Whatever your jeans size, most fannies fit into the flat, droopy or ample categories. You can’t trade genes with J.Lo, but you can tweak your workout to maximize your caboose’s natural gifts, says Pete McCall, an exercise physiologist in San Diego for the American Council on Exercise, who designed this workout. In other words, the right routine can help round out the flat-bottomed, lift up the droopy and slim down the generously proportioned! Read about your rump’s go-to moves, then shape a butt you can get behind by doing your plan three times a week.

Is your butt flat?

Stand sideways in front of a mirror. If you say, “What butt?” you belong here.

Your bottom line In flat types, your pelvis may be rotated downward, which can shift much of the work the gluteus maximus muscles handle to your back and hamstring muscles, McCall says. Simply put, your glutes are on an extended vacation and never get the chance to fully develop. Plus, you may have less fat tissue in your fanny, so you miss out on booty bounty.

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Is your butt droopy?

Your cheeks hang down and merge with the top of your hamstrings.

Your bottom line For those with lower derrieres, the pelvis may be rotated upward; this means the standard moves don’t challenge your gluteus maximus muscles enough to get a rise out of them, literally. If you don’t add extra resistance or explosive movement, they just go through the motions, which allows gravity to move in and stake its saggy claim.

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Is your butt ample?

You’ve got plenty to work with, true, but your rear runneth over.

Your bottom line Send a thank-you note to Mom and Dad: An ample backside usually means you build glute muscles without having to try too hard, McCall says. You’ve got the tools; now make them work for you! Your goal: Get rid of jiggle. Drop extra fat that hides your assets, and firm your glutes and surrounding muscles to carve out a more defined, toned behind.

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