Certified Instructors
Mary Sullivan Kelly
Owner/Instructor
Mary opened True Pilates Boston in order to bring authentic classical Pilates to the area. Her goal is to provide a supportive and challenging environment that honors Joseph Pilates' intent: "complete coordination of body, mind, and spirit."
Mary is passionate about the Pilates method and the benefits it provides people from all walks of life and at all levels of physical fitness. She is awed by the many ‘light bulb’ moments this system provides, and the opportunity to see an exercise each day from a new vantage point. Mary has always enjoyed movement, or at least being on the move. That said, her dance background is more Elaine Benes than Martha Graham.
Mary is certified by Romana's Pilates, and trained with the world-class instructors at True Pilates New York who employ techniques that are as close to the original teaching of Joseph Pilates as are available anywhere. She believes firmly in the power of post-certification study. She is a graduate of the comprehensive Pilates Professional Advanced Teacher Training Program - The Red Thread, as well as the Advanced Contrology Program through Authentic Pilates, The Pilates Studio Portugal. In 2024, she completed the Classical Syllabus, a program designed to apply the Pilates method to individual needs. She regularly attends workshops and conferences to further her appreciation and application of the method. She also holds a BA from Simmons College and an MBA from Boston University.
Nancy Horne
INSTRUCTOR
Nancy started her Pilates journey a decade ago to alleviate the physical strain of frequent business travel. Subsequent auto collisions introduced her to the powerful role Pilates can play in healing the mind, body, and spirit.
Nancy is certified through Power Pilates. She holds a BA in American History from Harvard College and an MBA in Marketing from Columbia University. She lives on a pond in Wellesley, MA. When not teaching Pilates, Nancy is a business consultant specializing in Strategic Marketing and Product and Service Innovation.
Neill Shelton
INSTRUCTOR
Neill has been involved with movement from a young age, starting at age 6 with pliés at New England Ballet as well as his mother’s studio in Wayland, MA. His Pilates journey began with mat and apparatus classes at age 12, cross-training that helped to fuel a budding competitive figure skating career. Neill trained at an elite level in the Pairs discipline with his sister Lara, qualifying for the U.S. National Championships multiple times, and later embarking on a professional career lasting over 15 years performing with companies worldwide.
Recognizing how Pilates benefitted in his athletic endeavors, Neill decided to learn more about the craft and completed a 600-hour comprehensive Power Pilates certification in 2022. He furthered his understanding of the method by participating in the Advanced Contrology Program through Authentic Pilates New York in 2024 and 2025 and completing The Classical Syllabus program in 2024. A true believer in the method, Neill loves to help clients of any age and ability move better, whether that means getting out of bed and down the stairs or stepping into a spotlight of their own.
When he isn't on the ice or in the studio, Neill enjoys riding his bicycle, playing with his dog Skeeter, and long walks on the beach at sunset.