Muscular Effort Research Articles

Interdisciplinary evaluation of a robot physically collaborating with workers.

Collaborative Robots-CoBots-are emerging as a promising technological aid for workers. To date, most CoBots merely share their workspace or collaborate without contact, with their human partners. We claim that robots would be much more beneficial if they physically collaborated with the worker, on high payload tasks. To move high payloads, while remaining safe, the robot should use two or more lightweight arms. In this work, we address the following question: to what extent can robots help workers in physical human-robot collaboration tasks? To find an answer, we have gathered an interdisciplinary group, spanning from an industrial end user to cognitive ergonomists, and including biomechanicians and roboticists. We drew inspiration from an industrial process realized repetitively by workers of the SME HANKAMP (Netherlands). Eleven participants replicated the process, without and with the help of a robot. During the task, we monitored the participants' biomechanical activity. After the task, the participants completed a survey with usability and acceptability measures; seven workers of the SME completed the same survey. The results of our research are the following. First, by applying-for the first time in collaborative robotics-Potvin's method, we show that the robot substantially reduces the participants' muscular effort. Second: we design and present an unprecedented method for measuring the robot reliability and reproducibility in collaborative scenarios. Third: by correlating the worker's effort with the power measured by the robot, we show that the two agents act in energetic synergy. Fourth: the participant's increasing level of experience with robots shifts his/her focus from the robot's overall functionality towards finer expectations. Last but not least: workers and participants are willing to work with the robot and think it is useful.

A Robot-Assisted Framework for Rehabilitation Practices: Implementation and Experimental Results.

One of the most interesting characteristics of collaborative robots is their ability to be used in close cooperation scenarios. In industry, this facilitates the implementation of human-in-loop workflows. However, this feature can also be exploited in different fields, such as healthcare. In this paper, a rehabilitation framework for the upper limbs of neurological patients is presented, consisting of a collaborative robot that helps users perform three-dimensional trajectories. Such a practice is aimed at improving the coordination of patients by guiding their motions in a preferred direction. We present the mechatronic setup, along with a preliminary experimental set of results from 19 volunteers (patients and control subjects) who provided positive feedback on the training experience (52% of the subjects would return and 44% enjoyed performing the exercise). Patients were able to execute the exercise, with a maximum deviation from the trajectory of 16 mm. The muscular effort required was limited, with average maximum forces recorded at around 50 N.

Multisensory Evaluation of Muscle Activity and Human Manipulability during Upper Limb Motor Tasks.

In this work, we evaluate the relationship between human manipulability indices obtained from motion sensing cameras and a variety of muscular factors extracted from surface electromyography (sEMG) signals from the upper limb during specific movements that include the shoulder, elbow and wrist joints. The results show specific links between upper limb movements and manipulability, revealing that extreme poses show less manipulability, i.e., when the arms are fully extended or fully flexed. However, there is not a clear correlation between the sEMG signals' average activity and manipulability factors, which suggests that muscular activity is, at least, only indirectly related to human pose singularities. A possible means to infer these correlations, if any, would be the use of advanced deep learning techniques. We also analyze a set of EMG metrics that give insights into how muscular effort is distributed during the exercises. This set of metrics could be used to obtain good indicators for the quantitative evaluation of sequences of movements according to the milestones of a rehabilitation therapy or to plan more ergonomic and bearable movement phases in a working task.

Influence Technique Training Data sensor (Triton Wear) To improve biomechanical variables for some stages Performance and achievement 50m freestyle youth

