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A 3-2-2-2 array of linear accelerometers and a combination of a triaxial linear accelerometer and a triaxial angular rate sensor were mounted into a Hybrid III 50th percentile male ATD head-form and compared in a variety of short- and long-duration events. An appropriate low-pass filter cutoff frequency for differentiating the angular rate sensor data into angular accelerations was found by using a residual analysis to find individual cutoff frequencies for the three center of mass (COM) linear accelerometer channels and the three angular rate sensor channels and taking the arithmetic mean of the six cutoffs. The angular rate sensors provide more accurate rotational rates than integrated angular accelerations calculated from arrays of linear accelerometers and are less cumbersome, especially for events lasting longer than 200 ms.

Several studies have sought to investigate the biomechanics associated with “whiplash syndrome” by evaluating head kinematics in simulated low-speed rear-end collisions. However, the present study is the first to comprehensively measure head accelerations in six degrees of freedom for the purpose of estimating upper neck loads. In the first phase of the study, nine volunteers were instrumented with a sensor package to measure three-dimensional linear accelerations and angular velocities of the head during rear-end impacts while riding an amusement park bumper car. In the second phase, thirty volunteers were instrumented with the same sensors during selected vigorous activities, including hopping and skipping rope. The linear and rotational head accelerations as well as the calculated upper neck forces and moments for the two groups are presented and compared.