The Effect of Wrist Angle and Finger Grip on Maximum Trigger Pull Force
Category: Publication
Publication: Forensic Science International 370 (2025) 112430
Authors: Geoffrey T. Desmoulin, Marc-André Nolette, Kevin Gilmore, Theodore E. Milner
Summary: A forensic investigation into a shot fired by a handgun may require analysis of the body posture of the shooter or an opinion of whether the shot was deliberate or inadvertent. Determining the amount of force which can be applied to the trigger or the direction in which the handgun was pointing could be critical to the investigation. Studies investigating the effect of arm posture on whole hand maximum grip force suggest that maximum index finger force will be highly dependent on wrist angle and finger grip. The present study was designed to quantify the effect of these factors on maximum index finger trigger pull force. We found that even under almost optimal conditions, the trigger pull force is substantially reduced with wrist flexion and is significantly lower with a finger pad grip compared to a finger hook grip.
