After i did the mirroring, moving by the value of 1.3/2 and adjusting the feet, i walked it upto a 1000 frame. But after it passed frame 300 the feets are starting to stretch what is the reason for this
There is a description here
https://cgcookie.com/questions/6914-another-issue-with-x-deviation-on-the-ik-r
But also check the other answers on the video just before this video
https://cgcookie.com/lesson/rivet-walk-cycle-most-of-it#tab_qanda