Swimming is one of the sports with great muscular effort and complex motor performance that requires coordination and harmony between the movements of the parts of the body contributing to performance that defies the limits of humans. The development of physical abilities and the improvement of technical performance can only be separated from the support of scientific theories and technology, in order to improve training methods and feedback system based on the fusion of information and data using modern sensors and information collection system. On the performance and mechanical conditions of the swimmer to help develop performance and achievement, the researchers used for this purpose a device (Triton Wear data sensor) to collect information and feedback on performance, to prepare special exercises and correct thereal-time performance of 50 m swimmers. The research was conducted on a sample of swimmers amounting to (6) young swimmers whose technical and mechanical data was extracted after wearing the sensor under the head cover of each swimmer, and the performance data was analyzed on this system, and the experiment lasted for six weeks, during which special exercises and feedback were given. Instantaneous based on the sensor data of each member of the sample, and after conducting post-tests, it was shown that the exercises and feedback based on the sensor technology, had a direct impact on the improvement of the average performance of the sample in the 50-meter freestyle race and the improvement of all biomechanical values (such as average speed, frequency and length, acceleration and instantaneous strength) This improvement indicated that data collection and nutrition Using the sensor's multi-information fusion can be applied more precisely and differently in the training of different swimming races, and can find many motor problems in sports swimmers to describe training solutions for them, both for specific parts of the body and the body as a whole. Techniques for accurately identifying this valuable information can therefore be used for quantitative biomechanical analysis. And to reach the training process.

Age related changes in the Q angle of non-professional football players

BackgroundFootball practice involves a great muscular demand, leading to the development of the lower limbs that, on occasions, can cause deviations from the normal anthropometric values. The quadriceps angle (Q angle) is a value often taken as a reference for the alignment of the lower limbs. ObjectiveTo observe the changes of the Q angle in young football players, because of muscular effort, analyzing the differences between four groups of different ages and to determine whether the playing position might influence these variations. MethodsA cross sectional study was carried out with 104 male subjects divided into four groups according to age: under 8 years-old, 8-17 years-old, 17-21 years-old and over 21 years-old. A photograph was taken in standing position and the Q angle was plotted with KINOVEA® software. As for the reliability of the measurements, intraclass intra and interobserver coefficient were 0.958 and 0.860 respectively. The study was conducted in mid-season. ResultsQ angle value is greater in those under 8 years of age and decreases gradually and significantly (p < 0.005) until 17–21 years of age, where it stabilizes at values of 5.73° ± 2.78 for right Q angle and 5.88° ± 2.55 for left Q angle. Two way ANOVA demonstrated a significant group*position interaction for goalkeepers with a medium effect size in both angles (p < 0.001) with a medium effect (η2 Right Q angle = 0.31; η2 Left Q angle = 0.37). The values remain unchanged in subjects over 21 years of age (p > 0.005), except for goalkeepers, who suffered a difference in the evolution of the angle within their age category (p < 0.005) and with a high effect size with the other positions (value > 0.8) except forward (value < 0.5). ConclusionThis study determines that the Q angle in football players decreases with growth, reaching values below 15° at the end of development. Playing positions only influence players over the age of 21, and the Q-angle of goalkeepers is greater than that of other players.

Influence of Mechanical Ventilation Modes on the Efficacy of Nebulized Bronchodilators in the Treatment of Intubated Adult Patients with Obstructive Pulmonary Disease.

Little has been reported in terms of clinical outcomes to confirm the benefits of nebulized bronchodilators during mechanical ventilation (MV). Electrical Impedance Tomography (EIT) could be a valuable method to elucidate this gap. The purpose of this study is to evaluate the impact of nebulized bronchodilators during invasive MV with EIT by comparing three ventilation modes on the overall and regional lung ventilation and aeration in critically ill patients with obstructive pulmonary disease. A blind clinical trial in which eligible patients underwent nebulization with salbutamol sulfate (5 mg/1 mL) and ipratropium bromide (0.5 mg/2 mL) in the ventilation mode they were receiving. EIT evaluation was performed before and after the intervention. A joint and stratified analysis into ventilation mode groups was performed, with p < 0.05. Five of nineteen procedures occurred in controlled MV mode, seven in assisted mode and seven in spontaneous mode. In the intra-group analysis, the nebulization increased total ventilation in controlled (p = 0.04 and ⅆ = 2) and spontaneous (p = 0.01 and ⅆ = 1.5) MV modes. There was an increase in the dependent pulmonary region in assisted mode (p = 0.01 and ⅆ = 0.3) and in spontaneous mode (p = 0.02 and ⅆ = 1.6). There was no difference in the intergroup analysis. Nebulized bronchodilators reduce the aeration of non-dependent pulmonary regions and increase overall lung ventilation but there was no difference between the ventilation modes. As a limitation, it is important to note that the muscular effort in PSV and A/C PCV modes influences the impedance variation, and consequently the aeration and ventilation values. Thus, future studies are needed to evaluate this effort as well as the time on ventilator, time in UCI and other variables.

