Aim. The aim of the study was to investigate the applicability of a repeated change-of-direction (RCoD) test for NCAA Division-I male soccer players. Methods. The RCoD test consisted of 5 diagonal direction changes per repetition with a soccer ball to be struck at the end. Each player performed 15 repetitions with approximately 10 seconds to jog back between repetitions. Data were collected in two sessions. In the first session, 13 players were examined for heart rate responses and blood lactate concentrations. In the second session, 22 players were examined for the test's ability to discriminate the primary from secondary players (78.0±16.1 and 10.4±13.3 minutes per match, respectively). Results. Heart rate data were available only from 9 players due to artifacts. The peak heart rate (200.2±6.6 beats·min-1: 99.9±3.0% maximum) and blood lactate concentration (14.8±2.4 mmol·L-1 immediately after) resulted in approximately 3.5 and 6.4-fold increases from the resting values, respectively. These values appear comparable to those during intense periods of soccer matches. In addition, the average repetition time of the test was found to discriminate the primary (4.85±0.23 s) from the secondary players (5.10±0.24 s) (P=0.02). Conclusion. The RCoD test appears to induce physiological responses similar to intense periods of soccer matches with respect to heart rate and blood lactate concentration. Players with better average repetition times tend to be those who play major minutes.

Background-Ventricular hypertrophy is a physiological response to pressure overload that, if left untreated, can ultimately result in ventricular dysfunction, including diastolic dysfunction. The aim of this study was to test the hypothesis that frequency-dependent myofilament desensitization, a physiological response of healthy myocardium, is altered in hypertrophied myocardium. Methods and Results-New Zealand white rabbits underwent a pulmonary artery banding procedure to induce pressure overload. After 10 weeks, the animals were euthanized, hearts removed, and suitable trabeculae harvested from the free wall of the right ventricle. Twitch contractions, calibrated bis-fura-2 calcium transients, and myofilament calcium sensitivity (potassium contractures) were measured at frequencies of 1, 2, 3, and 4 Hz. The force frequency response, relaxation frequency response, and calcium frequency relationships were significantly blunted, and diastolic tension significantly increased with frequency in the pulmonary artery banding rabbits compared with sham-operated animals. Myofilament calcium sensitivity was virtually identical at 1 Hz in the treatment versus sham group (pCa 6.11 ± 0.03 versus 6.11 ± 0.06), but the frequency-dependent desensitization that takes place in the sham group (ΔpCa 0.14±0.06, P<0.05) was not observed in the pulmonary artery banding animals (ΔpCa 0.02±0.05). Analysis of myofilament protein phosphorylation revealed that the normally observed frequency-dependent phosphorylation of troponin-I is lost in pulmonary artery banding rabbits. Conclusions-The frequency-dependent myofilament desensitization is significantly impaired in right ventricular hypertrophy and contributes to the frequency-dependent elevation of diastolic tension in hypertrophy.

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Distraction from personal technology is a widely recognized problem in the modern classroom. Further, instructors have limited abilities to determine when students are waxing or waning in attentiveness. This evaluative experiment leverages the Apple Watch’s heart rate sensors to capture signs of attentiveness in participants simulating remote university lectures of differing interest levels as determined by YouTube commenters. Once captured, the heart rate data separated and analyzed to determine the effect of the lecture treatment on the participants’ heart rates. Twenty-seven students from Mississippi State University’s Electrical and Computer Engineering and Computer Science and Engineering departments elected to participate in the experiment, which shows a statistically relevant finding that the participants’ heart rates generally accelerated when presented interesting content and decelerated when treated with the uninteresting content, expressing with confidence the finding that the Apple Watch is capable of measuring attentiveness through heart rate.

The more we know about the circulation of CSF through ventricle system, brain parenchyma, subarachnoideal space and the development of intracranial pressure (ICP), the more we understand different pathologies and pathological processes of the central cervous system. The knowledge about the basic hydrodynamic charecteristics of craniospinal system is a key factor for understanding a wide range of pathological situations affecting CNS, these are for example intracranial hypertension, normal pressure hydrocephalus and syringomyelia. In the presented paper, we are presenting a newly developed measuring system Visionbrain that enables us to gain the biological data and consequently to analyse them. At the same time, the results of such measurements were used to specify the compertmental model of CSF circulation. The model devides craniospinal system into five divisions - two intracranial and three spinal. Such model is the third generation of this model and, compared to the older version, it includes two intracranial veins. Thanks to this stucture, the model enables us simultaneous modeling of heart and respiratory pulsations of CSF. Compared to the other published models, it also includes defined structure of spinal part. The model is derived using laws of conservation and it encompasses pressure...

