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Predicting shooting scores
from physical performance
data
Gregory S. Anderson
Predicting
shooting scores
525
Professor, Department of Kinesiology and Physical Education,
University College of the Fraser Valley, Mission, BC, Canada, and
Darryl B. Plecas
Professor, Department of Criminology and Criminal Justice, University
College of the Fraser Valley, Mission, BC, Canada
Keywords Recruitment, Police, Weapons, Training
Abstract Selecting the right people for police work is not only important for the employer, but is
also in the best interest of the public. Failure to screen out individuals who cannot perform the
physical duties has a large human and economic cost. The present study investigated whether
physical performance and anthropometric measures can predict recruits' handgun
marksmanship. While significant correlations were found between handgun marksmanship
and dominant grip strength, combined grip strength, forearm girth and second ray length,
significance was only found when the genders were analyzed together. A step-wise multiple
regression could not generate an equation to predict shooting score from the available data.
Task analyses performed by police departments in developed nations all
indicate that there is a core of essential job-related physical abilities and motor
tasks that must be performed in the regular course of duty (Anderson and
Plecas, 1999; Bonneau and Brown, 1995). Police work is generally quite
sedentary; yet, police are called upon to apprehend (which may include
running, tackling, pushing, pulling and wrestling), arrest and contain criminals
(perform take-downs and handcuffing), remove people from damaged vehicles
(lifting, carrying, pulling), control large crowds, and separate individuals who
are arguing or fighting (pushing, pulling, restraining). Several of these tasks
are extremely physically challenging. Further, the inability to perform these
duties would clearly endanger their fellow officers, themselves, and the general
public.
Having the ability to discharge a firearm safely and accurately is also an
essential skill for satisfactory job performance in police work. Giving the police
the means and authority to protect themselves, fellow officers and private
citizens from the dangerous actions of others is not new, nor are the reasons
obscure. New York City first issued revolvers to police officers in 1857, and
Theodore Roosevelt introduced standardized handgun instruction in 1895
(Morrison and Vila, 1998). Handgun instruction and training in the USA
This study was funded by the Attorney General's Office of British Columbia, through the Police
Academy of the Justice Institute of British Columbia.
Policing: An International Journal of
Police Strategies & Management,
Vol. 23 No. 4, 2000, pp. 525-537.
# MCB University Press, 1363-951X
PIJPSM
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526
became mainstream practice in the mid-1920s, influenced by the National Rifle
Association and the Federal Bureau of Investigation.
Several hundred persons are shot and killed in the USA each year by police
officers, while more than a thousand are wounded (Geller and Scott, 1992), even
though police officers often choose not to shoot during incidents which clearly
justify doing so (Frye, 1982). In a small sample of incidents involving the use of
deadly force in the province of British Columbia, Canada, Parent (1999) and
Parent and Verdun-Jones (1999) found that 47 per cent of the officers
discharged their firearms as a means of protecting their partner's life, while 33
per cent felt their own lives were in imminent danger, and 27 per cent used their
weapon to protect the lives of innocent bystanders. For these reasons, while the
discharge of firearms in the course of duty is rare, having proficiency in the use
of a firearm is essential to satisfactory job performance.
The irony is, that while the proficient use of a firearm can clearly be
identified as a bona fide occupational requirement for police officers, research
clearly demonstrates that police have limited marksmanship skills (Morrison
and Vila, 1998; Vila and Morrison, 1994; Geller and Scott, 1992). Police officers
consistently demonstrate poor shooting accuracy, especially during gunfights
(Vila and Morrison, 1994), even after extensive firearms training.
Several police agencies have initiated tests of physical abilities or fitness in
order to ensure prospective recruits can withstand the physical rigor of police
work (Osborn, 1976; Wilmore and Davis, 1979; Greenberg and Berger, 1983;
Farenholtz and Rhodes, 1990; Bonneau and Brown, 1995), while there are no
standardized tests to screen possible recruits for potential shooting ability.
While a few subjective tests (i.e. 30-trigger pull test with observation of
flinching or ``pulling''), and physical tests (i.e. a combined grip strength of 70kg)
have been utilized in the selection of recruits, no literature is available to
support their use.
The purpose of the present study was to identify easily measured physical
or anthropometric variables related to shooting ability in hopes of predicting
passing performances on the shooting component of police training. In
particular, the present study investigated the ability of various physical
parameters such as muscular strength, endurance and anthropometry to
predict recruit shooting scores.
Methods
Data were collected on a convenience sample of 65 police recruits (54 male and
11 female) during their first block of police officer training over an eight-month
period. Data were collected on three separate occasions: police officer physical
abilities test (POPAT) times were recorded prior to the recruits' acceptance into
the training program (part of a screening process); physical and anthropometric
data were assembled during their first block of training at which time shooting
scores were obtained. Shooting scores represent the recruits' final qualifying
scores that were recorded immediately after four days of intense firearms
training (firing approximately 1,200 rounds).
The British Columbia 48-shot firearms course of fire (BC48) involves a series
of volleys at two, five, ten and 25 meters (Justice Institute of British Columbia,
Police Academy). Each subject fired: six rounds at two meters with each tworound volley occurring in three seconds, shot from the hip; 12 rounds in tworound volleys (three seconds each) at five meters using two-handed ``flash sight
shooting'' with an untimed tactical reload after the second string; six rounds of
aimed fire within eight seconds from ten meters; 12 rounds in 45 seconds fired
from 25 meters, six each right- and left-handed kneeling at a barricade,
separated by a ``full stop emergency reload''; and 12 rounds in 45 seconds fired
from 25 meters, six each right- and left-handed standing at a barricade,
separated by a ``tactical reload.'' Points are awarded for accuracy on a B27
target, with a possible five points for each of the 48 shots for a total of 240
points; 192 points (80 per cent) are required for a passing score. The five-point
scoring area is an oval being 12 inches wide and 18 inches high. The average
recruit qualifying score over a two-year period was 206 points, similar to the
present cohort.
Anthropometric measures
Anthropometric measures are standardized measures of human size and
proportion. These measures included height recorded to the nearest 0.5cm,
weight recorded to the nearest 0.5kg, and a series of directly measured upper
extremity lengths, each measured to the nearest 0.1cm. Direct bone lengths
were measured using a segmometer, and included measures of humerus, ulnar,
hand, thumb and trigger finger length. Wrist and hand breadth were measured
using a Tommy II bone caliper (Rosscraft Industries, Canada), while forearm
girth was measured using a standard metal anthropometric tape (see Appendix
for detailed descriptions of measures).
