Chark and Robinson were the two guys I was interested in the most last year. I watched nearly every Jags game. Robinson has decent burst, but is not a top-end athlete compared to some of the runners of today and yesteryear, especially.
A long aside: One thing I've noticed. The running back position, now de-emphasized, is, while not barren in terms of athleticism, coming up short compared to other positions in terms of having world-class athletic specimens there. I was watching Fred Taylor highlights from earlier this decade last night, and the difference was just light years away how good he was. I know testing times are all decreasing and overall the positional athlete now to then is likely better, but it's the relative speed and athleticism we're all talking about when we talk about the game. I'm not seeing it from the current crop of RBs. Maybe Barkley and Taylor. That's really it.
Anyway, that's a long way around saying I'm not too impressed by Robinson's professional-relative (and let's make sure it's about comparing him to other professional football players, not Sunday Joe) athleticism or "burst," as it were, but it's relative to his competition at RB, which I also find lacking when compared to even earlier this decade.