I've tried a wide range of core workouts. Many feature fancy equipment like an abs wheel, stability ball, or Pilates ring. But, what I've learned and am here to share is that none of that is necessary ...

Really want to get into the deepest parts of your core? How about a plank? There are difficult varieties like the hardstyle plank and eight-point plank, a favorite of pro surfer Lakey Peterson. There ...