Therapeutic Microstreching. — A new recovery regeneration Technique

From our rugby friends:

http://www.rfu.com/takingpart/coach/coachresourcearchive/technicaljournalarchive/~/media/files/2009/coaching/articles/technicaljournal/2005/3rdquarter/microstretching.ashx

I don't know if this is truly a new technique or not (the latest article in the reference is 1999) but what I don't understand is how they came to understand that the intensity is "...30 to 40% of a maximum perceived stretch..." That seems rather nebulous in my books...