Use behavior and spatial characteristics of National Fitness Routes in China: an in situ observational study.

Background: The installation of outdoor gyms (OGs), also known as the National Fitness Route (NFR) program in China, is increasing in popularity as a government-funded solution to declining population physical activity (PA) levels. However, evidence regarding how these facilities are used and whether they effectively support PA remains limited. Methods: Systematic Results: A total of 9,704 person-observation records were collected, OGs accounted for 15.2% of all observation records, with seniors representing the largest user group. The air walker, leg and waist/back massager were the most frequently used types of OGs. Sitting, standing, and walking were the predominant activities, and behavioral activities exhibited clear spatial clustering around seating areas, dedicated pathways, and open activity spaces. After adjustment for potential confounders, age, time period, week period, temperature, air quality, and site characteristics were independently associated with MVPA, whereas gender and season were not. Conclusion: OGs use represented only a small proportion of activities observed within NFRs, indicating that these spaces function not only as settings for PA but also as important places for recreation and social interaction. Integrating age-appropriate OGs with walking paths, seating areas, tree shade, and flexible open spaces may better support diverse recreational behaviors and promote PA. These findings provide evidence-based guidance for optimizing the planning and spatial design of NFRs to support healthier and more inclusive public fitness environments.