Although evidence indicates that muscular fitness is foundational for ongoing participation in active play, exercise and sport, current national and international youth physical activity guidelines underplay the critical importance of strength-building activities during this developmental phase of life. In view of troubling trends in muscular fitness in today's youth, specific recommendations to address neuromuscular deficiencies are required. An understanding of the multidimensional development of youth physical inactivity and the importance of muscular fitness are needed to have the most significant impact on youth physical activity at the population level. The mounting evidence of the detrimental effects of physical inactivity on youth warrant a review of existing physical activity recommendations and guidelines. The proposed pediatric activity pyramid recognizes the shared importance of strength, skill, and aerobic activities required for the successful implementation of sustainable youth physical activity interventions.