This surprised me no end. I saw Gunther Von Hagen's Kürperwelten a.k.a. Bodyworks in Bochum, Germany today. Low and behold one of the whole body plastinates (a prosected cadaver essentially dipped in plastic/resin) was put in an L-sit position on a set of rings. Full PPT, no arched back and legs dead straight (oops). There was also a skeleton effectively in the same position next to it showing said PPT (no legs though)
You can see all the portions of the muscles and everything. Unfortunately due to Anatomy/body donor laws and ethics I have no pictures. I highly recommend you see the exhibition anyway but this made it relevant to us.
Mind you it is intense even after studying anatomy, the last part especially😄