Utilizing maximum strength. "Burhurmph" is onomatopoetic, representing the strained grunting sound one would make while utilizing his or her maximum strength in lifting, moving, defecating, etc. Warning: overuse of full burhurmph power can result in a hernia.
"Damn, this dresser is heavy. It won't budge! Looks like I'm gonna have to use Full Burhurmph Power. Here I go...burHURRRRRRRRRRMPH!