Citation

Sloan K, Robertson J, Fergusson M, Spratford W. Sci. Justice 2022; 62(2): 164-170.

Copyright

(Copyright © 2022, Forensic Science Society, Publisher Elsevier Publishing)

DOI

10.1016/j.scijus.2021.10.004

PMID

unavailable

Abstract

A human performance trial was conducted where the stabbing actions of 40 participants were investigated. A range of factors were assessed such as the action used when the blade shape and familiarity of the knife changed. A qualitative evaluation of these factors was presented in an earlier paper to precede the analysis of quantitative kinematic data in this paper. The data from participants was then compared to that obtained from a stabbing machine. A motion analysis system was used to measure parameters such as the joint angular displacement and absolute linear velocity at impact. Motion data was collected using a 12-camera Vicon MX motion analysis system.

RESULTS indicated that the mean absolute linear velocity of overarm stabbing actions was consistently higher than the underarm actions. Forensic textile damage examinations often involve testing of edged weapons by manually performing stabbing actions. An underlying fundamental limitation of manual simulation experiments is the natural variation inherent in human performance. Sufficient control measures can be implemented to successfully use manual simulation experiments in forensic testing and therefore this is the accepted practice. However, performance can be improved using a stabbing machine. A custom-built instrumental stabbing device has been shown to operate within the same parameters of the human participants and is therefore suitable for use in casework.

Language: en

Keywords

Biomechanics; Human stabbing performance; Kinematics of stabbing action; Knife damage; Stabbing machine; Textile damage examination