Liberi and the Racer Bike: Exergaming Technology for Children with Cerebral Palsy
Zi Ye, Hamilton A. Hernandez, T.C. Nicholas Graham, Darcy Fehlings, Lauren Switzer, Md Ameer Hamza, Irina Schumann · 2012 · Proceedings of the 14th International ACM SIGACCESS Conference on Computers and Accessibility (ASSETS 2012) · doi:10.1145/2384916.2384965
Summary
This demonstration paper presents Liberi, a multiplayer exercise video game, and a custom cycling-based exergaming station designed to enable children with cerebral palsy (CP) to engage in vigorous physical exercise while playing with peers. Children with CP face limited opportunities for physical activity due to muscle weakness, limited mobility, and spasticity, leading to muscular deconditioning and further reduced mobility over time. The system was developed through seven iterative participatory design sessions involving medical professionals, game designers, computer scientists, kinesiologists, physiotherapists, and eight children with CP. The physical station is a recumbent cycling platform that addresses three challenges: the physical challenge of safely transferring children from mobility aids, the control challenge of mapping pedalling input to game actions without requiring fine motor skills, and the vigour challenge of enabling sufficient energy expenditure. The game itself is a virtual world with multiple minigames, multiplayer interaction, and an in-game money-based reward system, all designed to avoid requiring quick, accurate, or fine motor movements that are difficult for children with CP.
Key findings
Seven of eight children with CP were able to effectively use the cycling-based exergaming station and play the game. Data collected during the design sessions demonstrated that the games were fun and engaging, and that the children were able to reach exertion levels recommended by the American College of Sports Medicine for health benefits. The participatory design process, involving a multidisciplinary team across seven sessions, was essential for iteratively refining both the physical station (for safety, comfort, and ease of use) and the game design (for playability, engagement, and appropriate difficulty). The recumbent bike design proved effective because it provides stability and comfort while naturally mapping cycling input to in-game avatar movement, and avoids the balance demands of upright cycling.
Relevance
This work addresses a critical gap in accessible physical activity for children with motor impairments. While commercial exergames like Nintendo Wii Sports and Kinect Adventures have been used for rehabilitation, they focus primarily on range of motion rather than cardiovascular fitness, and their hardware is not designed for children with significant motor limitations. The Liberi project demonstrates that purpose-built exergaming hardware and software, designed with children with CP from the outset, can enable vigorous exercise that would otherwise be inaccessible. For accessibility practitioners and game designers, the three design challenges identified (physical, control, vigour) provide a useful framework for thinking about accessible active gaming. The emphasis on multiplayer social play — not just solo rehabilitation exercises — recognises that social participation is as important as physical benefit for children with disabilities.
Tags: cerebral palsy · exergame · children · physical activity · participatory design · motor impairment · rehabilitation · game accessibility