Controls are not properly moving when playing animation

Hello! I am pretty new to cinematics and animation, so I may missed some basic setting. I have a bridge with legs. Each leg is pointed at one of the controllers, which are not attached to anything, so I can easily move them around, just like IK controls.

However, when I try to make a basic moving animation, this happens:

Whan causes my legs to be static when animation is being played? when going frame by frame, it looks more-less normal