Head supported mass, including helmets, night vision, communications, and other attachments, is a two-edged sword. Though such technologies generally increase soldier survivability, there are functional occupational limits to how much mass may be borne effectively and safely. The chronic effects of an increased head supported mass include acute and degenerative cervical spine injuries. To understand the role this increased mass plays in chronic cervical spine injuries, the sensitivity of intervertebral stresses to the location and magnitude of the head supported mass was assessed using the Duke University Human and Neck Model (DUHNM). The DUHNM is a hybrid multibody and finite element model equipped with active musculature and anatomically accurate stiffness of spinal units. The region of interest included head supported mass from 0 to 5 kg at locations 0-100 mm from the head center of gravity in the vertical and horizontal directions. Simulations include the effects of running (~1 g-1 Hz sinusoidal input), jumping from low height (4 g-100 ms half sine input), and parachute drops (~10 g-50 ms half sine input) on maximum neck forces and moments. Extreme scenarios show increasing mass as well as the distance anterior the center of gravity increase the maximum moment and force in the neck by nearly an order of magnitude. Based on these simulations, we provide initial contours for design guidance envelopes for head supported mass and center of gravity location in terms of career longevity and assumed occupational scenarios for head supported mass under repeated impact loading.