Modulation Of Airway Reactivity With Chronic Mechanical Strain

Inclusion Criteria: * Children 8-17 yrs olds with severe asthma (N=120) will be recruited from the Pediatric High Risk Asthma Clinic and Pulmonary Clinics at Riley Hospital for Children at Indiana University Health. * Severe asthma will be defined by the need for medication therapies following steps 4-6 according to the National Institutes of Health's Asthma Care Quick Reference, September 2012 or high dose of inhaled corticosteroids * On a stable regimen of asthma medications for at least 8 weeks prior to enrollment without systemic corticosteroids for ≥ 4 weeks Exclusion Criteria: * Obese (\>95% predicted BMI) * Congenital heart disease or chronic lung disease * History of pneumothorax * Inability to perform pulmonary function testing * Oxygen saturation \<93% * forced expiratory volume at one second (FEV1) \<70% predicted * Provocative concentration causing a 20% drop in FEV1 from baseline (PC20) ≥16 mg/ml of methacholine.