Performance measures
Physical or performance data included measures of muscular strength,
endurance, and balance, and a POPAT. These tests included:
Maximal grip strength ± using a Takei handgrip dynamometer, maximum
grip strength of dominant and non-dominant hands was measured to the
nearest kilogram. A combined grip strength was calculated by adding the best
results recorded for each hand.
Grip strength fatigue ± a drop-off score was recorded over 20 maximal pulls
on a handgrip dynamometer on five-second intervals using the dominant hand.
Each pull was recorded, with the drop-off measured as the difference between
the first and 20th pull in the sequence expressed as a percentage of the first
pull.
Static push-up ± the time (recorded in seconds) that a recruit could maintain a
static position with their thumbs under their shoulders, elbows bent at 908 of
flexion while pivoting on their toes.
Anterior-posterior balance ± with the feet positioned comfortably apart
facing along the length of a unidirectional wobble (balance) board, measuring
Predicting
shooting scores
527
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528
anterior-posterior stability, recorded as the number of times the board touched
the ground was recorded over a period of 30 seconds.
Side-to-side balance ± with the feet positioned shoulder width apart on a
unidirectional wobble (balance) board, measuring side-to-side stability,
recorded as the number of times the board touched the ground was recorded for
a period of 30 seconds.
30-trigger pull test ± using a deactivated Berretta handgun the recruit, using
each hand on separate occasions, squeezed the trigger 30 times on one second
intervals. A pass was recorded if the recruit could complete the 30 trigger pulls
without noticeable movement of the gun barrel upon pulling.
POPAT ± The POPAT is designed to ``predict the potential physical ability
of the participant to resolve a critical incident involving the average male
suspect'' (Farenholtz and Rhodes, 1990, p. 46). The test is a standard recruit
screening tests used by municipal police departments in British Columbia, with
similar test of physical ability used by the RCMP and other provincial police
agencies in Canada (Anderson and Plecas, 1999; Bonneau and Brown, 1995).
The test involves a 400 meter agility run which includes changes in direction,
stride length, and stair climbing; a pushing and pulling apparatus
demonstrating the ability to dynamically control 35kg (80lbs) of resistance; a
series of squat thrusts; and a lift and carry of 45.5kg (100lbs) over a 15.6m (50
foot) distance. Times were recorded to the nearest second.
Data analysis
The SPSS statistical package was used to compute Pearson-product correlation
coefficients to establish the relationships between final qualifying shooting
scores and the physical and anthropometric variables measured in each of the
combined, male and female groupings. Significant differences (p < 0.05)
between gender groupings were established for each variable using two-tailed
t-tests. A step-wise multiple-regression analysis was performed to predict
shooting scores from physical and performance data.
Results
Subjects participating in this study were members of four separate classes
moving through police training at a training academy. Descriptive statistics
can be found in Table I.
Height
(cm)
Table I.
Mean descriptive
subject data
Weight
(kg)
Forearm
girth
(cm)
Combined
grip
strength
(kg)
Hand
length
(cm)
Hand
breadth
(cm)
Combined
178.7
82.6
26.1
104.8
19.7
8.6
Male
180.5
84.8
26.5
112.5
20.0
8.8
Female
169.8
65.0
24.4
67.4
18.2
7.4
Significant correlations were found between shooting score and POPAT times,
dominant grip strength, combined grip strength, forearm girth, and second ray
length. However, significant correlations were found only when genders are
analyzed together (Table II). Not a single significant relationship was found
between shooting score and any variable measured in the gender-specific
groups. Significant correlations in the combined-gender sample were facilitated
by significant gender differences in independent variables. Significant
differences between scores of males and females were found for several
variables, as outlined in Table III.
The relationships that existed between variables are demonstrated in a
series of figures. There was a significant relationship (r = 0.38) between
shooting score and combined grip strength (Figure 1), although the data for
each gender group show no significant pattern. The relationship between
shooting score and POPAT time was also significant (r = ±0.38) as was the
Variable
Sex
SS
PAT
Shooting score
(SS)
M/F
M
F
1.00
1.00
1.00
POPAT
(PAT)
M/F
M
F
±0.38
0.03
±0.15
Dominant grip
(DG)
M/F
M
F
0.38 ±0.45
0.02 0.11
±0.01 ±0.48
Combined grip
(CG)
M/F
M
F
0.38 ±0.47 0.98
±0.01 0.05 0.96
0.00 0.31 0.91
Static push-up
(SPU)
M/F
M
F
0.10 ±0.41 0.36 0.39
0.01 ±0.21 ±0.05 0.06
±0.34 ±0.18 0.61 0.45
1.00
1.00
1.00
Forearm girth
(FG)
M/F
M
F
0.28 ±0.28 0.66 0.65
±0.08 0.29 ±0.46 0.42
0.28 0.37 0.83 0.83
0.33
0.05
0.29
2nd ray length
(2RL)
M/F
M
F
0.28 ±0.38 0.58 0.59 ±0.15
0.16 ±0.06 0.36 0.37 ±0.43
±0.20 0.17 0.59 0.63 0.21
Drop-off score
(DO)
M/F
M
F
0.05 ±0.24 0.37 0.40
±0.05 0.02 0.22 0.29
±0.27 ±0.49 ±0.28 ±0.41
Weight
(WT)
M/F
M
F
CG
SPU
FG
2RL
DO
529
WT
1.00
1.00
1.00
0.28 ±0.11
0.16 0.29
0.80 0.50
Note: Significance denoted by bold
DG
Predicting
shooting scores
1.00
1.00
1.00
1.00
1.00
1.00
0.77 0.73
0.60 0.50
0.80 0.60
1.00
1.00
1.00
0.35
0.19
0.25
1.00
1.00
1.00
0.20 0.32 0.14
0.13 0.03 ±0.03
0.35 ±0.30 ±0.45
0.13
0.02
0.40
1.00
1.00
1.00
0.67 0.59 0.21
0.74 0.43 ±0.02
0.80 0.32 ±0.74
1.00
1.00
1.00
Table II.
A correlation matrix
reporting relationships
between shooting
scores and physical
and anthropometric
variables
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Table III.
Differences between
gender groupings
Figure 1.
The relationship
between shooting scores
and combined grip
strength in male (&)
and female (^)
groupings
Variable
Sex
N
Mean
SD
Sig
Shooting score
M
F
53
11
212.7
180.7
19.7
25.8
0.00
POPAT (sec)
M
F
51
10
193.0
225.2
15.1
14.4
0.00
Dominant grip (kg)
M
F
53
11
57.0
34.3
7.3
5.0
0.00
Combined grip (kg)
M
F
53
11
112.5
67.4
13.3
8.6
0.00
Static push-up (sec)
M
F
52
11
84.3
46.0
40.0
22.5
0.01
Drop-off score (%)
M
F
53
11
17.0
13.2
10.4
12.7
0.29
Balance (S-S: no.)
