Acute effects of caffeine supplementation on cortical arousal, anxiety, physiological response and marksmanship in close quarter combat

Acute Effects of a Session with The EXOPULSE Mollii Suit in a Fibromyalgia Patient: A Case Report

Fibromyalgia is a chronic disorder characterized by widespread musculoskeletal pain and associated fatigue, sleep disturbances, and other cognitive and somatic symptoms. A multidisciplinary approach including pharmacological therapies along with behavioral therapy, exercise, patient education, and pain management is a possible solution for the treatment of this disease. The EXOPULSE Mollii^® method (EXONEURAL NETWORK AB, Danderyd, Sweden) is an innovative approach for non-invasive and self-administered electrical stimulation with multiple electrodes incorporated in a full-body suit, with already proven benefits for other diseases. Therefore, the present case report study aims to evaluate the effects that a 60 min session with the EXOPULSE Mollii suit has on a female fibromyalgia patient. After the intervention, we can conclude that a 60 min session with the EXOPULSE Mollii suit has beneficial effects on pain perception, muscle oxygenation, parasympathetic modulation, and function in a female fibromyalgia patient.

The role of death anxiety on marksmanship performance: a virtual reality simulator study

Despite the well-established relationship between state anxiety and marksmanship performance, few efforts have examined the individual differences that affect the extent to which individuals experience state anxiety in combat situations. Thus, further studies are needed to increase the probability of mission accomplishment, which could ultimately serve to safely bring soldiers home. The present study examined how death anxiety, a trait-based difference affects state anxiety, which in turn affects shooting performance on a battlefield. In particular, we used a virtual reality simulator to create a realistic engagement setting in which simulated death anxiety is salient. On a sample of 99 active-duty enlisted men in the Republic of Korea Army, we found that death anxiety, and not trait anxiety, increased state anxiety, which in turn decreased marksmanship performance. Overall, the current findings highlight the role of death anxiety in combat situations. The practical implications and avenues for future research are also discussed.

New Training Program for the New Requirements of Combat of Tactical Athletes

Actual theaters of operations are complex contexts where soldiers must face different situations, such as symmetrical, asymmetrical, or close quarter combat. The requirements of the actual battlefield are different to the traditional conditioning military training. This new changing scenario produces an activation of the innate fight or flight defense mechanisms with large activations of the anaerobic metabolic pathways and the sympathetic autonomic nervous system. In these scenarios, the anaerobic, aerobic, and strength demands are so specific and the time to improve all training demands in the units is limited. We propose a new training periodization for the military population based on the latest research into the psychophysiological response of soldiers in actual theaters of operations (actual military missions) and actual civilian models of training and periodization to develop a specific, easy, and reliable periodization model for actual tactical athletes. This training intervention was developed in order to improve operational training according to the demands of actual theaters of operations, based on recent research in military and civilian populations. We tried to conduct a proposal that is easy to apply, with minimal use of material different to what could be found in a military base and that could be implemented in a short period of time.

The effect of experience on the psychophysiological response and shooting performance under acute physical stress of soldiers

Present research studied the psychophysiological response and shooting performance taking into consideration the experience of the soldier after a physical stress protocol, which leaded to acute fatigue conditions. Sixty soldiers were divided into experienced and non-experienced groups to conduct a high-intensity interval training (HIIT) based on endurance type exercises (10 intervals of 40 m run at maximum intensity with 2 changes of direction and 45 s of recovery. Psychophysiological and shooting performance variables were measured before, during and after the HIIT protocol. Significant increases in heart rate, blood lactate, lower limbs strength, as well as a significant decrease in blood oxygen saturation and body temperature were found in both groups. Shooting performance was affected by experience and fatigue, being more accentuated in non-experienced. Present HIIT protocol elicited a similar psychophysiological response than in previously reported combat manoeuvres, thus proving to be an optimal stimuli approach/intervention for soldier's specific physical preparation.

Psychophysiological respond in a swimming ultra-endurance event

BACKGROUND

Ultra-endurance events under critical environmental conditions represent unique stress, resulting in acute marked adaptations to the cardiovascular, respiratory, metabolic and neuromuscular systems of the organism. In line with this, no studies in swimming events were found thus far.

