By Jen Murphy | Photographs by Michal Czerwonka for The Wall Street JournalJuly 31, 2021 6:00 am ET Strong, powerful legs and glutes are the secret weapons of elite rowers. “A rowing workout is most closely related to a squat jump or dead lift,” says Jack Nunn, a former member of the USRowing national team and founder of Roworx Fitness in Long Beach, Calif. “Nearly 70% of the power coming from the rowing stroke is driven through the legs and back,” says Mr. Nunn, whose father, John Nunn, competed in and coached rowing in the Olympics. The lower-body movement in the rowing stroke helps strengthen the quadriceps and hamstrings, key muscles that protect the knee joint, Mr. Nunn says. If you don’t have access to a boat or a rowing machine, he says, mimicking the lower body rowing motion on land is as simple as adding squats into your routine. “When I underwent two knee surgeries, both doctors told me to start doing standard standing squats to [...]