Estimating marksmanship performance during walking while maintaining weapon aim.

Marksmanship performance while moving is a critical skill among tactical athletes due to the high demands of their occupational duties. Qualifications for dynamic marksmanship performance are not standardized across tactical athlete groups, which may limit comprehensive assessment of tactical athlete performance for situational awareness and adaptability to an unpredictable environment. Although static marksmanship performance provides foundational information on skills and level of ability, research is lacking on factors that influence dynamic marksmanship performance to best prepare tactical athletes for duties. The purpose of this study was to identify whether static marksmanship performance, speed of movement, load carriage, and biomechanical factors while 'shooting on the move' influenced dynamic marksmanship performance. Twenty-four male tactical athletes (22 active-duty Army Soldiers, two civilian SWAT operators; age: 23.83 ± 5.47 years; height: 1.80 ± 0.08 m; weight: 81.04 ± 7.87 kg) participated; final analyses did not include data from the two civilian operators to maintain sample homogeneity. Tactical athletes completed static and dynamic ('shoot on the move') marksmanship tasks under three load conditions: (1) no load (NL), (2) half kit (HK) of 11.34 kg, and (3) full kit (KIT) of 22.68 kg. Dynamic marksmanship was completed under three speed conditions: (1) self-selected slow speed, (2) standard speed, and (3) self-selected fast speed. Hip, knee, and ankle kinematics were collected via wireless inertial measurement units. Spatiotemporal parameters were collected via optical detection system. Marksmanship performance (accuracy) was collected via open-air acoustic target scoring and mean radial error (MRE) was calculated for both static and dynamic marksmanship tasks. Linear mixed-effects models were fit with dynamic MRE as the outcome variable with fixed effects of static MRE, load condition, speed condition, kinematics, and spatiotemporal parameters, adjusting for body mass. Alpha level was set a priori at p ≤ 0.10. The final statistical model included fixed effects of static MRE, load condition, speed condition, and time spent in double limb support. Static MRE (p < 0.01) and time spent in double limb support (p = 0.01) were significant factors. For each 1 cm increase in static MRE there was a 0.66 cm increase in dynamic MRE. For every 1% increase in time spent in double limb support while 'shooting on the move' there was a 0.13 cm increase in dynamic MRE. Findings from this study highlight that tactical athletes who have larger static stance MRE and spend a longer time in double limb support during a gait cycle exhibit an increase in MRE during 'shoot on the move' trials. Overall, dynamic shooting accuracy is not affected by lower extremity joint angles, load carriage, or speed of movement. Although strong relationships are known between gait speed, load, and lower extremity kinematics, the differences in tactical gait compared to normal gait and multi-task paradigm that likely favors marksmanship accuracy seem to present novel movement characteristics unique to occupational gait. Further investigation is warranted to identify other potential factors that may improve or worsen dynamic marksmanship performance.

Can target effects or discomfort ratings discriminate between small-arms weapon configurations?

Defence acquisitions use accuracy measures as a discriminating factor in weapon purchases, but assessments are generally completed in static, supported postures at static targets with few differences being seen between configurations. The aim of this study was to investigate whether an assessment requiring repositioning between shots could reveal differences. Participants shot at a static target under four conditions: an unweighted rifle and the addition of a mass fixed at three different positions. Accuracy and timing as well as discomfort measures were captured and compared. Hit percentage, consistency and timing varied over time, and timing increased with the addition of mass in two out of the three conditions. There was an increase in discomfort with the addition of mass further from the participant. The results showed that relying on accuracy and consistency measures alone to make acquisition decisions could have the consequence of purchasing equipment not fit for the human. Practitioner Summary: This research shows that relying on accuracy and consistency measures alone to make weapon-system acquisition decisions could have the consequence of purchasing equipment not fit for the user. Further research should focus on 'upstream' issues such as muscle fatigue and aim point stability in order to better understand human-weapon-system interactions.

Prior Mental Fatigue Impairs Marksmanship Decision Performance.

