I've been using gymnastic bodies fundamentals to rehabilitate my lower back from what was likely persistent muscle strain (MRIs were inconclusive) and have made tremendous progress.
I've been doing the straddle up (PE2/MN) for a while, and I've noticed that the more tired my back, the more frequent I will feel a sensation of joints/vertebrae rubbing or clicking in my lower back on the left side. This most frequently occurs when I am lowering back down. The area is somewhat consistent with the area of my original chronic back pain. I'm not quite sure what to call the sensation, and suggestions on that would be helpful to help my searching.
Some more info: After a long time of doing just three sets of three reps (along with the jefferson curls, which I originally had problems with, but solved via another post), I came across a straddle up video that inspired me to try the exercise slower, and to start raising my upper body before my legs. This seemed to help a lot, and I was progressing up to four sets of nine reps. However, during this time, I was also progressing on the Arch Up (PE3/SL), and as my arch up progressed towards five sets of ten reps, it understandably caused me to fail at the straddle up, because the arch up is a large load on my lower back. I just swapped the order of the Arch Up and Straddle Up to account for this.
I mention the arch up to note that my back is not weak, but that there is a spot in my back that is weak, likely causing me to lose lower back stability during the straddle up, specifically when lowering back down.
Any suggestions on what to call the sensation, or what muscles to research or focus on to provide the necessary stability?
Thanks!