Everyone knows you need to be tough to be successful as endurance athlete. But it’s just as important to be smart. All the toughness in the world won’t allow you to reach your full potential if that toughness isn’t balanced with good judgment.

Just ask Franziska Kühne, a 33-year-old wife and mother of two from Frankfurt, Germany, who is studying toward a master’s degree in science and technology. Having lost her mother at age 14, Franziska channeled her grief and depression into ultra-endurance cycling events such as the 2014 Trans Am Bike Race (riding 160 km per day for 47 days) and the 2018 Silk Road Race. But she failed to finish a number of other events, in part because her training was never very good. “I just compensated with mental toughness (not mental fitness),” she explains, “which I used to think endurance challenges were all about.”

After giving birth to her second child in August 2020 following a difficult pregnancy that resulted in 20 kg of weight gain, Franziska decided to try something different. Having burned out on cycling, she started running, and instead of winging it with her training, she chose an 80/20 plan. Smart.

“Over the past 16 weeks I have improved my fastest kilometer by almost a minute, my 5k went from 38:50 to 30:28, and I ran 10 km, 21 km and 30 km for the first time ever,” she reports. “Oh, and I lost 22 kg in the process.” With the end of the COVID-19 pandemic now in sight, Franziska signed up for an October trail marathon, for which she will prepare with the Level 1 80/20 plan. We’d wish her luck, but with her combination of toughness and smarts, she clearly doesn’t need it!