An emphatic NO! In general, you should never pay for a PhD; they should pay you. Unless you hope to go into an academic career in sports science (good luck with that, pal..), a PhD will not only be worthless, it will probably make you "overqualified" and would seriously compromise your employability (e.g., if you wanted to work at a community college or High School). A good Masters degree is always worthwhile, however. Also, a PhD in NZ would follow, more-or-less, the British system. You would do nothing but research your project; you won't be taking a bunch of interesting graduate-level courses because they don't offer them (unlike, say, UCLA). You could finish the whole PhD without having learned much of anything besides what you did your project on! I speak as a Professor.