> What then of these reports I've heard of aborigines
> running hundreds of
> miles while tracking game?

I saw a documentary once that showed hunter-gatherers
in Africa running (jogging actually) constantly (hours
per day) in search of game. The narrator explained
that they could keep this pace up almost indefinitely.
However, the consensus was that they did not engage in
this activity on a daily basis, but rather "as the
need arose". Could be 2-3 times per week, or 2-3 times
per month.

I think we may have something of a semantics problem
with the issue of how long each day h-g's "worked".
Studies have indicated that they hunted/gathered food
a couple of hours each day. Sounds reasonable to me.
But, what about other activities? Erecting shelter,
tanning pelts, weaving, crafting spears or
bows/arrows, getting "dolled up" for the upcoming
human sacrifice - all of those things took up some
(perhaps most) of what we might consider "free time".
And, of course, there must have been some time for
"play".

The "play" angle is something we should not overlook.
I believe that most of their "play" (mock battles,
dancing, rock-throwing contests, whatever) was very
likely a natural *instinctive* exercise regimen,
"designed" to keep them at a basic level of fitness
just in case the need arose. Similar to the (much)
later religiously oriented exercise regimen of
kneeling, standing, bowing, genuflecting, running from
lions, etc., that was "designed" to keep the peasants
at a level of fitness appropriate for working in the
fields.

IMHO