Over a drag-race type event of, say, 100yrds with evenly matched riders which of the following would win and why?
1) Sack, used sack-race style
2) Space-hopper

Which technique is the sack race dude using? If its the two footed leap then the space-hopper would win. If its the one foot in each corner and using a running style then sack wins.

Space hopper, aided by the extra propulsion, over the sack.

Having quite recently taken part in an off-road space hopper race I can confirm that they handle like a pig on acid.

I would put my money on the sack.

Good point SBZ, but in this case the sack rider is free to use whichever technique he thinks will be faster. The sack in question isn’t very big though, almost tube-like, so not a great deal of room to move.
(Actual sack hasn’t arrived yet, hence speculating pointlessly before the race actually takes place. If it is successful we may stage a 24hr sack-race)

Crikey HTS, so slow that by the time you returned your hair had all grown back.

I’m the one in the middle.

Space hopper as the chances of falling are slimmer.

Space hoppers are rubbish for speed, but are more fun than a stinky sack

FIGHT!

The best sack technique is to put one foot in each corner and sort of gallop with your hips slightly sideways, so a hybrid between the two footed leap and a run.

I cleaned up at school sports days every time.

Are we talking 26″ or 29″ ‘hopper, and tubed or tubeless?

Size of hopper depends on how much air one puts into it. And it is tubeless,
Sack is 36″ and slso tubeless.