This paper presents the results obtained for the estimation of design parameters for a set of structures used in the manufacture of lower limb exoskeletons, based on its dynamic analysis and on the analysis of materials used in medicine and bioengineering. To develop the work, the models of a serial mechanism, a parallelogram mechanism with 4 bars and a mechanism with gravitational compensation by springs and bars are estimated and tested with different metallic and polymeric materials when they perform a trajectory of a pre-established gaitprofile. The results estimated that the maximum torque generated in the mechanism’s joints is smaller in structures made with polymers than in structures with metallic structures. In addition, from the dynamic perspective of the structures, the components of the torques generated in them were estimated, showing the advantages obtained when reducing them. These results identify the relationship between materials and design for the manufacture of new lower limb exoskeletons, comparing their characteristics for reducing the efforts that must be made by the engines and for minimizing the complexity of the control strategies.