Forget crunches, planks, and sit-ups — I use this simple Pilates exercise to strengthen my core, lower back, glutes and shoulders, all while working on my stability and posture

A woman's abs.

I’ve been practicing Pilates for the past decade and credit it with keeping me injury-free as I’ve trained for six marathons and rebuilding my core and pelvic floor postpartum. Pilates centers around strengthening your center — all of the exercises involved are designed to work on the deep stabilizer muscles in your midsection. My go-to routine includes Pilates toe taps, bridge marches, dead bugs and, of course, the not-so-humble bird dog.

While the bird dog might look easy, when done with correct form, it is anything but. Read on to find out how to do the Pilates bird dog, and the modifications to try once you’ve mastered it.