An experimental-computational framework for quantifying football heading biomechanics

Barnes-Wood, Megan 2025. An experimental-computational framework for quantifying football heading biomechanics. PhD Thesis, Cardiff University. Item availability restricted.

Preview	PDF - Accepted Post-Print Version Download (9MB) | Preview
	PDF (Cardiff University Electronic Publication Form) - Supplemental Material Restricted to Repository staff only Download (312kB)

Abstract

Football heading represents a unique and widely performed head impact exposure in sport. While typically subconcussive on an event-by-event basis, repeated heading has been associated with adverse neurological outcomes, motivating growing concern regarding the biomechanical mechanisms governing brain loading during play. This thesis aimed to develop and apply an integrated experimental–computational framework to characterise head kinematics, estimate brain strain response, and investigate the influence of football-related parameters during controlled football heading. Instrumented mouthguards (iMGs) were employed to capture in vivo head kinematics during purposeful headers performed by amateur football players. Linear acceleration, angular velocity, and angular acceleration time histories were extracted and processed to provide event-level descriptions of head motion. These kinematic data were subsequently applied as boundary conditions to a validated finite element (FE) model of the human head to estimate tissue-level deformation, quantified using 95th percentile maximum principal strain (MPS95) and a 10% threshold of cumulative strain damage measure (CSDM10). This approach enabled direct linkage between externally measured head motion and predicted internal brain strain response. Whole-cohort (n = 7) analysis demonstrated clear relationships between head kinematics and brain strain estimates. Angular acceleration emerged as the dominant predictor of brain strain magnitude, exhibiting a stronger association with MPS95 than linear acceleration or angular velocity. While pass distance influenced group-averaged kinematics and strain, statistical modelling showed that the effect of pass distance on predicted brain strain was mediated through rotational dynamics rather than acting as an independent predictor. These findings reinforce the central role of rotational loading in governing brain deformation during football heading. Substantial inter- and intra-individual variability was observed across the amateur cohort. Certain participants consistently exhibited elevated kinematic and strain responses, while others demonstrated relatively stable behaviour across heading conditions. Intra-individual analysis revealed that similar angular acceleration magnitudes could produce divergent strain outcomes within the same participant, highlighting the influence of execution-specific factors beyond peak kinematic descriptors. High-speed video analysis provided qualitative context for these findings, illustrating how differences in posture, head–neck alignment, and ball contact location contribute to variability in mechanical response. Comparison with a single elite-level participant provided proof-of-concept evidence that playing level may influence head-ball interaction dynamics. The elite participant generally exhibited reduced angular acceleration and predicted brain strain despite comparable kinematic demands. Analysis of ball rebound behaviour showed that elite headers were associated with higher coefficients of restitution, indicating more efficient energy transfer back to the ball. However, high rebound efficiency alone did not guarantee low brain strain, underscoring the multifactorial nature of head loading during heading. An FE model of a contemporary FIFA Quality Pro-certified football was developed using experimentally derived hyperelastic and viscoelastic material properties obtained from quasi-static tensile testing and dynamic mechanical analysis. The model was validated against experimental ball-on-plate impacts, accurately reproducing the coefficient of restitution, contact duration and deformation behaviour across a range of inbound velocities and inflation pressures. Integration of the validated football FE model with an FE brain model enabled systematic investigation of the influence of football parameters within a coupled simulation framework. Inbound velocity was identified as the dominant determinant of head kinematics and predicted brain strain, while inflation pressure acted as a consistent secondary modifier. The findings demonstrated that football properties permitted within existing regulatory limits can produce meaningful differences in brain strain, highlighting the potential for equipment-based mitigation strategies alongside technique-focused interventions. Finally, a proof-of-concept application of an MRI-derived subject-specific FE brain model demonstrated the feasibility of extending the computational framework to participant-specific anatomy. Under identical experimentally measured loading conditions, predicted brain strain differed from the generic model, indicating that anatomical personalisation may influence tissue-level deformation. However, this comparison should be interpreted as exploratory, highlighting the potential value of participant-specific modelling for future investigations. Collectively, this thesis provides a comprehensive mechanistic investigation of football heading biomechanics. By integrating in vivo measurements, validated FEM, and parametric analysis of football properties, it advances understanding of how rotational dynamics, individual technique, ball behaviour, and anatomy interact to govern predicted brain strain during heading. The findings support a shift toward technique focused and equipment-informed risk mitigation strategies and establish a scalable framework for future research into personalised brain injury assessment in football.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Schools > Engineering
Uncontrolled Keywords:	1. Finite Element Modelling 2. Subject-specific Modelling 3. Brain strain 4. Instrumented mouthguards 5. Brain injury biomechanics 6. Football heading
Date of First Compliant Deposit:	4 August 2026
Last Modified:	07 Aug 2026 09:49
URI:	https://orca.cardiff.ac.uk/id/eprint/188404

Actions (repository staff only)

Edit Item