The article was one of several in a book called “The Hurdles” edited by Jess Jarver and published by T&F News. Lots of interesting material in there. I really think that most hurdlers just get their lead leg over and down in whatever way works for them. As long as they lead with their knee, I don’t obsess about it. To me, trail leg action is much more crucial. In fact, I think trail leg action affects lead leg action much more than the other way around. If you are looking for resources, check out hurdlesfirst.com.