Some of you may spend countless sessions at the gym—running, squatting and lunging—in an attempt to strengthen and improve the appearance of your backside. But, you may often wonder, “What is the best method for toning my butt?”

To get to the bottom of this dilemma, the American Council on Exercise (ACE) commissioned the University of Wisconsin, La Crosse, to examine various exercises used to work the gluteus muscles—the three muscles that form your butt.

Researchers chose eight popular gluteal exercises to test—traditional squats, single-leg squats, vertical leg press, quadruped hip extensions, horizontal leg press, step-ups, lunges and four-way hip extensions. All eight were evaluated by how much they activated each of the three glute muscles.

The result…there wasn’t one dominant winner. While two exercises, the horizontal and vertical leg presses showed mediocre results, the other six produced similarly strong outcomes.

The researchers did highlight the traditional squat and quadruped hip extension as possibly having the greatest toning affect.

During testing, participants conducted the quadruped hip extension without any weight. Researchers predict that the potential for better results may increase by adding ankle weights. To do this exercise:

1. Get onto all fours.
2. Your back should be straight and parallel to the floor, eyes looking down, arms straight, palms forward.
3. Lift one leg, while keeping the knee at 90 degrees.
4. Stop when the foot is pointed towards the ceiling.
5. Return the knee to the floor. Do up to 12 reps.
6. Repeat with the other leg.

All eight activities can help you strengthen and tone. The best routine should include a combination of various exercises, in order to prevent injury or boredom.