From Noakes Lore of Running, Mr. Walter George (100-up inventor):
"By modern standards, George trained very lightly, claiming that he traned on 'beer and enjoyment.' For the first six years of his running career, his only training involved doing '100-up' exercises. This entailed little more than running on the spot flexing his knees alternately to hip level. The idea was to build up training until he was able to repeat the exercise 100 times at maximum speed."