Ultrasound-guided fasciotomy for chronic exertional forearm compartment syndrome: a cadaveric feasibility study

ObjectivesChronic exertional forearm compartment syndrome is observed in patients who engage in physical activity requiring repetitive isometric muscular effort of the wrist during prolonged grasping. Open fasciotomy was considered as the gold-standard treatment, for its ability to release all compartments. However, its invasiveness means that high-level athletes have to abstain from competition for a long period of time. For this reason, minimally invasive techniques have been developed, to allow faster recovery.The objective of this cadaveric study was to evaluate the feasibility and reproducibility of ultrasound-guided palmar fasciotomy in the treatment of chronic exertional forearm compartment syndrome. MethodsSurgery consisted in ultrasound-guided palmar fasciotomy of the superficial anterior compartment, using a single minimally invasive approach. Twenty forearms were then dissected by an independent operator, (1) to check complete fasciotomy and (2) to screen for iatrogenic lesions on the tendons, veins and superficial sensory branches. ResultsSixteen fasciotomies were total and 4 partial: i.e., a release rate of 80%. The superficial sensory branches were intact, and notably the branches of the medial cutaneous nerve of the forearm. Mean surgery time was 9 min, progressively decreasing with the repetition of the ultrasound-guided procedure. ConclusionsUltrasound-guided fasciotomy in the management of chronic exertional forearm compartment syndrome appears to be a simple, effective, safe and reproducible technique.

Physical perfection of students is in group псм from volley-ball. Relevance of the study

The main objective of "Physical Education" in higher education institution is the development of students' physical qualities and motor abilities. The solution of this problem is facilitated by the students involvement in various sectional activities, in particular, volleyball. The aim of this work is to highlight the main means of ensuring the optimal level of development of the physical qualities of students involved in the volleyball section. Methods of analysis: analysis of scientific sources, comparison, synthesis. Results: Motor activity in volleyball is characterized by a variety of actions, in particular: running of different intensity, walking, jumping, hitting the ball, stopping, falling, serving, passing, blocking, etc. Therefore, special attention in the process of training should be paid to the development of physical abilities: speed, strength, agility, endurance, flexibility and jumping ability. A fast player can win the time and space compare to the opponent who has the ability to successfully solve tactical problems. The combination of speed and strength allows the player to perform successfully various game combinations. A strong player is able to overcome external resistance or counteract it with the help of muscular efforts. Agile - masters new techniques easily, adapts to different game conditions better, able to perform new motor learning accurately, economically, quickly. During the game, athletes perform multiple accelerations, so the presence of endurance is equally important for them. In volleyball, the elasticity of the muscles and ligaments of the lower extremities and the spinal column is important, therefore, in the classroom, special attention should be paid to the development of flexibility. No less important motor ability of a volleyball player is jumping ability. It depends on the level of development of speed-strength qualities and is based on the strength of the muscles, the speed of their contractions and coordination of movements. Therefore, jumping exercises should be used on every lesson. Conclusions: teaching and training in volleyball is an integral part of a single pedagogical process, in which one should keep the basic provisions, and excellent results can only be achieved with a high level of physical and technical preparedness of the players. Properly chosen teaching methodology and successful organization of classes are quite important in the preparation of the team.

Straining to void at preoperative urodynamic study as a risk factor for prolapse recurrence after surgery

