The risk of involuntary firearms discharge.
OBJECTIVE
To investigate whether unintended muscle activity induced by motor overflow can result in the unintentional discharge of a firearm.


BACKGROUND
In the past few years an increasing number of people have been injured, sometimes fatally, as a result of police weapons being discharged involuntarily.


METHODS
Two experiments were performed using a pistol fitted with sensors to register the pressure exerted on the hand stock and the trigger. In Study 1, 34 police officers reacted to a set case using the prepared pistol. In Study 2, 25 participants performed 13 tasks requiring the use of different limbs.


RESULTS
In Study 1, about 20% of participating officers made contact with the trigger, thus violating police regulations to keep the trigger finger outside the trigger guard at all times until a conscious decision to fire has been made. Study 2 showed that motor activity in different limbs leads to a significant increase in grip force exerted on a firearm (significant results for 12 of 13 trials, Bonferroni-corrected p < .004). Furthermore, pressure on the trigger resulting from involuntary muscle contractions was, in certain cases, sufficient to unintentionally discharge a weapon.


CONCLUSIONS
Unintentional discharges attributable to involuntary muscle activity can be a real danger for police officers when carrying out their duties.


CONCLUSIONS
Results may help improve police training with the aim of reducing the danger of involuntary discharges in real-life situations.
Heim
Christopher
C
Johann Wolfgang Goethe-Universität Frankfurt, Institute of Sports Science, Frankfurt, Germany. c.heim@sport.uni-frankfurt.de
Schmidtbleicher
Dietmar
D
Niebergall
Eckhard
E
D000059:Accidents; D000328:Adult; D004867:Equipment Design; D005260:Female; D005389:Firearms; D005858:Germany; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D016495:Police; D018570:Risk Assessment