Work and volunteer experience

[WMK]

I'm a Canadian student currently doing my B.A. I plan to apply to several MPH programs for Fall 2012 admission, with the University of Toronto health promotion program being my #1 choice (like so many people apparently). I have a strong GPA and my major falls into the course areas favoured by the U of T program. However, I have little work or volunteer experience related to public health, because despite knowing I want to pursue public health I've always spent too much time focusing on my schoolwork! I know this may mean I have to take a year off to try and gain work experience in the area. However, this year (my fourth year) I'd like to try and get started on gaining experience. I have two options - one is to secure a leadership position in a health-related volunteer program at my university; the other is to take a research assistant position offered to me by a professor in an area related to public health. I would love to do both, as both would interest me, and I would hopefully be able to still do some volunteer work even if I took the RA position, albeit not in a leadership role. I'm torn between the two, and thus wondering - which of these opportunities might better prepare me for an MPH program? I notice that one of U of T's requirements is experience in social justice work, so I figure the volunteer experience may be better for that, but at the same time I don't want to throw away the RA opportunity. Any advice or thoughts would be very much appreciated! Thank you.