Without a doubt A Centurion requires lots of training Miles. A lot of time on your feet.  I attribute part my success to strength training. I use Planks, push-ups and pull-ups.  I do each of these exercises twice a week.  Core work drives the engine. Strong arms drive your legs.

PLANKS  Currently I do 15 minutes of planks. Three sets back to back of : 3 minute front plank, 1 minute right side plank, 1 minute left side plank.

PUSH-UPS  Currently I do 4 sets of 60 push-ups.  I train on a eight tenths of a mile road loop. I do a set of push-ups each time I pass the start line on laps 2 thru 5.

PULL-UPS  Currently I do 4 sets of 4 pull-ups. You can feel pull-ups in almost every muscle you have.  My goal is to work up to 4 sets of 10.

Note: I did not start out with these numbers. I built up to this point over a three year period.

My Regular weekly schedule looks like this:

Saturday: Walk one hour, 4 sets of 60 push-ups.
Sunday: Walk four hours
Monday: Walk one hour, 4 sets of 4 pull-ups, 15 minutes of Planks
Tuesday: Walk one hour, 4 sets of 60 push-ups.
Wednesday: Walk two hours
Thursday: Walk one hour, 4 sets of 4 pull-ups, 15 minutes of Planks
Friday: Day Off

Becoming a Centurion is no accident. You have to work for it.