Validity and Comprehensibility of Physical Activity Scales for Children With Sport Injuries

Background: Adult physical activity scales are used with children but may not be valid in this population. This study assesses the appropriateness and comprehensibility of currently used physical activity scales in children, identifies sources of response errors, and suggests scale modifications. Methods: Cognitive interviews were conducted with 30 children who had a lower extremity injury, purposefully sampled based on age and sex. Interviews were conducted to identify children's comprehension of 6 physical activity questionnaires: Tegner activity scale, Cincinnati Knee Rating System, KOOS-Child, Marx activity scale, HSS Pedi-FABS, and KOS sports activity scale. Results: The Tegner scale uses complex activity level descriptions (eg, competitive vs. recreational sports, types of sports and inclusion of work-related physical activity). Activity frequency, description of movement, and sport type in the Cincinnati Knee Rating System led to response mapping issues in many children. Most children felt the KOOS-Child pictures depicting activities were helpful, but not all found the 7-day timeframe relevant. Whereas, most children found the Marx scale and HSS Pedi-FABS items clear, concise, and easy to answer. Children reported difficulties differentiating between endurance and duration items used in the HSS Pedi-FABS. The consistent response format of the KOS sports activity scale was considered a positive attribute although children had trouble comprehending terms such as grating and grinding. Conclusions: Children found some scales too difficult to answer, whereas others required modifications, particularly in general instruction, language, question format, and mapping (matching an answer to potential options) to adapt to the specific needs of children. Level of Evidence: Level II.