In the October issue of Women’s Health, First Lady Michelle Obama and her personal trainer of more than a decade, Cornell McClellan, speak out about the 45-year-old mom’s buzzed-about fitness routine.

McClellan — who began Mrs. O at his Chicago fitness studio in 1997 — says the secret of achieving the First Lady’s finely-toned biceps lie in triceps pushdowns and hammer curls. McClellan says he’s put Obama through the paces more than 1,870 times in their years together — sometimes as early as 5:30AM.