I divide up my lifting/coaching career into two broad phases:
Phase 1 — the total confusion stage
- Constantly making ineffective guesses whenever I had a problem
- I felt insecure with clients and had to cling to certainty and fear-based narratives without knowing it
Phase 2 — the current phase, the understanding stage
- I’m a highly effective problem solver
- I’ve worked with 100s of coaches all around the world and help them get better at their jobs with success
- I feel incredibly confident with clients now and can coach anyone who walks in the door
Want to know what one of the main drivers of all of these changes were?
My understanding of physics.
Before physics, I didn’t have a language, a way to describe or truly see anything in the gym.
After physics, I have a clear and accurate map of the territory I’m working with in any given scenario.
The purpose of this article is to give you one of the most essential components of physics, something I like to call the Rule of 90.
A 90-degree angle is where it’s easiest for a force to rotate any object.
Rule of 90
The Rule of 90 states that a 90-degree angle between a force and another segment is the point at which that force is most effective.
In other words, a 90-degree angle is where it’s easiest for a force to rotate any object.
This matters in exercise, because looking for 90-degree angles informs us about what an exercise is actually loading and how you might change it if it’s not working out.
Here’s an example:
Note how the force of the dumbbell (white arrow) interacts with the moving segment, the forearm (red line), at 90 degrees in this position.
This is the position the dumbbell has the best ability to act against the forearm, and where the biceps need to overcome the greatest amount of resistance.
Why does this matter?
Understanding the Rule of 90 tells you:
- Where an exercise is heavier vs. lighter
- What muscles are actually loaded, based on where the challenge is
- Why your compound movements feel off, like why you never feel your quads in a squat
The Rule of 90 also informs us about how we can make changes if a client has pain, for example.
If, in the curl example, my client gets pain where the dumbbell loads them the most, I know I can decrease load in that position simply by changing where the load is 90:
Notice now how, just by leaning backward, I’ve changed the elbow angle where 90 occurs. And now I’ve potentially removed the pain issue a client had just because I moved the 90 position to a different elbow-angle position (clients think you’re a magician when you do this FYI).
Looking for 90-degree relationships gives you a simple, accurate way to understand what an exercise is loading and how to change it when it’s not working.
Understanding the Rule of 90 completely changed how I saw everything in the gym and how well I can coach as a result. And it’s one of the major topics I’ll be deep-diving into in my upcoming foundations course.
If you want to give yourself the confidence to make good decisions in the gym on your own, without needing to rely on anyone else for answers, the foundations course is for you.
Join the waitlist now by clicking below to be the first to be able to apply.
