Green’s Dictionary of Slang

(US sporting) to fix a sporting competition.

1868		H.W. Woodruff Trotting Horse of America 207: In all her hippodroming (and she was hippodromed with a good deal) her owner and driver never threw away a heat.
1896		H. Chadwick Spalding’s Official Baseball Guide 54: After the opening game had been drawn, the Boston club defeated the Clevelands in the next four games, thereby utterly depriving the enemies of the professional class of any chance to cry ‘hippodroming’ [DA].
1919		Van Loan ‘Nine Assists & Two Errors’ in Score by Innings (2004) 417: If we hippodrome it he’ll tumble [...] It’s got to be a close score.
1948		Chicago Trib. 1 Feb. 13/1: Cynics argue there is a great deal of hippodroming [in ice hockey] [DA].