You've got 20 minutes to do as many pull-ups, squats (free-squat, or air squat),
push-ups, and sit-ups and back extensions as possible. There's one rule; the total
number of reps must include equal counts of each exercise. Work hard and fast.
(I'd suggest you try reps of five of each and see if you can move continuously for the thirty minutes.)
The qualities and capacities that are important in running - such factors as will power,
the ability to apply effort during extreme fatigue and the acceptance of pain - have a
radiating power that subtly influences one's life.
Today's link is intended for coaches and trainers. It deals with a successful approach
to minimizing liability: http://mason.gmu.edu/~jkozlows/p&r396.htm