M
F
22
7
11.2
15.9
4.2
6.9
0.04
2nd Ray length (cm)
M
F
54
11
18.5
17.1
0.9
0.6
0.00
Forearm girth (cm)
M
F
54
11
29.8
24.6
2.2
2.0
0.00
relationship between shooting score and forearm girth (r = 0.28) (Figures 2 and
3). While significant correlations are demonstrated in each of these figures in
the combined-gender group, there were no significant relations between
shooting score and any of the variables in the male or female sub-groups.
Step-wise regression analyses were performed on the combined-gender
sample, and the male and female sub-samples. In each case step-wise
regression analysis indicates that shooting score could not be predicted from
the variables measured in this study (p > 0.05). The type of gun used during the
shooting qualification, however, significantly impacted on the results obtained,
with those using the Beretta (model 94F) obtaining a significantly lower
qualifying score (p < 0.05) than those using the Glock (model 22), regardless of
gender.
Predicting
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531
Discussion
Police departments spend a significant amount of time and money on the
selection and training of new recruits. In the selection process several criterion
measures are used to establish recruit suitability and during training, recruits
are required to meet minimum standards in several areas ± including shooting.
However, while strict criteria are set in the physical, cognitive, emotional and
psychological domains for recruit suitability, no selection criteria are available
to identify those recruits who are not likely to be successful in obtaining the
Figure 2.
The relationship
between shooting scores
and POPAT times in
male (&) and female
(^) groupings
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532
Figure 3.
The relationship
between shooting scores
and forearm in male (&)
and female (^)
groupings
required qualifying score at the end of their firearms training program. Such a
screening device would save the department both time and money.
While shooting is a complex motor skill, accuracy depends on aligning the
bore and target while maintaining the alignment through a trigger-pull
sequence. This requires the shooter to maintain a stable, static position. Normal
variability in this alignment, or steadiness, is termed wobble (Vila and
Morrison, 1994). When the target is close, greater wobble can be tolerated
without influencing the number of target hits; however, as the distance
increases, less wobble can be tolerated. In their calculations, Vila and Morrison
(1994) suggest that to be confident that the target will be hit 100 per cent of the
time at a distance beyond seven meters, wobble must be less than 3mm, with a
wobble of 4.3mm reducing the number of hits to 50 per cent.
Physical parameters that influence wobble may include lever lengths,
muscular strength or endurance, core stability and/or proprioceptive reflexes
involved in balance. Static upper body strength and endurance is required to
maintain the gun in a shooting position. The amount of force required will be
related to the length of the arm (boney lever) and the weight of the gun, with
less force required to hold the gun in position at the end of a shorter lever. For
example, Atkins (1993) reports an the average mass of a semi-automatic
handgun to be 873 grams (30.8oz., depending on caliber and number of rounds).
To hold this mass at the end of a 78.2cm lever (assuming the balance point of
the lever was at 60 per cent of its length) would require 8.2kg of force (without
holding the mass of the forearm). Reducing the length of the lever by 10cm
would reduce the force required to hold the gun in position by 1kg (being
7.2kg). For these reasons measures such as static push-ups (upper body
muscular endurance) and arm lever lengths may be logically related to
shooting scores obtained.
The stability of the gun in the shooting position has been associated with the
size of the grip of the gun, trigger reach and hand size, or their interaction
(Atkins, 1993). Holding the firearm correctly entails grasping the gun in a
manner that aligns the forearm, web between the thumb and trigger finger, and
the bore of the gun. In such a position the distal joint of the trigger finger must
be able to fit comfortably over the middle of the trigger to allow maximum
leverage and a smooth trigger pull (Atkins, 1993). With any given grip size, an
officer with a larger hand, or longer trigger finger (second ray length) may have
the advantage, allowing for better hand positioning and better alignment of the
joints through which recoil will be absorbed. While this was not supported in
either gender grouping in the present study, there was a significant
relationship between the length of the trigger finger (second ray) in the
combined sample of males and females. Further, shooting scores obtained on
the smaller gripped gun were significantly better than those obtained on the
larger gripped gun. This difference held true across gender and could logically
be attributed to the lever advantage for trigger pull gained with the smaller
gripped gun, requiring less force to overcome the 2.3kg resistance of the trigger
pull (5lbs). This is supported by the findings of the US Army Human
Engineering Laboratory (as reported in Atkins, 1993) who found small-handed
women to have problems firing the XM10 candidate pistol in double action
mode.
Studies have not examined the length of the thumb (first ray). If held
correctly, with the gun drawn to the web between the thumb and forefinger, the
thumb will offer stability on the medial side. To compensate for smaller hands,
shooters may align the backstrap of the gun with the base of the thumb, and the
thumb becomes much more important (Atkins, 1993). In either case, the thumb
will provide resistance to recoil, and provide stability to the gun so it does not
need to be repositioned between rounds. However, as with hand size, the
present study did not find thumb length to be a factor in the present analysis.
Core stability and balance are important in reducing the body sway
observed in a static position, and hence wobble. Core stability involves static
contractions of muscles in the trunk, while balance requires the reflexive
actions of muscles in the lower leg and body core. Both of these components are
required to maintain body position in an unstable environment (such as on a
body ball or balance board). Each component is trainable, requiring a minimum
amount of muscular strength and trained neural pathways. The present study
examined the contributions of balance and core stability using an unstable
environment ± a wobble or balance board ± which allowed movement in one
plane of motion (side-to-side or front-to-back). No relationship was found
between stability in either plane of motion and shooting scores.
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Strength, and in particular hand strength, has been recognized as a limiting
factor in firearms proficiency, especially in smaller females (Newberry, 1991;
Atkins, 1993). The strength of the hand is dictated primarily by muscles of the
forearm which cross the wrist via long tendons to insert into the palm of the
hand and fingers. These muscles control the grip on a gun and also the trigger
pull. For this reason, forearm girth was measured in the present study as an
indication of forearm muscle mass, while grip strength of the dominant hand
and combined grip strength of both hands were measured as direct indicators
of static muscular strength. Shooting scores, however, were not related to
forearm girth or grip strength in male or female sub-groups.
