Background: Virtual reality presents a platform for therapeutic gaming, and incorporation of immersive biofeedback on gait may enhance outcomes in rehabilitation. Time is limited in therapeutic practice, therefore any potential gait training tool requires a short set up time, while maintaining clinical relevance and accuracy. The aim of this study was to develop, validate, and establish the usability of an avatar-based application for biofeedback-enhanced gait training with minimal set up time. Methods: A simplified, eight marker model was developed using eight passive markers placed on anatomical landmarks. This allowed for visualisation of avatar-based biofeedback on pelvis kinematics, hip and knee sagittal angles in real-time. Retrospective gait analysis data from typically developing children (n = 41) and children with cerebral palsy (n = 25), were used to validate eight marker model. Gait outcomes were compared to the Human Body Model using statistical parametric mapping. Usability for use in clinical practice was tested in five clinical rehabilitation centers with the system usability score. Findings: Gait outcomes of Human Body Model and eight marker model were comparable, with small differences in gait parameters. The discrepancies between models were <5°, except for knee extension where eight marker model showed significantly less knee extension, especially towards full extension. The application was considered of ‘high marginal acceptability’ (system usability score, mean 68 (SD 13)). Interpretation: Gait biofeedback can be achieved, to acceptable accuracy for within-session gait training, using an eight marker model. The application may be considered usable and implemented for use in patient populations undergoing gait training. ... Read more

Children with cerebral palsy (CP) often have gait limitations and this is a key target of rehabilitation. Gait training can be an effective intervention to improve functional outcomes such as walking speed and endurance [1]. Virtual reality (VR) is a valuable tool in gait training to increase engagement, however, games must be therapeutically principled. One advantage of VR is that it allows for addition of augmented biofeedback. Biofeedback can improve communication between patient and therapist, while the implementation of gamification and motor learning principles may increase motivation and skill retention. Therapy may target gait parameters, such as step length, knee extension or ankle power generation, with a functional goal to increase walking speed. These gait parameters are interlinked and the most effective target for biofeedback is unknown. ... Read more

A common gait limitation in cerebral palsy (CP) is a reduced ability to generate power at the ankle during push off. This may be due a number of factors, such as muscle weakness or disrupted neuromuscular control. It has been shown that with the use real-time feedback, children with CP can improve key gait parameters such as knee and hip extension [1]. However, it is not known if children can improve ankle power, or, how they would achieve this change at the neuromuscular level. The use of synergy analysis to describe dynamic motor control (DMC) in CP is growing and has been shown to be predictive of treatment outcomes [2]. ... Read more