The July 20, 1909 NYT reports on a new world record in what I interpret to be speed walking or "pedestrianism":

WINNIPEG - Announcement was made to-day that at the Canadian athletic championship meet here Saturday, George H. Goulding of Toronto in the mile walk broke the world's record in 6:25 1-5. This lowered not only the American record of 6:29 2-5, but also clipped four-fifths of a second off the world's mark made by G. E. Larner at Brighton, England, in 1904.

The current American indoor record is 5:38.2 held by Tim Lewis.

So, given a century of technological and human capital improvement the speed walk has improved 22%. Not bad.