At last, the secret to first lady Michelle Obama's sculpted arms. Tricep pushdowns and hammer curls.

So says Cornell McClellan, Mrs Obama's longtime personal trainer, who described the workout routine of his famous client in the October issue of Women's Health magazine. She began working with McClellan in 1997 at his Chicago fitness studio.

"She's truly committed herself to the importance of health and fitness," he says.

McClellan said that at the end of an intense routine of cardio workouts and weight training, Mrs Obama finishes with the "arm-shaping superset" of tricep pushdowns and hammer curls to tone one of the most commented-upon pair of arms in the world. Mrs Obama often wears sleeveless outfits.

The details of Mrs Obama's fitness routine came as part of a series of interviews by President Barack Obama and Mrs Obama on health care and their personal fitness and nutrition habits.

Obama was interviewed by Men's Health; he also was featured in the magazine last November. Mrs Obama gave her first interviews to Women's Health and Children's Health, a new magazine by Rodale Inc., publisher of the men's and women's health magazines.

Obama is again on the cover of Men's Health, while his wife graces the cover of Children's Health. She is joined by some of the Bancroft Elementary School pupils who have been involved with the White House garden.

Obama said he works out six days a week, two cardio days and four weightlifting days split between the upper and lower body. He also discussed his effort to overhaul the US health care system and his late mother's bout with cancer.

"My blood pressure is pretty low, and I tend to be a healthy eater," he said in the interview. "So I probably could get away with cutting (my workouts) back a little bit. The main reason I do it is just to clear my head and relieve me of stress."

Mrs Obama cited small changes to her family's diet that she says have made a difference.