When Business Insider interviewed this year's Boston marathon champ, Desiree Linden, the two-time Olympian revealed plenty of details about her extreme fitness regime. But she also made clear that much of the work it takes to become the first American woman to win the race since 1985 is mental.

"You find out that you're more resilient than you ever thought," Linden has said of her chosen sport.

And while you will probably never choose to copy Linden's two breakfasts and 12-mile morning runs, many of the tricks she uses to cultivate her mental resilience can be put to use by anyone looking to increase their grit.

1. Use the 40-percent rule.

"When we think we're down and out, there's still a little bit more," the runner told Business Insider's Áine Cain. "It's figuring out where the very bottom of your well is. And every time you're, like, 'Wow, that was a little more than I thought.' You can keep pushing that threshold."

This insight isn't unique to distance runners. Navy SEALs apparently call it the 40-percent rule: Whenever you think you've hit your limit, you're actually only about 40 percent there. Reminding yourself that when your body (or mind) is freaking out, you don't necessarily have to take its warnings seriously is one great way to improve your resilience. But having the equanimity to stay calm and talk yourself through tough spots obviously benefits from practice.

2. Sleep enough.

Seriously, it's that simple. Going without sleep isn't a sign you're hard. It's a sign you don't understand that performing at your best requires adequate time to recharge, and that's true whether you're running a marathon or leading a team in an incredibly tough market.

"The best recovery tool you have is your bed. Just get sleep," is Linden's simple advice.

3. When the going gets tough, stay in the moment.

Linden isn't the only distance runner who recommends trying to keep from thinking too far ahead when the going gets tough. It's advice you hear from marathoners and ultramarathoners again and again. Panic is far less likely if you get in the flow and keep your mind on the present. That's a truth you can put to use whether you're running 26.2 miles or giving a high-stakes presentation to a huge audience.

"Once you get out the door, it's, like, 'OK, just enjoy this step and this mile and this moment,'" Linden tells BI. "People tend to think about how much they have left or put a negative spin on it. Just being present in that moment is always really helpful."