Your Strongest Core Muscle Isn't Your Abs—It's Your Diaphragm

When most people think about improving their core, they picture planks, crunches, or heavy carries. But one of your most important core muscles isn't even visible.

It's your diaphragm.

Known primarily as the muscle responsible for breathing, the diaphragm also plays a critical role in spinal stability, posture, balance, and athletic performance. New research suggests that training this often-overlooked muscle may improve far more than your breathing—it could help you move better, stabilize your spine, and even reduce low back discomfort.

Here's what the latest science says about inspiratory muscle training (IMT) and why athletes, lifters, runners, and active adults may want to start paying attention.

What Is Inspiratory Muscle Training?

Inspiratory Muscle Training (IMT) is exactly what it sounds like—strength training for the muscles you use to inhale.

Instead of lifting weights with your arms or legs, IMT uses a handheld resistance device that makes each breath more challenging. Over time, your diaphragm and other breathing muscles adapt much like any other skeletal muscle.

Most IMT protocols require only about 30 breaths twice per day, making it one of the shortest performance-training methods available.

Your Diaphragm Is More Than a Breathing Muscle

Many people don't realize that the diaphragm is actually part of your body's deep core stabilization system.

Your core isn't just your abs. It's made up of several muscles working together, including:

• Diaphragm
• Transverse abdominis
• Multifidus
• Pelvic floor muscles

Together these muscles create pressure inside the abdomen that helps stabilize the spine before movement even begins.

Research has shown that the diaphragm contributes directly to spinal stability by increasing intra-abdominal pressure and supporting the lumbar spine during movement.

New Research: Stronger Breathing Muscles Improved More Than Breathing

A 2026 randomized controlled trial published in the European Journal of Sport Science examined whether strengthening the breathing muscles could improve performance in professional dancers.

Thirty-six professional dancers completed an eight-week training program. The intervention group trained twice daily using an inspiratory resistance device set at approximately 60% of their maximal inspiratory pressure, while the control group performed the same breathing protocol using only minimal resistance.

After just eight weeks, the higher-resistance group demonstrated significant improvements in:

• Inspiratory muscle strength
• Expiratory muscle strength
• Diaphragm thickness
• Dynamic balance
• Hip and back extensor endurance
• Functional low back disability scores

These improvements were significantly greater than those seen in the low-resistance control group.

1. A Stronger Diaphragm

Perhaps the most interesting finding was that participants actually increased the thickness of their diaphragm after training.

Like any muscle, the diaphragm appears capable of adapting to progressive overload. Researchers observed increased diaphragm thickness during maximal inspiration, suggesting structural improvements in the muscle itself.

This supports previous research showing that inspiratory muscle training can strengthen respiratory muscles and improve breathing efficiency.

2. Better Balance and Stability

One of the study's biggest surprises wasn't related to breathing at all.

The participants improved their dynamic balance significantly.

Why?

The diaphragm isn't just responsible for pulling air into the lungs—it also helps stabilize the torso during movement.

As breathing muscles become stronger, they appear better able to generate intra-abdominal pressure, providing additional support for the spine and improving postural control.

Previous research has found that respiratory muscle strength correlates with balance performance in dancers and other athletic populations.

3. Improved Core Endurance

Researchers also measured endurance of the hip and back extensor muscles using the Biering-Sørensen Test.

Participants performing progressive inspiratory muscle training increased trunk endurance substantially more than the control group.

This suggests that improving breathing muscles may indirectly improve the endurance of muscles responsible for maintaining posture during prolonged activity.

For athletes, this could translate into maintaining better technique later into workouts or competition.

4. Reduced Low Back Disability

Participants also reported meaningful improvements in low back function.

Although the study wasn't designed as a back pain treatment trial, researchers believe improved diaphragm function may enhance spinal stabilization while reducing unnecessary stress on surrounding muscles.

Previous research has similarly linked diaphragmatic function with spinal stability and chronic low back pain.

Can Inspiratory Muscle Training Help Athletes?

Growing evidence suggests the answer is yes.

Multiple systematic reviews have shown that inspiratory muscle training can improve:

• Maximal inspiratory pressure
• Respiratory muscle endurance
• Exercise tolerance
• Running economy
• Sport performance in some athletes

While benefits vary depending on the sport, athletes participating in endurance events, CrossFit®, cycling, rowing, swimming, and high-intensity interval training appear to benefit the most.

How Much Inspiratory Muscle Training Is Needed?

The protocol used in the recent study was surprisingly manageable:

• 30 resisted breaths
• Twice per day
• Every day
• 8 weeks
• Resistance set at approximately 60% of maximal inspiratory pressure

Many commercial inspiratory muscle trainers allow resistance to be adjusted as breathing strength improves.

Who May Benefit?

Inspiratory muscle training may be useful for:

• Strength athletes
• Runners
• Cyclists
• Swimmers
• CrossFit athletes
• Golfers
• Martial artists
• Individuals with recurring low back discomfort
• Older adults looking to improve balance

Even recreational exercisers may benefit from stronger breathing muscles, especially if workouts regularly leave them gasping for air.

The Bottom Line

Most people spend hours strengthening muscles they can see while completely ignoring one of the most important muscles they can't.

Your diaphragm is far more than a breathing muscle.

Emerging research suggests that improving inspiratory muscle strength may enhance balance, core stability, trunk endurance, athletic performance, and even spinal health.

While inspiratory muscle training isn't a replacement for strength training, mobility work, or proper programming, it may be one of the easiest performance upgrades you can add to your routine.

Sometimes getting stronger starts with something as simple as taking a better breath.

Frequently Asked Questions

What is inspiratory muscle training?

Inspiratory muscle training (IMT) is a form of resistance training that strengthens the muscles used during inhalation, primarily the diaphragm.

Does inspiratory muscle training improve athletic performance?

Research suggests IMT can improve breathing muscle strength, exercise tolerance, balance, and endurance, particularly in endurance athletes.

How long does inspiratory muscle training take?

Most research protocols involve approximately 30 resisted breaths twice daily, requiring only a few minutes per session.

Can inspiratory muscle training help back pain?

Emerging evidence suggests stronger diaphragmatic function may improve spinal stability and reduce disability associated with low back pain, although more research is needed.

References:

1. Aksu H, Devran S, Morkuzu S, Bayraktar B. The Effects of Inspiratory Muscle Training on Diaphragm Thickness, Respiratory Muscle Strength, Balance, and Core Stability in Professional Dancers: A Randomized Controlled Trial. European Journal of Sport Science. 2026.
2. Fernández-Lázaro D, et al. Inspiratory Muscle Training Program Using the PowerBreathe®: Does It Have Ergogenic Potential for Respiratory and/or Athletic Performance? International Journal of Environmental Research and Public Health. 2021.
3. Enright SJ, et al. Effect of High-Intensity Inspiratory Muscle Training on Lung Volumes, Diaphragm Thickness, and Exercise Capacity in Healthy Subjects. Physical Therapy. 2006.
4. Kocjan J, et al. Impact of Diaphragm Function Parameters on Balance Maintenance. PLOS ONE. 2018.
5. Hodges PW, et al. Intra-Abdominal Pressure Increases Stiffness of the Lumbar Spine. Journal of Biomechanics. 2005.