SRT | Slow Resistance Training
Setting the global standard for low-impact, high-intensity modern Pilates
Who SRT is For?
For Instructors and Aspiring Instructors
For New and Existing Studios
Work with the SRT team to train you and your instructors in the method, supporting a consistent approach to tempo, tension, and time across your classes.
The Science of
Tempo, Tension, & Time
Smart, efficient, and results-driven training that
adapts to every fitness level
We blend three powerhouse training principles: slow-twitch muscle science, the all-in-one versatility of the Modern Pilates reformer, and the time-efficiency of resistance training supersets. This isn’t just a workout — it’s a system designed to get the most out of every essential element of physical fitness.
The Science of
Tempo, Tension, & Time
Smart, efficient, and results-driven training that
adapts to every fitness level
We blend three powerhouse training principles: slow-twitch muscle science, the all-in-one versatility of the Modern Pilates reformer, and the time-efficiency of resistance training supersets. This isn’t just a workout — it’s a system designed to get the most out of every essential element of physical fitness.
From Education
to Execution
We don’t just train instructors
—we develop experts.
SRT’s education program bridges science and practice, giving trainers the tools to understand movement on a higher level and deliver a world-class experience from their very first session. Our framework builds knowledge, confidence, and clarity—so your trainers can deliver exceptional classes faster, with a deeper understanding of what makes SRT so effective.
The SRT Experience
It’s not just what you do—it’s how it feels.
SRT classes build focus, power, and precision through controlled movement and community energy. Every trainer, every cue, and every second under tension is part of a system designed to challenge, support, and transform you—inside and out.
Every detail of the APXformer is built to support how instructors teach and how students move—from intuitive setup and smooth transitions to controlled resistance that makes movement easier.
Built for SRT, while adaptable for modern Pilates and strength-based formats.
Every detail of the APXformer is built to support how instructors teach and how students move—from intuitive setup and smooth transitions to controlled resistance that makes movement easier.
Built for SRT, while adaptable for modern Pilates and strength-based formats.
Find SRT Around the World
A growing network of instructors and studios connected through the SRT method.
Our instructor and studio directories help students find SRT-trained professionals and locations connected to the SRT community.
Each listing reflects the standards we uphold through training, certification, and continuing education.
Our Founder
Piper Michelle YI
It was love at first lunge. Piper tried her first Modern Pilates class in 2007 and she knew she’d found something worth building a life around. The Modern Reformer offered limitless options to accommodate our favorite fitness exercises– It just needed a system to execute an effective and progressive experience. Nearly two decades later, that spark has evolved into SRT: a global set of principles taught in hundreds of studios across the world.
Based in Los Angeles, SRT founder Piper Michelle Yi has certified more than 6,000 instructors across 15 countries and helped shape the systems behind some of the biggest brands in Modern Pilates. She serves as a Principal Trainer for the Frame Reformer, the innovative equipment brand co-founded by Dua Lipa, where she continues to bridge science, creativity, and accessibility in movement.
A former fashion designer, professional rock climber, jiu-jitsu competitor, and CBS Survivor alum, Piper brings an artistic eye and athletic precision to everything she teaches. Her upbeat, clear, and empowering coaching style transforms science into something you can feel—making complex movement simple, and simple movement deeply effective.
Piper’s mission is simple: to make us stronger, more confident, and deeply connected to what our bodies can do—and to empower coaches to teach with purpose, clarity, and heart.
A Global Team
of Leaders
Behind every great system is a great team.
Piper has developed and mentored an elite team of Master Trainers—experienced coaches who uphold SRT’s standards of excellence and bring the SRT principles to life in studios around the world. Together, they train, test, and support new educators, ensuring that every SRT class delivers the precision, challenge, and empowerment the workout is known for.
Train with
SRT Leaders
Learn from the Master Trainers who carry the method forward.
SRT trainings are led by experienced Master Trainers who understand the method in practice — from teaching structure and cueing to pace, control, and progression.
They train, assess, and support instructors across the SRT network, helping keep the method consistent as it grows.
