One of the first exercises I did when I started CrossFit was this move called an AbMat sit-up, named after the mat you place under your lower back for support. I couldn't believe how sore I was for ...

Say what you like about CrossFit, but the athletes at the top of the sport are in phenomenal shape. Engines that can go all day, strength, flexibility and abs that pop: they have it all. The latter is ...