Let's watch a motivational speaker break a cement brick on Don Mattingly's chest

Before Wednesday's 6-2 win over the Mets, the Marlins were treated to a clubhouse presentation by Radical Reality -- a motivational speaking group from Northern California. 
And by "motivational," of course, we mean "skilled in the art of smashing cement blocks on other people's stomachs."

"It's good for the guys," Miami manager and victim of the aforementioned block-breaking Don Mattingly told MLB.com's Joe Frisaro. And apparently, wielding sledgehammers is just the beginning: "I've seen some of them before, but when he rips up a phone book, it's pretty serious," Mattingly said. "I can barely rip three pieces of paper." 
At least Mattingly can take comfort in the fact that other MLB managers have been there before -- then-Braves skipper Fredi Gonzalez had a cinderblock smashed on his chest back in 2015.