The past week or so has been focused on really training her 2-on-2-off behaviour so that she knows it inside and out. There should be absolutely no doubt in her mind what she is supposed to do on one of the contact obstacles. She runs on with speed and drive and she sticks her 2-on-2-off position at the end until released. No matter what distractions are going on, and no matter how aroused she is.
To train this I broke out all sorts of distractions. Waving toys around, loud noises (video games), dropping food on the ground, new locations. Her job is to maintain that position. Obviously she makes mistakes, or if the distraction is too great she forgets to touch her "target" (which for the most part we are no longer using, she just needs to touch her nose to the ground). The idea is to essentially proof the behaviour so that no matter what is happening, she always runs to the end of the frame and touches her nose to the ground.