First one is the sort of "not doing much" hind end

Same horse, working in more extension,
correctly from his hindquarters.
See the difference in the placement
of the hind leg (thrusting one).

And this one, is actually collected;
again, note the hind leg and angle of the
cannon as the horse pushes off with it.
BTW, all same horse, all same day,
and he was fox trotting in all of them.

Pictures and information by Lee Ziegler (website).