So I realize this is more basic than most, but...
I've been alternating doing straightforward planks on my hands, planks where my hands are on a ball, and planks where my legs are on a ball (and thus elevated). the planks where my hands are on the ball are by far the most difficult for me. But I don't know if one of these variations is most ideal for my eventual (hopeful) development of gymnastic skills?
Also I have a hard time hitting my obliques with most exercises... Is there anything better than side planks? Preferably relatively low level since that's where I am (I think).
Many thanks!
-Ben