Cheating or how to find a way to have more movement:
There is a simple way to go around this movement rule...
Leaping!
a character can leap up to (strength + athletics) x2 yards horizontally in one action.
so keeping an action for leaping could be a very good idea, it can make your character jump out of range or in contrary, jump in the middle of a fight, without spending an entire round moving (simple action).
Remember that jumping to a non-stable ground can be dangerous, your character can fall down and it is dangerous in the middle of a fight.
Another thing is if the action takes place in a corridor or any place with no high ceiling, there a jump can prove useless! And if your enemy uses his reflexive movement to go in another room, your character can't simply jump in angles!
Nevertheless leaping is a very good method to increase your movement capacities for a round, as it takes only one action.
It is not stated in the core rules book how many leaping actions a character can take in a single round. As most of the jumps doesn't involve rolling dice it could be virtually possible for a character to take an infinite number of leaping actions in a round, so here, we will limit these leaping actions to the athletics ability number (min 1).
exemple: a character with 3 in athletics can jump up to 3 times in a single round. Once again, it is possible to do more if these leaps are part of a stunt.