She's about eighteen here, and the editorial documents her intense training regime for the 1982 film Personal Best. No one embodies that healthy American beauty from the late seventies and early eighties quite like Mariel (and Lauren Hutton of course). I love that even though this is a US Vogue story, all the clothing is functional and humble - predating all the high tech sportswear that is so the norm these days.
US Vogue April 1980 "Mariel Hemingway - Fitness as a way of life" by John Stember
Image Source: The Fashion Spot