Influence of gender
Females in the present study had an average grip strength equivalent to 60 per
cent of the average grip strength of the males, a hand length 1.8cm (0.7in) and
trigger finger 1.4cm (0.55in) shorter, and a hand breadth 1.4cm (0.55in)
narrower than that of their male counterparts ± consistent with other findings
(Atkins, 1993; Gordon et al., 1988). The females in the present study also had
significantly lower shooting scores during qualifying. With the spread in
shooting scores between genders any differences in physical parameters
related to gender inflate a correlation between shooting scores and physical
parameters in a combined-gender grouping. This is clearly evident in the
present study.
Females in the present study were on average smaller than the males (see
Table I), had lower measures of strength, and had lower shooting scores. With
two distinct groups with some spread between the data, a correlation will be
inflated. While it is logical to assume that relationships between shooting
ability and physical parameters exist, and a significant correlation can be
found in the combined-gender group, the present study was unable to find any
combination of physical attributes that would allow one to predict shooting
scores from physical performance and anthropometric data. Organizations
which have found relationships between physical parameters and shooting
scores may have fallen prey to spurious relationships dictated by combining
genders in the analyses. Figures 1 through Figure 3 demonstrate that once
gender is controlled, physical parameters are not related to shooting ability
(male and female data do not have a significant slope).
Part of the gender difference in shooting scores in the present study may be
the result of the firearms training schedule. Recruits shoot on average 1,200
rounds in four days, and then perform a standard pistol qualification test of 48
rounds. Differential fatigue between the stronger male than the weaker female
(p < 0.00) over the four days of training could account for poorer shooting
scores in the females (although this is only speculative as drop-off scores in
grip strength were not significantly correlated to shooting scores). The amount
of rounds fired in a four-day period is unrealistic and extremely demanding.
Practicing once fatigued also reduces fine motor abilities and may contribute to
the development of bad habits, such as poor muscle recruitment patterns as
seen in flinching.
Recommendations
Shooting requires a mastery of technique, being a fine motor skill, and may be
more related to refinement of fine motor skills than any parameter related to
gross motor skill (strength, endurance) or lever lengths. Having said this,
Konttinen et al. (1995) found that motor control alone was not sufficient in
obtaining shooting accuracy. Shooting accuracy may be the result of complex
interactions between visual and motor stimuli (perception, cognition and
musculo-skeletal input), modified by the emotional and psychological state of
the marksman (Konttinen et al., 1995; Vila and Morrison, 1994). Arousal may
have a major impact on shooting precision, as well as the decision-making
process which initiates the shooting response. For example, Rose and Christina
(1990) found that the number of aborted shots increased when attentional
demands were placed on the shooters. This may well be related to incidents of
hyper-vigilance (or freezing) when police officers have large attentional
demands imposed upon them during violent confrontations. Any further
attempts at predicting shooting ability and screening for shooting success
should include affective measures such as attentional control.
While handgun technology has increased over the last 100 years, there is
little evidence of improved police shooting, even though police spend more time
in training and on the range shooting. The reasons may lie in the type of
training they receive. Many of the present training regimes do not resemble the
nature of true conflicts in which police are expected to shoot (Baratta, 1999;
Morrison and Vila, 1998; Tate, 1998). In fact, there is a total lack of information
validating present firearms training regimes (Vila and Morrison, 1994). Most
conflicts that result in officer deaths are unpredictable, and occur as the result
of routine duties such as traffic stops (which are seldom deadly).The majority
of these conflicts occur under conditions of poor visibility (i.e. night) and at
distances of less than seven meters (Baratta, 1999). In these situations officers
rarely have time to pull the firearm, point it using sight-aiming, and fire, yet
police are traditionally trained using sight-shooting at distances of ten or more
meters. While there are several courses of fire that are used regularly that
include many facets of gunfighting, such as the Federal Law Enforcement
Training Center's practical pistol course, data are required to validate the
qualifying methods (course of fire) and the training procedures (i.e. point vs
aimed shooting).
Conclusions
The results of the present study would indicate that one cannot predict
shooting ability from any combination of gross motor performance tasks. The
present results do not support the practice of using grip strength or a 30-trigger
pull test in the selection of police recruits. For example, should a minimum grip
requirement of 35kg on each hand be used in recruit selection, the test would
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eliminate as many female recruits during the selection process which could
pass the shooting as it would those who could not pass. This would indicate
that flipping a coin would be as accurate as grip strength in predicting shooting
success in this group (however, one must be cautious in interpreting the lack of
significance with only 11 women in the sample). Minimum grip strength and
the 30-trigger pull tests, if used, should only be used to determine those
individuals who may need remedial work and should not be used as a selection
criterion.
While present study does not support the notion that a minimal grip
strength or hand size is required to shoot accurately, the lack of any significant
relationship may mean the present subjects were all above the criterion
required. If this were true a broader, gender-specific sample which included
smaller and weaker individuals may indicate a lower limit in strength and hand
size which can be used as criterion measures. There is still a lot of work to be
done in determining factors related to the shooting success of police officers,
determining the ``best'' approach to firearms training while developing a
realistic course of fire which better mimics real life situations and can be used
in handgun qualifying.
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Konttinen, N., Lyytinen, H. and Konttinen, R. (1995), ``Brain slow potentials reflecting successful
shooting performance'', Research Quarterly for Exercise and Sport, Vol. 66, pp. 64-72.
Morrison, G.B. and Vila, B.J. (1998), ``Police handgun qualification: practical measure or aimless
activity?'', Policing: An International Journal of Police Strategies & Management, Vol. 21,
pp. 510-33.
Newberry, A. (1991), ``Firearms strength training'', FBI Memorandum, 6 October.
Osborn, G.D. (1976), ``Physical agility testing: validating physical agility tests'', The Police Chief,
January, pp. 43-5.
Parent, R. (1999), ``Shots fired: firearm discharges by municipal police in British Columbia'',
Gazette: Journal of the RCMP, February/March, pp. 2-9.
Parent, R. and Verdun-Jones, S. (1999), ``Deadly force: police firearm use in British Columbia'', The
Police Journal, July, pp. 209-24.
Rose, D.J. and Christina, R.W. (1990), ``Attentional demands of precise pistol shooting as a
function of skill level'', Research Quarterly, Vol. 16, pp. 111-13.
Tate, H. (1998), ``Point shooting vs. aimed shooting'', Law and Order, December, pp. 26-8.
Vila, B.J. and Morrison, G.B. (1994), ``Biological limits to police combat handgun shooting
accuracy'', American Journal of Police, Vol. 13, pp. 1-30.
Wilmore, J.H. and Davis, J.A. (1979), ``Validation of a physical abilities field test for the selection
of State traffic officers'', Journal of Occupational Medicine, Vol. 21 No. 1, pp. 33-40.