Major depressive disorder (MDD) is one of the most common psychiatric illnesses and causes significant disturbances in daily functioning. Research on heart-rate variability (HRV) biofeedback training suggests that HRV is an efficacious adjunct to psychotherapy in reducing depressive symptoms. The purpose of this study was to examine neurological changes in depressed individuals who were randomized to either a psychotherapy plus HRV biofeedback training or to a treatment as usual group. A control group with no history of depression was also studied. We collected psychological, physiological, and imaging data from 30 participants (10 in an experimental group, 10 in a treatment as usual group, and the other 10 in a healthy control group) at baseline and follow-up. Regions of interest (ROIs) included anterior cingulate cortex, hippocampus, and amygdala. Participants from the experimental group went through 5 weekly HRV trainings in conjunction with traditional psychotherapy approaches. The treatment as usual group only received psychotherapy. The healthy controls did not receive any HRV training or therapy services. Overall, we found significant improvements in the experimental group's depression score, overall distress level, and HRV measurements relative to the TAU and control groups. However, we did not find significant HRV and resting-state connectivity group differences among experimental group relative to healthy controls. Together, results suggest that HRV training helps to reduce depressed participants' overall distress level and depressive symptoms. However, findings do not show any changes in participants' imaging data. These findings serve as pilot data on literature related to HRV biofeedback training in a depressed population.

Purpose: An experimental study to examine the effects of CardioWaves interval training (IT) and continuous training (CT) on resting blood pressure, resting heart rate, and mind-body wellness. Methods: Fifty-two normotensive (blood pressure <120/80 mmHg), pre-hypertensive (120-139/80-89 mmHg), and hypertensive (>140/90 mmHg) participants were randomly assigned and equally divided between the IT and CT groups. Both groups participated in the assigned exercise protocol thirty minutes per day, four days per week for eight weeks. Resting blood pressure, resting heart rate, and mind-body wellness were measured pre- and post-intervention. Results: A total of 47 participants (15 females and 32 males) were included in the analysis. The IT group had a non-significant trend of reduced systolic blood pressure (SBP) and increased diastolic blood pressure (DBP) while the CT group had a statistically significant decrease in awake SBP (p=0.01) and total SBP (p=0.01) and a non-significant decrease in DBP. With both groups combined, the female participants had a statistically significant decrease in awake SBP (p=0.002), asleep SBP (p=0.01), total SBP (p=0.003), awake DBP (p=0.02), and total DBP (p=0.05). The male participants had an increase in SBP and DBP with total DBP showing a statistically significant increase (p=0.05). Neither group had consistent change in resting heart rate. Both groups showed improved mind-body wellness. Conclusion: IT and CT reduced resting blood pressure, with CT having a greater effect. Resting heart rate did not change in either group. Additionally, both IT and CT improved mind-body wellness.

