ENGLEWOOD, Colo. — As the Denver Broncos fine-tune the playbook to fit Tim Tebow's game, they have become increasingly reliant on the ground game.

With the approach, they're off and running.

Relying on an unconventional option-style offense led by an unorthodox quarterback, Denver has suddenly surged back into contention in the mediocre AFC West. The Broncos (4-5) have won three of their last four games with everyone pretty much knowing exactly what they are going to do — run and run some more.

Not that it's mattered.

So unique is this read option — similar to what Tebow ran during his days at Florida — that teams are struggling to contain it.