A319 First Officer reported that when they began the takeoff roll their rudder pedals went to the floor. Takeoff was rejected and the aircraft returned to the gate for maintenance.

Narrative

As I applied normal rudder inputs for takeoff; my pedals went all the way to the floor. During preflight the Captain and myself saw me pull the rudders into takeoff position and lock into place like they normally do. During takeoff they went out of the locked position and to the floor; I called no rudder on my side - your controls". Captain took control and aborted the takeoff. We taxied off the active runway. We did checklists and ATC calls per SOP. We then troubleshot the rudder pedals. As the Captain watched I noticed that the rudder pedals went out of the locked position when set to a mid-position or further away. In other words if they were close to me they remained locked; but did not stay locked when I went mid position or further. I did this 4-5 times and the pedals kept unlocking. When taxied back to the gate; and pedals worked fine once we blocked in. Maintenance also checked them twice; so the aircraft was ops checked good. Pedals appear to be operating normally at this time."