"Long Jump is how much horizontal distance a Trainer
or Pokémon can jump in meters. This value for Trainers
is equal to half of their Acrobatics Rank." <- as described in the PTU 1.04 core book

so 0 would mean you can't jump forward? :s
But I guess you don't even need to jump 0.5 since you can probably do that in a single step...
so I can just put down a 0 in this case.
still I don't think this value has to be rounded down though, as its not really a skill check, but a specific distance one can jump.