If you need a reminder why teachers are so awesome, look no further than Kyle Gurkovich, a middle school math teacher in New Jersey by day and hulk by night. OK, we’re kidding about that last part, but only slightly.

Last weekend, Gurkovich regained his title as the world record holder (pending final approval from Guinness World Records) for the most pull-ups completed in 24 hours. He managed to do 4,234 deadlift pull-ups (or approximately 4,000 more than we could do if our life depended on it). Check out the video below to see his impressive form as he whizzes by the previous world record.

The best part of this story is the reason Gurkovich spent a whole day doing pull-ups: Last February, one of his former students, Daniel Nols, passed away after battling cancer, and Gurkovich knew he wanted to do something to raise money in Daniel’s memory. “I already spent a lot of time at the gym, and I ended up doing a lot of pull-ups,” Gurkovich says. “One day I was working out with one of my buddies and we were both saying that there must be some sort of pull-up record.”

It turns out there was a world record for the most pull-ups in a 24-hour period: 4,030 at the time. Attempting this kind of feat seems crazy to most people, but Gurkovich already had three 24-hour Tough Mudder races under his belt, so he knew he was up to the challenge. The next week, he started preparing. First it was 600 pull-ups a day and then he worked his way up to more than a thousand. He estimates that he’s done more than 24,000 pull-ups in the last year.

All of those pull-ups—and the subsequent sore days—paid off: Gurkovich has raised more than $10,000 for Memorial Sloan Kettering Cancer Center in Daniel’s honor. And he’s not done! His ultimate goal: 5,000 pull-ups in one day.

If you’re motivated to give it a try (just a single pull-up, not the record), here’s a handy guide.