The Relationship Between Maximal Oxygen Consumption and Inspiratory Muscle Activation Pattern Under Loaded Inspiratory Muscle Tests in Healthy Adults

Study Overview
=================
Brief Summary
-----------------
Maximal oxygen consumption, VO2max, is the gold standard to evaluate human aerobic fitness, which stands for the maximal capacity of cardiorespiratory system and musculoskeletal system to transport and utilize oxygen. Previous study showed that there is significant correlation between maximal oxygen consumption from cardiopulmonary exercise test and strength and endurance of lower extremities. In people with sedentary lifestyle, they often limited by the lower limb muscle performance during cardiopulmonary exercise test. Their breathing patterns are more irregular than athletes during cardiopulmonary exercise test. However, there is no study comparing the activation pattern of respiratory muscles between these two groups. Whether the breathing pattern in people with lower exercise capacity is less efficient under exertional activities still unknown. The purpose of this study is to investigate the relationship between maximal oxygen consumption and inspiratory muscle activation pattern in healthy adults.

Official Title
-----------------
The Relationship Between Maximal Oxygen Consumption and Inspiratory Muscle Activation Pattern Under Loaded Inspiratory Muscle Tests in Healthy Adults

Conditions
-----------------
Healthy

Intervention / Treatment
-----------------
* Other: Loaded inspiratory muscle test and cardiopulmonary exercise test


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Healthy adults (age > 20 years old) Be able to cooperate with the measurements of this study Exclusion Criteria: any clinical diagnosis that will influence the measurement, including any history of neuromyopathy angina, acute myocardial infarction in the previous one month pregnancy history of syncope during exercise any musculoskeletal system disorder that unable to perform cardiopulmonary exercise test

Ages Eligible for Study
-----------------
Minimum Age: 20 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Healthy group<br>Subjects are above 20 years old. Their condition is healthy with no history of inspiratory disease. They can cooperate with the measurements of this study. | Other: Loaded inspiratory muscle test and cardiopulmonary exercise test<br>* This is an observational study. Loaded inspiratory muscle test is setting at 30% of maximal inspiratory pressure. Subjects will perform only 15 breaths under this intensity to exam the performance of their inspiratory muscles. Loaded inspiratory muscle test is not for training. Cardiopulmonary exercise test is performed by using bicycle ergometer. These two tests will be performed at least 1 week separately.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Diaphragm and Sternocleidomastoid muscle activation | Root mean square values | during the loaded inspiratory muscle test condition; it would take about 3 minutes | 
| Maximal exercise capacity | Maximal oxygen consumption | during the cardiopulmonary exercise test; it would take about 12 to 15 minutes |