Marksmanship deficits caused by an exhaustive whole-body lifting task with and without torso-borne loads.

Studies of exhaustive exercise on marksmanship are inconclusive and have not measured trigger pull latencies (LAT) nor considered impact of added torso loads. This study examined the impact of exhaustive whole-body exercise and torso loading on accuracy, precision, and latency during a marksmanship test. Twelve men lifted a 20.5-kg box on to a 1.55-m high shelf until they could not maintain a 12 lifts·min⁻¹ pace. Within 25 seconds of ending the lifting task, the subjects started a 10-minute rifle marksmanship test (8 shots·min⁻¹). During lifting and shooting, the subjects wore 2 different loads: NOLOAD = boots, uniform, and helmet (5.9 kg) and LOAD = a torso-borne load (29.9 kg) + NOLOAD. With the LOAD, the subjects were only able to work for 69% as long, perform 31% as many lifts, or do 38% as much total work compared with the NOLOAD condition. Despite performing less total external work during LOAD, the heart rate (HR) was more than 25% higher than NOLOAD. Measures of accuracy and precision improved and stabilized after minute 3. Overall, LAT increased (p < 0.025) for LOAD (mean ± SE, 2,522 ± 81 milliseconds), compared with NOLOAD (2,240 ± 121). During 0-4 minutes, LAT for LOAD was 14% greater than for NOLOAD (p < 0.05); from 4 to 10 minutes, LAT did not differ. Exhaustive whole-body exercise transiently degraded accuracy regardless of load. In the LOAD condition, LAT was immediately increased and sustained for 10 minutes; in the NOLOAD condition, LAT increased gradually. Although load did not decrease accuracy, it increased the time to engage targets, which can impact fighting effectiveness and survivability.

Implications for studying team cognition and team performance in network-centric warfare paradigms.

Network-centric warfare's (NCW) information-rich systems involving sophisticated sensors, tracking systems, smart weapons, and enhanced digital communications threaten to overload combatants with voluminous amounts of data. It is unclear whether warfighters will perceive such extensive data as actionable information to which they will respond accurately in a timely enough manner. Members of small teams in command and control centers, operating in crew-served vehicles, or simply "grunting it out" as ground-pounding infantrymen, may be disparately separated by space, but will communicate and be connected by electronic linkages, e.g., radio, text messages, situation displays, or global positioning data. However, team members will also have to remember shared mental models of tasks at hand, pay attention to and share common situation awareness in complex operational environments, perform team cognition and team coordination, and integrate both lower and higher cognitive processes with those of team behaviors. Such exceptional capabilities are required more now than ever before; such capabilities today are far from assured. After two workshops to establish performance metrics for assessing cognitive performance of military personnel in NCW, this preface introduces five manuscripts addressing team cognition and team performance from both a theoretical and a practical perspective. The authors of this preface question if NCW, and perhaps the politico-social ramifications of modern warfare, have already outstripped behavioral scientists' approach to researching team cognition and team performance-expertise that is so crucially needed for combatants on the rapidly changing 21st-century battlegrounds.

Cognitive performance and communications in a network-centric battle laboratory.

Many of the technological advances in the information sciences that make the network-centric battlefield possible will also foster methodologies that enable the study of the warfighter in this environment. Specifically, the tactical events and computer networks in a battle laboratory can be designed with capabilities to facilitate capture and analysis of embedded operational performance metrics. This paper refers to the Air Maneuver Battle Laboratory environment, its command and control components, its synthetic battle environment, and its basic communications structure as an example. This paper also introduces two papers. In the first paper, O'Donnell, Moise, and Schmidt describe their generalized methodology to evaluate personnel during performance of operational tasks. They discuss a cognitive taxonomy, test generator, and synthetic cognitive and motor tests with applicability to military or civilian tasks. Personnel are evaluated with these synthetic tests for those very cognitive skills and capabilities most required to successfully perform the actual operational task of interest. Perhaps the illustrative and innovative measurement methodologies described will encourage others to consider how new approaches can be used to leverage the study of cognitive performance of the future warfighter in a network-centric environment. The second paper by Whitmore discusses how communications and embedded operational performance metrics may be acquired in teams. Whitmore highlights some critical aspects leading to the successful measurement of team performance in realistic console operations; discusses the idea of process and outcome measures; presents two types of team data collection systems; and provides an example of team performance assessment.

Cysteinyl leukotriene blockade does not prevent acute mountain sickness.

BACKGROUND: Acute Mountain Sickness (AMS) is a multi-system disorder that is characterized by headache, anorexia, nausea, vomiting, insomnia, lassitude, and malaise. The syndrome is common in unacclimatized low altitude residents who rapidly ascend to terrestrial elevations exceeding 2,500 m. AMS may be a manifestation of hypoxia-induced cerebral edema resulting, in part, from increased capillary permeability. HYPOTHESIS: We hypothesized that cysteinyl leukotrienes (CysLTs) may be involved in the pathogenesis of AMS, as these compounds are known to increase endothelial permeability. METHODS: To test this hypothesis, we orally administered a CysLTs type-1 receptor antagonist (montelukast) to 11 subjects prior to and during exposure to high altitude (4,300 m) in a hypobaric chamber in a randomized, placebo-controlled, crossover design. We measured the resulting prevalence and/or severity of AMS, plasma CysLTs levels and urinary CysLTE4, and associated physiological responses. RESULTS: At 12 h exposure, AMS prevalence and symptom severity was lower (p = 0.002) during montelukast administration compared with placebo, but not different at 22 h exposure. Plasma CysLTs and urinary LTE4 levels were not significantly elevated at 22 h exposure, nor did these CysLTs levels correlate with AMS severity. Compared with placebo, montelukast administration was not associated with any significant differences in physiologic measures at sea level or high altitude. CONCLUSIONS: These results do not support a role for the CysLTs mediating the early development of AMS through the CysLT-1 receptor.