The Truth About the Inguinal Crease
Credit: Viktor Gladkov / Getty Images

Blame it on Mark Walhberg in those Calvin Klein adds or Brad Pitt in Fight Club: Ever since celebrities have showed off that v-shaped line below their abs, there's been a furor over how to get that love line, moneymaker, or, as it's officially called, inguinal crease. Despite what many trainers would have us believe, there's only one answer to this: Get skinny – five percent body fat-skinny.

People often mistake this piece of anatomy for a muscle, but it isn't one. "Basically, the inguinal crease is just two ligaments that originate from hips," says Cedric Bryant, chief science officer at the American Council on Exercise. "The fact of the matter is we all have moneymakers, but they're usually covered in subterraneous fat. It's only when you significantly trim that fat that you're able to see the crease. It doesn't become evident until you get down to 5 to 8 percent body fat."

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Since it's a matter of body fat percentage, not training, that explains why you sometimes see defined creases on naturally super-skinny guys who've never set foot in a gym. It's also why most men's creases remain hidden. Even if you work out regularly and eat a decent diet, it's a tall order to get your body fat low enough for your crease to pop.

But is having less than 8 percent body fat even healthy? Or is a visible crease a sure sign that you need to double down on dinner? "It depends on how you arrive at that percentage of body fat," Bryant says. "Some people are blessed with great genetics and a low body fat percentage, so they display a lot of definition in that area. For everyone else, it requires a lot of discipline in exercise and eating. Provided you're not doing way too much extreme exercise and severely limiting your caloric intake, it shouldn't be a risk to get that lean."

Bryant says the best way to lower overall body fat percentage – and potentially reveal your crease – is thorough a mix of resistance training and cardio workouts, which should include interval training. "Also, you'll need to maintain a diet that meets your energy needs but is healthy and balanced and allows you to create a caloric deficit," he says.

If you're already fairly lean, working the abdominal and other core muscles around it can help you firm up the entire area and possibly give your crease more definition. "Not much ties into the inguinal ligament except the transverse abdominis muscle," says Mike Fantigrassi, director of professional services at the National Academy of Sports Medicine. To do these: Lay on your back, exhale deeply, draw your belly button in toward your spine as much as you can, and hold it. "You'll feel tension in your belly." But we suggest only getting into this exercise after a long, restrictive diet – otherwise, you might as well just focus on your functional fitness, or more goal-oriented training