The key guidelines for school-aged children and adolescents focus on three types of activity—aerobic, musclestrengthening, and bone strengthening. Each has important health benefts. Certain activities can be aerobic aswell as muscle or bone strengthening. Illustrations of these activities can be found in the real-life examples atthe end of this chapter.Aerobic activities are those in which young people rhythmically move their large muscles for a sustainedperiod of time. Running, hopping, skipping, jumping rope, swimming, dancing, and bicycling are all examplesof aerobic activities. Aerobic activities increase cardiorespiratory ftness. Children often do activities in shortbursts, which may not technically be aerobic. However, the Guidelines uses the term aerobic to refer to thesetypes of activities, even if they are done only briefy.