Grant: Discovery Grants Program - Individual

This research program is to provide a better understanding of how sensory information about contact with the environment is realized and how mechanical considerations of the foot are interrelated in order to have efficient and functional balance reactions during locomotion. This program will allow for the training of highly qualified personnel in very specialized methodological and scientific techniques. The underlying motivation is to understand how contact pressures/forces under the feet are being transformed into neural signals and then how that is produced as functional outcomes. There are several components of investigation that will build upon previous findings in the ongoing research program. The first component will determine the effects of foot sensation reduction/faciltation on the ability to generate balance reactions to unexpected perturbations during gait. Secondly, fine-wire electromyography (EMG), a method that can quantitatively record muscle activity from very specific deep muscles of the lower limb, and surface EMG will be used to understand the muscle activity patterns used to generate balance reactions to unexpected gait perturbations. The third component will involve understanding the effects of mechanical modulations (arch support, footwear) on producing balancing reactions. These experiments will evaluate if the movements and muscle activation patterns transform into functional balance recovery patterns (kinematic and kinetic analysis) to successfully maintain balance. These will systematically evaluate the contribution of the foot sensation and foot mechanics towards functionally significant balance responses during locomotion. The experimental conditions will consist of level surface gait and perturbed gait where unexpected external perturbations may involve surface translation or change surface orientation. These conditions will be performed when the participants have normal foot sensation, reduced foot sensation (via hypothermia) and when the foot sensation is facilitated. This approach will allow for a complete evaluation of the process of receiving mechanical contact information from the environment and how much of the information is transferred into the CNS, then to muscle activity and finally to functional balance responses. Thus by selectively reducing or facilitating the sensation from the feet the contribution of the mechanoreceptors can be systematically evaluated. The expected significance of this research program is in two areas of importance. Firstly, quantifying the contribution of plantar-surface mechanoreception to the balance control of locomotion. Secondly, this understanding could provide important information for the advancement of an assistive device that would facilitate plantar-surface mechanoreception for older adults whom are at risk of falling due to age-related deterioration of the sensation from the bottom of the feet.