Langer 2018.

Study characteristics
Methods	Study design: RCT Study grouping: parallel‐group
Participants	Baseline characteristics IMT N (randomized/analyzed): 10/10 Loss to follow‐up or excluded: 0 Age, mean (SD) in years: 73 (4) Gender (M/F): 4/6 BMI, mean (SD), kg/m²: 24.1 (4.6) Control/sham N (randomized/analyzed): 10/10 Loss to follow‐up or excluded: 0 Age, mean (SD) in years: 67 (8) Gender (M/F): 3/7 BMI, mean (SD), kg/m²: 25.1 (6.7) Overall N (randomized/analyzed): 20/20 Loss to follow‐up or excluded: 0 Age, mean (SD) in years: 70 (7) Gender (M/F): 7/13 BMI, mean (SD), kg/m²: 24.6 (5.6) COPD stage (GOLD): moderate to very severe Included criteria Participants were clinically stable COPD patients with reduced inspiratory muscle strength (Pimax < 70 cmH2O measured at plethysmographic FRC) Persistent activity‐related dyspnea (BDI < 9) despite optimal medical therapy Excluded criteria Inability to perform physiological testing Active cardiovascular comorbidity (i.e.severe heart failure with reduced left ventricular ejection fraction, cardiomyopathy, recent acute myocardial infarction, cardiac arrhythmias, or stroke), or other conditions that could impact dyspnea or exercise capacity
Interventions	Intervention characteristics IMT: the training was performed with a home‐based protocol using an electronic device: Powerbreathe KH2 (HAB International, Southam, UK). Participants trained 2‐3 daily sessions of 30 breaths (4‐5 min/session) performed 7 days/week for 8 weeks. The training load started at around 40% of PImax and it was increased weekly until the highest tolerable intensity Control/sham: this group performed IMT at a load of < 10% of PImax
Outcomes	Dyspnea: Borg isotime cycle ergometer test) peak exercise cycle ergometer test) Notes: Borg measured at isotime: cycle ergometer test Dyspnea: BDI‐TDI: Total Dyspnea: mMRC Functional exercise capacity: Exercise time (constant cycle ergometer test) Respiratory muscle strength: PImax  RV FRC Respiratory muscle endurance time (Tlim) Notes: measured through breathing against 50%‐60% of PImax Laboratory exercise test: VO2peak (Constant cycle ergometer test) (L/min) Respiratory function: FEV1 (L)
Identification	Sponsorship source: this work was supported by the Ontario Thoracic Society, Spear/StartEndowment Fund, Queen’s University. D. Langer received a postdoctoral fellowship and travel grant from the Research Foundation Flanders; thePowerBreathe devices used in the study were provided by HaB International Country: Canada Setting: Queen’s University Health Sciences and Affiliated Teaching Hospitals Author's name: D. E. O’Donnell Institution: Respiratory Investigation Unit, Queen’s University and Kingston Health Sciences Centre Email: odonnell@queensu.ca Address: 102 Stuart St., Kingston, ON, Canada, K7L 2V6 Clinical trial register: NCT01900873
Notes	webplotdigitizer used to extract IMT training load intensity. Adjusted analysis were provided.