Can Respiratory Muscle Training Devices (IMT) Really Improve Cycling Performance? POWERbreathe vs Airofit Tested

In the cycling world, power meters, heart rate monitors, and smart trainers have long been standard equipment, but there’s one often-overlooked training dimension—the respiratory muscles. Respiratory muscle training devices (Inspiratory Muscle Trainer, IMT) have gained increasing attention in recent years, but can they really make you ride faster?

The Respiratory Muscle Fatigue Theory

Why Do Respiratory Muscles Become a Limiting Factor?

During high-intensity riding, breathing frequency can reach 50-60 breaths per minute, with ventilation exceeding 150 L/min. At this point, the oxygen consumption of the respiratory muscles (primarily the diaphragm and intercostal muscles) can account for 10-15% of total body oxygen uptake.

The key mechanism lies in the “Respiratory Muscle Metaboreflex”: when respiratory muscles fatigue, it triggers a sympathetic nervous system reflex, causing vasoconstriction in the limbs and reduced blood flow. In simple terms, fatigued respiratory muscles “steal” blood supply from the legs.

What Does the Scientific Research Say?

A 2011 meta-analysis by Professor McConnell showed:

• Inspiratory muscle training (IMT) can improve maximal inspiratory pressure (MIP) by approximately 20-30%
• Time-trial performance improved by 2-7%
• Breathlessness ratings (RPE-breathlessness) during high-intensity exercise significantly decreased
• Repeated sprint ability improved

A 2020 study by Shei et al. further confirmed that 6 weeks of IMT training can:

• Delay the onset of the respiratory muscle metaboreflex
• Improve exercise efficiency at submaximal intensities
• Enhance exercise performance under (simulated) high-altitude conditions

However, other studies have noted that for elite athletes who already undergo extensive aerobic training, the additional benefits of IMT may be smaller.

POWERbreathe vs Airofit: Comparison of Two Devices

POWERbreathe K5 (Professional Version)

POWERbreathe is a pioneer in the respiratory muscle training field, commercialized by Professor McConnell’s research team.

How it works: Pure resistance-based inspiratory training. Through an adjustable spring valve, it increases resistance during inhalation, forcing the diaphragm and intercostal muscles to contract more forcefully.

K5 Features:

• Electronically controlled resistance, precise to 1 cmH2O
• Real-time display of inspiratory force, speed, and volume
• Automatic progressive load adjustment
• Training data exportable to computer
• S-Index (inspiratory muscle strength index) tracking

Training Protocol:

• Twice daily, 30 breaths per session
• Resistance set at 50-70% of maximal inspiratory pressure (MIP)
• Each breath should be a maximal, rapid inhalation
• 6 weeks constitutes one training cycle

Price: K5 approximately NT$15,000-18,000; entry-level mechanical version K1 approximately NT$3,000-4,000

Airofit PRO 2.0

Airofit comes from Denmark, marketed with a more modern design and app integration.

How it works: Provides both inspiratory and expiratory resistance training, with the addition of lung capacity and breathing control training.

PRO 2.0 Features:

• Bluetooth connection to mobile app
• Gamified training interface guiding breathing rhythm
• Trains both inspiratory and expiratory muscles simultaneously
• Multiple built-in training modes: strength, lung capacity, relaxation
• Real-time breathing flow charts

Training Protocol:

• 1-2 sessions daily, 5-10 minutes per session
• App automatically guides training intensity and mode
• Includes strength training, endurance training, and relaxation training
• 8 weeks is the recommended entry-level cycle

Price: PRO 2.0 approximately NT$8,000-10,000

Comparison Table

Item	POWERbreathe K5	Airofit PRO 2.0
Training Type	Inspiratory muscles only	Inspiratory + Expiratory
Scientific Background	Extensive clinical research support	Less research available
Training Time	Approximately 3 minutes per session	5-10 minutes per session
App Integration	Basic (requires USB)	Excellent (real-time Bluetooth)
Data Accuracy	Medical grade	Consumer grade
User Experience	Function-oriented	User-friendly
Suitable For	Advanced riders seeking data	Beginner to intermediate riders

Hands-On Testing Experience

8-Week Training Plan

The author, with a training status of FTP 280W, conducted an 8-week crossover test:

First 4 Weeks: POWERbreathe K5

• Initial MIP: 120 cmH2O
• MIP after 4 weeks: 142 cmH2O (18% improvement)
• Subjective feeling: noticeably reduced breathlessness during high-intensity climbing
• Drawback: training process is monotonous and easy to forget

Last 4 Weeks: Airofit PRO 2.0

• App guidance made training much more enjoyable
• Expiratory training provided a different training stimulus
• Data tracking is intuitive and easy to understand
• Relaxation training mode was particularly useful before races

Changes in Cycling Performance

20-minute FTP test after 8 weeks:

• FTP increased from 280W to 285W (1.8%)—but this could be attributed to overall training effects
• More notable change: RPE (rating of perceived exertion) at the same power decreased by approximately 0.5-1 point
• Breathing control during the final stages of long climbs (such as Wuling) improved noticeably

Who Is Best Suited for IMT?

Highly Recommended

• Riders who often feel “out of breath” during races: This is a classic symptom of respiratory muscle fatigue
• High-altitude race participants: Such as Wuling KOM, Tataka—thinner air places greater demands on respiratory muscles
• Riders with an asthma history: Research shows IMT can improve exercise-induced asthma
• Older riders (50+): Respiratory muscle strength declines with age, making IMT benefits more pronounced

Limited Benefits May Apply

• Elite athletes (FTP > 5 W/kg): Respiratory muscles may not be the limiting factor
• Riders with already high training volume: Aerobic training itself strengthens the respiratory muscles

Scientific Respiratory Muscle Training Protocol

Beginner Phase (Weeks 1-2)

• Twice daily, 30 breaths per session
• Resistance: 40-50% of MIP
• Focus on correct inhalation technique: primarily diaphragmatic breathing

Advanced Phase (Weeks 3-6)

• Twice daily, 30 breaths per session
• Resistance progressively increased to 60-70% of MIP
• Can be incorporated as part of warm-up before riding

Maintenance Phase (From Week 7)

• Once daily, 30 breaths per session
• Resistance maintained at 60% of MIP
• Perform one set of low-intensity warm-up breathing 2 hours before races

Important Reminders

• Avoid doing IMT immediately after high-intensity training (respiratory muscles are already fatigued)
• Best timing: after waking up and before riding
• Keep the training device clean, washing regularly with warm water

Purchase and Usage Recommendations in Taiwan

• POWERbreathe can be purchased via Shopee or Amazon; be careful to identify genuine products
• Airofit ships directly to Taiwan from the official website, with shipping costs around NT$500
• Beginners are advised to start with the POWERbreathe K1 mechanical version (around NT$3,000) to confirm they can maintain consistent training before upgrading

Respiratory muscle training is not magic, but for the right users, it can be a low-investment, high-return training tool. Just 5 minutes a day might mean breathing just a little easier on that crucial climb.

Related Reading

• Cycling Respiratory Muscle Training: Research on Inspiratory Muscle Training (IMT) and Its Improvement of Endurance Performance
• Respiratory Muscle Training: The Scientific Benefits of Inspiratory Muscle Training (IMT) on Cycling Performance
• Cycling Respiratory Muscle Training: The Benefits of Strengthening Respiratory Muscles on Riding Endurance
• Running Respiratory Muscle Training (IMT): The Science of Improving V̇O2max by 2–3% in 3 Months