Sarah,
Your review of the literature is excellent.  You will find this topic
covered nicely in Mohrbacher & Stock (1997).  Breastfeeding mothers may
need to give some extra attention to the care of their breasts right
before exercise by nursing to decrease fullness.  During exercise,
breasts should be supported well, but not too tightly bound.  Mother may
nurse after exercise as soon as she sees her baby.  Baby may or may not
indicate s/he notices a change in the taste of the milk.

There is another article more recent than the ones you mention.  You'll
have to do a lit search, but I believe you'll find it if you check the
Lactnet archives.  Someone reported somewhere a decrease in the amount
of IgA immediately following exercise.  So IgA may decrease to 30% its
normal volume.  So what?  It's still 30% more than is contained in
artificial baby milk, and is not significant when added to the rest of
the day's intake.

Good luck with your studies.  I'm happy to see such terrific budding
nurse clinicians on Lactnet.

Mohrbacher, N., & Stock, J. (1997) The Breastfeeding Answer Book, Rev.
Ed. (pp 381-382) Schaumberg, IL: La Leche League International.
:-D
--
Jeanne Mitchell, LLLL, RN, IBCLC
Austin, TX
"Be kind, for everyone you meet is fighting a harder battle."
Plato