Modal analysis technique is used in order to characterize the human head-neck system in vivo. The extracted modal characteristics consist of a first natural frequency at 1.3±0.1 Hz associated with head-neck extension motion and a second mode at 8±0.7 Hz associated with head translation. By recording experimentally the apparent mass of dummies head-neck system under the same experimental condition as the volunteer subjects, it was possible to compare the human and the dummies frequency response functions and to evaluate their bio-fidelity. The evaluation methodology based on validation parameters extracted in the frequency domain is tested on six dummy necks and on a FEM of head-neck system. Only BioRID is presented in this paper. The results of the two models are similar and present natural frequencies close to the volunteers. Beside dummy evaluation this study also gives new insight into injury mechanisms given that a given natural frequency can be related to a specific neck deformation.