Shouting people apart was something tongue masters did. Not apprentices. Even as dragonborn with knowledge of the full Unrelenting force, meditation from paarthurnax, and apocryphal knowledge of the shout cannot shout people apart.

They were outnumbered 5 to 1 and ambushed.

Your choices in this situation are

1. become arrow pincushion

2. surrender

Take http://www.youtube.com/watch?v=2Z1DZb4T5T4 for example. You're not making it out of there if the person in charge doesn't want you to.

The rag used to gag Ulfric had been soaked in Torchbug Juice. Learned men and small Children across Skyrim know that this juice is so noxious that having a rag soaked in it stuffed into your mouth is enough to prevent you from focusing mentally well enough to form any words, much less a shout.

I was simply responding to your post on why Ulfric wasn't able to defeat the Imperials when he was able to defeat the Forsworn. His shouting ability exaggerated or not, my point was the Imperials weren't going to take any chances, and to use your imagination when wondering how he wasn't able to defeat the Imperials. You came up with a good explanation - it has been exaggerated so much that we foolishly expected him to not get captured so easily, when he wasn't really a match for the numbers the Imperials brought to the ambush.

when I took soltiude recently he was spamming battle cry, he could have used that against the imperials

your words bring me to shame. So many times as the dragonborn have I shouted weapons out of the enemy hands and then proceeded to kill them with mine. Or have I shouted them off cliffs. Set them on fire or froze them in place and watched them shatter when they fell?

Its actually not clear Ulfric shouted the king off his feet and then stabbed him. He could have shouted him off his feet to make the point, then let the king back up on his feet and stabbed him during the dual. We don't actually know.

The fact that nobody else who saw or mentioned the duel ever mentions the sword makes me think that Ulfric may have buttered up the story to make it sound like less of actual murder/act of cowardice and more of a warrior's duel. Maybe the dead child-king's death was an accident.

Still, even with two shouts, lore wise he would still be more powerful than the average Nord.

The Solitude Court witnessed the duel.