Muscle Activity Simulation according to Steering Angles during the Turning of a Two-Person Tricycle for the Elderly and Persons with Disability

Objective: The aim of this study was to analyze and validate the stability of turning during cycling by simulating the key muscle activities of the rider during the turning process. This research aimed to contribute to the development of recreational assistive devices that enable elderly individuals and those with disabilities to enjoy leisure activities with their families.BRBackground: The development of assistive devices for the elderly and individuals with disabilities has gained significant importance in fostering inclusive leisure activities. Simulations have proven to be valuable tools in research for effectively assessing the safety and stability of such devices. In this context, this study specifically aimed to simulate a two-person tricycle designed for use by a family member riding with an elderly individual or a person with a disability. Furthermore, previous research has identified steering stability as a high-priority element in the analysis of safety design components using the Analytic Hierarchy Process (AHP).BRMethod: To evaluate the stability of turning during cycling, the study utilized the AnyBody Modeling System. This system was employed to simulate the muscle activities in specific human body parts, including the lower limb, upper limb, and trunk body, under eight different turning conditions. These conditions encompassed two different speeds (5㎞ and 10㎞) and four steering angles (5°, 10°, 15°, and 20°). The simulations were conducted with five moving parts remaining constant including the saddle and pelvis, both feet and the pedal, and both hands and the handle.BRResults: The results of the simulations revealed that muscle activities increased as both speed and steering angle increased. Specifically, for the upper limb and the trunk body, muscle activities exhibited a greater increase as the steering angle became larger. Notably, the upper limb muscle activities showed an approximately three-fold increase at 5㎞ and a 5° steering angle, in contrast to 20°. Similarly, at 10㎞, a two to three-fold increase in muscle activities was observed.BRConclusion: Through the analysis of the muscular activity that places a burden on the driver's upper body and arms during steering, we have obtained data for improving steering structure, steering control during cornering, and driving guidelines.BRApplication: The application of the human modeling system employed in this study holds significant potential for assessing the stability of novel assistive devices that lack predetermined specifications. This methodology can be invaluable in the development and validation of new innovative devices.