Inflating a space hopper is not very different from inflating a football. You can do it with a hand pump, foot pump, or even an electric pump. You only need the right attachment to fit the pump into the valve. One difference is that hopper balls are much larger than a typical football. That said, hopper balls are not particularly heavy like that of a football. So most healthy adults will be able to inflate it using lung power alone, albeit with a lot of effort. Many hopper balls come with a hand pump in the box. So, that itself is going to be sufficient.