Appendix. Descriptions of anthropometric measures
Humerus length ± measured from the acromion process of the scapula to the olecranon process of
the elbow.
Ulnar length ± measured from the olecranon process of the ulna to the distal portion of the styloid
process of the radius.
Hand length ± measured from the distal portion of the styloid process of the radius to the distal
portion of the third digit.
1st ray length ± measured from the distal portion of the styloid process of the radius to the distal
portion of the first digit or thumb.
2nd ray length ± measured from the distal portion of the styloid process of the radius to the distal
portion of the second digit or trigger finger.
Wrist breadth ± measured across the distal aspect of the radius and ulna.
Hand breadth ± measured across the distal portions of the second through fifth metacarpals.
Forearm girth ± measuring the maximum circumference around the proximal muscle mass of the
forearm.
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http://www.emerald-library.com
Predicting shooting scores
from physical performance
data
Gregory S. Anderson
Predicting
shooting scores
525
Professor, Department of Kinesiology and Physical Education,
University College of the Fraser Valley, Mission, BC, Canada, and
Darryl B. Plecas
Professor, Department of Criminology and Criminal Justice, University
College of the Fraser Valley, Mission, BC, Canada
Keywords Recruitment, Police, Weapons, Training
Abstract Selecting the right people for police work is not only important for the employer, but is
also in the best interest of the public. Failure to screen out individuals who cannot perform the
physical duties has a large human and economic cost. The present study investigated whether
physical performance and anthropometric measures can predict recruits' handgun
marksmanship. While significant correlations were found between handgun marksmanship
and dominant grip strength, combined grip strength, forearm girth and second ray length,
significance was only found when the genders were analyzed together. A step-wise multiple
regression could not generate an equation to predict shooting score from the available data.
Task analyses performed by police departments in developed nations all
indicate that there is a core of essential job-related physical abilities and motor
tasks that must be performed in the regular course of duty (Anderson and
Plecas, 1999; Bonneau and Brown, 1995). Police work is generally quite
sedentary; yet, police are called upon to apprehend (which may include
running, tackling, pushing, pulling and wrestling), arrest and contain criminals
(perform take-downs and handcuffing), remove people from damaged vehicles
(lifting, carrying, pulling), control large crowds, and separate individuals who
are arguing or fighting (pushing, pulling, restraining). Several of these tasks
are extremely physically challenging. Further, the inability to perform these
duties would clearly endanger their fellow officers, themselves, and the general
public.
Having the ability to discharge a firearm safely and accurately is also an
essential skill for satisfactory job performance in police work. Giving the police
the means and authority to protect themselves, fellow officers and private
citizens from the dangerous actions of others is not new, nor are the reasons
obscure. New York City first issued revolvers to police officers in 1857, and
Theodore Roosevelt introduced standardized handgun instruction in 1895
(Morrison and Vila, 1998). Handgun instruction and training in the USA
This study was funded by the Attorney General's Office of British Columbia, through the Police
Academy of the Justice Institute of British Columbia.
Policing: An International Journal of
Police Strategies & Management,
Vol. 23 No. 4, 2000, pp. 525-537.
# MCB University Press, 1363-951X
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became mainstream practice in the mid-1920s, influenced by the National Rifle
Association and the Federal Bureau of Investigation.
Several hundred persons are shot and killed in the USA each year by police
officers, while more than a thousand are wounded (Geller and Scott, 1992), even
though police officers often choose not to shoot during incidents which clearly
justify doing so (Frye, 1982). In a small sample of incidents involving the use of
deadly force in the province of British Columbia, Canada, Parent (1999) and
Parent and Verdun-Jones (1999) found that 47 per cent of the officers
discharged their firearms as a means of protecting their partner's life, while 33
per cent felt their own lives were in imminent danger, and 27 per cent used their
weapon to protect the lives of innocent bystanders. For these reasons, while the
discharge of firearms in the course of duty is rare, having proficiency in the use
of a firearm is essential to satisfactory job performance.
The irony is, that while the proficient use of a firearm can clearly be
identified as a bona fide occupational requirement for police officers, research
clearly demonstrates that police have limited marksmanship skills (Morrison
and Vila, 1998; Vila and Morrison, 1994; Geller and Scott, 1992). Police officers
consistently demonstrate poor shooting accuracy, especially during gunfights
(Vila and Morrison, 1994), even after extensive firearms training.
Several police agencies have initiated tests of physical abilities or fitness in
order to ensure prospective recruits can withstand the physical rigor of police
work (Osborn, 1976; Wilmore and Davis, 1979; Greenberg and Berger, 1983;
Farenholtz and Rhodes, 1990; Bonneau and Brown, 1995), while there are no
standardized tests to screen possible recruits for potential shooting ability.
While a few subjective tests (i.e. 30-trigger pull test with observation of
flinching or ``pulling''), and physical tests (i.e. a combined grip strength of 70kg)
have been utilized in the selection of recruits, no literature is available to
support their use.
The purpose of the present study was to identify easily measured physical
or anthropometric variables related to shooting ability in hopes of predicting
passing performances on the shooting component of police training. In
particular, the present study investigated the ability of various physical
parameters such as muscular strength, endurance and anthropometry to
predict recruit shooting scores.
Methods
Data were collected on a convenience sample of 65 police recruits (54 male and
11 female) during their first block of police officer training over an eight-month
period. Data were collected on three separate occasions: police officer physical
abilities test (POPAT) times were recorded prior to the recruits' acceptance into
the training program (part of a screening process); physical and anthropometric
data were assembled during their first block of training at which time shooting
scores were obtained. Shooting scores represent the recruits' final qualifying
scores that were recorded immediately after four days of intense firearms
training (firing approximately 1,200 rounds).
The British Columbia 48-shot firearms course of fire (BC48) involves a series
of volleys at two, five, ten and 25 meters (Justice Institute of British Columbia,
Police Academy). Each subject fired: six rounds at two meters with each tworound volley occurring in three seconds, shot from the hip; 12 rounds in tworound volleys (three seconds each) at five meters using two-handed ``flash sight
shooting'' with an untimed tactical reload after the second string; six rounds of
aimed fire within eight seconds from ten meters; 12 rounds in 45 seconds fired
from 25 meters, six each right- and left-handed kneeling at a barricade,
separated by a ``full stop emergency reload''; and 12 rounds in 45 seconds fired
from 25 meters, six each right- and left-handed standing at a barricade,
separated by a ``tactical reload.'' Points are awarded for accuracy on a B27
target, with a possible five points for each of the 48 shots for a total of 240
points; 192 points (80 per cent) are required for a passing score. The five-point
scoring area is an oval being 12 inches wide and 18 inches high. The average
recruit qualifying score over a two-year period was 206 points, similar to the
present cohort.