Military training and operations can place significant demands on cognitive and physical resources of service members, resulting in heightened stress and fatigue, elevated risk of accidents and injuries, and diminished cognitive and occupational performance. Transcutaneous electrical stimulation (TES) is a novel, non-invasive neuromodulatory technique being investigated as a means to improve alertness and preserve performance under stress with few-to-no side effects. Despite the recent increase in research using TES, few studies have explored the effects of stimulation of the trigeminal nerve on cognition and the human stress response. Therefore, the aims of this study were to elucidate the effects of TES on biochemical and physiological responses to stress, cognition, and marksmanship performance under cognitive load. Participants in this repeated measures, crossover-design study included 23 healthy male (n = 18) and female (n = 5) civilians and members of the military ranging in age from 19 to 37 (mean 24.00 ± 5.65) years. Study procedures occurred in the afternoon on five consecutive days, including two testing days involving administration of active or sham TES to the right supraorbital region of the face using a commercially-available device (Thync One, Cerevast Therapeutics). To evaluate the effects of TES on the stress response, participants were required to complete a prolonged, cognitively challenging target discrimination task using a simulated firing range, which has been previously demonstrated to induce a reliable stress response in human research volunteers. Computer-assisted cognitive tasks were administered before and after rifle marksmanship in order to provide complementary assessment of functional domains challenged during the marksmanship task. Salivary markers of cortisol and α-amylase were collected at several time points during the testing day, and electrocardiography (ECG) and photoplethysmography (PPG), both markers of heart rate variability and stress responding, were monitored continuously. Linear mixed models with random slopes were used to analyze the effect of stimulation condition (active versus sham TES) on marksmanship and cognitive, physiological, and salivary outcomes across the testing period and at each measurement time point. No significant effects of stimulation condition or the interactions between stimulation condition and measurement time point were found for salivary stress biomarkers (punadj range 0.12 – 0.98) or for cognitive (punadj range 0.25 – 0.88) and physical workload (punadj range 0.31 – 0.79). There were no significant effects of stimulation condition on time-series indicators of heart rate variability (punadj range 0.10 – 0.96) except for pNN50 when measured with PPG (β = -4.97, punadj = 0.04, padj = n.s., d < 0.01). There were, however, significant stimulation condition by time interaction effects on mean heart rate, mean R-R interval, SDNN, RMSSD, and pNN50 (punadj range 0.12 – 0.98, d range < 0.01 – 0.02), indicating that trigeminal TES using the Thync One device increased activity of both the sympathetic and parasympathetic nervous systems during marksmanship and cognitive testing. Similar effects were noted on frequency-series indicators of heart rate variability using both ECG and PPG, in which stimulation condition effects were noted on ECG high frequency absolute (β = 8.50, punadj < 0.01, padj = 0.01, d < 0.01) and relative powers (β = -8.54, punadj < 0.01, padj = 0.01, d < 0.01), as well as PPG very low frequency power (β = -367.98, punadj < 0.01, padj = n.s., d = 0.12). Effects of the interaction between stimulation condition and measurement time point were noted on very low, low, and high frequency powers (punadj range < 0.01 – 0.048, d range < 0.01 – 0.21), as well as the ratio of low- to high-frequency powers in ECG (punadj range < 0.01 – 0.048, d < 0.01 for all). These results also suggest that trigeminal TES increased activity of both the sympathetic and parasympathetic nervous systems during marksmanship and cognitive testing. Furthermore, significant effects of stimulation condition were noted on marksmanship shot accuracy (β = 0.14, punadj = 0.01, padj = n.s., d = 0.60) and distance of shots from the targets’ center of mass (β = -0.08, punadj = 0.02, padj = n.s., d = 0.56), indicating that trigeminal TES impaired shot accuracy. There were also significant condition-by-time interaction effects on target detection latency (β = 220.46, punadj = 0.04, padj = n.s., d = 0.49); significant impairments in shot latency observed during the first marksmanship session in the active TES condition only resolved by the second marksmanship session. There were no significant effects of TES on accuracy or response times for neuropsychological tasks assessing response inhibition, sustained attention, and working memory (punadj range 0.09 – 0.98). Active trigeminal TES did, however, significantly reduce the standard deviation of response times on a measure of sustained attention and response inhibition (β = -16.29, punadj = 0.045, padj = n.s., d = 0.43). Although the literature suggests that TES may benefit stress and performance, these results do not support that conclusion. Overall, these analyses found that TES using a commercially available device did not influence chemical biomarkers of stress, but did influence markers of physiological stress, as well as cognitive and marksmanship performance under high cognitive load. TES was associated with impairments in marksmanship performance as well as increases in both sympathetic and parasympathetic nervous system activity. Further studies using different stimulation parameters, including multiple sessions of stimulation, will be necessary to more fully characterize possible influences of trigeminal nerve stimulation on stress responding and marksmanship performance or other military relevant tasks. In addition, this project underscores the need for more investigation into the mechanisms of effect of the Thync One device and other devices applying TES of the trigeminal nerve.

Many variations of conveyor, facility, and trailer designs are available to aid the human operator in manual materials handling (MMH). This thesis describes an investigation to determine which of four different designs used in trailer MMH place the least physical stress on the human operator when unloading materials. Each trailer MMH design was evaluated by the criteria of biomechanical loading, working posture, physiological measure, and subjective rating of exertion. These four methods were used to generate four dependent measures: L5/S1 Compression Force, OWAS Action Category, mean heart rate, and Borg CR-10 RPE. While no single assessment method provided a clear means for quantifying level differences in physical stress among MMH conditions, the methods employed furnished insight into which techniques and protocols might be useful in studying similar working situations. Based on relative sensitivity, ease of application, and administrative and equipment costs, the OWAS method was recommended as an assessment method useful for evaluating similar MMH work. The summary results of the four methods provided information to meet the experimental goals of this research and allowed conclusions to be drawn for the major areas of interest. Specifically, statistically significant differences were found between the Drop-frame - Floor Rollers condition and all other conditions in the SSPM - Placement analysis, between the Flat-floor - Power and the Drop-frame - Suspended Rollers conditions in the OWAS - Acquisition analysis, and between the Drop-frame - Suspended Rollers and the Drop-frame - Floor Rollers conditions in the OWAS - Placement analysis. / Master of Science