Q: I read that you think Walking Lunges are an advanced exercise and beginners should not do them. Why?
A: First off, they are far too dynamic and require too much motor learning for a beginner. They will tend to pitch forward with they upper body and/or use their back leg to push them through. The action should actually be more of a "pull" with their forward leg while maintain a tight and tall torso. Once we progress to walking lunges, that's exactly what I cue: "Pull your hips through with your front leg and stay tight and tall". You can also have them drag their back foot to learn how to pull through. The only down side is it tears up your shoe.
Second, beginners will often complain the next day of a pulled groin. It's not actually a pulled groin, they are just really, really, really friggin' sore in their adductors.
My advice is that if you want to keep a new client, don't have them perform walking lunges to soon. They will be way too sore and you will look like you don't know how to teach an exercise. But if you dislike the person, day 1, walking lunge the hell out of them :-)
A nice progression is to begin with a Split Squat, which I consider "static supported". Next move to a Slideboard or Valslide Lunge. This becomes more dynamic and teaches the person to pull the hips through (with out shredding their shoes). After that, progress to walking lunges, which become even more dynamic due to a great eccentric emphasis. Spend 3 weeks with each exercise and you have a nice 9 week progression.