top of page

My New Obsession, The Infrasternal Angle

Updated: Feb 14, 2021

The simplest tool with a complex sounding name.

I’ve been struggling with what I’d like to “blog” about because I just keep hearing other people’s ideas and none of them speak to me. Now I’ve finally realized what I want to write about - STUFF I CARE ABOUT. Shocker. Stuff I care about is typically things that better my patients and things that involve good, pain-free movement of the human body, so stick with me if that’s what you’re interested in learning about, too.

I realize I’m probably late to the party but I’ve also been living in heavy TBI/concussion population land for the past few years BUT oh em gee I’m stoked on this concept of the infrasternal angle aka “ISA”! This concept is based on using this portion of the body to measure where the breath goes and how it moves, or doesn’t move, one’s body.

I’ve always known deep down that breath matters A TON in rehab and performance but never had an objective way of measuring or seeing it to truly implement addressing it. This ISA concept changes EVERYTHING for my logical brain and that’s why I love it so much. It makes perfect sense. If you know and use this tool, KUDDOS. If not, stick with me and I’ll explain what I’ve gathered thus far.

[>>See Bill Hartman (the ISA OG) or Zac Cupples for SO MUCH MORE in-depth info.<<]

Here’s the nuts and bolts, Simplified Sally/Alexis version.

Measure the area between the midline of you/your patient (I’ll stick with “you” from here on) where your flexible/floating ribs meet. A wide sternal angle is >100 degrees, a narrow sternal angle is < 90 degrees.

The ideal person has a dynamic ISA and rests at about 90 degrees but they can vary their breathing and spacing, hence the name “dynamic”. Unlikely you, sorry. The bigger picture goal is to be dynamic and stack your diaphragm over your pelvic floor and be round in shape, hence “360 degree breath” you’ll commonly hear.

What typically happens, though, is we form these compensations to where we either expand and get stuck in expansion (wide ISA, think squished front to back and sides are flared) OR we can’t properly utilize our bucket handle side rib movement, and are TOO compressed side to side (narrow ISA, think left and right sides squished together).

You might be thinking - which am I!? Well, lay down on your back and measure yourself as best you can, have a friend or spouse test or ask your friendly neighborhood physical therapist!

You might be a wide ISA if: you can squat/move heavy weight relatively easily but your mobility is lacking to get there.

You might be a narrow ISA if: you can get into a squat position pretty easily but typically don’t move tons of weight into and out of that position.

When looking for and then treating these two variations here’s some simple, general rules:

Wide ISA (>100 degrees):

  • Primary limitations in flexion, abduction & external rotation (think shoulders and hips)

  • Sacrum nutated “forward”; increased lumbar lordosis

  • Upper body/torso leans backwards to compensate (not fall forward) turning the calf muscles on overtime

What to work on:

  • Chops, cross body, compressing the sides (side lying exercises!)

  • Bilateral upper extremities into 120 degrees and above to kick in serratus anterior and assist in compression

  • Load the front of the body (goblet squats, front squats, etc) to promote posterior expansion

  • Utilize tools to facilitate flexion, abduction, and external rotation (ie: band around the knees when squatting,

  • Elevated the heels in squatting

  • Use a forceful exhale to kick in external obliques & help with lateral compression

Narrow ISA (<90 degrees):

  • Primary limitations in extension, adduction & internal rotation (think shoulders and hips)

  • Sacrum counter-nutated “backwards”; Flat low back/decreased lumbar lordosis

  • Upper body/torso leans forward & hunches to compensate (not fall backward)

What to work on:

  • Expansion of the sides, bilateral upper extremities in 90 degrees of flexion

  • Utilize tools to facilitate extension, adduction and internal rotation (ie: deadlifts, exercises with ball or block between the knees to promote adduction, etc)

  • Elevate the toes in squatting

  • Use an open mouth sigh exhale

This list is potentially endless and this is literally just a smidgen of an overview and a quick and dirty kinda way of looking at ISAs, but regardless I hope you learned something! Try to implement these tools and see if your pain “magically” decreases and mobility improves!

What are you?

What have YOU found to be beneficial in correctives?

Let me know! Comment below!

Remember to move often and move well! And if you don’t know how, ask a professional you trust!

Always respectfully,


Dr. Alexis Booth, PT, DPT, CSCS

CEO & Founder

Body Better Physical Therapy

Milton, FL 32583

(850) 400-6063


bottom of page