It's a combination of both really.
Jens is bringing in good guest trainers, that are showing his team useful techniques, and it looks (maybe an editing trick) like Jens is just pushing his team harder.
Also, it doesn't hurt that he has a pretty damn good assortment of fighters.
On a side note, I wonder if Jens threatens to bite anyone that's bailing during a workout? Have you seen that man's grill?!? I'd work my ass off to avoid getting a chunk taken out of me by those "things."
i'm a monster
i'm a maven
i know this world is changin'
never gave in
never gave up
i'm the only thing i'm afraid of