Swimmers will dive into Pacific surf for only the second Olympic beach start since Rio. Racing runs through the Venice canals.

Moore went stiff on the turf after USC linebacker Desman Stephens II drove his shoulder into Moore's head as Moore began a feet-first slide, then was rushed to an LA hospital in a neck brace.

The race wound through Jackson Park and six South Side neighborhoods, with many runners using it as a tune-up for next month's Chicago Marathon.