Exploration of biomechanics, mental workload and metabolism factors during prosthetic gait

Progress in prosthetics development have greatly improved everyday life of people with lower limb amputations. However, efficiently operating a prosthetic device requires a complex learning process, as users need to familiarize with the biomechanics of prosthetic-assisted gait. Both mental and physical workloads play a role in this process, with significant implications for prosthetic use and acceptance. In this perspective review, we explore the intricate relationships between these elements in lower limb prosthetic users and foster the discussion about the possible correlation between various metrics and their use in the fields of biomechanics, cognitive and physical fatigue. First, we describe all compensatory movements that may be performed during prosthetic-assisted gait. We then examine the two loads: mental workload (MWL) and physical load, which are both reflected in the metabolic cost required for prosthetic use. From this analysis, we envision that prosthetic gait could be regulated by different factors, namely, biomechanics, MWL and metabolism. The main goal of this perspective is to foster discussion across these three domains, defining all types of 'loads' imposed on the patient using objective and cross related descriptors. We argue that such descriptors should be analyzed through specific approaches and protocols in order to be quantified in absolute manner. Being able to univocally describe the single inference of these macro areas to bionic limbs use, could lead to new paradigms in the patient's rehabilitation process and in the design of future robotic prostheses.