From the 2009 Youth Risk Behavior Surveillance System:
During the past 7 days, on how many days were you physically active for a total of at least 60 minutes per day? (Add up all the time you spend in any kind of physical activity that increases your heart rate and makes you breathe hard some of the time.)
Above description is for aerobic physical activity only. A question to assess muscle-strengthening activity is not currently on the YRBSS questionnaire, but it is intended to be added in the future.