Heading in football. Part 2: Biomechanics of ball heading and head response

Abstract

Objectives: Controversy surrounding the long term effects of repeated impacts from heading has raised awareness among the public and the medical community. However, there is little information about the human response to the impacts and what measures can be taken to alter their effect. The objective of the current study was to gain a better understanding of heading biomechanics through the implementation of a numerical model and subsequent investigation of parameters related to heading technique and ball characteristics. Methods: A controlled laboratory study was carried out with seven active football players, aged 20-23 years who underwent medical screening and were instrumented with accelerometers mounted in bite plates and electromyographic electrodes on the major neck muscle groups. Balls were delivered at two speeds (6 m/s and 8 m/s) as the subjects demonstrated several specific heading manoeuvres. Photographic targets were tracked via high speed video to measure heading kinematics. One subject demonstrating reasonably averaged flexion-extension muscle activity phased with head acceleration data and upper torso kinematics was used to validate a biofidelic 50th percentile human numerical model with detailed representation of the head and neck. Results: Heading kinematics and subject responses were used with a detailed numerical model to simulate impact biomechanics for a baseline heading scenario. Changes to heading techniques and ball characteristics which mitigated head impact response were identified. Conclusion: A numerical model combined with biomechanical measurement techniques is an important tool for parametric investigation of strategies to reduce head impact severity via changes in heading technique or the physical properties of the ball. N umerical models have been used by researchers to gain a better understanding of football heading biomechanics and methods for reducing head impact response. 1-4The advantages of numerical models include repeatability, ease of altering and controlling specific model characteristics, and ability to acquire detailed response information. Recognised disadvantages include the need for validation of the models for conditions under which the model is exercised.An early modelling effort consisted of a rigid body representing the head, seven bodies for the neck, and one for the torso.1 Springs and dampers interconnected the bodies to represent the overall interactions of the discs, ligaments, and muscles. The model was validated for passive football impact conditions represented by force-time functions and with experimental data. The effects of head/ball mass ratio, impact velocity, and elasticity were investigated to propose safe playing conditions. Linear and angular acceleration injury criteria from automotive safety research were employed to assess the risk of acute brain injury.A numerical model employed by Ziejewski et al consisted of three dimensional rigid bodies implemented in the Articulate Total Body (ATB) computer simulation software.2 Normally consisting of ...

Analytical modelling of soccer heading

“…Peak skull acceleration occurs within the first 15 ms after the soccer ball impact. This agrees with the published experimental data (Naunheim et al 2003a;Shewchenko et al 2005). In the second phase of the motion, the peak skull acceleration is higher than that of the brain.…”

“…We have also validated our model against head acceleration data obtained from published literatures (Bayly et al 2002;Naunheim et al 2003a;Shewchenko et al 2005;Withnall et al 2005). They have performed soccer heading experiments on both human subjects and surrogates.…”

“…The model produces the relationship between the velocity of soccer ball before impact and the resultant linear accelerations of the skull and brain. Data obtained for skull accelerations were compared with published experimental data of head accelerations during soccer heading (Bayly et al 2002;Naunheim et al 2003a;Shewchenko et al 2005;Withnall et al 2005). In addition, the brain accelerations were validated with an experiment performed on an instrumented dummy skull.…”

The Influence of Head Impact Threshold for Reporting Data in Contact and Collision Sports: Systematic Review and Original Data Analysis

“…An area of increasing interest in these injuries are the forces involved and research 5,20,24,38,41,45,53,65,78,87,88,90,91,97,109,110,112,113,119,120 has been sought to better determine the head linear and rotational accelerations involved in these injuries. Head impact dynamics have been analysed through the use of video analysis, 65 in game measurements, 20,24,32,53,76,90,91,94,96,112,119 numerical methods 5,38,97,120 and reconstructions using anthropometric test devices 41,78,87,88,109,110,113 in helmeted sports such as American football 20, 24, 91, 119 and ice hockey 90,112 and in un-helmeted sports such as soccer 45 and rugby union. 53 The on-field assessment of head impacts has been captured with a head impact telemetry system (HITS) (Simbex, LLC, Lebanon, NH) using helmet mounted accelerometers enabling determination of the head linear and rotational accelerations in American foot...…”

Forensische Beurteilung des Kopfstoßes

“…(Nach [9]) So zeigen die von Schneider[27] ermittelten Ergebnisse einer Studie zum Fußballkopfstoß, dass ein wesentlicher Einfluss der Muskelspannung auf die zu erwartenden Kopfbeschleunigungen nicht anzunehmen ist. Der marginale Einfluss der Muskelspannung auf die resultierenden linearen Kopfbeschleunigungen wurde auch durch andere Studien bestätigt[28]. Angesichts der vergleichbaren Stoßdauer legt dies nahe, dass eine wesentliche Erhöhung der effektiven Masse infolge angespannter Nackenmuskulatur nicht zu erwarten ist.In Zusammenarbeit mit dem Institut für Sportwissenschaft und Sport der Universität der Bundeswehr München erfolgten experimentelle Untersuchungen zur Ermittlung der beim Kopf-zu-Kopf-Stoß vorliegenden Kräfteverhältnisse.…”