there's muscular action - the yanginess really depends on the application. if you're getting kicked there, best tighten up
standing or moving meditation should be soft, gentle, but with enough activity to produce a positive effect on the interplay of the moving structures of breath, not too hard so as to constrict blood flow and energy. explore the amount of travel for the breathing structures when aligning them, select the middle optimal 70%, ascertain the most energetic points of all of the structures and bring them to their most energetic points concurrently (with the energy focused on the dantien, if doing dantien breathing...)
I dont have the kung fu body conditioning DVD, so I dont know exactly what is said in there, but these points are generally applicable to static as well as dynamic forms.