Subjects with chronic obstructive pulmonary disease (COPD) frequently develop considerable deterioration in exercise capacity in association with weakness and deconditioning of the respiratory muscles, which can be corrected with specific therapies. While pulmonary rehabilitation is a central component in the rather complex manangement of COPD, there is currently a lack of centers able to provide appropriate rehabilitation services in the Czech Republic. The main objective of this study will be to fully evaluate the utility of the Test of Incremental Respiratory Endurance (TIRE) as an at-home inspiratory muscle training method in subjects with COPD, while comparing the effectiveness of this novel training approach to the outcomes of more traditional ispiratory muscle training protocols.

This prospective, randomized controlled trial will include 2 treatment groups and 1 sham intervention group in a 1:1:1 ratio. All participants will undergo a certain type of IMT regardless of group assignment, which will be perfomed via two different devices. The trial will comprise of an 8-week at-home training period with remote supervision followed by 4 months of unsupervised, independent inspiratory muscle training. Study outcomes will include measures of inspiratory muscle strength and endurance, pulmonary function, COPD-specific symptomatology, functional exercise capacity, surrogate markers of mortality risk, mental health status and health-related quality of life of participants. While investigators acknowledge the value of standard inspiratory muscle training protocols which use Threshold devices, investigators believe that the TIRE training has the potential to provide additional clinical benefits since it is able to modulate all aspects of muscular performance, including strength, endurance and work capacity. Investigators hypothesize that, as a home-based stand-alone rehabilitative therapy, TIRE will be superior to standard IMT in improving COPD-related measures.

Eligible participants will be randomly assigned to one of the following three distinct home-based IMT protocols: (1) TIRE, (2) Standard, and (3) Sham (i.e. Low Resistance). All subjects will undergo 8 weeks of daily unsupervised IMT using either a PrO2® device (Design Net, Smithfield, USA) or Threshold device at home. All training modalities require the subjects to be seated and wearing a nose clip while performing the required breaths. Subjects will be instructed on respective training procedures and complete first training session in the presence of a research team member upon enrollment. Regardless of training method, participants will be instructed to fill in diary cards at the end of each training session, in which participants document how many breaths were able to perform. This information will be later used for compliance assessment. Participants will be also provided with user guides developed by investigators research team with detailed instructions regarding equipment set-up, training protocol and contact information. In addition, subjects will receive weekly phone calls from week 0 to week 8 to encourage compliance and adherence to the study protocol, to address any subject questions or concerns, and to collect information regarding participants current symptomatology.

Inclusion Criteria:

• individuals over the age of 40
• clinical and functional diagnosis of COPD
• Global Initiative of Chronic Obstructive Lung Disease (GOLD) - stages I to IV
• evidence of inspiratory muscle weakness, defined as a MIP ≤ 80 cmH2O and a SMIP ≤ 427 PTU
• ability to operate a computer, tablet or smartphone
• clinical stability with no history of infections or exacerbation of respiratory symptoms for at least two months prior to study enrollment
• non-participation in exercise programs in the past 12 months.

Exclusion Criteria:

• subjects with history of lung surgery, lung cancer,
• any diagnosed cognitive (i.e. Mini Mental State Examination score < 24),
• orthopedic, neurological or neuromuscular disorders