young girls/women at the peak of physical maintenance ease
(from about 15~25) human chronological erosion and/or gravity hasn't set in yet, 'stealing' their easy ability to maintain a pert, perky body.
john and don saw a group of perkers and they got "moist"
judy was in her late twenties and spent lots of time exercising, she consequently looked better than those perkers!
putting on her "muumuu", jan remembered when she ran with perkers!