Our Focus Is On You Whether you need Physical Therapy, Sports Therapy, Rehabilitation, Orthotics, 3DMAPS or ASTYM.
The Functional Performance Center is located in Tempe, AZ, and has been treating patients here since December, 2001. Our staff is dedicated to providing the best treatment and customer service possible. Thanks to our wonderfully dedicated patients, we appreciate the continued opportunity to provide top quality functional physical therapy.
Our evaluations and treatment strategies are centered around “function” and movement.
Our Mission Statement:
To encourage transformation using science and compassion to build authentic life-long relationships for all those we are blessed to help improve their function and lives!
Our Core Values:
Faith – To consistently demonstrate through our actions and words, the confidence we have in our mission to serve others and each team member by knowing we are all loved and share that love.
Collaboration – We will do this together or not at all.
Patient-Centric – This experience is about “you” our patient. Our goal is to treat you like we would treat our best friend on their birthday.
FUNction – To always adhere to the principles, strategies and techniques of Applied Functional Science to optimize human function. Always make it FUN!
Compassion – Unwavering commitment. Regardless of religion, race, ethnicity, gender or political views.
Meet Our Physical Therapists
Derek Steveson, PT, DPT, FAFS, ASTYM Cert.
In December, 2001, Dr. Derek Steveson founded the Functional Performance Center as a way to fill the need to provide high level professional health services to our community. He earned his Doctor of Physical Therapy degree from Creighton University in 1996. He served as the Official Rehabilitation Consultant to the Arizona Diamondbacks from 2001-2007, has had the distinct privilege of being the colleague of Dr. Gary Gray, PT, and closely associated with the Gray Institute since 1997.
Dr. Derek has mentored nearly 100 doctoral students and lectured all over the world on the principles, strategies, and techniques of Applied Functional Science and Functional Biomechanics from the Gray Institute. He has prescribed over 5,000 custom-molded biomechanical foot orthotics as well. Dr. Derek is an ASTYM-certified provider and trained in 3D Maps Movement Analysis Screening.
In 2007, Derek invented what was known as the Core Stick and now known as the Core Momentum Trainer (CMTtm), which is a unique device that allows for the muscles of the core to be activated and strengthened in all planes of motion. (See our Resources page to order your CMTtm from Escape Fitness.)
Derek is involved with philanthropy and fundraising for local and international non-profit organizations, and enjoy working out and playing with his nephew, Eli.
- Former Faculty Member, Gray Institute of Functional Transformation
- Guest Lecturer on functional biomechanics
- Former Member, Board of Directors, Connecting to Serve
- Sponsored numerous fundraisers for non-profits locally and overseas – Mission Africa / Not For Sale Campaign
Sara Ullenbruch, PT, DPT, ITPT, ASTYM Cert., Certificate of Competency in Vestibular Rehabilitation
Dr. Sara Ullenbruch joined Functional Performance Center in January, 2014. She graduated from Wayne State University in Detroit, Michigan, with a Doctor of Physical Therapy degree in 2013. She also earned a Bachelor of Science degree in biology from Siena Heights University in 2010 where she played volleyball, pole vaulted, and threw javelin.
Sara is a Vestibular Physical Therapist, who completed her Certificate of Competency in Vestibular Rehabilitation in 2020. She treats balance deficits, dizziness, vertigo, BPPV and many other issues affecting the inner ear. Sara is an ImPACT Trained Physical Therapist, which helps her diagnose and manage concussions as well as create concussion-focused rehabilitation protocols for all patient types. She is a Certified ASTYM Provider, has completed courses from The Gray Institute including 3DMAPS Movement Analysis Screening, and continues to be passionate about treating patients using Applied Functional Science.
Sara is originally from Michigan and moved to Arizona originally for an internship at Functional Performance Center. Her hobbies include Krav Maga, Muay Thai, hiking, and playing with her pack of dogs. She is a Black Belt in Krav Maga and an instructor at East Valley Krav Maga.
Brooke Iseler, PT, DPT, ASTYM Cert.
Dr. Brooke Iseler joined Functional Performance Center in February, 2017. She graduated from Wayne State University in Detroit, Michigan, with a Doctor of Physical Therapy degree in 2016. She did her undergraduate studies at Central Michigan University, earning a Bachelor of Science degree in Psychology in 2012. She enjoys working with athletes of all ages with various orthopedic conditions.
Since joining the team at FPC, Brooke has received her ASTYM certification and is trained in custom-molded orthotic fabrication. She has also taken courses from the Gray Institute and is trained in the philosophy of Applied Functional Science. She loves working with patients of all ages, with a variety of orthopedic conditions, at all points of the recovery process. She enjoys being a clinical instructor to both Doctor of Physical Therapy students and Physical Therapy Assistant students.
Originally from Michigan, Brooke moved to Arizona in 2017, and has planted some roots here. She enjoys sports of all types, having played softball and basketball throughout her life. Growing up, she also was involved with equestrian and still loves to ride when visiting family back in Michigan.
Allison Mackay, PT, DPT
Dr. Allison Mackay joined the Functional Performance Center team in June, 2021. She graduated from University of North Dakota in 2013, with her Doctorate of Physical Therapy. She earned her Bachelor of Science degree in Community Nutrition from University of North Dakota in 2010.
“My mission is to provide a unique and meaningful experience to patients, addressing their individual needs, providing them with hope and encouragement, gifting them with movement, to help them achieve their wants, needs, and desires.”
Allison has a love of movement and community, inspiring her to work toward continuously improving health and thus, positively transforming lives. Her passion lies within working with runners of all ages and capabilities – helping them return to their running routines and maximizing their abilities, while cheering them on along the way. She has completed her Certification in Applied Functional Science (2015) and Fellowship in Applied Functional Science (2017) from the Gray Institute. Allison has also served as a PlayCoachMate (2019) and attended multiple Gray Institute continuing education courses. She is also certified in Functional Dry Needling. She has served as a volunteer assistant coach for Desert Vista Boy’s Cross Country team and is active in the local triathlon community.
Allison is originally from northern Minnesota. She enjoys spending time with her husband and daughter, running, triathlons, cycling, and hiking.