Characterisation of lower limb kinematic parameters to estimate hip and knee lift assistance strategy during sit-to-walk

Malaysia is set to be an aged nation by 2030. An aged population poses a unique set of challenges to the healthcare network, as a result of geriatric syndromes. Geriatric syndromes such as increased risk of falls, a general decline in functionality and muscle mass - limits the individual's ability to perform vital movements in their daily lives. As a result, falls are common among older adults. Simple tasks such as standing up from sitting and walking, getting up from a chair, getting out of bed, or even leaving the toilet can be dangerous and even fatal. Therefore, in this proposal a wearable system that provides hip and knee lift assistance to older adults during sit-to-walk is envisioned. To do this, we must first identify the sit-to-walk strategy being employed. Subsequently, the required torque at the knee/hip to generate lift needs to be determined. Literature has shown that the torque generated at the hip and knee joints differ based on the strategy employed. However, literature has been unable to identify a suitable parameter to distinguish sit-to-walk strategies and thus the required torque about the knee/hip in real-time. Hence, we seek to achieve this by characterising lower limb kinematic parameters during sit-to-walk motion, to establish its relationship to the hip and knee lift torque profile and sit-to-walk strategies. This relationship will then be the basis to design a model that determines the required strategy and estimate the hip/knee torque requirement for lift assistance during sit-to-walk motion. To achieve this, a timed-up-and-go experimental set-up will be conducted to collect sit-to-walk motion data. The findings from this study will enable the development of a wearable solution to provide lift assistance during sit-to-walk for older adults, thus retaining their mobility and quality of life, while reducing stress on the national healthcare network.