Hi all,
I was taught to make my own push rods early on in my modeling experience.
GOAL stiff and light. Stiff for obvious reasons but light is VERY important to preserve servos in those "sudden stop" situations.
Medium to hard balsa is fine so are the arrow shafts. Bamboo from the dollar store used for plant stakes is really fun as well. recycled carbon fishin' poles are really nice.

Minnflyer's pics are super, I like to wrap the string back past the hole for the wire bend. UNwaxxed dental floss is handy on the bench for this kind of stuff.

The Sullivan style flexible rod in a tube rigs are handy for some situations but they require support with balsa cross pieces in the fuse.

It sounds as if the original poster has this problem.??? Many cheap ARF trainers require a bit of surgery to add push rod support.