How does ichigo have so much spirit energy?

Question

i mean when he protected rukia they said to stop that he had to have a tremendesly amount of spirit energy and i was shocked!!!

Answer 1

his dad is a shinigimi (death god)

Answer 2

Well, it's because he's dad was a former Shinigami Captain and maybe because he has that hollow inside him that gives him spirit energy.  

Answer 3

Well, his dad is a shinigami :P

Answer 4

I am reluctant to tell you anything, as it kills a lot of the storyline and....oh, others already spilled the beans

Answer 5

**SPOILER**

He probably inherited it.  His father was a captain in the Soul Society.