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.