The SISU Backyard Ultra at Lake Rebecca brings together running, grit, community, and a true Finnish touch — complete with a sauna and swim option after your run.

Inspired by the Finnish word sisu — meaning determination, toughness, resilience, and the willingness to keep going when things get hard — this race is built to challenge runners of all experience levels.

The format is simple, but the challenge is not: runners complete a 4.167-mile loop every hour, on the hour. Finish the loop with time to spare, and you can rest, refuel, change gear, hit the sauna, take a swim, or get ready for the next start. When the next hour begins, everyone still in the race starts again.

If you do not finish the loop within the hour, or you are unable to start the next loop on time, your race is over. Everyone else keeps going.

That is the beauty of the backyard ultra: there is no set finish line. Your goal might be one loop, a half marathon, a marathon, 50K, 50 miles, 100 miles, or simply one more loop than you thought you could do. At SISU, every runner gets to define their own version of success.

Our loop at Lake Rebecca will include a mix of gravel, asphalt, and trail, giving runners a scenic and varied course throughout the day and night.

Whether you are attempting your first backyard ultra, chasing a new distance, or just coming to experience something different, SISU is designed to be hard, welcoming, memorable, and fun.

Come run one loop. Come chase your first ultra. Come see how far you can go.

Bring your crew, bring your friends, bring your stubbornness.

This is SISU.