Comparison of impact data in the center of gravity and soft palate of a NOCSAE head form with and without sports helmets

Purpose. Research is needed to establish an approach for the measurement of head acceleration experienced during impact in actual athletic situations. The purpose of this study was to develop a method to measure head acceleration. By establishing baseline acceleration measurements of a standardized headform at various impact sites with accelerometers located at (1) the headform center of gravity (HFCOG), (2) the simulated soft palate position (mouthpiece), and (3) the helmet, the sports medicine professional may know the level of acceleration exposure that may lead to concussion or brain injury. The relationship between the mouthpiece and HFCOG acceleration was determined, which can eventually allow for the measurement of head accelerations during actual competition and practice.;Three studies were conducted to meet the research goals. The first study was to determine the accuracy and reliability of an accelerometer attached to a mouthpiece to measure the actual acceleration imparted to the COG of a headform when impacted. There was a strong relationship between the mouthpiece and HFCOG acceleration (g) and Severity Index (SI). A predictive statistical model was developed from the regression analysis. The observed mouthpiece acceleration (g) and SI measures were utilized in this equation to predict the actual HFCOG acceleration (g) and SI measures experienced by the headform upon impact. It was also demonstrated that the mouthpiece acceleration (g) and SI measures were reliable at predicting HFCOG acceleration (g) and SI measures upon impact.;The second study determined if the mouthpiece accelerometer g and SI measurement was a more accurate and reliable measure of headform COG acceleration than that of an accelerometer attached to a helmet fitted on the headform. Mouthpiece accelerometer measures were significantly more accurate and reliable measure of HFCOG acceleration (g) and SI than the helmet measures.;The third study investigated if drop height and impact site location affected the relationship established among the mouthpiece, helmet, and HFCOG g and SI measures in the first two studies. The relationships among the three-accelerometer placements were not affected by changing drop height or impact site. The accuracy and reliability of the mouthpiece accelerometer was a significantly better measure of HFCOG acceleration (g) and SI than the helmet accelerometer at all drop heights and impact sites.;The measurement of HFCOG acceleration (g) and SI can be reliably predicted from an accelerometer attached to a mouthpiece during impact. The mouthpiece acceleration (g) and SI measure were also more representative of headform COG acceleration (g) and SI than that of the helmet. Drop heights and impacts sites did not affect the relationships between the mouthpiece and HFCOG and helmet and HFCOG g and SI measures. Use of the mouthpiece accelerometer will allow for direct assessment of head accelerations in the field.