The walk path is not a finite distance. It can be lengthened or shortened. The runs,walks,struts,etc. inside the WD however ARE finite. That means if your walk path is too long in relation to your stride. The WD has to do something about it to make up the difference. In this case. It has to add a few key frames of action to make up the difference. And you get an unwanted repeated action. If you take that same animation you put in that example and cut the number of frames down from 120 to approx 80. It will not jerk anymore. And it will work just fine. ScottA