Did Cheruiyot have to sign a waiver?

Cheruiyot seeking compensation

It was a real scare last year when the winner of the Chicago Marathon slipped and fell on his back as he crossed the finish line. Originally reported as "collapsed" not "slipped," he was taken to the hospital right away and had been okay, in the sense that he didn't die and can still run professionally, winning Boston last month.

But he's had major headaches since then, and I'm sure they are major and resulted from the fall. The fall has been attributed to the slippery painted banner/advertisement on the ground right before the timing mat. I imagined that it's like running on the crosswalk's white stripes when they're wet, which I try to avoid. So, Cheruiyot is asking for some money for the damages he suffered. If I were on the jury for this, I'd sympathize with him and award him however much. Afterall, my birthday jury gave $1,ooo,ooo to a guy who's never been a professional drummer who claimed that he can't play drums anymore after a car accident.

But this has me wondering: did Cheruiyot sign a waiver when he signed up for the marathon? Whenever I register for a race, I have to sign or check a box on a form that promises that I won't claim the race organizers, the city, the sponsors, etc. in case of any injuries and accident. It's the standard fine print. But do top pros like him register for races the same way? I mean, pros are invited to races and don't have to pay the entry fees. I wonder if he had to fill out a form at all or sign some contract. And if he did, did he also "assume all risks associated with participating in this event, including but not limited to falls, contact with other participants, effect of weather, traffic, and conditions of the road" (active.com) like the rest of us?