"Just like pro footballers are too slow to be world class sprinters"
Ever heard of Willie Gault? Standout WR for the Bears and Raiders. Also.......A star in both football and track at the University of Tennessee, Gault was part of a world record-setting 4 x 100 meter relay team, a 110 meter hurdler who would have gone to the 1980 Summer Olympics if the United States had not boycotted the event (he did attend the Olympic Boycott Games, where he won a bronze medal in the 100 meter race) and a bobsledder (he made the American Olympic team on one occasion).
And still lighting up the track in his older age.......On June 24, 2006, Gault set a world record of 10.72 seconds in the master's 100 meters, a division for athletes aged 45 to 49. On April 26, 2008, Gault (at age 47) set a new world record of 21.80 seconds in the M45-49 age-group for 200m. (Gault's info taken from Wikipedia).