Flat abs symbolize peak physical fitness, and in the celebrity tabloids abs have also become a kind of yardstick for sex appeal.
But the craze for buff abs isn’t only about looking good without a shirt. Training the abs is often associated with vanity, but that perception is changing, thanks to the "core fitness" principles espoused by high-profile professional trainers like Chris Robinson, author of The Core Connection, trainer to celebrities, Pilates expert, and champion Muay Thai fighter.
"Every movement should initiate from the stomach region," Robinson says. "If you curl your little finger, you should still feel your stomach."
The abs, also known as the rectus abdominis, are bands of muscle connecting the pelvis with the rib cage. It’s these muscles that form a "six pack" when they’re well developed and not hidden under belly fat. The abs get the most press, but they don’t work alone. They function with a group of other so-called "core" muscles, including the obliques, which wrap around the sides of the torso, and muscles that move the spine and pelvis.
The core muscles are important because they connect the upper and lower body; they’re essential for the coordinated movement of the whole body. Strengthening the core muscles can make you more fit for all kinds of activity.
Having relatively weak abs compared to your back muscles can make you more prone to muscle injuries and lower back pain. The back is normally somewhat stronger than the abs, but there shouldn’t be a drastic imbalance between them, says William Kraemer, PhD, an exercise physiologist at the University of Connecticut and a member of the American College of Sports Medicine.
"It’s always a relationship between the front and back. You’ve got to train both sides of the body," he says.
Robinson says he sees more men than women with greater strength in the back muscles than in the abs. "Ninety percent of my male clients, as opposed to 20% of my female clients, have that issue."