These Founders (Really) Fight

Alex Tehrani
7 of 9

This Ain't No TED Talk

"When you spar with Mike, you kind of do it in public. With other people watching you, it's very nerve wracking. You think, 'what if I look stupid?'" says David Chen, pictured, a student of Onello who co-founded early-stage start-up NunaHealth. "It's almost the same as when you give a presentation to a conference or something. It helps, because giving a presentation is so much more pleasant than being chased around the ring."