"The essence of strength..." Knuckles said, using only his feet to dodge her advances "...is resistance. You lift weights because the weight resists bein' lifted. You run fast because your body resists bein' shoved forward. You fly because gravity resists you being off the ground. Makes sense, right? What I'm telling you is that to get strong - really strong - you need to do things the hard way."

He almost let her hit his nose. Then moved incrementally to the side at the last possible millisecond.

Because he's a little bit of a dick.

"If I didn't teach ya how to do stuff the hard way, I wouldn't be teaching you anything worth anything. Punching at full strength is easy. Punching when you're worn out and have nothin' left and you feel like your hands weigh a ton? There's the challenge."