User-centered design and structural validation of a multifunctional fitness wheelchair

Long-term sedentary lifestyles among wheelchair users frequently lead to secondary complications such as muscle atrophy and joint stiffness. This study aims to develop an innovative multifunctional fitness wheelchair that integrates upper-limb resistance training with daily mobility to promote daily exercise.

A user-centered design framework was employed, beginning with semi-structured interviews and Kawakita Jiro (KJ) analysis, a qualitative affinity diagram technique for sorting interview data, to identify 13 key functional and experiential requirements. These needs were categorised using the Kano model and prioritised through an objective entropy-based weighting method. Based on these prioritised user needs, we designed a multifunctional wheelchair that supports chest, shoulder, and hand-shoulder resistance training. Structural integrity was evaluated via finite element analysis (FEA) in Abaqus, while kinematic feasibility and spatial layout were validated through a scaled physical mock-up.

Fitness training functionality (W = 0.1438), adjustability (W = 0.1360), and postural comfort (W = 0.1334) emerged as the most critical design drivers. FEA results revealed a maximum deformation of 1.596 mm and a peak stress of 381.3 MPa under a 980 N load, yielding a safety factor of 1.20 for the rotating armrest, which confirms structural reliability for intensive exercise. The mock-up successfully validated fluid transitions between training modes without geometric interference.

By integrating resistance training into daily mobility, this design offers a practical solution that reduces sedentary-related health risks and supports long-term physical maintenance outside clinical settings.