A report is given of the development of sets of measures with which to determine the physical fitness status and activity patterns of 10- to 17-year-old school children and youths. Three groups of physical education experts worked on the task of identifying and agreeing upon appropriate measures. The first panel determined that the most valid measures for measuring physical fitness status tested five elements: (1) cardiorespiratory endurance; (2) muscular strength; (3) muscular endurance; (4) body composition; and (5) flexibility. The second panel considered the most feasible, valid, and reliable ways to measure these elements through school-based, mass-testing programs. The third panel sought to determine items to be included in a questionnaire that could be used to monitor trends and patterns of participation in school physical education programs, public recreation programs, and participation in other physical activities. A discussion is presented of the results of each meeting, the protocols identified for administration of the measures, the rationale behind selection of the measures, and descriptions of concerns about or disagreements with the measures. The questionnaire developed to identify patterns and levels of physical activity among youth is appended. (JD)