Maximal Expiratory Pressure
Maximal expiratory pressure will be evaluated using standard methods in the pulmonary function laboratory, with the highest value (cm H2O) taken within 10 percent of the other readings as per American Thoracic Society recommendations.
Respiratory Muscle Endurance
Respiratory muscle endurance (endurance time measured in seconds) will be assessed using a manual threshold loading device (Philips Threshold trainer).
Inspiratory Muscle Training Workload
Total IMT workload per session (product of inspiratory muscle force and inhaled volume expressed in Joules) will be extracted from the IMT device in the experimental group.
Inspiratory Muscle Training Load
Inspiratory muscle training Load (cm H2O) will be abstracted from the IMT device in the experimental group.
Inspiratory Muscle Training Mean Power
Inspiratory muscle training mean power per breath (Watts) will be abstracted from the IMT device in the experimental group.
Inspiratory Muscle Training Mean Volume
Inspiratory muscle training mean volume per breath (Litres) will be abstracted from the IMT device in the experimental group.
Medical Research Council Dyspnea Scale
The Medical Research Council Dyspnea Scale will be used to assess the effect of breathlessness on daily activities. The scale comprises five statements that describe the range of respiratory dyspnea from none (Grade 1) to severe with difficulties performing self-care (Grade 5).
Borg Dyspnea Scale
The 10-point Borg Dyspnea Scale will be used throughout the study to adjust the intensity of inspiratory muscle training sessions The lowest score (0) corresponds to the sensation of normal breathing (absence of dyspnea) and the highest score (10) corresponds to the maximum possible sensation of dyspnea.
Borg Dyspnea Scale
The 10-point Borg Dyspnea Scale will be used during cardiopulmonary exercise testing to characterize degree of dyspnea. The lowest score (0) corresponds to the sensation of normal breathing (absence of dyspnea) and the highest score (10) corresponds to the maximum possible sensation of dyspnea.
Qualitative Assessment of Dyspnea
The 18-point Qualitative Dyspnea Scale will be ascertained at the end of cardiopulmonary exercise testing. Participants will be presented with a list of 18 descriptors characterizing their dyspnea and will be asked to rank the top three.
Qualitative Assessment of Dyspnea
The 18-point Qualitative Dyspnea Scale will be ascertained at the end of respiratory muscle endurance testing. Participants will be presented with a list of 18 descriptors characterizing their dyspnea and will be asked to rank the top three.
Oscillometry
Oscillometry will be performed in the pulmonary function laboratory following the protocol from the European Respiratory Society.
Spirometry (Forced Vital Capacity)
Spirometry (forced vital capacity) will be measured in the pulmonary function laboratory following the American Thoracic Society Guidelines.
Spirometry (Forced Expiratory Volume in 1 Second)
Spirometry (forced expiratory volume in 1 second) will be measured in the pulmonary function laboratory following the American Thoracic Society Guidelines.
Lung Volumes (Total Lung Capacity)
Lung volumes (i.e., Total Lung Capacity) will be measured in the pulmonary function laboratory following the American Thoracic Society Guidelines.
Lung Volumes (Inspiratory Capacity)
Lung volumes (i.e., inspiratory capacity) will be measured in the pulmonary function laboratory following the American Thoracic Society Guidelines.
Lung Volumes (Residual Volume)
Lung volumes (i.e., Residual Volume) will be measured in the pulmonary function laboratory following the American Thoracic Society Guidelines.
Diaphragm Thickness
The right hemi-diaphragm thickness will be measured using a 13 megahertz ultrasound transducer.
Diaphragm Thickening Fraction
The right hemi-diaphragm thickening fraction will be measured using a 13 megahertz ultrasound transducer.
Peak Oxygen Uptake During Cardiopulmonary Exercise Testing
Cardiopulmonary exercise test-based assessment of peak oxygen uptake (VO2 peak) will be performed on a cycle ergometer.
Ventilatory Response During Cardiopulmonary Exercise Testing
Ventilatory response will be assessed during cardiopulmonary exercise testing (on a cycle ergometer) with exhaled gas measurements captured breath by breath.
Heart Rate Response During Cardiopulmonary Exercise Testing
Heart rate response will be assessed during cardiopulmonary exercise testing on a cycle ergometer.
Pre-frontal Cortical Neural Activity During Cardiopulmonary Exercise Testing
Oxygenated and total hemoglobin of the prefrontal cortex will be measured with Functional Near Infrared Spectroscopy during cardiopulmonary exercise testing.
Physical Activity Levels
Physical activity (daily steps) will be measured via a tracking device (Fitbit, San Francisco, USA) for a 7-day period.
Leisure-Time Exercise
Leisure-time exercise will be measured via the 3-item Godin Leisure-Time Exercise Questionnaire - Leisure Score Index. The Leisure Score Index is used to rank individuals from the lowest to highest exercise levels: sedentary (score less than 14 units); moderately active (score of 14-23 units); and active (24 units or more).
Health-Related Quality of Life
The Short-Form 36 Health Survey (SF-36) will be used to assess general health-related quality of life. The SF-36 consists of eight scaled scores (total score ranging from 0 to 100), with lower scores representing lower health-related quality of life.
Depression, Anxiety and Stress Scale
The Depression, Anxiety and Stress Scale (DASS-21) questionnaire has 21 items to assess mood (anxiety, depression, and stress). Each statement for the three domains is given a score of 0 (not applicable) to 3 (applicable most of the time) with scores categorized as follows: Normal, Mild, Moderate, Severe, and Extremely Severe.
Participant Study Recruitment
Recruitment-success percentage and reasons for participation/non-participation in the study will be collected.
Participant Retention in the Study
Participant retention will be assessed by measuring participant follow-up with testing throughout the study period.
Adherence to Inspiratory Muscle Training Load
Adherence to the IMT intervention will be tracked electronically via the IMT device (i.e., percentage of the maximal inspiratory pressure prescribed).
Adherence to Inspiratory Muscle Training Days
Adherence to the IMT intervention will be tracked using a participant log to record the number of training days completed each week.
Adverse Events During Inspiratory Muscle Training Practice (Safety and Tolerability)
Any adverse events (i.e. prolonged muscle soreness, pneumothorax) with IMT will be assessed throughout the study period.
Participant Satisfaction with the IMT Intervention
A multiple-choice and free-form questionnaire assessing the participants' satisfaction with the IMT intervention will be completed by study participants.