Effects of Working Posture on Exercise Intensity and Upper- and Lower-Limb Muscle Workload during Home Gardening Activities

Background and objective: Home gardening is widely practiced as an accessible form of physical activities across age groups and are increasingly incorporated into agro-healing and therapeutic horticulture programs. Although these activities are often classified as light- to moderate-intensity based on energy expenditure, repetitive working postures such as squatting and trunk flexion may impose substantial localized musculoskeletal load. This study aimed to investigate exercise intensity and muscle workload in the upper and lower limbs during typical home gardening activities based on working posture.Methods: 10 healthy young adult males participated in controlled laboratory experiments involving two common home gardening tasks: lifting flower pots and watering plants. Each task was performed under two different posture conditions, resulting in four experimental postures in total. Exercise intensity was quantified using metabolic equivalents (METs), while muscle workload of the upper and lower extremities was assessed using surface electromyography and normalized to maximum voluntary contraction (%MVC).Results: Based on MET values, pot lifting was classified as a moderate-intensity physical activity, whereas watering was categorized as a light-intensity activity. Despite the relatively low MET levels, several upper limb muscles exceeded high-risk workload thresholds, indicating substantial localized muscle demand. In particular, the anterior deltoid consistently showed high activation across tasks and postures. Muscle workload patterns varied depending on both task type and working posture, with increased trunk muscle demand observed in bending postures and sustained shoulder muscle workload during watering activities.Conclusion: These findings demonstrate that energy expenditure alone may not adequately reflect localized musculoskeletal load during home gardening activities. A combined assessment using both METs and %MVC is therefore necessary to accurately evaluate physical demands and potential injury risk. The results provide practical evidence for designing posture-sensitive, muscle-specific, and safer home gardening and agro-healing programs.