"According to the National Weather Service the use of 'short, distinctive given names in written as well as spoken communications is quicker and less subject to error' than 'more cumbersome' identification methods, so since 1953 storms have been assigned female given names. "This convenience and logic inspired our granting a special group of workouts women’s names, but anything that leaves you flat on your back and incapacitated only to lure you back for more at a later date certainly deserves naming." - Greg Glassman
You can read Glassman's comments about the first generation of benchmark "girl" workouts ("Angie", "Barbara", "Chelsea", "Diane", "Elizabeth", and "Fran") here.
Glassman goes on to say,
"If you can blast through without stopping, these workouts take about 4 minutes apiece. If you’re less than a weightlifting gymnast with the lungs of a porpoise, your times will reflect that."
Note that the world record time for "Fran" is now 1:57.