Material Participation: scope of "hours of activity"

My husband teaches at an optometry school.  Occasionally (4 times last year), he will lecture at a conference or at meeting.  He receives 1099-MISC's for these times.  These times are related to his occupation.  In the definition of material participation, it talks about the hours of activity.  Is that the actual speaking engagements or does that also include his job, because the speaking engagements are related to his job?