Real-time biofeedback of gait parameters using infrared position sensors

Developing sensor technologies for avoiding foot contact with obstacles or uneven surfaces is a potentially powerful intervention for maintaining balance while undertaking hazardous gait tasks. Such interventions are particularly important in individuals influenced either by ageing or gait pathologies. This research describes an infrared sensor system that provides real-time feedback of toe position with respect to the support surface to enable safer ground clearance. Infrared position sensors were used to monitor shoe end points and foot trajectory with respect to the walking surface. Vertical displacement of the toe was displayed in real-time using a data projector such that subjects could adjust their toe clearance. Ten healthy young and 10 healthy older subjects undertook normal unconstrained walking (no-feedback) and in a following condition (biofeedback) were instructed to maintain minimum toe clearance (MTC) within a target band defined using the no-feedback toe clearance characteristics [lower bound: 1.5 x baseline mean MTC, upper bound: lower bound + 3 x SD]. Both groups significantly increased toe clearance above baseline, confirming that on-line feedback of a kinematic gait parameter can be utilized by both young and older adults to change their lower limb trajectory. Poincaré analysis undertaken on MTC time-series data from successive gait cycles confirmed that the younger participants were more stable during both baseline and feedback and capable of maintaining MTC within narrow bounds without shifting from an established locomotor pattern. The results highlighted that real-time biofeedback of foot trajectory gait parameters has potential to assist in gait rehabilitation and other biomedical and healthcare applications.