Keeping the intensity down doesn't always translate to easy. The backing up a long run the day after a long ride does hurt. It is a style of discomfort I had almost forgotten about. It just doesn't exist I. The same way when training for single sport. I have surpassed my usual long session headache that hits a couple after training. An hour with the feet up is the minimum that is required. Even though slow and kind of a struggle with the carry over fatigue from riding at least the run was still very enjoyable.