METHODS

This research aimed to analyze the psychophysiological response of swimmers in an ultra-endurance swimming event. Changes in the rate of perceived exertion, blood lactate concentration, 1000m swimming time and cortical arousal were measured in 19 male volunteer swimmers (28.0±5.6 years; 175.0±7.9 cm; 70.1±7.8 kg) in 3 moments during a 24h swimming event.

RESULTS

We found a significant increase in lactate concentration after series 1, decreasing the values in series 2 and series 3. Cortical arousal decreased significantly in series 3 respect the basal sample. Rate of perceived exertion significantly increased in the swimming ultra-endurance event and 1000m swimming time was maintained during the series analyzed.

CONCLUSIONS

An ultra-endurance swimming event produced an increase in blood lactate concentration and rated of perceived exertion and a decrease in cortical arousal, not affecting average swimming velocity along the event.

The effects of caffeine on marksmanship accuracy and reaction time: a systematic review

Military and law enforcement personnel are required to maintain optimal marksman accuracy and reaction time during extended duty hours amidst environmental stressors. Although caffeine is commonly used to mitigate the consequences of fatigue, the effects of caffeine on marksmanship accuracy are inconclusive. The purpose of this review was to determine the effect of caffeine on marksman accuracy and reaction time. A literature search was conducted and 17 articles were selected for review based on relevance and methodological quality. Caffeine consistently improved marksman reaction time but did not improve marksmanship accuracy. However, there is some evidence that caffeine attenuates performance decrements in marksman accuracy caused by stress and fatigue if optimal dosing strategies are employed. Dosing strategies timed according to hours of wakefulness and time before testing could prevent performance deterioration. Doses of 100-200 mg every 2 hours may effectively improve accuracy during extended duty; however, further research is needed. Practitioner Summary: The purpose of this review was to determine the effect of caffeine on marksman accuracy and reaction time. A literature search was conducted and 17 articles were selected for review based on relevance and methodological quality. Caffeine consistently improved marksman reaction time but did not improve marksmanship accuracy.

Psychophysiological Stress Response of a Paralympic Athlete During an Ultra-Endurance Event. A Case Study

Psychophysiological response of athletes with spinal cord injurie has not been reported yet in scientific literature. The aim of this study is to examine the psychophysiological stress response of Paralympic athlete during competitive activities. We collected the following psychophysiological measurements: anxiety-trait, anxiety-state, locus of control, perceived psychological stress, stress-copying style, rate of perceived exertion, perceived muscle pain, body temperature, forced vital capacity, blood oxygen saturation, blood glucose and lactate concentrations, isometric hand strength, cortical arousal, heart rate variability, heart rate and velocities of a female Paralympic spinal cord injured athlete in a 11 h and 44 min ultraendurance mountain event. An ultraendurance mountain even produced an increase in the sympathetic autonomous modulation, heart rate, lactate, muscular pain and rated of perceived exertion and a decrease in cortical arousal, hand strength and respiratory muscle in a spinal cord injurie female athlete during. The Paralympic athletes presented a low psychological inflexibility, high life engagement, strong internal locus of control, a low trait and state anxiety and medium perceived psychological stress. These results are consistent with the expected response during a highly stressful situation and consistent with previous findings in athletes without spinal cord injurie.

Psychophysiological response of different aircrew in normobaric hypoxia training

Hypoxia remains the most important hazard in high altitude flights, but there is still a need for deeper analysis of the effect of hypoxia exposition in the psychophysiological and cognitive functions. The aim of this study was to study the effect of hypoxia training in cortical arousal, autonomic modulation, muscle strength and cognitive function. We analysed 23 male aircrew personnel of the Spanish Army and Air Force (10 Helicopter Pilots, 7 Transport Aircrew, 3 Transport Pilots and 3 F-18 Fighter Pilots) before, during and after a normobaric hypoxia exposition. Hypoxia produced an increase in perceived stress and effort, a higher Heart Rate and a decreased function of breath muscles. Working memory and pattern recognition were impaired after hypoxia exposition. Significant differences were found in cognitive tests performance among aircrew groups, suggesting differences on their previous training. These results can improve specific training for better preparation of pilots and aircrews for hypoxic threats. Practitioner summary: Distinct aircrew preparation produces a different hypoxia exposition effect on psychophysiological response and cognitive functions. Hypoxia produced an increase in Heart Rate, a decreased function of breath muscles, being more negatively affected in Transport Pilots. Cognition abilities were impaired after hypoxia exposition, independently of the aircrew group.

