Due to the lack of studies examining the impact of inspiratory muscle training (IMT) on the severity of exercise-induced bronchoconstriction (EIB) and exercise performance, the specific aim of this study is to assess the efficacy of flow-resistive IMT on EIB severity and symptoms, short-acting beta-2-agonist medication use, operating lung volumes, respiratory and limb locomotor muscle deoxygenation during constant-load cycling exercise, exertional dyspnea, and cycling time-trial performance.
To the investigators knowledge, no study has been conducted assessing the impact of inspiratory muscle training (IMT) on exercise-induced bronchoconstriction (EIB) severity, exertional dyspnea, and cycling time-trial performance. A review noted that studies examining the impact of IMT on asthma have all demonstrated an increase in inspiratory muscle strength (maximal inspiratory pressure, MIP) and endurance (sustained maximal inspiratory pressure). In addition, it has been observed that the reduction in the perception of dyspnea following and during exercise leads to a reduction in short-acting beta-2-agonist (SABA) use and fewer asthma symptoms. The same review also noted the lack of data available to explain the impacts of IMT on exercise performance and tolerance in athletes with EIB. Due to the lack of studies examining the impact of IMT on the severity of EIB and exercise performance, the specific aim of this study is to assess the efficacy of flow-resistive IMT on EIB severity and symptoms, SABA medication use, operating lung volumes, respiratory and limb locomotor muscle deoxygenation during constant-load cycling exercise, femoral blood flow, exertional dyspnea, and cycling time-trial performance. It is hypothesized that eight weeks of IMT will reduce EIB's severity and symptoms, respiratory and limb locomotor muscle deoxygenation, improve operating lung volumes, and exertional dyspnea and improve cycling time-trial performance.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
17
The flow-resistive protocol using the device requires participants to maximally inhale as hard as they can and as long as they can against a small leak (2mm diameter hole) until task failure. This records maximum inspiratory pressure (MIP) and sustained maximal inspiratory pressure (SMIP) values which will be recorded and the best is chosen for the software template by the participant to continue their training session (previously described in arm/group description). The use of the device occurs three times a week, and used for 6-8 weeks.
School of Public Health-Bloomington
Bloomington, Indiana, United States
Exercise-Induced Bronchoconstriction (EIB) Severity
More specifically, the pre- and post-values of the percentage drop in forced expiratory volume in 1 second (FEV1) from the eucapnic voluntary hyperpnea (EVH) test before and after IMT will be measured. Percentage drop in forced expiratory volume in 1 second (FEV1) will be reported in percentages.
Time frame: 8 weeks
Maximum Inspiratory Pressure and Sustained Maximum Inspiratory Pressure
More specifically, the pre- to post-values of maximum inspiratory pressure (reported as cmH2O) and sustained maximum inspiratory pressure (reported as pressure time units) before and after IMT will be measured.
Time frame: 8 weeks
16-km Cycling Time-Trial Time to Completion
More specifically, differences in 16-km cycling time-trial completion time (seconds) before and after IMT.
Time frame: 8 weeks
16-km Cycling Time-Trial Power Output
More specifically, differences in 16-km cycling time-trial power output (watts) before and after IMT.
Time frame: 8 weeks
Constant Load Performance
More specifically, differences in constant load performance (i.e., power output \[watts\]) before and after IMT.
Time frame: 8 weeks
Perception of Breathing Intensity and Unpleasantness and Leg Fatigue
More specifically, whether IMT affects an individual's perception of exertional dyspnea (revised Borg Scales from 0-10 to rate breathing intensity and unpleasantness) and revised Borg Scales from 0-10 to rate leg fatigue during constant load cycling and a 16-km cycling time-trial. Scores will be reported as whole numbers between 0-10. Higher scores indicate extreme intensity, unpleasantness, or fatigue.
Time frame: 8 weeks
Deoxygenation of the respiratory and limb locomotor muscles by near-infrared spectroscopy
More specifically, the effects of IMT on the deoxygenation of the respiratory and limb locomotor muscles during constant load cycling and a 16-km cycling time-trial
Time frame: 8 weeks
Femoral blood flow (FBF) of the limb locomotor muscles by ultrasound
More specifically, the effects of IMT on femoral blood flow (FBF) of the limb locomotor muscles during constant load cycling
Time frame: 8 weeks
Lung Volumes
More specifically, the effects of IMT on operating lung volumes during constant load cycling and a 16-km cycling time-trial.
Time frame: 8 weeks
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