As we know, core holds everything together and is essential to crossfit so here is some more core exercise to help with that.
1: 3x30-40 second holds of weighted supermans. ( only add weight in small increments but make sure you can complete the hold without weight befor you add anything.)
2: Weighted front planks 3x max holds w/ 45#
Here is a video of two Olympic lifters demostrating the weighted superman.