Higher use of techniques studied and performance in melee combat produce a higher psychophysiological stress response

We aimed to analyse the effectiveness of an operative training in soldiers' psychophysiological and melee combat performance. Nineteen soldiers performed a 50-hr training for 10 weeks. After training, they were divided into two groups: higher performance group (HPG) and lower performance group (LPG), then they conducted a realistic melee simulation where psychophysiological response, task performance, and the utilization of techniques learned were measured. HPG presented a significantly (p < 0.05) higher heart rate, blood lactate, and jump height; a lower blood oxygen saturation, task performance mark, use of studied techniques than LPG after the simulation; and a higher low frequency/high frequency ratio of heart rate variability previous the simulation than LPG. Independent of performance and the use of studied techniques by the participants, the melee simulation produced an increase in fight or flight response, increasing rated of stress and perceived exertion, sympathetic modulation, and physiological response. A specific melee combat training program induced different modifications in psychophysiological and task performance depending on the level of studied technique used. HPG presented a significantly higher cardiovascular response than LPG and time perception, and memory presented no differences between groups; also HPG presented a significantly higher use of studied techniques.

Psychophysiological response to acute-high-stress combat situations in professional soldiers

The study of psychophysiological responses of soldiers in combat situations remains a challenge, especially in melee combat-a close proximity unarmed fight-defined by high unpredictability. Gaining knowledge about psychophysiological changes in high-stress situations is required to optimise training. This study aimed to analyse modifications in autonomic modulation, cortical arousal, heart rate, muscle strength, blood lactate concentration, and rating of perceived exertion of veteran soldiers in a melee combat simulation. Twenty veteran soldiers were analysed before and after a melee combat simulation in accordance with realistic situations that occur in actual operations areas. The simulation consisted of actions performed by a binomial unit in a security and protection mission in an operations area. The melee combat caused an increase in sympathetic modulation, blood lactate concentration, heart rate, muscle strength, a decreased tendency in cortical arousal, and a lower rating of perceived exertion than the organic response measured. An intense fight-flight response was observed in soldiers by the limbic system activation, causing a misinterpretation of perceived exertion. Finally, implications for the design of simulation environments for tactics training in high-stress professions are discussed.

Effect of experience, equipment and fire actions in psychophysiological response and memory of soldiers in actual underground operations

The present study aimed to analyze the effect of underground operations on the psychophysiological and memory response of soldiers taking into consideration experience, the use of nocturne vision systems and previous combat actions on the psychophysiological response. Seventy participants were recruited and divided in four groups, three experimental groups with different experimental conditions, SNFV (Soldiers No-Fire Night-Vision), SFV (Soldiers Fire Night-Vision), SNFNV (Soldiers No-Fire No Night-Vision), and one control group, CNFV (Control No-Fire Night-Vision). We analyzed modifications in psychophysiological and memory response pre and post an underground operation. The underground operation produced a significant increase (p < 0.05) in blood lactate, blood oxygen saturation, rated perceived exertion, heart rate, cognitive and somatic anxiety and sympathetic modulation in all groups. Groups with higher stress values scored higher incorrect items in the memory post mission questionnaire. The higher psychophysiological activation correlated positively with cognitive impairment and lower memory. We concluded that an underground operation produced an increase in psychophysiological activation and a negative effect on memory, being modulated by previous training and experience. The lack of special equipment as night vision systems in underground operations induced similar stress response than prior combat actions, decreasing conciseness of time.

Psychophysiological, Body Composition, Biomechanical and Autonomic Modulation Analysis Procedures in an Ultraendurance Mountain Race

The current research aimed to analyze psychophysiological, body composition, biomechanical and autonomic modifications in an ultraendurance mountain race. We analyzed 11 finisher voluntary athletes that participated in a 51.2 km ultraendurance mountain race. We measured before and after the mountain ultraendurance event the following parameters: Rate of perceived exertion, body composition, cortical arousal, blood pressure, body temperature, forced vital capacity, blood oxygen saturation, isometric hand strength and heart rate variability parameters. The results of temperature, rate of perceived exertion, heart rate and the percentage of body water at the end of the race increased significantly. However, the variables of body weight, body fat, muscle, body mass index, abdominal fat, blood oxygen saturation, systolic and diastolic blood pressure, cortical arousal and hands and legs strength significantly decreased after the race. The square root of the average of the sum of the differences squared between normal adjacent R-R intervals, percentage of differences between normal adjacent R-R intervals, high-frequency, sensitivity of the short-term variability, and long-term variability decreased significantly after the race. By contrary low-frequency increased significantly at the end of the race. An ultraendurance mountain event produced a large anticipatory anxiety response, an increase in sympathetic modulation, body fat consumption, percentage of body water, and RPE, not affecting the cortical arousal.

