Toyko 2020: Early morning marathon swimming in Tokyo

HIGHLIGHTS FROM RIO: Sharon van Rouwendaal and Ferry Weertman made it a Dutch sweep of the gold medals competing off hot and sunny Copacabana Beach.

WHAT’S NEW: Start times for the two 10-kilometer events were moved up to 6:30 a.m. local time to avoid expected heat later in the day. Water quality at Odaiba Marine Park has been an issue, with renewed screening being done. The course features a backdrop of the Tokyo skyline and the Rainbow Bridge.

TOKYO EXPECTATIONS: Two hours of racing typically comes down to seconds at the finish. Strategy plays a part, with some swimmers choosing to sprint right from the start, while others conserve their energy in hopes of closing with a rush. Twenty-five swimmers compete in both races. Watch for kicking, athletes swimming on top of each other or knocking into each other. Those kinds of actions can cause disqualifications and affect who wins the medals.

ATHLETES TO WATCH: Germany’s Florian Wellbrock is the current world champion in the 10k. He’ll be challenged by 2016 bronze medalist Marc-Antoine Olivier, who finished 0.2 seconds behind Wellbrock at worlds. Also in the men’s mix are defending Olympic champion Weertman, former world champion Jordan Wilimovsky of the U.S. and Gregorio Paltrinieri of Italy. In the women’s race, China’s Xin Xin comes in as the current world champion. Van Rouwendaal will be back to defend her gold, while 2016 silver medalist Rachele Bruni of Italy and 2012 silver medalist Haley Anderson of the U.S. are contenders.

GOLD MEDAL MOMENTS: Aug. 4, women’s 10k; Aug. 5, men’s 10k

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