Pilates can do a lot for your body, including building a strong core, improving back health and developing good postures. The exercise system can even help develop your glute muscles, though Pilates alone is unlikely to turn a flat tush into one worthy of a rap song.
Anatomy of Your Butt
Three primary muscles make up your buttocks: the gluteus maximum, gluteus minimus and gluteus medius. Even though your glute max gets all the attention because it's the biggest and often the roundest, all three deserve exercise attention.
Your gluteus maximus helps you rise from a squatting position and propels you forward when you jump or sprint — think of the round glutes you see on Olympic sprinters. The gluteus medius and minimus have similar roles, depending on your position of movement. They help you raise the leg out to the side and stabilize the pelvis as you walk and run.
What Makes Your Butt Grow
Any exercise that stimulates these muscles with resistance encourages them to grow, but your genetics determine if that will be in a round shape or a wider, flatter shape.
Resistance is key in adding muscle mass. Use heavy, fatiguing resistance to optimally break down muscle fibers so they grow back thicker and stronger. Mat Pilates, which uses just your body weight, does offer some exercises that do activate your glute muscles, but probably won't challenge them adequately to build notable muscle size. You'll experience better function and endurance in the muscles as a results of mat Pilates, however.
Reformer Pilates could help you develop some glute muscle as you can adjust the springs and cables to different levels of resistance. Whether this resistance is enough to challenge your muscles to grow depends on your starting point. If you've already been heavy squatting and lunging out on the gym floor, a Reformer session may help improve your body mechanics so you better execute these exercises and get more results, but it's unlikely to contribute to muscle size.
If you're relatively new to resistance exercise, the resistance provided by the Reformer, and even your body weight on the mat, will help you build up underdeveloped glute muscles and make your glutes bigger than they were before you started. Only you can decide if this is the big butt you're after.
Best Exercises for a Shapely Butt
Pilates offers a number of exercises that do activate all three muscles of your glutes. When developed butt muscles are your goal, use them in addition to moves such as barbell back squats, weighted lunges, single-leg squats, donkey kicks and weighted step ups.
Three major buttock builders borrowed from Pilates include:
Flutter Kicks: Lie on your abdomen on a mat, and turn your head to rest one cheek on the floor. Let your arms lay by your sides and extend your legs behind you. Squeeze the legs toward each other and lift them up off the mat. Keep your hips pressed toward the floor as you flutter straight legs for 30 to 60 seconds.
One-Legged Pelvic Tilt: You might know this move as a hip bridge. Lie on your back on a mat, bend your knees and plant your feet about hip-distance apart. Lift your hips and feel a squeeze through your booty. Raise your right leg straight up to the ceiling, keeping your hips lifted. Slowly lower your hips almost to the floor and then lift back up to the maximum height. Repeat 10 to 15 times, then switch sides with the left leg lifted.
Side Leg Kicks: Lie on your right side with your hips and shoulders stacked. Inhale and raise your left leg as high as you can. Exhale and lower back down. Repeat 10 to 15 times, then switch sides.