Wheelchair-accessible fitness systems are described to provide total body strength, range of motion, and cardiovascular training to users in retirement and rehabilitation settings. Resistance is provided through a collection of resistance bands that are designed for low-stress and high-efficacy use. Additional system functionality can be incorporated to provide physical-therapist options for controlled rehabilitation exercises. Sensors can be connected to the resistance bands to provide important user-generated data, which can be collected and managed. The systems can accommodate any type of chair, rehabilitation ball, or wheelchair assembly. The systems are optionally collapsible and portable.