Linear and Angular Head Accelerations in Daily Life

The purpose of this study was to determine the linear accelerations, angular rates, and angular accelerations of the center of gravity of the head during daily activities and to determine the effect of angular terms on the linear accelerations. A total of 700 experiments were conducted with 18 subjects performing 13 different tasks. Resultant maxima were 93.6 m/s² for linear acceleration, 931.3 rad/s for angular acceleration and 9.03 rad/s for angular rate. Comparisons by gender were statistically significant in 21.9% of cases. Qualitatively, subject effort appeared to be the most important factor.

Average error was strongly influenced by the type of motion in each event, ranging from -3.1% to 115.2% when converting from mouthpiece resultant accelerations to center of gravity acceleration. Error increases as angular rates and accelerations increase. Mouthpiece array accelerations are statistically significantly different than center of gravity accelerations in 86.3% of comparisons. Array designs from the literature are significantly different than center of gravity accelerations with equal frequency to the mouthpiece. Peak accelerations from Allen et al 1994 may require correction of up to 2G and 80% to obtain center of gravity accelerations. Angular terms must be accounted for even at daily activity levels.