The Effect of Montelukast on Difficulty in Breathing After Exercise in Pediatric Patients (MK0476-377)(COMPLETED)

Inclusion Criteria: * The child is 4 years to 14 years of age * The child is a non smoker * The child has exercise-induced bronchoconstriction (EIB) Exclusion Criteria: * The child has active or chronic breathing disease, other than asthma * The child has required insertion of a breathing tube for asthma * The child had major surgery within the last 4 weeks * The child is currently in the hospital * The child has or had an upper respiratory tract infection within the last 2 weeks * The child has been hospitalized or visited the emergency room or had a change in their medication for asthma within the last 4 weeks * The child has been in a research study in the last 4 weeks * The child has stomach, brain, heart, kidney or liver disease * The child drinks more that 4 caffeinated drinks a day