Psychophysiological Response and Fine Motor Skills in High-Altitude Parachute Jumps

Clemente-Suárez, Vicente Javier, José Juan Robles-Pérez, Ketty Herrera-Mendoza, Beliña Herrera-Tapias, and Jesús Fernández-Lucas. Psychophysiological response and fine motor skills in high-altitude parachute jumps. High Alt Med Biol 18:392-399, 2017.-We analyzed the psychophysiological response and specific fine motor skill of an experienced jumper in HALO (high altitude low opening) and HAHO (high altitude high opening) parachute jumps. Eight HALO and eight HAHO jumpers were analyzed. They jumped at 5500 m, HALO jumpers opened the parachute at 500 m and HAHO jumpers at 4300 m of altitude. Before and after the jumps, parameters of muscle strength, cortical arousal, blood creatine kinase (CK) and glucose, blood oxygen saturation, rate of perceived exertion (RPE), and specific fine motor skills of an experienced jumper were assessed; during the jump, heart rate (HR), HR variability, and speed were evaluated. HALO and HAHO jumps produced a significant increase in CK, lactate, and RPE, and a decrease in glucose. HAHO decreased cortical arousal, presented a higher sympathetic modulation, and a higher HR during the jump than HALO. HALO and HAHO produced an increase in the physiological, sympathetic modulation and muscle destruction, and a decrease in cortical arousal and a higher blood lactate concentration only in the HAHO jump. Also, somatic and cognitive anxiety correlated with higher strength manifestation and muscle destruction. This novel research could be used to improve actual training systems in both civil and military parachute jumpers.

Use of Minicameras to Improve Operative Procedure in Security Forces

The aim of the present study was to analyze pistol and compact rifle marksmanship in close quarter combat (CQC). There is currently a controversy about what weapon is most appropriate to use in CQC, short weapon as pistols or long weapons as rifle. Forty two participants conducted two close quarter combat simulations, one with pistol and one with compact rifle. Marksmanship and time to cover the simulation were measured. Data obtained showed no significant differences between pistol and compact rifle. In addition, it was observed a tendency to obtain higher scores with compact rifle, probably be due to the higher stability provided in the shot action. Compact rifle could be an effective election in actual theaters of operation in which asymmetrical and symmetrical combat are combined and also in police interventions due to compact rifle provide higher fire power and range and obtained the same shooting performance than pistol. To the best of our knowledge this is the first study that provides empirical data to solve the discussion about the efficiency of the use of rifle and pistol in close quarter combat in military and police interventions. These results could be used to improve the military and police interventions efficiency.

Combat Stress Decreases Memory of Warfighters in Action

The present research aimed to analyze the effect of combat stress in the psychophysiological response and attention and memory of warfighters in a simulated combat situation. Variables of blood oxygen saturation, heart rate, blood glucose, blood lactate, body temperature, lower body muscular strength manifestation, cortical arousal, autonomic modulation, state anxiety and memory and attention through a postmission questionnaire were analyzed before and after a combat simulation in 20 male professional Spanish Army warfighters. The combat simulation produces a significant increase (p < 0.05) in explosive leg strength, rated perceived exertion, blood glucose, blood lactate, somatic anxiety, heart rate, and low frequency domain of the HRV (LF) and a significant decrease of high frequency domain of the heart rate variability (HF). The percentage of correct response in the postmission questionnaire parameters show that elements more related with a physical integrity threat are the most correctly remembered. There were significant differences in the postmission questionnaire variables when participants were divided by the cortical arousal post: sounds no response, mobile phone correct, mobile phone no response, odours correct. The correlation analysis showed positive correlations: LF post/body temperature post, HF post/correct sound, body temperature post/glucose post, CFFTpre/lactate post, CFFT post/wrong sound, glucose post/AC pre, AC post/wrong fusil, AS post/SC post and SC post/wrong olfactory; and negative correlations: LF post/correct sound, body temperature post/lactate post and glucose post/lactate post. This data suggest that combat stress actives fight-flight system of soldiers. As conclusion, Combat stress produces an increased psychophysiological response that cause a selective decrease of memory, depending on the nature, dangerous or harmless of the objects.

