The human body is daily exposed to vibrations of different nature. In the case of Manual Wheelchair (MWC) users, these vibrations are even present at the core of one's locomotion and, according to literature, have detrimental effect on their anatomical structures. Various parameters are likely to affect the vibration exposure for MWC users: ground irregularities, user’s characteristics, MWC settings and defects such as micro-cracks and mechanical fatigue. Further, the 2020-circular-economy law pushes for the second-hand use of refurbished, thus maybe defective, MWC. These evidence highlight the need to finely address the vibration exposure of the interacting User/MWC couple for a better MWC user care. Under this framework, the objectives of HandiVib are to quantify the vibration exposure of the User/MWC couple to understand the incurred risk of injury and subsequently propose new procedures to evaluate the MWC suitability. To fulfill these objectives, HandiVib lies on three hypotheses. The vibration exposure of MWC users (H1) conveys to a raise in the musculoskeletal loads, increasing the risk of injury; (H2) has consequences that depend on the user’s level of disability (H3) is expected to rise using a MWC with degraded mechanical conditions (e.g. microcracks, mechanical fatigue). To reach these aims, the overall goal of this project will be to investigate the vibration exposure for a wide number of User/MWC couples and situations. Proven methods in the field of human body exposure to vibration will be implemented. An experimental framework will be designed associating an MWC ergometer and electrodynamic shakers able to simulate the ground excitation a MWC is exposed to under real conditions. This setup, combined to biomechanical models will be helpful to determine vibration transmission and intervertebral forces affecting the user under various levels of disability and MWC mechanical states. The project’s originality lies in the simultaneous evaluation of vibration transmission through the body and musculoskeletal loads. HandiVib will proceed into three technical work packages: one will aim at designing a dedicated experimental setup and two others will address the project’s hypotheses based on experimentation and biomechanical modeling. HandiVib will be led by D. Chadefaux, associate professor at the Université Sorbonne Paris Nord (USPN) since 2018. D. Chadefaux conducts her research activities about the optimization of the human-equipment interactions under shock and vibrations at the Institut de Biomécanique Humaine Georges Charpak (Arts et Métiers - Sciences et Technologie). Regarding the project’s execution, the team will be composed of senior researchers from the IBHGC, the INI-CERAH, the Hopital Raymond Poincaré (Garches), and Politecnico di Milano. Given its potential to improve MWC users care and to promote innovation for MWC evaluation, Handivib meets the intentions of the research theme 8.7 “Technologies pour la santé”. Experimental outcomes will provide a tool to the clinician to evaluate the risk of injury incurred for a given MWC mechanical condition. Findings will also contribute to innovating procedures of interest to determine whether a MWC complies with safety standards. Through a simple lumped-element model, a physical model could be developed to enhance the design of test dummies reproducing faithfully the user effect on a MWC. Findings will also contribute to detect mechanical defects in a MWC: a testing platform will be developed to evaluate the suitability of a refurbished MWC for further use. The experimental database collected will favour understanding the specificity of each pathology with respect to vibration exposure. HandiVib will contribute to guide MWC user in their MWC choice and tuning in accordance with rehabilitation therapists’ recommendations to minimize the risk of injury induced by the vibration exposure.

Locomotion with a manual wheelchair (MWC) submits the upper-limbs of the manual wheelchair users (MWU) to an important stress, which varies according to the environment. To assist MWU in selecting the paths that preserve their upper limbs, a cost reflecting the physical demand of the successive situations along the possible paths must be attributed. In the current state of knowledge and accessibility standards, an obstacle has no graduation and can only be marked as crossable or not, which cannot reflect, neither the heterogeneity of the situations, nor the link between their accessibility and the physical and technical abilities of the MWU. To go beyond these limitations, this project aims at defining biomechanical costs that can be attributed to the environmental situations, and that could be implemented in future optimal path selection algorithms. This will make it possible to provide MWU with individualized paths taking into account their individual capacities. To do so, a musculoskeletal model will be developed to quantify various biomechanical quantities that will serve as input data for the definition of the biomechanical costs. These costs will be computed for various situations, reproduced in a realistic MWC locomotion simulator developed in the framework of this proposal. Such a project will provide original and useful data for accessibility evaluation, planning of urban development services and assistance adaptation. It will also be the basis for further work on MWU evaluation and paths characterization to provide personalized cost-optimal paths.