Everything you need for the Challenge is there. (Check your spam folder if you don't see the email after ~5 minutes.)
You can do the workouts in any mode - skiing, cycling, ski striding, running and so on. Be careful roller skiing at higher speeds.
Do you have a skiing buddy who would enjoy this challenge? Share this link with them.
Nordic Ski Lab is a member-supported online platform and global community for skate and classic cross-country skiing enthusiasts and coaches.