The Science of Hard Workouts: Double Threshold, HIIT, Interval Training & Everything in-between

Understanding the inside and out of hard workouts and interval training. From energy systems to neuromuscular coordination to how to write workouts for specific adaptations, this covers it all.

Your Instructor


Steve Magness
Steve Magness

Frequently Asked Questions


When does the course start and finish?
The course starts now and never ends! It is a completely self-paced online course - you decide when you start and when you finish.
How long do I have access to the course?
How does lifetime access sound? After enrolling, you have unlimited access to this course for as long as you like - across any and all devices you own.
What if I am unhappy with the course?
We would never want you to be unhappy! If you are unsatisfied with your purchase, contact us in the first 30 days and we will give you a full refund.

Get started now!