Heads Up! A Biomechanical Pilot Investigation of Soccer Heading Using Instrumented Mouthguards (iMGs)

Abstract

Soccer players purposefully head the ball, raising concerns about reduced tolerance to concussion and potential long-term brain health. By combining qualitative video analysis with custom-fit instrumented mouthguards (iMGs), we aimed to categorize header kinematics (peak linear acceleration (PLA) and peak angular acceleration (PAA)) by header type and ball delivery method. iMGs were fitted to 10 male collegiate players for twelve matches. A total of 133 headers were verified and contextualized via video review. The most common header type (38.7%), as well as the preceding ball delivery method (47.4%), was found to be a pass. Approximately one-quarter of header impacts (27.0%) occurred below 10 g. For header type, there were no significant differences in kinematics, with shot attempts having the highest median PLA and PAA. For ball delivery methods, goal kicks had significantly greater PAA than long balls and pass attempts. The current study highlights the utility of qualitative video analysis in combination with real-time head kinematic data from iMGs to understand the mechanism and severity of header impacts. The pilot findings indicate that high-speed ball delivery methods result in higher head kinematics and should be a focus of future mitigation strategies.

Head Exposure to Acceleration Database in Sport (HEADSport): a kinematic signal processing method to enable instrumented mouthguard (iMG) field-based inter-study comparisons

“…The PLA at the head CG and PAA were extracted from each on-field HAE based on the (1) Prevent Biometrics processed output; (2) HEADSport filter method; (3) Butterworth-200Hz; (4) CFC180 filter. Median, IQR and maximum values for PLA and PAA were compared for each filtering method using mixed linear effects modelling, with an alpha level of p<0.05 and has previously been described in detail 28 29. The HEADSport filter method, Butterworth-200Hz and CFC filters were applied to the raw kinematic signals and at the same stages as the Prevent Biometrics processed output.…”

“…Median, IQR and maximum values for PLA and PAA were compared for each filtering method using mixed linear effects modelling, with an alpha level of p<0.05 and has previously been described in detail. 28 29 The HEADSport filter method, Butterworth-200Hz and CFC filters were applied to the raw kinematic signals and at the same stages as the Prevent Biometrics processed output. Transforming the linear acceleration signal at the iMG to the head CG was validated by getting the same results as the Prevent Biometrics processed output when using 200 Hz (−6 dB cut-off frequency) for class 0 impacts.…”