You can weigh other options if you want to be outside. You can roll your treadmill outdoors during your workout and then return it to your home for storage. Other options that may fit your workout goals include a rebounder, or mini-trampoline. You can walk and run outdoors in the fresh air, and then easily transport it inside. Small exercise machines that only have foot pedals, such as mini-steppers, are also easily moved outdoors and back in.