The biomechanics of load carriage in isolated human subjects has been the subject of many studies in the literature (see e.g.: Heglund et al., 1995; Castillo et al., 2014; Bastien et al., 2016). In comparison there is virtually nothing published yet on the biomechanics of collective load carriage, i.e. the lifting and carrying of the same load by two or more individuals. Our project consists in exploring the changes occurring in the kinematics and kinetics of locomotion when two humans transport collectively the same load and in quantifying their energetic performance. The subjects are equipped with markers placed at different locations on their body and are filmed during their displacement by 13 infrared transmitter-receiver video cameras (Vicon©), allowing the 3D reconstruction and analysis of the displacement of their body segments. Force sensors allow to measure the forces exerted by the subjects on the ground and on the handles they use to transport the load. The individuals are considered as a conservative assembly of solids with frictionless joints. This concept is applied to the whole formed by the two subjects and the load they carry, creating what we call a Poly-Articulated Collective System (PACS). The inverse dynamic method allows to assess the internal forces and muscular moments which induce the cohesion and movement of the body segments, respectively.
Bastien, G. J., Willems, P. A., Schepens, B., Heglund, N. C., 2016. The mechanics of head-supported load carriage by Nepalese porters. Journal of Experimental Biology 219, 3626–3634.
Castillo, E., Lieberman, G., McCarty, L., Lieberman, D., 2014. Effects of pole compliance and step frequency on the biomechanics and economy of pole carrying during human walking. Journal of Applied Physiology 177, 507-517.
Heglund, N. C., Willems, P. A., Penta, M., Cavagna, G. A., 1995. Energy- saving gait mechanics with head-supported loads. Nature 375(6526), 52–54.