Dear readers, I'm sorry. When I asked Lifehacker staffers what's been missing from our fitness challenges, the resounding answer was that we all need to spend a month working on our plank game.
Planks are my personal least favourite exercise, but I have to admit they have some pluses when it comes to a fitness challenge. You can do a plank anywhere, such as your hotel room floor, or even (if you don't mind a few stares) in the middle of your open-plan office.
There's also a clear way to measure progress: On the first day, how long can you stay in position? I bet you anything you'll be able to hold it longer by the end of the month.
So brush up on how to do the perfect plank, and time yourself (either today, or when the challenge officially starts on the first of the month.) Afterward, try to do at least one plank a day.
Remember, you don't have to hold a plank until you collapse; it's fine to do stints of 10 seconds or 30 seconds or whatever is doable for you. You're still building strength, and it will pay off in the end.