Condition category
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status
Results overdue

Plain English Summary

Background and study aims
Asthma is a common long-term health condition caused by inflammation of the small tubes (bronchi) that carry air in and out of the lungs. Symptoms vary in severity and include coughing, wheezing, a tightness in the chest and feeling breathless. It occurs when the sufferer comes in contact with something that irritates their lungs – a trigger - causing their airways to narrow and an increase in the production of phlegm in their airways. Common triggers include house dust mites, animal fur, pollen, cigarette smoke, exercise and viral infections (such as a cold). Sometimes, as it can be more difficult for asthma sufferers to take a breath, the respiratory muscles (the muscles that help a person to breathe) can become overworked, or overloaded. This can be alleviated though physiotherapy treatments (interventions) that reduce the demand on the muscles or strengthen them. There is some scientific literature demonstrating that strengthening the muscles that help a person to breathe in (the inspiratory muscles) does help to reduce symptoms. However, more scientific evidence is needed. This study looks at the effects of inspiratory muscle training (IMT) on the strength, endurance and function of these muscles, as well as a person’s quality of life, the number of hospital admissions, and any worsening of a patient’s condition.

Who can participate?
Asthma sufferers aged between 20-70.

What does the study involve?
Participants are randomly allocated to one of two groups, a IMT group or a control group. All participants attend two educational sessions on asthma care and information about the respiratory system, the symptoms of asthma and what can influence it, how to prevent a worsening of symptoms, training on good breathing techniques and information regarding regular physical activity. Those in the IMT group also receive IMT training twice a day, over 5 days for a period of 8 weeks. All participants are assessed before the study begins, after the 8 week study period and then again 3 months later.

What are the possible benefits and risks of participating?
The participant receives a report with the results of lung function tests and inspiratory muscle strength for his/her knowledge and medical care and the results of this study can be used in future studies contributing to the advancement of science. Potential risks include a shortness of breath and faster heart rate during the test.

Where is the study run from?
Federal University of Minas Gerais (Brazil)

When is the study starting and how long is it expected to run for?
March 2014 to February 2018

Who is funding the study?
National Council for Scientific and Technological Development (Brazil)

Who is the main contact?
Professor Verônica Franco Parreira

Trial website

Contact information



Primary contact

Prof Verônica Franco Parreira


Contact details

Departamento de Fisioterapia - EEFFTO
Avenida Antonio Carlos
Belo Horizonte - MG

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Effects of a high intensity inspiratory muscle training program versus an education program on inspiratory muscle strengh and endurance, functional capacity and quality of life in patients with asthma: a randomised controlled trial.


Study hypothesis

Inspiratory muscle training (IMT) associated to an educational program improves inspiratory muscle strength and endurance, functional capacity and quality of life in patients with asthma more than only an educational program.

Ethics approval

Universidade Federal de Minas Gerais Ethics Committee, 23/10/2014, ref: CAAE: 35493714.1.0000.5149

Study design

Randomised controlled trial - single centre

Primary study design


Secondary study design

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet




Description of intervention:
1. IMT Group (IMT plus educational program)
2. Control Group (educational program)

Inspiratory muscle training (IMT): six sets of 30 breaths per day, divided in twice per day, five days a week, during eight weeks, with PowerBreathe K3. Minimum load of 50% of maximal inspiratory pressure, weekly adjusted.

Educational program: two individual (or with family) sessions on asthma care, including: knowledge about respiratory system, symptoms of asthma and factors that influence it, preventive strategies to avoid exacerbations, training about correct inhalation technique, encouragement for regular physical activity.

Intervention type



Drug names

Primary outcome measure

1. Inspiratory muscle strength - maximal inspiratory pressure assessed by a digital manovacuometer
2. Inspiratory muscle endurance – time, volume, flow, work and power assessed by an electronic tapered flow resistive loading device
3. Functional capacity – maximal distance covered during shuttle walking test
4. Quality of life - Brazilian version of the Asthma Quality of Life Questionnaire

Assessed at baseline, 8 weeks and 3 months.

Secondary outcome measures

1. Lung function: Forced expiratory volume in the first second-FEV1, forced vital capacity-FVC and peak expiratory flow-PEF
2. Hospital admissions
3. Number of exacerbations

Assessed at baseline, 8 weeks and 3 months.

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Patients with asthma according to GINA - an increase in FEV1 of > 12% and 200mL after administration of a bronchodilator indicates reversible airflow limitation consistent with asthma
2. Age between 20 and 70 years old
3. No smokers
4. Asthma control test above 18 points; 5.- Auto report of absence of cardiac and neurological diseases

Participant type


Age group




Target number of participants

40 partcipants

Participant exclusion criteria

1. Fever
2. Flu symptoms or respiratory infection in the seven days prior to evaluation
3. Orthopedic and neurological problems
4. Inability to understand or carry out any study procedures

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Federal University of Minas Gerais

Sponsor information


Federal University of Minas Gerais

Sponsor details

Physiotherapy Department.
Avenida Antônio Carlos
6627. Pampulha.
Belo Horizonte
+55 31 3409-5000

Sponsor type




Funder type


Funder name

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Alternative name(s)

Brazilian National Council for Research and Development, National Council for Scientific and Technological Development, CNPq

Funding Body Type

government organisation

Funding Body Subtype

National government



Results and Publications

Publication and dissemination plan

Planned publication in a peer reviewed journal.

Intention to publish date


Participant level data

Not expected to be available

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

04/07/2020: The intention to publish date has been changed from 31/12/2019 to 28/02/2021. 12/04/2017: The overall trial dates have been updated from 03/03/2014 - 28/02/2018 to 23/10/2014 - 28/02/2019 and the recruitment dates have been updated from 06/04/2015 - 31/07/2017 to 20/05/2016 - 31/12/2018.