Muscular and Kinematic Responses to Rear-End and Oblique Collisions in a Bumper Car-Based Whiplash Model

W. Valdez, J.M. Asensio-Gil, C.J. Carpintero-Rubio, C. Rodríguez-Morcillo, J.R. Jiménez-Octavio

International Research Council on Biomechanics of Injury - IRCOBI Europe 2025, Vilnius (Lithuania). 10-12 September 2025

Summary:

This study investigates cervical muscle and head–neck kinematic responses during low-speed collisions using bumper cars as a test platform. Thirty-four healthy adult volunteers experienced four collision conditions: rear-end (neutral head), rear-end with head turned ~45°, oblique impacts, and unstructured free-driving to simulate real-world unpredictability. Surface EMG, 3D motion capture, and inertial sensors measured muscle activity and kinematics. Preliminary results show females exhibited significantly higher normalized cervical muscle activation than males across all conditions, especially in the posterior paraspinal muscles during rear-end and oblique impacts. These findings suggest sex-specific differences in muscular responses to whiplash-relevant loading, with potential implications for understanding injury risk. The study provides novel data on the influence of head posture, impact direction, anticipation, and sex on low-speed impact biomechanics.

Spanish layman's summary:

Estudio con autos de choque (34 adultos): las mujeres activan más los músculos cervicales que los hombres en impactos lentos traseros, cabeza girada, oblicuos y conducción libre. EMG y captura 3D revelan que postura, dirección y sexo modulan la biomecánica del latigazo y riesgo de lesión.

English layman's summary:

Bumper-car study on 34 adults shows females’ neck muscles activate more than males in low-speed rear, turned-head, oblique and free-drive impacts. EMG & motion capture reveal posture, direction and sex shape whiplash-relevant biomechanics. Insights guide safer headrests and improved whiplash models.

Keywords: Accident Reconstruction, Injury Biomechanics, Whiplash, Surface Electromyography, Volunteer Testing, Bumper car testing

Published in: IRCOBI Conference Proceedings, vol. 25, ISSN: 2235-3151

Publication date: 12-Sep-2025.

Citation:
W. Valdez, J.M. Asensio-Gil, C.J. Carpintero-Rubio, C. Rodríguez-Morcillo, J.R. Jiménez-Octavio, "Muscular and Kinematic Responses to Rear-End and Oblique Collisions in a Bumper Car-Based Whiplash Model", presented at International Research Council on Biomechanics of Injury - IRCOBI Europe 2025, Vilnius, Lithuania, 10-12 September 2025. In: IRCOBI Conference Proceedings, vol. 25

IIT-25-235C