Core Strength

Not Swiss balls, not crunches, not anything that you see advertised on television. Your abs are designed to stabilize your trunk and you should train them as such. There's nothing wrong with a little flex sometimes (the occasional GHD sit-up or ab mat sit-up) though I like those more as metcon exercises. But I can guarantee that if you get good at the overhead squat, the clean, the deadlift, and the jerk you will have a strong core. You've got to practice these regularly, and the beauty is that this kind of training improves your other workouts. This is how you keep a strong core during your runs and even your pull-ups! So practice!

Now, there are two ways to go about this. The first is the longer higher rep version that I'm doing. Take a moderate weight that you can do for at least 20 reps in a row and throw them into a workout as part of a couplet (OHS and Runs or OHS and pull-ups).

The second strategy is actually a better test of core strength than a way to build it, though I think it is valuable for both. Jack up the weight to something you can only do a few times, or even once. The big goal is to get to your bodyweight. And then your bodyweight x15. I am FAAAAAAAAAAR from this, but it is something to shoot for. Check this guy out to see what it really looks like.

http://media.crossfit.com/cf-video/CrossFit_BWx15OHS.mov