"Obviously, we all know what builds strength -- lifting heavy or explosive."
This is only partially correct in regards to ring strength training.
Normal conditioning protocols are ineffective for strengthening the biceps tendon sufficiently to engage in advanced ring strength elements. In fact many very strong athletes have injured their elbows by attempting to train these elements without first preparing the biceps tendon. It is important to understand that failing to prepare the biceps tendon prior to this training is preparing to fail.
Preparing the Elbows and Biceps for Iron Cross Training
Yours in Fitness,