Ryan created the ILU method after years of testing what actually works. His clients include doctors, athletes, executives and people starting at zero.

” I find his knowledge of anatomy and muscle development unsurpassed.”

Dr. Del Dorscheid MD PhD, St. Paul’s Hospital

Ready to train without burning yourself out?

Ryan Booth’s ILU strength training book explains how to alternate demanding workouts with genuinely low-intensity sessions to manage fatigue and make room for recovery.

Developed while Ryan rebuilt after cervical spine surgery, ILU: Interruptive Linear Undulations offers a practical framework for sustainable strength programming.

ILU: Interruptive Linear Undulations

Name: ILU: Interruptive Linear Undulations
Author: Ryan Booth

A sustainable strength-training system designed to balance demanding workouts with recovery.

Ryan Booth works as an actor and personal trainer in Vancouver. On screen, he has guest star and leading roles in film and TV. In the gym, he runs Ryan Booth Performance Inc., helping clients recover from injury.

What Is Interruptive Linear Undulations?

Interruptive Linear Undulations (ILU) is Ryan Booth’s framework for alternating high- and low-intensity strength training. It helps you organize demanding sessions, keep recovery sessions genuinely easy, and adjust training to performance and readiness.

What you’ll learn from the ILU book

How high- and low-intensity sessions fit together.
Why lighter weights do not automatically mean lower training stress.
How to adjust training when fatigue or readiness changes.
How to apply the framework with barbells, treadmill work and everyday training.

Written for personal trainers, coaches and people who want a practical approach to sustainable strength training.

ILU Book: Frequently Asked Questions

Where can I buy ILU: Interruptive Linear Undulations?

Buy ILU on Amazon, or buy the digital edition on Lulu. Current prices and available formats are shown by each retailer.

Is the book suitable for personal trainers and coaches?

Yes. The book introduces a framework for planning strength training around workload, fatigue and readiness. It is also intended for readers who want to understand how to balance demanding training with recovery.

Is light weight always low-intensity training?

No. Light weights taken close to failure can still create substantial fatigue. ILU distinguishes the weight you lift from the overall stress of a session, so recovery work stays genuinely low intensity.

What is the difference between the ILU book and course?

The book introduces the method. The ILU online continuing education course expands it into self-paced study with course materials, a final assessment and a certificate upon successful completion. Course enrollment includes the ILU digital book.

Does buying the book provide CEUs or CECs?

Book purchase alone does not include the course assessment or completion certificate. For approved continuing education credits, enroll in and successfully complete the ILU course.

P.S. This program works with barbells, treadmills and real life.

Want to go deeper?

The ILU course expands the method into a complete continuing-education program for trainers and coaches.

Explore the ILU course