Anthropometric measures
Anthropometric measures are standardized measures of human size and
proportion. These measures included height recorded to the nearest 0.5cm,
weight recorded to the nearest 0.5kg, and a series of directly measured upper
extremity lengths, each measured to the nearest 0.1cm. Direct bone lengths
were measured using a segmometer, and included measures of humerus, ulnar,
hand, thumb and trigger finger length. Wrist and hand breadth were measured
using a Tommy II bone caliper (Rosscraft Industries, Canada), while forearm
girth was measured using a standard metal anthropometric tape (see Appendix
for detailed descriptions of measures).
Performance measures
Physical or performance data included measures of muscular strength,
endurance, and balance, and a POPAT. These tests included:
Maximal grip strength ± using a Takei handgrip dynamometer, maximum
grip strength of dominant and non-dominant hands was measured to the
nearest kilogram. A combined grip strength was calculated by adding the best
results recorded for each hand.
Grip strength fatigue ± a drop-off score was recorded over 20 maximal pulls
on a handgrip dynamometer on five-second intervals using the dominant hand.
Each pull was recorded, with the drop-off measured as the difference between
the first and 20th pull in the sequence expressed as a percentage of the first
pull.
Static push-up ± the time (recorded in seconds) that a recruit could maintain a
static position with their thumbs under their shoulders, elbows bent at 908 of
flexion while pivoting on their toes.
Anterior-posterior balance ± with the feet positioned comfortably apart
facing along the length of a unidirectional wobble (balance) board, measuring
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anterior-posterior stability, recorded as the number of times the board touched
the ground was recorded over a period of 30 seconds.
Side-to-side balance ± with the feet positioned shoulder width apart on a
unidirectional wobble (balance) board, measuring side-to-side stability,
recorded as the number of times the board touched the ground was recorded for
a period of 30 seconds.
30-trigger pull test ± using a deactivated Berretta handgun the recruit, using
each hand on separate occasions, squeezed the trigger 30 times on one second
intervals. A pass was recorded if the recruit could complete the 30 trigger pulls
without noticeable movement of the gun barrel upon pulling.
POPAT ± The POPAT is designed to ``predict the potential physical ability
of the participant to resolve a critical incident involving the average male
suspect'' (Farenholtz and Rhodes, 1990, p. 46). The test is a standard recruit
screening tests used by municipal police departments in British Columbia, with
similar test of physical ability used by the RCMP and other provincial police
agencies in Canada (Anderson and Plecas, 1999; Bonneau and Brown, 1995).
The test involves a 400 meter agility run which includes changes in direction,
stride length, and stair climbing; a pushing and pulling apparatus
demonstrating the ability to dynamically control 35kg (80lbs) of resistance; a
series of squat thrusts; and a lift and carry of 45.5kg (100lbs) over a 15.6m (50
foot) distance. Times were recorded to the nearest second.
Data analysis
The SPSS statistical package was used to compute Pearson-product correlation
coefficients to establish the relationships between final qualifying shooting
scores and the physical and anthropometric variables measured in each of the
combined, male and female groupings. Significant differences (p < 0.05)
between gender groupings were established for each variable using two-tailed
t-tests. A step-wise multiple-regression analysis was performed to predict
shooting scores from physical and performance data.
Results
Subjects participating in this study were members of four separate classes
moving through police training at a training academy. Descriptive statistics
can be found in Table I.
Height
(cm)
Table I.
Mean descriptive
subject data
Weight
(kg)
Forearm
girth
(cm)
Combined
grip
strength
(kg)
Hand
length
(cm)
Hand
breadth
(cm)
Combined
178.7
82.6
26.1
104.8
19.7
8.6
Male
180.5
84.8
26.5
112.5
20.0
8.8
Female
169.8
65.0
24.4
67.4
18.2
7.4
Significant correlations were found between shooting score and POPAT times,
dominant grip strength, combined grip strength, forearm girth, and second ray
length. However, significant correlations were found only when genders are
analyzed together (Table II). Not a single significant relationship was found
between shooting score and any variable measured in the gender-specific
groups. Significant correlations in the combined-gender sample were facilitated
by significant gender differences in independent variables. Significant
differences between scores of males and females were found for several
variables, as outlined in Table III.
The relationships that existed between variables are demonstrated in a
series of figures. There was a significant relationship (r = 0.38) between
shooting score and combined grip strength (Figure 1), although the data for
each gender group show no significant pattern. The relationship between
shooting score and POPAT time was also significant (r = ±0.38) as was the
Variable
Sex
SS
PAT
Shooting score
(SS)
M/F
M
F
1.00
1.00
1.00
POPAT
(PAT)
M/F
M
F
±0.38
0.03
±0.15
Dominant grip
(DG)
M/F
M
F
0.38 ±0.45
0.02 0.11
±0.01 ±0.48
Combined grip
(CG)
M/F
M
F
0.38 ±0.47 0.98
±0.01 0.05 0.96
0.00 0.31 0.91
Static push-up
(SPU)
M/F
M
F
0.10 ±0.41 0.36 0.39
0.01 ±0.21 ±0.05 0.06
±0.34 ±0.18 0.61 0.45
1.00
1.00
1.00
Forearm girth
(FG)
M/F
M
F
0.28 ±0.28 0.66 0.65
±0.08 0.29 ±0.46 0.42
0.28 0.37 0.83 0.83
0.33
0.05
0.29
2nd ray length
(2RL)
M/F
M
F
0.28 ±0.38 0.58 0.59 ±0.15
0.16 ±0.06 0.36 0.37 ±0.43
±0.20 0.17 0.59 0.63 0.21
Drop-off score
(DO)
M/F
M
F
0.05 ±0.24 0.37 0.40
±0.05 0.02 0.22 0.29
±0.27 ±0.49 ±0.28 ±0.41
Weight
(WT)
M/F
M
F
CG
SPU
FG
2RL
DO
529
WT
1.00
1.00
1.00
0.28 ±0.11
0.16 0.29
0.80 0.50
Note: Significance denoted by bold
DG
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1.00
1.00
1.00
1.00
1.00
1.00
0.77 0.73
0.60 0.50
0.80 0.60
1.00
1.00
1.00
0.35
0.19
0.25
1.00
1.00
1.00
0.20 0.32 0.14
0.13 0.03 ±0.03
0.35 ±0.30 ±0.45
0.13
0.02
0.40
1.00
1.00
1.00
0.67 0.59 0.21
0.74 0.43 ±0.02
0.80 0.32 ±0.74
1.00
1.00
1.00
Table II.
