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meet the team


Seth Greiner, PT, MSPT

Seth Greiner is the Founder and Owner of Greiner Physical Therapy, a provider of home and on-site physical therapy and personal training in the heart of the Hamptons.


Seth graduated from Boston University in 2005 with cum laude distinction, earning his Bachelor and Master degrees. While studying at BU, he received his Personal Training Certification from the National Academy of Sports Medicine (NASM) a worldwide leader in the field of fitness. He is a certified Golf Trainer through the Titleist Performance Institute (TPI).  


Seth’s patient centered treatment approach maximizes a person’s ability to function and move. Practicing with relentless passion, he remains dedicated to helping his patients achieve their goals.  He believes that listening to each patient's unique story is key to helping them move better.  He enjoys working with people across all age and activity levels, competitive athletes, recreational weekend warriors, and people exercising for the first time in their life!


Over the past 15 years he's worked in hospitals, schools, and outpatient clinics throughout the tri-state area. He has completed hundreds of hours of continuing education, most recently with a focus on management of Parkinson's disease. Seth is the head coach at Rock Steady Boxing Hampton Bays, a noncontact boxing exercise class.  The classes help people with Parkinson's disease fight back to remain strong and independent


In 2015 Seth launched a mobile physical therapy practice, delivering services directly to patients and clients in the heart of the Hamptons. In 2021 the practice expanded to add on onsite location in Speonk, NY., providing outstanding outpatient care in the heart of the Hamptons.

Seth lives in East Quogue, NY with his wife and their two daughters. He is a loyal Steelers, Penguins, and Mets fan. He enjoys designing and exercising with High Intensity Interval Training (H.I.I.T) programs, practicing yoga, playing tennis, and spending time outdoors with his family.


Anthony Fuentes, PT, DPT

Anthony Fuentes, PT, DPT, is a dedicated professional in the field of physical therapy, whose journey in healthcare began with a strong educational foundation.


He pursued his passion for helping others by first earning a degree in Exercise Science from Adelphi University. Building upon this knowledge, Anthony further honed his skills, obtaining licensure as a Physical Therapist Assistant through Suffolk Community College in 2018. His commitment to excellence led him to pursue advanced education, culminating in the attainment of a Doctor of Physical Therapy degree from Stony Brook University in 2023.


Since 2012, Anthony has been making a significant impact in the field of physical therapy, offering his expertise to improve the lives of countless individuals. Beyond his professional endeavors, Anthony embraces an active lifestyle, engaging in activities such as CrossFit, hiking, and pickleball, which further underscores his passion for promoting physical well-being.

Anthony Fuentes Physical Therapist
Anthony Fuentes Physical Therapist
Anthony Fuentes Physical Therapist

Ashley Yens-Markland

Ashley Yens-Markland is the office manager at Greiner Physical Therapy. She graduated Magna Cum Laude from The College of Staten Island with a Bachelor of Science and in 2017   She also obtained her Health IT certification in 2017 and wants to pursue an MBA in Health management.  The core values that drive her are integrity, teamwork, trust, growth, communication, and passion. 


Ashley loves to make her patients smile and gives her maximum effort to improve her patients lives. She actively roots for her patients to succeed and takes satisfaction when they achieve their goals. When she is away from the office she enjoys dancing, reading, and dining out with friends.  


Her favorite movies are all the Transformers movies, favorite book is Kindred, and favorite podcast is In Totality with Megan Ashley.  


Her favorite quotes are “If there is no struggle there is no progress” - Frederick Douglass and 

 “A life is not important except in the impact it has on other lives” - Jackie Robinson. 


Ashley is married and lives in Long Island with her husband and four beautiful children. 

Ashley Yens

Breahna Arnold

Breahna Arnold is a Level 2 Certified Functional Strength Coach, as well as holding many other certifications. She also continues to grow her foundation by her on going education. To be a great coach you need to understand human movement, your craft as well as the modalities and theories you teach. 


With strong principles she incorporates the fundamentals needed to have a successful workout program. Mobility, agility, strength, stability and conditioning are just a few of the areas you will master while in her care. 


Even while taking great strides to ensure each session is productive, she makes sure to bring an element of fun. Introducing new exercises as well as new challenges to achieve. Working out has to be enjoyable and rewarding at the end of the day.

Breahna Arnold Personal Trainer
Breahna Arnold Personal Trainer
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