"I am with hflam, use IK to place the feet or hands, but then select parent body parts, legs for the feet, arms for hands, etc. and SET a keyframe there.  Once IK is turned back off body elements tend to shift a bit too, and slight adjustments are often required."

I really Dont think many of you understand the extent of this problem.

There are times when you need IK to assist in a motion like lowering oneself down by bending the knees but the feet stay "pinned" in place
this easily achieved by lowering or raising the hip on theY axis and setting some key frames.

the problem is later down the timeline,

I want to create a jumping motion where having his feet"pinned" would be a hinderance so I "turn off' IK for the feet.

But some how the IK "refuses" to completely  "let go" and makes the figure basicly unusable for any lower body motion thereafter
this is because poser does not have a real Ik solver but as actually faked as millighost described .

Cheers

My website

YouTube Channel