In the “CBS This Morning” series Pushing the Limits, Nancy Chen looks at the fate of thousands of athletes who were training for the Olympic trials when the COVID-19 pandemic hit. The summer games were postponed until 2021. What’s happened since has tested their limits in every way. Chen spoke with athletes vying for a spot on Team USA, including two former Olympians — gymnast Laurie Hernandez and fencer Daryl Homer — as well as first-time Olympic hopeful Kyle Merber. She takes a look at how these athletes have had to develop a different kind of strength.