Walk cycle for 2 meters per second?

Good day all,

So, I am new to game animation and understanding meters per second rule here and there. I am animating a walk cycle and it is from frames 1-49. Starts at frame 1 and ends at frame 49. I know 1 unit or 1 meter in maya is done in increments of 1. For example if the character is moving at a rate of 2 meters per second then the character's feet in space need to move back -2 from frame 1 -30. But let's say the characters walk cycle does not end exactly at frame 30. Where do I key Translate Z to -2? Frame 30 or frame 49 when the cycle ends smoothly? I hope this makes sense.

Please advise and thanks, Steve