About the Lab

A specialist in tennis biomechanics and kinetic chain efficiency, Tim has built a reputation for translating complex movement science into practical, on-court performance. His work extends beyond stroke mechanics into how the body interacts with the racquet, strings, and load over time. This is now a core principle at Tennis Lab FX.

His background spans elite tennis environments, including work with the USTA, New York Junior Tennis League, Arthur Ashe Foundation, and high performance roles at private member clubs and organized programs such as Courtsense Tennis Academy. He has also trained with and supported ATP and WTA professionals, giving him direct exposure to the demands of the highest level of the sport.

As a player, Tim competed at the NCAA Division I level, with experience in national and international tournaments and ITF events — bringing firsthand understanding of competitive tennis and its physical demands.

What separates his approach is depth. His studies extend into sports psychology, physics, strength training, movement disciplines, and performance nutrition, allowing him to build complete tennis performance systems — not just coaching sessions.

At Tennis Lab FX, this translates into a precision-first philosophy: every racquet setup, string choice, and customization decision is treated as part of the athlete's performance system, not an afterthought. For pros and beginners alike.

Tim's work is driven by one principle: maximize potential through precision, regardless of level, age, or starting point.

His connection to the sport deepened through a friendship that spans more than three decades with Roman Prokes, whose RPNY community became a touchstone for serious players across the city. When that chapter closed, Jonathan felt the weight of what had been lost and the pull of what could still exist. Rather than let that spirit fade, he decided to carry it forward.

Tennis Lab FX was born from that conviction. Alongside his friend and coach Tim, Jonathan set out to build something that honored the legacy of RPNY while creating a home of its own — a place where craft, care, and love for the game live under one roof in Midtown Manhattan.

With nearly two decades of experience on the professional circuit, Ana has become known for her precision in racquet stringing and customization. She's worked at some of the world's top tournaments — including the US Open, Australian Open, Miami Open, and Indian Wells — supporting elite athletes who rely on flawless racquet preparation. Her work ensures every frame performs with the consistency and control players need under pressure.

At Tennis Lab FX, Ana leads by example, combining deep technical knowledge with a calm, meticulous approach. Her reputation for accuracy, reliability, and quality craftsmanship sets the tone for our stringing team and reflects the tour-level standards we deliver every day. Fluent in English and Spanish, Ana connects effortlessly with players from around the world who trust her attention to detail and expertise.

Len Filatov is an experienced professional tennis stringer with an impressive background in the sport. He is a certified stringer and has honed his skills through years of dedicated practice and hands-on experience. Len has had the privilege of stringing for prestigious events, including the US Open, where he contributed his expertise to support professional players at the highest level of competition.

In addition to his stringing work at major tournaments, Len has strung for several high-profile players, gaining a deep understanding of the unique preferences and requirements of elite athletes. His passion for tennis and commitment to precision make him a trusted figure in the stringing community. Len's extensive knowledge of strings, tension, and racquet performance has made him a go-to resource for players looking to optimize their equipment and elevate their game.

Yat has strung racquets at the highest level for over 40 years. He has worked with players at all four Grand Slams and some of the biggest names in tennis, including Rafael Nadal, Pete Sampras, John McEnroe, and Martina Navratilova. His experience covers decades of innovation in custom stringing, racquet tuning, and frame care.

At Tennis Lab FX, Yat leads team training and stringing education. He ensures every frame is handled with tour-level precision and trains the next generation of stringers to match that same focus on detail and feel.

These days, he's on the court a little more himself, still learning, and genuinely curious about the world he's now part of professionally.

At Tennis Lab FX, Johnny leads the digital side of the operation, building and maintaining the website, developing the tools that help customers find the right gear, and supporting the team's marketing efforts. He's the reason the lab runs as smoothly online as it does in person.