Measuring Your Breathing Strength: What Maximal Inspiratory Pressure Tells Us About Your Diaphragm

If you’ve been working with us on your breathing, you’ve probably heard us talk about the diaphragm a lot. It’s the primary muscle of breathing, and when it isn’t working the way it should, it can contribute to shortness of breath, fatigue, poor exercise tolerance, and Breathing Pattern Disorders (BPD). But until recently, one piece of the puzzle was hard to measure in a clinical setting: exactly how strong is your diaphragm, and how much progress are you actually making?

That’s why we’re excited to share that our clinic now has a Maximal Inspiratory Pressure (MIP) device to help us assess and track diaphragm strength in our clients managing Breathing Pattern Disorder.

What Is Maximal Inspiratory Pressure?

Maximal Inspiratory Pressure is a simple, non-invasive measurement that tells us how much force your inspiratory muscles, primarily the diaphragm, along with some accessory muscles, can generate when you inhale as hard as possible against resistance.

During the test, you breathe in forcefully through a small handheld device (a manometer) starting from residual volume (after fully exhaling). The device captures the peak pressure your muscles produce, measured in centimeters of water (cmH₂O). A few efforts are usually taken to get a reliable maximum value.

In plain terms: MIP is essentially a strength test for your breathing muscles, similar to how a grip strength test measures the strength of your hand and forearm muscles.

Why Does This Matter for the Diaphragm?

The diaphragm is responsible for roughly 80% of the work of quiet breathing. When it’s strong and coordinated, breathing feels effortless. When it’s weak, deconditioned, or not being used properly, the body compensates by recruiting accessory muscles in the neck, shoulders, and upper chest. Over time, this compensation pattern is one of the hallmarks of a Breathing Pattern Disorder.

MIP gives us an objective number that reflects diaphragm and inspiratory muscle strength. Instead of relying only on observation and how a client feels, we now have data that helps us:

• Establish a baseline for how strong your inspiratory muscles are at the start of care
• Identify true inspiratory muscle weakness versus a purely mechanical or pattern-based breathing issue
• Track objective progress over the course of treatment, not just symptom changes
• Individualize training loads when we introduce resistance-based training

How MIP Fits Into Managing Breathing Pattern Disorder

Breathing Pattern Disorder can show up as chest tightness, air hunger, dizziness, fatigue with activity, or a general sense that a deep breath is hard to get. There are usually multiple contributing factors: posture, rib cage mobility, stress and nervous system regulation, and yes, muscle strength.

Adding MIP testing to our assessment toolkit means we can better answer the question: is this a strength problem, a coordination/mechanics problem, or both? That distinction matters, because the treatment approach is different.

• If mechanics and coordination are the primary issue, our focus is on breathing retraining, restoring diaphragmatic breathing, improving rib expansion, and reducing over-reliance on the neck and shoulders.
• If true inspiratory muscle weakness is identified through a low MIP score, we know that targeted strengthening will be an important part of the plan, alongside mechanics work.

This is where MIP testing connects directly to a tool we’ve talked about before on the blog: Inspiratory Muscle Training (IMT).

Connecting MIP to Inspiratory Muscle Training

In our previous blog post on Inspiratory Muscle Training, we explained how IMT uses a handheld device to apply resistance to your inhale, essentially acting as a “gym program” for your diaphragm. Over time, this builds strength, endurance, and efficiency in the respiratory muscles.

MIP and IMT go hand in hand:

1. MIP tells us where you’re starting from. Just like we wouldn’t prescribe a strength program for your legs without knowing your baseline, we don’t want to guess at inspiratory muscle resistance settings. Your MIP score helps us set an appropriate, individualized starting load for IMT.
2. MIP lets us track whether IMT is working. As you progress through an IMT program, we can re-test MIP to objectively confirm that diaphragm strength is improving, not just assume it based on how training feels.
3. MIP helps us sequence your care correctly. As we discussed in the IMT article, we don’t want to strengthen dysfunction. If breathing mechanics are inefficient, adding resistance too early can reinforce poor patterns. MIP testing, combined with a thorough mechanics assessment, helps us decide when it’s the right time to introduce IMT and how aggressively to progress it.

What to Expect if MIP Testing Is Part of Your Plan

If MIP testing is relevant to your assessment, it’s quick and straightforward:

• You’ll be guided through a few maximal inhalation efforts through the device
• We’ll record your best, most reliable value
• We’ll use this, alongside your posture, rib mobility, and breathing pattern assessment, to build your treatment plan
• If appropriate, we may re-test periodically to track your progress over time

There’s no special preparation needed, and most clients find the test itself takes just a few minutes.

The Bottom Line

Breathing Pattern Disorder is complex, and no single test tells the whole story. But adding Maximal Inspiratory Pressure testing to our assessment toolkit gives us a clearer, more objective picture of diaphragm strength — which helps us build smarter, more individualized treatment plans, and connect that plan more precisely to tools like Inspiratory Muscle Training when strengthening is needed.

If you’ve been struggling with shortness of breath, fatigue with activity, or a sense that your breathing just isn’t as efficient as it should be, we’d love to help. Book an appointment with us in Kingston, ON, and let’s find out what your breathing pattern and diaphragm strength are telling us.