I intentionally have not purchased a road bike for many reasons, among them, if I owned a road bike, I would feel compelled to compete in triathlons, the training for which includes “brick” workouts. Generally, brick workouts are a part of tri- or du-athlon (I suppose probably biathlon, too, but I’m not sure. As an aside, any Olympic sport that has its roots in a military discipline is hard core.) training, and they consist of doing two disciplines right after the other, to mimic a race situation, including the transition.
Today, I did my version of a brick workout: a 4-mile run followed by a 1.5 hour jivamukti yoga session. Wow. I think I need a nap now. But only after I shower.