Hard is relative.....for me it`s "enough to stimulate, and less to overtrain"
always working progressive with a given Training-Programm. Starting out "not all out" (but also not to easy), and than gradually keep the intensity up over a period of 5-8 Weeks, until i reach a plateau (can`t improve for longer than 1 week, than it`s time to take a short rest and starting out with a new programm).
Bodybuilding it`s not easy, but indeed there are other sports like triathlon, bycycle-racing, .....which are a bit harder.