ObjectivesStraining to void is the need to make a muscular effort in order to initiate, maintain or improve the urinary stream, through an increase in abdominal pressure. This pattern of bladder emptying is frequently observed in women with pelvic organ prolapse causing urinary obstruction, to overcome the increased resistance to urine flow. However, frequent increases in abdominal pressure are a risk factor for developing pelvic organ prolapse, and might play a role in its recurrence after surgery. The aim of this study was to investigate the role of straining identified at urodynamic study in prolapse recurrence after surgical repair. Study designThis was a retrospective study on women submitted to prolapse repair by vaginal hysterectomy with modified McCall culdoplasty and anterior colporraphy. All patients underwent a preoperative urodynamic evaluation including a pressure-flow study performed after prolapse reduction by means of a vaginal pessary; straining was defined by a simultaneous and similar increase in intravesical and abdominal pressures of at least 10 cmH2O over the baseline during bladder emptying, corresponding to intermittent peaks of urine flow. Patients were divided into two groups according to the presence or absence of straining, and they were compared for surgical results at 12 months and for the rate of anterior or central recurrence over time. ResultsWomen with straining (n = 16), compared to women with normal voiding (n = 43), showed a higher risk of anterior recurrence over time at Kaplan-Meier curves, for both stage II (p = 0.02) and stage III prolapse (p = 0.02). No difference was seen for central recurrence during the follow up period. POP-Q staging at 12 months was similar for the two groups, except for the location of the Aa point which was significantly better for women without straining (−1.6 ± 0.1 cm vs −0.8 ± 0.3 cm, p = 0.03). ConclusionsStraining to void identified in preoperative urodynamic study seems to increase the risk of anterior recurrence after surgical repair of pelvic organ prolapse.

Ergonomic Design and Assessment of an Improved Handle for a Laparoscopic Dissector Based on 3D Anthropometry.

Laparoscopic surgery (LS) has been shown to provide great benefits to patients compared with open surgery. However, surgeons experience discomfort, low-efficiency, and even musculoskeletal disorders (MSDs) because of the poor ergonomic design of laparoscopic instruments. A methodology for the ergonomic design of laparoscopic dissector handles considering three-dimensional (3D) hand anthropometry and dynamic hand positions was addressed in this research. Two types of hand positions for grasping and stretching were scanned from 21 volunteers using a high-resolution 3D scanner. The 3D anthropometric data were extracted from these 3D hand pose models and used to design an improved handle (IH) that provides additional support for the thumb, a better fit to the purlicue, and a more flexible grasp for the index finger. Thirty subjects were invited to evaluate the IH in terms of muscular effort, goniometric study of motion, and efficiency and effectiveness during four trials of a laparoscopic training task. Questionnaires provided subjective parameters for ergonomic assessment. Positive results included less muscle load in the trapezius as well as significant but small angular differences in the upper limb. No significant reduction in the trial time and no increased percentage of the achievement were observed between the IH and the commercial handle (CH). Improved intuitiveness, comfort, precision, stability, and overall satisfaction were reported. IH provides significant ergonomic advantages in laparoscopic training tasks, demonstrating that the proposed methodology based on 3D anthropometry is a powerful tool for the handle design of laparoscopic dissectors and other surgical instruments.

Influence of a Hybrid Manual–Electric Wheelchair Propulsion System on the User’s Muscular Effort

Abstract Self-propelled wheelchairs favour the rehabilitation process, forcing the user to be physically active. Unfortunately, in most cases, the manual propulsion is not adapted to the individual needs and physical capabilities of the user. This paper presents the results of operational tests of a wheelchair equipped with a hybrid propulsion system in which the muscle strength generated by the user is assisted by two independent electric motors. The research aimed to investigate the influence of the applied control algorithm and the assistance factor (W) on the value of the muscular effort (MA) while propelling the wheelchair with the use of push rims. A modified ARmedical AR-405 wheelchair equipped with two MagicPie 5 electric motors built into the wheelchair’s hubs with a power of 500 W was used in this research. The tests were carried out on a wheelchair test bench simulating the moment of resistance within the range of 8–11 Nm. Surface electromyography was employed for the measurement of MA, specifically, a four-channel Noraxon Mini DTS apparatus. The research was carried out on five patients from the group of C50 anthropometric dimensions. The effort was measured for four muscles: deltoid–anterior part, deltoid–posteriori part, and triceps brachii and extensor carpi radialis longus. The effectiveness of the hybrid propulsion system was observed based on the extensor carpi radialis longus muscle. In this case, for the standard wheelchair, the MA ranged from 93% to 123%. In contrast, for a wheelchair equipped with the hybrid propulsion system, at W = 70%, the MA was within the range of 43%–75%.

