Injury data from unhelmeted football head impacts evaluated against critical strain tolerance curves

Abstract

Concussion is a prevalent injury in collision and contact sports, but the biomechanics of concussion has mainly been assessed for helmeted head impacts. Concussion and no-injury cases had previously been reconstructed using rigid body simulations from a larger video database of unhelmeted head impact cases from Australian rules football, rugby union and rugby league. The KTH finite element human head model was used to simulate the 27 concussion and 13 no-injury cases, and the maximum principle strain levels in the corpus callosum were evaluated. The rotational kinematics and strain levels were compared to critical strain tolerance curves and reconstructed pedestrian impacts from the literature. It was found that the 5% critical strain tolerance curve equated to a maximum principal strain level of approximately 0.20 and was associated with concussive impacts involving prolonged loss of consciousness. The results suggest rotational kinematics above 4500 rad/s2 and 33 rad/s for peak resultant angular acceleration and maximum change in resultant angular velocity, respectively, as tentative tolerance levels for concussion involving prolonged loss of consciousness. Cases involving short duration or no loss of consciousness had similar rotational kinematics and strain levels in the corpus callosum, suggesting that these injuries are of similar severity. The findings support the hypothesis that sports concussions share some biomechanical characteristics with diffuse axonal injury

Why Most Traumatic Brain Injuries are Not Caused by Linear Acceleration but Skull Fractures are

“…Visible brain lesions were noted in both translated and rotated groups but with a greater frequency and severity after rotation. Patton et al (2012) suggested rotational kinematics above 4500 rad/s 2 and 33 rad/s for peak resultant angular acceleration and maximum change in resultant angular velocity, respectively, to predict concussions involving loss of consciousness lasting longer than 1 min in rugby and Australian football impacts. Recently, Rowson et al (2012) recorded 57 concussions and a large number of sub-concussive impacts during the 2007–2009 collegiate American football season, and proposed 6383 rad/s 2 in rotational acceleration associated with 28.3 rad/s in rotational velocity to represent a 50% risk of concussion.…”

Low-Rank Representation of Head Impact Kinematics: A Data-Driven Emulator

“…Images were generated using 3DSlicer from ATLAS-based anatomical representation in FreeSurfer (Zhang et al, 2018). 0.2 (Patton et al, 2012), MPS CC = 0.2 (Kleiven, 2007), and FS CC = 0.074 .…”

The Strain Rates in the Brain, Brainstem, Dura, and Skull under Dynamic Loadings

“…Franceschini et al [38] have experimentally studied the mechanical behavior of human brain tissue at strain rates ranging between 0.0055 and 0.0093 s −1 . Although their results are valid to be employed for studies in quasistatic loading, those material properties have been used in many computational simulations of TBI at dynamic loads [39,40]. It was confirmed [16,41] that, in addition to selecting an appropriate constitutive model, using the material constants derived from a mismatched strain rate may considerably affect the validity of the results.…”