strength, size, build, fitness DO NOT affect it at all
PES status is for your medical condition, you can be physically fit, but medically unfit..
That's why u see those rubgy players being Pes C

Main things that will make u go below PES A
poor eyesight (~800,900 or less)
any minor back problem
Pes C would be things like
broken bones, serious asthma, paika(C2L2), pai chiu(C1L1), spinal problem(C9L2), eyes have problem focusing(C1L2), skin problem (C1L3)etc
Pes E can be things like hearing problem, hernia, nervous system problem, 30F (severly emfemminate), 302 (gay), etc