A comparison of Expert and Novice marksmanship performance and postural mechanics using inertial measurement units (IMUs) during dynamic live-fire shooting.

Marksmanship is a foundational Soldier skill required for all active-duty military personnel regardless of duty position. This research compared shooting performance and underlying postural mechanics of Expert and Novice marksmen during a dynamic, live-fire shooting task. Eighteen military personnel volunteered to participate in this study (n = 9 Experts and n = 9 Novices).

Females and males use different hip and knee mechanics in response to symmetric military-relevant loads.

The purpose of this study was to determine if females and males use different hip and knee mechanics when walking with standardized military-relevant symmetric loads. Fifteen females and fifteen males walked on a treadmill for 2-min at a constant speed under three symmetric load conditions (unloaded: 1.71 kg, medium: 15 kg, heavy: 26 kg).

Load Carriage and Physical Exertion Influence Cognitive Control in Military Scenarios.

Introduction: Physical exertion has both beneficial and detrimental effects on cognitive performance, particularly cognitive control. Research into physical exertion under conditions of load carriage is particularly important given that military personnel and first responders must perform optimally under such combinatorial physical stressors. The present work sought to characterize cognitive control as a function of physical exertion and load carriage in a military operational scenario.

Spatiotemporal Parameters are not Substantially Influenced by Load Carriage or Inclination During Treadmill and Overground Walking.

Influences of load carriage and inclination on spatiotemporal parameters were examined during treadmill and overground walking. Ten soldiers walked on a treadmill and overground with three load conditions (00 kg, 20 kg, 40 kg) during level, uphill (6% grade) and downhill (-6% grade) inclinations at self-selected speed, which was constant across conditions. Mean values and standard deviations for double support percentage, stride length and a step rate were compared across conditions.

Lower limb flexion posture relates to energy absorption during drop landings with soldier-relevant body borne loads.

Fifteen military personnel performed 30-cm drop landings to quantify how body borne load (light, ∼6 kg, medium, ∼20 kg, and heavy, ∼40 kg) impacts lower limb kinematics and knee joint energy absorption during landing, and determine whether greater lower limb flexion increases energy absorption while landing with load. Participants decreased peak hip (P = 0.002), and knee flexion (P = 0.

The Effects of Load Carriage and Physical Fatigue on Cognitive Performance.

In the current study, ten participants walked for two hours while carrying no load or a 40 kg load. During the second hour, treadmill grade was manipulated between a constant downhill or changing between flat, uphill, and downhill grades. Throughout the prolonged walk, participants performed two cognitive tasks, an auditory go no/go task and a visual target detection task.

Soldier-relevant loads impact lower limb biomechanics during anticipated and unanticipated single-leg cutting movements.

This study quantified how body borne load impacts hip and knee biomechanics during anticipated and unanticipated single-leg cutting maneuvers. Fifteen male military personnel performed a series of single-leg cutting maneuvers with three different load configurations (light, ~6 kg, medium, ~20 kg, and heavy, ~40 kg). Subject-based means of the specific lower limb biomechanical variables were submitted to repeated measures ANOVA to test the main and interaction effects of body borne load and movement type.

Body borne loads impact walk-to-run and running biomechanics.

The purpose of this study was to perform a biomechanics-based assessment of body borne load during the walk-to-run transition and steady-state running because historical research has limited load carriage assessment to prolonged walking. Fifteen male military personnel had trunk and lower limb biomechanics examined during these locomotor tasks with three different load configurations (light, ∼6 kg, medium, ∼20 kg, and heavy, ∼40 kg). Subject-based means of the dependent variables were submitted to repeated measures ANOVA to test the effects of load configuration.

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.

Carrying a rifle with both hands affects upper body transverse plane kinematics and pelvis-trunk coordination.

The purpose of this study was to assess how carrying a rifle in both hands affects upper body motion and coordination during locomotion. In total, 11 male soldiers walked (1.34 m/s) and ran (2.

Effects of a lower-body exoskeleton device on metabolic cost and gait biomechanics during load carriage.

This study investigated the effects on metabolic cost and gait biomechanics of using a prototype lower-body exoskeleton (EXO) to carry loads. Nine US Army participants walked at 1.34 m/s on a 0% grade for 8 min carrying military loads of 20 kg, 40 kg and 55 kg with and without the EXO.

Nonlinear analysis of gait kinematics to track changes in oxygen consumption in prolonged load carriage walking: a pilot study.

Linking human mechanical work to physiological work for the purpose of developing a model of physical fatigue is a complex problem that cannot be solved easily by conventional biomechanical analysis. The purpose of the study was to determine if two nonlinear analysis methods can address the fundamental issue of utilizing kinematic data to track oxygen consumption from a prolonged walking trial: we evaluated the effectiveness of dynamical systems and fractal analysis in this study. Further, we selected, oxygen consumption as a measure to represent the underlying physiological measure of fatigue.

The effects of a lower body exoskeleton load carriage assistive device on limits of stability and postural sway.

The study investigated the effects of using a lower body prototype exoskeleton (EXO) on static limits of stability and postural sway. Measurements were taken with participants, 10 US Army enlisted men, standing on a force platform. The men were tested with and without the EXO (15 kg) while carrying military loads of 20, 40 and 55 kg.

The effects of movement and physical exertion on soldier vigilance.

Introduction: The effects of movement and physical exertion on cognitive processes remain unclear. Some studies report improvements in information processing while others report decrements or no change. To address relationships between movement, physical exertion, and cognitive performance, vigilance performance while soldiers walked with a heavy (40 kg) load was examined.

Discrete bandwidth visual feedback increases structure of output as compared to continuous visual feedback in isometric force control tasks.

Background: Performance variability measures provide a partial picture of force control ability. Nonlinear analyses can reveal important information related to the randomness and complexity of the data, providing a more complete picture of the physiological process.

Methods: We investigated the effects of visual feedback on the structure and performance of the force output from isometric force control tasks.

Effects of carried weight on random motion and traditional measures of postural sway.

The purpose of the study was to investigate the effects of load weight carried by soldiers upon postural sway. Fourteen US Army enlisted men participated. Postural sway and muscle activity were measured while participants stood on a force plate.

Cervical electromyographic activity during low-speed rear impact.

Whiplash motion of the neck is characterized by having an extension-flexion motion of the neck. It has been previously assumed that muscles do not play a role in the injury. Eight healthy males were seated in a car seat mounted on a sled.

Range of motion and motion patterns in patients with low back pain before and after rehabilitation.

Study Design: Data were collected from 27 patients who were participating in a rehabilitation program for chronic low back pain. The patients were tested on day 2 and day 11 of a 2-week rehabilitation program.

Objectives: To determine specific characteristics of trunk motion associated with long-term dysfunction caused by low back pain of various origin, to determine if a neural network analysis system can be effective in distinguishing between patterns, and to determine if the rehabilitation has an effect on range and pattern of motion.