stamina.Value-2
			print("Gay")
			if game.Players.LocalPlayer.Stamina.Value <= 2 then
				game.Players.LocalPlayer.Stamina.Value = 0
			end
			wait(0.1)
		end
		running = false
	end
end)

It sprints based on player's agility and drains the player's stamina by 2 every 1/10th of a second(second block of code)

Experimented until it worked, but I have a strong feeling that there will be a bug somewhere and it can be improved