Hey, new guy here!
Now that the introductions are done, i'm having a strange problem on movements like Hollow Body, L-sit progressions and similars. My upper body starts to shake when i for example try to lift my legs on L-sit, lying leg raises, or straighten them at hollow body. It does not feel tiring at all, i can hold the position just fine, i can breathe normally, talk while being in it. It's just that my core shakes uncontrollably.
What could be the cause of this?