Here is a decent video on how to do the “100 up” and age old running practice technique developed as discussed in a three-page essay from 1908 titled “W. G. George’s Own Account From the 100-Up Exercise.” According to legend, this single drill turned a 16-year-old with almost no running experience into the foremost racer of his day.

In George’s words: “By its constant practice and regular use alone, I have myself established many records on the running path and won more amateur track-championships than any other individual.” And it was safe, George said: the 100-Up is “incapable of harm when practiced discreetly.”