A correlation matrix
reporting relationships
between shooting
scores and physical
and anthropometric
variables
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Table III.
Differences between
gender groupings
Figure 1.
The relationship
between shooting scores
and combined grip
strength in male (&)
and female (^)
groupings
Variable
Sex
N
Mean
SD
Sig
Shooting score
M
F
53
11
212.7
180.7
19.7
25.8
0.00
POPAT (sec)
M
F
51
10
193.0
225.2
15.1
14.4
0.00
Dominant grip (kg)
M
F
53
11
57.0
34.3
7.3
5.0
0.00
Combined grip (kg)
M
F
53
11
112.5
67.4
13.3
8.6
0.00
Static push-up (sec)
M
F
52
11
84.3
46.0
40.0
22.5
0.01
Drop-off score (%)
M
F
53
11
17.0
13.2
10.4
12.7
0.29
Balance (S-S: no.)
M
F
22
7
11.2
15.9
4.2
6.9
0.04
2nd Ray length (cm)
M
F
54
11
18.5
17.1
0.9
0.6
0.00
Forearm girth (cm)
M
F
54
11
29.8
24.6
2.2
2.0
0.00
relationship between shooting score and forearm girth (r = 0.28) (Figures 2 and
3). While significant correlations are demonstrated in each of these figures in
the combined-gender group, there were no significant relations between
shooting score and any of the variables in the male or female sub-groups.
Step-wise regression analyses were performed on the combined-gender
sample, and the male and female sub-samples. In each case step-wise
regression analysis indicates that shooting score could not be predicted from
the variables measured in this study (p > 0.05). The type of gun used during the
shooting qualification, however, significantly impacted on the results obtained,
with those using the Beretta (model 94F) obtaining a significantly lower
qualifying score (p < 0.05) than those using the Glock (model 22), regardless of
gender.
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Discussion
Police departments spend a significant amount of time and money on the
selection and training of new recruits. In the selection process several criterion
measures are used to establish recruit suitability and during training, recruits
are required to meet minimum standards in several areas ± including shooting.
However, while strict criteria are set in the physical, cognitive, emotional and
psychological domains for recruit suitability, no selection criteria are available
to identify those recruits who are not likely to be successful in obtaining the
Figure 2.
The relationship
between shooting scores
and POPAT times in
male (&) and female
(^) groupings
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Figure 3.
The relationship
between shooting scores
and forearm in male (&)
and female (^)
groupings
required qualifying score at the end of their firearms training program. Such a
screening device would save the department both time and money.
While shooting is a complex motor skill, accuracy depends on aligning the
bore and target while maintaining the alignment through a trigger-pull
sequence. This requires the shooter to maintain a stable, static position. Normal
variability in this alignment, or steadiness, is termed wobble (Vila and
Morrison, 1994). When the target is close, greater wobble can be tolerated
without influencing the number of target hits; however, as the distance
increases, less wobble can be tolerated. In their calculations, Vila and Morrison
(1994) suggest that to be confident that the target will be hit 100 per cent of the
time at a distance beyond seven meters, wobble must be less than 3mm, with a
wobble of 4.3mm reducing the number of hits to 50 per cent.
Physical parameters that influence wobble may include lever lengths,
muscular strength or endurance, core stability and/or proprioceptive reflexes
involved in balance. Static upper body strength and endurance is required to
maintain the gun in a shooting position. The amount of force required will be
related to the length of the arm (boney lever) and the weight of the gun, with
less force required to hold the gun in position at the end of a shorter lever. For
example, Atkins (1993) reports an the average mass of a semi-automatic
handgun to be 873 grams (30.8oz., depending on caliber and number of rounds).
To hold this mass at the end of a 78.2cm lever (assuming the balance point of
the lever was at 60 per cent of its length) would require 8.2kg of force (without
holding the mass of the forearm). Reducing the length of the lever by 10cm
would reduce the force required to hold the gun in position by 1kg (being
7.2kg). For these reasons measures such as static push-ups (upper body
muscular endurance) and arm lever lengths may be logically related to
shooting scores obtained.
The stability of the gun in the shooting position has been associated with the
size of the grip of the gun, trigger reach and hand size, or their interaction
(Atkins, 1993). Holding the firearm correctly entails grasping the gun in a
manner that aligns the forearm, web between the thumb and trigger finger, and
the bore of the gun. In such a position the distal joint of the trigger finger must
be able to fit comfortably over the middle of the trigger to allow maximum
leverage and a smooth trigger pull (Atkins, 1993). With any given grip size, an
officer with a larger hand, or longer trigger finger (second ray length) may have
the advantage, allowing for better hand positioning and better alignment of the
joints through which recoil will be absorbed. While this was not supported in
either gender grouping in the present study, there was a significant
relationship between the length of the trigger finger (second ray) in the
combined sample of males and females. Further, shooting scores obtained on
the smaller gripped gun were significantly better than those obtained on the
larger gripped gun. This difference held true across gender and could logically
be attributed to the lever advantage for trigger pull gained with the smaller
gripped gun, requiring less force to overcome the 2.3kg resistance of the trigger
pull (5lbs). This is supported by the findings of the US Army Human
Engineering Laboratory (as reported in Atkins, 1993) who found small-handed
women to have problems firing the XM10 candidate pistol in double action
mode.
Studies have not examined the length of the thumb (first ray). If held
correctly, with the gun drawn to the web between the thumb and forefinger, the
thumb will offer stability on the medial side. To compensate for smaller hands,
shooters may align the backstrap of the gun with the base of the thumb, and the
thumb becomes much more important (Atkins, 1993). In either case, the thumb
will provide resistance to recoil, and provide stability to the gun so it does not
need to be repositioned between rounds. However, as with hand size, the
present study did not find thumb length to be a factor in the present analysis.
Core stability and balance are important in reducing the body sway
observed in a static position, and hence wobble. Core stability involves static
contractions of muscles in the trunk, while balance requires the reflexive
actions of muscles in the lower leg and body core. Both of these components are
required to maintain body position in an unstable environment (such as on a
body ball or balance board). Each component is trainable, requiring a minimum
amount of muscular strength and trained neural pathways. The present study
examined the contributions of balance and core stability using an unstable
environment ± a wobble or balance board ± which allowed movement in one
plane of motion (side-to-side or front-to-back). No relationship was found
between stability in either plane of motion and shooting scores.
