Table 1.

Bibliography search of IMT devices.

Author	Publication Date	Device	Type of Devices	Subject Study	Duration	Method	Results
Petrovic et al.	2012	Respifit ${\mathrm{S}}^{\mathrm{TM}}$	Threshold	20 COPD	8 weeks	Direct by cardiopulmonary and stress test	Enhances inspiratory muscle function, dyspnea, and quality of life.
Magadle et al.	2007	PowerBreathe®	Resistive load and	34 COPD	12 weeks	6MWT, SGRQ	Enhances inspiratory muscle function and dyspnea perception.
Tounsi et al.	2021	PowerBreathe®	Resistive load and	32 COPD	8 weeks	BBS, ABC, 6MWT	Enhances inspiratory muscle function and functional balance according to BBS and ABC.
Charususin et al.	2018	PowerBreathe®	Resistive load and	219 COPD	5–8 weeks	6MWT.	No differences in 6MWT. Gains in respiratory muscle function and also endurance exercise capacity.
Langer et al.	2018	PowerBreathe®	Resistive load and	20 COPD	8 weeks	PImax, T.lim	Improvments in Pi,max and T,lim. Telemonitorization.
Beaumont et al.	2015	Threshold IMT®	Threshold	23 COPD	3 weeks	Borg scale, 6MWT, PImax. Cycle ergometer	Subgroup of patients with FEV1 < 50% pred., dyspnea was significantly improved.
McCreery et al.	2021	PrO2 Fit	Resistive load	10 BQ	8 weeks	VO2, VCO2 and pulmonary function (FVC, FEV1)	Increased inspiratory muscle strength and endurance. Telemonitorization.
Formiga et al.	2018	PrO2 Fit	Resistive load	81 COPD	1 day	FEV1, FVC, 6MWT, MIP, ID, SMIP.	Increased inspiratory muscle strength and endurance
Formiga et al.	2020	PrO2 Fit	Resistive load	On going	8 weeks	mMRC, FEV1, FVC, 6MWT.	Test of incremental respiratory endurance training method has the potential to provide additional clinical benefits in COPD.
Daynes et al.	2018	Aerosure Medic®	Resistive load	23 COPD	8 weeks	mMRC, PImax, PEmax. ISWT, ESWT	Improvmente PI max, PE max, and reducing dyspnoea.
Stavrou et al.	2021	AeroFit IMT® MicroRPM	Resistive load	21 athletes	1 day	PSQI, pulmonary function test, ergospirometry	Compare both not differences between devices. AirOFitPRO™ is easier to operate as a device and provides more information.
Bernardi et al.	2015	SpiroTiger®	Resistive load	20 COPD	4 weeks	Spirometry 6MWT, VO2max, SGRQ	Increased inspiratory muscle and quality of life.
Włodarczyk et al.	2015	SpiroTiger®	Voluntary isocapnic hyperpnea	-	-	6MWT	Improve quality of life and distance in 6MWT
Gonzalez-Montesinos et al.	2020	FeelBreathe®	Nasal restriction	18 COPD	8 weeks	PI max y VO2max	Positive effects in dynamic hyperinflation, breathing pattern, and breathing efficiency, with higher expiratory and inspiratory time.
Arnedillo et al.	2020	FeelBreathe®	Nasal restriction	16 COPD	8 weeks	Inspiratory muscle strength (PImax), dyspnea (mMRC), quality of life (CAT) and exercise capacity (6MWT)	Improvements in quality of life, dyspnea, exercise capacity, and inspiratory muscle strength
Gonzalez-Montesinos et al.	2021	FeelBreathe®	Nasal restriction	20 COPD	8 weeks	VO2, VCO2, respiratory rate	FB added to a pulmonary rehabilitation program in COPD patients could improve tolerance in the incremental exercise test and energy efficiency

COPD: Chronic Obstructive Pulmonary Disease. SGRQ: St. George Respiratory Questionnaire score. BBS: Berg Balance Scale. ABC: activity specific Balance Confidence scale. 6MWT: 6 min walking test. PImax: maximal inspiratory mouth pressure. T,lim: endurance capacity of inspiratory muscles. BQ: Bronchiectasis. FEV₁: forced expiratory volume in the first second. FVC: forced vital capacity. PImax: maximal inspiratory pressure, PEmax: maximal expiratory pressure. ID: inspiratory duration. SMIP: sustained maximal inspiratory pressure. mMRC: modified Medical Research Council. ISWT: incremental shuttle walk test. ESWT: endurance shuttle walk test. PSQI: Pittsburgh Sleep Quality Index. RR: respiratory rate, VO₂: oxygen consumption, VCO₂: carbon dioxide production. FB: FeelBreathe^®.