Effect of Parachute Jump in the Psychophysiological Response of Soldiers in Urban Combat

The study of organic and psychological response during combat situations has been poorly reported despite its importance for soldiers training and specific instruction, so it was proposed as aim of the present investigation to analyze the effect of a tactical parachute simulated jump in psycho-physiological response of paratroopers' warfighters during an urban combat simulation. 19 male paratroopers (31.9 ± 6.2 year old; 173.6 ± 5.3 cm; 73.8 ± 8.3 Kg) of the Spanish Army were divided in two groups: parachute jump group (n:11) that conducted a simulated parachute jump and a urban combat maneuver and a non-parachute jump group (n:8) that only conducted an urban combat maneuver. We analyzed before and after the maneuver the rated perceived exertion, legs strength manifestation, blood lactate, cortical activation, heart rate variability, blood oxygen saturation and pressure, skin temperature, fine motor skills, and anxiety state. A tactical parachute simulated jump prior to an urban combat maneuver produce significantly (p < 0.05) higher heart rate and decrease in specific fine motor skills in comparison with no jump situation in professional Army paratroopers. Independently of the parachute jump, an urban combat maneuver produces a significant increase in rated perceived exertion, blood lactate, heart rate, legs strength, sympathetic modulation and anxiety response as well as a significant decrease in blood oxygen saturation and parasympathetic modulation.

The Application of Cortical Arousal Assessment to Control Neuromuscular Fatigue During Strength Training

The author's aim was to analyze the cortical arousal response during a conventional strength training session as a method to assess central nervous system fatigue. Sixteen trained men were recruited to perform the maximum number of training series composed of 6 exercises of 10 repetition each, at the intensity of 70% of the 1 maximum repetition, with a rest period of 2 min between exercises and 5 min between series, until exhaustion. Cortical arousal was measured using the critical flicker fusion threshold before, after warm-up, after each exercises series, after the recovery phase between series, and 15 min and 30 min after finishing the training session. Participants could not finish the fourth series of exercise, corresponding with a significant decrease of cortical arousal respect to the warm-up value. The assessment of cortical arousal using CFFT during a strength training session could be a fast and efficient method for assessing central nervous fatigue. Practically, coaches could modify the training protocol according to the individual cortical arousal response in order to improve training efficiency and prevent injuries.

Psycho-physiological response in an automatic parachute jump

Parachute jump is an extreme activity that elicits an intense stress response that affects jumpers' body systems being able to put them at risk. The present research analysed modifications in blood oxygen saturation (BOS), heart rate (HR), cortisol, glucose, lactate, creatine kinase (CK), muscles strength, cortical arousal, autonomic modulation, pistol magazine reload time (PMRT) and state anxiety before and after an automatic open parachute jump in 38 male Spanish soldiers (25.6 ± 5.9 years). A MANOVA with samples as a fixed factor and Effect Size (ES) were conducted. MANOVA showed (Wilks lambda = .225; F = 5.980; P = .000) a significantly increase in cortisol (6.2 ± 3.2 vs. 8.2 ± 4.3 nmol/l; P = .025; ES = .47), HR (75.0 ± 14.6 vs. 87.4 ± 17.3 bpm; P = .004; ES = .72), lactate (1.8 ± 1.2 vs. 4.4 ± 2.2 mmol · l^-1; P = .002; ES = 1.18), sympathetic nervous system and leg strength manifestation after the parachute jump. By contrary BOS, PMRT (55.6 ± 27.6 vs. 48.0 ± 16.7 s; P = .021; ES = .46) and somatic anxiety (SA), evaluated by CSAI2R questionnaire, decreased. An automatic parachute jump increased physiological and cortical response and decreased SA of participants. This stress response can affect the jumpers' abilities and allow us to have a better understanding of the organism stress response and to improve training for both military and sport parachute jumps.