This thesis presents two studies related to head injury. The study presented in Chapter 1 reviewed findings of cranial movement in animal and human specimens and evaluate the validity of cranial movement due to manual manipulation in humans through engineering analysis. The study had two parts. In Part I, the literature was reviewed to determine the cranial motion in animals and humans. Engineering analysis was done in Part II to determine the amount of force necessary to cause cranial motion in the studies from Part I using skull stiffness values from published studies. Chapter 2 explored data collection methodologies used in frontal sled tests. Several data collection methodologies exist for collecting kinematic data, such as Vicon motion analysis, video analysis, and sensors. Head trajectories from motion data and accelerometer data were plotted up to maximum forward excursion of the head for eight frontal sled tests, four conducted at Virginia Tech and four at the University of Virginia. In addition, the percent difference between maximum forward excursion values from sensor and motion data were calculated. Finally, Chapter 3 discusses the literary contributions of each study and to which journals they will be submitted. / Master of Science