About Us


Nellie Brook, Founder of Mixx


After earning her Master of Arts degree in exercise and sport science from the University of Sydney, Nellie spent 14 years developing and providing Pilates programs for people with specific medical requirements such as patients with chronic back pain, spinal stenosis, hip and knee replacement and more. Nellie spent 6 years as the Pilates department manager at Fitness and Wellness services in New Jersey, and has operated her own Pilates studio in Sydney, Australia. Now she’s bringing her years of experience and care to California, to help you achieve your own goals.


Aisling has been teaching at MIXX since our opening.  Aisling began practicing pilates to eliminate aches and pains caused by more than 15 years as a competitive crew rower in the UK. She is originally from Ireland although has lived in several countries. After leaving her legal career in the UK to travel, she found herself without a pilates instructor so she completed comprehensive training in mat and apparatus from schools in the Netherlands and California. She also has an interest in pilates for breast cancer recovery after completing the Pink Ribbon Program in post-operative workouts. Outside the Mixx studio, she can be found exploring on her bicycle or drinking coffee.


Smadar is coming to MIXX with 10 years of experience in teaching Pilates. Smadar was first interested in Pilates because of her own back problem and was amazed to learn how Pilates improves injuries and posture. In 2011, she was licensed as a Pilates Mat Instructor and taught in Israel before moving to California in 2013. She is STOTT PILATES Certified, a mother of two, and enjoys staying active with Pilates, hiking, and yoga.

Aisling Macmillan, Instructor


Smadar Sweiry, Instructor


Christy Kirkpatrick, Instructor


Christy was born and raised in Bozeman Montana. She left at an early age to train at the Joffrey Ballet School and fell in love with Pilates through her mentor at ballet school. Pilates and ballet have been an instrumental force in her life since she was very young. After dancing with Milwaukee Ballet and the SF Opera Ballet she chose to end her dance career and get a degree in social work at San Francisco State University. After graduating from SFSU Christy found a new passion in working with women recovering from chemical dependency. While working at a treatment center that focused on mind, body, and spiritual connection to overcome addiction and trauma Christy became passionate about bringing Pilates to people who might not have the resources to experience the wonderful benefits of Pilates. 

Christy lives in Los Altos with her husband, two young sons and Nutella, her adorable golden retriever. Christy is excited to join the MIXX family and looks forward to seeing you on the reformer! 



Katie K. Griffin, Instructor


Katie K. Griffin is a Bay Area Dance Artist. With over 34 years of dance experience and 25 years  of teaching throughout California, she offers a unique approach to her instruction that opens the  minds and bodies of her students in ways they’ve not experienced before. Katie holds her  Bachelor of Fine Arts Degree in Modern Dance with an emphasis in Modern Dance Perfor mance from California State University Long Beach. She!s an instructor for the Dance for Parkinson!s community, and has recently added Pilates to her credentials. She holds her certifi cation in Plant Based Nutrition from Cornell University and will be delving further into body work  studies in the coming year.

A note from Nellie:

I created MIXX after years of exploring, studying and teaching different training and exercise methods.

As a mom of two and a wife to a super busy husband with my own career ambitions, I always tried to find the complete program that best fits my (changing) body and my (busy) mind, as well as my schedule, life priorities and most importantly... my budget. Workout by workout, through struggles and success, I created the MIXX concept. 

I am so happy I now get to share MIXX with you! It’s a revolutionary method, yet simple and focused on helping you reach your own goals for mind and body.

See you at the studio!