The ISA isn't the answer. It's the question.
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💡 Most people measuring ISAs are looking for a fixed answer. But in the UHPC Model, the infrasternal angle (ISA) isn't a number — it's a behavior. And if you're basing your entire intervention strategy off "wide vs narrow," you're likely missing the point.
In this episode of the UHPC Podcast, Bill Hartman and Chris Wicus break down what the ISA really tells you (and what it doesn't). It's one of the most searched topics on our YouTube page — and also one of the most misunderstood.
You'll learn:
🔸 Why the ISA is a proxy measure.
🔸 The most common errors people make when assessing rib cage shape.
🔸 How compression, compensatory strategy, and behavior blur structural bias.
🔸 When your "narrow" isn't really narrow — and how to know.
🔸 Why trusting the process matters more than getting the angle right.
⚠️ If you've ever had someone tell you you're "wide" — only to later learn you're "actually narrow" — this episode explains why that happens, and how to interpret ISA inside the full system.
🧠 The ISA doesn't predict outcomes. The response to intervention does. Learn how to measure, sense, and course-correct inside the only coherent movement model that connects structure, behavior, and constraint.
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🧑💻 Learn directly from Bill Hartman
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⏱️ Chapters
0:00 — Why the ISA conversation keeps coming back
Chris and Bill discuss how the YouTube algorithm loves ISA content — but it often draws people in through the wrong lens. They talk about why the ISA is misunderstood and why it's not a stand-alone model.
1:50 — What the ISA actually is
Not a number. Not a diagnosis. It's a proxy for rib cage behavior during breathing — and it requires context, structure, and experience to interpret properly.
4:36 — Experience matters more than accuracy
Why you need more reps to understand ISA. The difference between making a wrong call and letting the response reveal your answer.
10:52 — What not to do when measuring ISA
Bill explains why using a goniometer, fixating on symmetry, or basing your entire intervention off of ISA alone will lead you down the wrong path.
13:44 — Archetypes, compensation, and behavior
They dig into how structure becomes more apparent after compensation is resolved — not at the beginning — and why this trips people up.
19:36 — Why behavior reveals more than structure
ISA "types" can look the same under compression. But when behavior is reorganized, structure becomes clear.
22:36 — Measurement is a beginning, not a conclusion
This wraps with how to let the system show you where to go — even if your initial measurement was off — by using process, response, and KPIs.
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29 min