"Who measured the speed?" and "How was it measured?" Here is one quote regarding running speed from a source listed in the Bibliography:
"Estimates of maximum speed in the cheetah vary from 60 miles per hour to nearly 80 miles per hour. The slower speeds have been made in artificial situations, for example on a dog racing track with a hare as bait. Observations in the wild that employed stop watches and measurements of distances convered should more accurately assess top speeds. One such record shows that a cheetah covered more than 700 yards in 20 seconds, which is a rate of more than 71 miles per hour (Bourliere, 1954:6-7). My own observations do not corroborate Bourliere's. A cheetah seldom runs at top speed for more than 200-300 yards. Moreover, in Florida a captive cheetah was accurately clocked at 71 miles per hour top speed (K. Sevrin, pers. comm.) for a short distance."
Quoted from Page 4, THE CHEETAH By Randall L. Eaton, 1982, Robert E. Krieger Publishing Company, Inc.