On the failed play on 3rd-and-1, Matt Ryan handed it off to Michael Turner on a designed run to the left. There were three main reasons as to why this play failed: bad blocking by the line, the fact that the play was predictable and Turner's inability to hit the hole hard enough to push people through.
On the left side of the offensive line, the Falcons haven't been able to get much push. Comparatively, on runs to the left side, the Falcons have been gaining just 3.45 yards per carry this season, as opposed to the 3.91 yards per carry on runs to the right.
It also failed due to an obvious play call in the situation.
It was 3rd-and-goal from the one and the Falcons tried passing it on first down. The Falcons have been trying to run to the left on almost every short yardage situation this year. Had they called another pass, or even a run to the other side, it wouldn't have been as obvious as the running play they did call.
Michael Turner also has to get to the hole much quicker than he did.
He had multiple side steps in the back field instead of charging forward like the raging bull he can be. If he charges forward, he doesn't lose a yard, instead at least getting to the goal line, despite the poor blocking and play call.