Purpose: Mental fatigue has been shown to impair subsequent physical performance in continuous and discontinuous exercise. However, its influence on subsequent fine-motor performance in an applied setting (e.g., marksmanship for trained soldiers) is relatively unknown. The purpose of this study was to investigate whether prior mental fatigue influences subsequent marksmanship performance as measured by shooting accuracy and judgment of soldiers in a live-fire scenario. Methods: Twenty trained infantry soldiers engaged targets after completing either a mental fatigue or control intervention in a repeated measure design. Heart rate variability and the NASA-TLX were used to gauge physiological and subjective effects of the interventions. Target hit proportion, projectile group accuracy, and precision were used to measure marksmanship accuracy. Marksmanship accuracy was assessed by measuring bullet group accuracy (i.e., how close a group of shots are relative to center of mass) and bullet group precision (i.e., how close are each individual shot to each other). Additionally, marksmanship decision accuracy (correctly shooting vs. correctly withholding shot) when engaging targets was used to examine marksmanship performance. Results: Soldiers rated the mentally fatiguing task (59.88 ± 23.7) as having greater mental workload relative to the control intervention [31.29 ± 12.3, t(19) = 1.72, p < 0.001]. Additionally, soldiers completing the mental fatigue intervention (96.04 ± = 37.1) also had lower time-domain (standard deviation of normal to normal R-R intervals) heart rate variability relative to the control [134.39 ± 47.4, t(18) = 3.59, p < 0.001]. Projectile group accuracy and group precision failed to show differences between interventions [t(19) = 0.98, p = 0.34, t(19) = 0.18, p = 0.87, respectively]. Marksmanship decision errors significantly increased after soldiers completed the mental fatigue intervention (48% ± 22.4) relative to the control intervention [M = 32% ± 79.9, t(19) = 4.39, p < 0.001]. There was a significant negative correlation between shooting response time and errors of commission (r = -0.61; p = 0.004) when preceded by the mental fatigue intervention, but not the control (r = -0.31; p = 0.17). Conclusion: The mental fatigue intervention was successful in eliciting fatigue which was supported subjectively and objectively. Marksmanship judgment performance is significantly reduced when soldiers are mentally fatigued, although shot accuracy is not.

Shooter-System Performance Variability as a Function of Recoil Dynamics.

OBJECTIVE: The goal of this study was to quantify shooter performance relative to subtle variations in recoil energy. BACKGROUND: Marksmanship performance remains undefined for subtle distinctions in weapon recoil energy across common small-arms platforms. METHOD: Weapons were customized using multiple components and ammunition types. Firing scenarios were designed to examine the effect of recoil energy on shooter timing and accuracy. RESULTS: The results suggest that recoil condition does not affect timing during firing sequences designed to elicit differences in timed-fire performance. Recoil condition did, however, influence shot placement, with accuracy decreasing as the energy associated with firing increased. Subjective recoil estimations were quantified according to relative magnitude and spatial distribution of perceived energy transferred at shooter-weapon surface contact locations. CONCLUSION: The absence of differences in time to engage may be reflective of resistance to recoil-induced point-of-aim deviation based on experience. Distinctions in performance were revealed despite subtle differences in recoil energy between conditions. An instrument that may be sensitive to shooter perception of subtle differences in recoil energy during firing was also developed. APPLICATION: The findings inform performance expectations for small-arms systems relative to recoil energy levels transferred to the shooter during dynamic firing events.

Visual, haptic and bimodal scene perception: evidence for a unitary representation.

Participants studied seven meaningful scene-regions bordered by removable boundaries (30s each). In Experiment 1 (N = 80) participants used visual or haptic exploration and then minutes later, reconstructed boundary position using the same or the alternate modality. Participants in all groups shifted boundary placement outward (boundary extension), but visual study yielded the greater error. Critically, this modality-specific difference in boundary extension transferred without cost in the cross-modal conditions, suggesting a functionally unitary scene representation. In Experiment 2 (N = 20), bimodal study led to boundary extension that did not differ from haptic exploration alone, suggesting that bimodal spatial memory was constrained by the more "conservative" haptic modality. In Experiment 3 (N = 20), as in picture studies, boundary memory was tested 30s after viewing each scene-region and as with pictures, boundary extension still occurred. Results suggest that scene representation is organized around an amodal spatial core that organizes bottom-up information from multiple modalities in combination with top-down expectations about the surrounding world.