First post - little help with a sentence

Raak wrote:

Hello there I'm going to be doing a CELTA (TEFL, ELT) course in August. I'm putting together a handwritten story which the interviewer has requested. Can someone please take a look at the following sentence and advise me on whether it looks okay please? "Nothing is more rewarding than pushing yourself to your [the] limit and then digging deeper, finding that extra reserve of strength and pushing on even harder." Go ahead and use 'oneself' - and then replace 'your' with 'the'.  I think this makes it less cumbersome than using two "ones", which can be an awkward attempt at not 'preaching' with 'you'. What I'm particularly concerned with is my use of "yourself" and "your" - is it generally frowned upon to use these universal forms of the pronoun in a formal sense?   Debatable, unfortunately. Also, while I'm being paranoid, is my use of the comma in the sentence correct? Can anyone please critique my example.