I have the Walk/Jog dvd, and I don't think it would be too much stress if you do the alternate moves. (She has the one lady to her side doing a lower-impact version.) The whole point of the video is the pace rather than the actual jogging, and it does help to get you moving a little faster. It's interval training, and I can tell a difference in my calorie burn when I include the short segments of jogging. Haven't tried the Walk/Kick one yet, so I'm no help there.
Hope this helps!
~Elisha