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Strength, and in particular hand strength, has been recognized as a limiting
factor in firearms proficiency, especially in smaller females (Newberry, 1991;
Atkins, 1993). The strength of the hand is dictated primarily by muscles of the
forearm which cross the wrist via long tendons to insert into the palm of the
hand and fingers. These muscles control the grip on a gun and also the trigger
pull. For this reason, forearm girth was measured in the present study as an
indication of forearm muscle mass, while grip strength of the dominant hand
and combined grip strength of both hands were measured as direct indicators
of static muscular strength. Shooting scores, however, were not related to
forearm girth or grip strength in male or female sub-groups.
Influence of gender
Females in the present study had an average grip strength equivalent to 60 per
cent of the average grip strength of the males, a hand length 1.8cm (0.7in) and
trigger finger 1.4cm (0.55in) shorter, and a hand breadth 1.4cm (0.55in)
narrower than that of their male counterparts ± consistent with other findings
(Atkins, 1993; Gordon et al., 1988). The females in the present study also had
significantly lower shooting scores during qualifying. With the spread in
shooting scores between genders any differences in physical parameters
related to gender inflate a correlation between shooting scores and physical
parameters in a combined-gender grouping. This is clearly evident in the
present study.
Females in the present study were on average smaller than the males (see
Table I), had lower measures of strength, and had lower shooting scores. With
two distinct groups with some spread between the data, a correlation will be
inflated. While it is logical to assume that relationships between shooting
ability and physical parameters exist, and a significant correlation can be
found in the combined-gender group, the present study was unable to find any
combination of physical attributes that would allow one to predict shooting
scores from physical performance and anthropometric data. Organizations
which have found relationships between physical parameters and shooting
scores may have fallen prey to spurious relationships dictated by combining
genders in the analyses. Figures 1 through Figure 3 demonstrate that once
gender is controlled, physical parameters are not related to shooting ability
(male and female data do not have a significant slope).
Part of the gender difference in shooting scores in the present study may be
the result of the firearms training schedule. Recruits shoot on average 1,200
rounds in four days, and then perform a standard pistol qualification test of 48
rounds. Differential fatigue between the stronger male than the weaker female
(p < 0.00) over the four days of training could account for poorer shooting
scores in the females (although this is only speculative as drop-off scores in
grip strength were not significantly correlated to shooting scores). The amount
of rounds fired in a four-day period is unrealistic and extremely demanding.
Practicing once fatigued also reduces fine motor abilities and may contribute to
the development of bad habits, such as poor muscle recruitment patterns as
seen in flinching.
Recommendations
Shooting requires a mastery of technique, being a fine motor skill, and may be
more related to refinement of fine motor skills than any parameter related to
gross motor skill (strength, endurance) or lever lengths. Having said this,
Konttinen et al. (1995) found that motor control alone was not sufficient in
obtaining shooting accuracy. Shooting accuracy may be the result of complex
interactions between visual and motor stimuli (perception, cognition and
musculo-skeletal input), modified by the emotional and psychological state of
the marksman (Konttinen et al., 1995; Vila and Morrison, 1994). Arousal may
have a major impact on shooting precision, as well as the decision-making
process which initiates the shooting response. For example, Rose and Christina
(1990) found that the number of aborted shots increased when attentional
demands were placed on the shooters. This may well be related to incidents of
hyper-vigilance (or freezing) when police officers have large attentional
demands imposed upon them during violent confrontations. Any further
attempts at predicting shooting ability and screening for shooting success
should include affective measures such as attentional control.
While handgun technology has increased over the last 100 years, there is
little evidence of improved police shooting, even though police spend more time
in training and on the range shooting. The reasons may lie in the type of
training they receive. Many of the present training regimes do not resemble the
nature of true conflicts in which police are expected to shoot (Baratta, 1999;
Morrison and Vila, 1998; Tate, 1998). In fact, there is a total lack of information
validating present firearms training regimes (Vila and Morrison, 1994). Most
conflicts that result in officer deaths are unpredictable, and occur as the result
of routine duties such as traffic stops (which are seldom deadly).The majority
of these conflicts occur under conditions of poor visibility (i.e. night) and at
distances of less than seven meters (Baratta, 1999). In these situations officers
rarely have time to pull the firearm, point it using sight-aiming, and fire, yet
police are traditionally trained using sight-shooting at distances of ten or more
meters. While there are several courses of fire that are used regularly that
include many facets of gunfighting, such as the Federal Law Enforcement
Training Center's practical pistol course, data are required to validate the
qualifying methods (course of fire) and the training procedures (i.e. point vs
aimed shooting).
Conclusions
The results of the present study would indicate that one cannot predict
shooting ability from any combination of gross motor performance tasks. The
present results do not support the practice of using grip strength or a 30-trigger
pull test in the selection of police recruits. For example, should a minimum grip
requirement of 35kg on each hand be used in recruit selection, the test would
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eliminate as many female recruits during the selection process which could
pass the shooting as it would those who could not pass. This would indicate
that flipping a coin would be as accurate as grip strength in predicting shooting
success in this group (however, one must be cautious in interpreting the lack of
significance with only 11 women in the sample). Minimum grip strength and
the 30-trigger pull tests, if used, should only be used to determine those
individuals who may need remedial work and should not be used as a selection
criterion.
While present study does not support the notion that a minimal grip
strength or hand size is required to shoot accurately, the lack of any significant
relationship may mean the present subjects were all above the criterion
required. If this were true a broader, gender-specific sample which included
smaller and weaker individuals may indicate a lower limit in strength and hand
size which can be used as criterion measures. There is still a lot of work to be
done in determining factors related to the shooting success of police officers,
determining the ``best'' approach to firearms training while developing a
realistic course of fire which better mimics real life situations and can be used
in handgun qualifying.
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Appendix. Descriptions of anthropometric measures
Humerus length ± measured from the acromion process of the scapula to the olecranon process of
the elbow.
Ulnar length ± measured from the olecranon process of the ulna to the distal portion of the styloid
process of the radius.
Hand length ± measured from the distal portion of the styloid process of the radius to the distal
portion of the third digit.
1st ray length ± measured from the distal portion of the styloid process of the radius to the distal
portion of the first digit or thumb.
2nd ray length ± measured from the distal portion of the styloid process of the radius to the distal
portion of the second digit or trigger finger.
Wrist breadth ± measured across the distal aspect of the radius and ulna.
Hand breadth ± measured across the distal portions of the second through fifth metacarpals.
Forearm girth ± measuring the maximum circumference around the proximal muscle mass of the
forearm.
Predicting
shooting scores
537