Ever since two-time Olympic 800 meter runner Nick Symmonds, 35, retired from professional running in 2017, he has kept himself busy checking off tough—and sometimes wacky—athletic challenges in his free time. Last year, he announced that he wanted to become the first man in history to run a sub-4 minute mile and summit Everest. Then earlier this month, he ran the fastest known 100 meters run wearing ski boots, finishing in 13.71 seconds (the previous record was 14.09). While summiting Everest is still on the bucket list, his most recent challenge was a task most of us can relate to:...