10/16/1995 at 01:00 AM EDT
Stretch, two, three, four...other leg, two, three, four.... Whether they're still svelte and sexy at 56, like the incomparable Ali MacGraw, or beauteously buffed up like former fatty turned author, diet counselor and infomercial celebrity Susan Powter, 37 (seen here and on page 119), the stars sweat and slim with an inspirational fervor. After all, their looks pay for their lunches—and their Lam borghinis. So before you go into your cool-down routine, pump through the following 37 pages for an aerobic—and entertaining—take on toning up, Hollywood style.