Hybrid robotic and electrical stimulation assistance can enhance performance and reduce mental demand.

Combining functional electrical stimulation (FES) and robotics may enhance recovery after stroke, by providing neural feedback with the former while improving quality of motion and minimizing muscular fatigue with the latter. Here, we explored whether and how FES, robot assistance and their combination, affect users' performance, effort, fatigue and user experience. 15 healthy participants performed a wrist flexion/extension tracking task with FES and/or robotic assistance. Tracking performance improved during the hybrid FES-robot and the robot-only assistance conditions in comparison to no assistance, but no improvement is observed when only FES is used. Fatigue, muscular and voluntary effort are estimated from electromyographic recording. Total muscle contraction and volitional activity are lowest with robotic assistance, whereas fatigue level do not change between the conditions. The NASA-Task Load Index answers indicate that participants found the task less mentally demanding during the hybrid and robot conditions than the FES condition. The addition of robotic assistance to FES training might thus facilitate an increased user engagement compared to robot training and allow longer motor training session than with FES assistance.

A Phonological Study of Mosuli Dialect Assimilation

Assimilation is a phonological process which refers to the change of one sound by another sound under the influence of a third sound. The main reason behind this change is the speaker's tendency to economize the muscular effort or make ease of articulation or both. This study aims at finding out the assimilation patterns in Mosuli dialect( ) and divide these patterns in this dialect( ) according to the following factors:&#x0D; &#x0D; Degree of influence.&#x0D; &#x0D; 2. The direction of influence (i.e., voicing, place of articulation, manner of articulation and Tafxim). The results show that Mosuli dialect tends to ease of articulation than that of economize the muscular effort, also they show that the Mosuli dialect uses only regressive assimilation depending on the factor of direction of influence, also the study shows the use of complete and partial assimilation depending on the degree of influence.

Evaluation of anti-rollback systems in manual wheelchairs: muscular activity and upper limb kinematics during propulsion

Self-propelling a wheelchair up a hill requires intense muscular effort and introduces the risk of the wheelchair rolling down. The purpose of this paper was to assess the user's muscular activity during ramp climbing. Tests were carried out on a group of 10 subjects who had to propel a wheelchair up a standardized wheelchair ramp. Basic parameters of upper limb kinematics were measured to determine the total push-rim rotation angle. This was 105.91° for a wheelchair with a stiff anti-rollback system, 99.39° for a wheelchair without an anti-rollback system and 98.18° for a wheelchair with a flexible anti-rollback system. The upper limb muscle effort was measured at 55 ± 19% for the wheelchair without an anti-rollback system, 59 ± 19% for the wheelchair with a stiff anti-rollback system and 70 ± 46% for the wheelchair with a flexible anti-rollback system. The conducted research showed an increase in muscle effort while using anti-rollback systems. In the case of push-rim rotation angle, no significant differences in the value of the rotation angle were found.

ANALYSIS OF SCIENTIFIC RESEARCH ON THE SENSIMOTOR DEVELOPMENT OF CHILDREN WITH DISORDERS OF INTELLECTUAL DEVELOPMENT

The article provides a theoretical analysis of research on the problem of sensorimotor development with children with violation of intellectual development. Theoretical aspects of sensorimotor development of children with intellectual disabilities in the following areas are considered: vestibular-postural reactions and bilateral coordination. Motor mechanisms affect the general development of the child, his ability to work and master the curriculum. Studies have shown the effect of physical activity on mental activity and academic performance. Imperfections of the motor sphere of children with PIR are revealed. Children's gait is unstable, movements are chaotic, poorly coordinated, poorly regulated muscular effort, impaired visual-motor coordination, inability to imitate, underdevelopment of differentiated finger movements. The disadvantages of arbitrary movements are pronounced. Theoretical analysis of scientific research on the role of the central nervous system in the construction of movements. Spinal cord, medulla, diencephalon, cerebellum, large hemispheres perform their functions. Simple movements (reflective) provide normal performance of more complex movements performed due to the lower parts of the central nervous system (spinal, medulla, midbrain). More complex postures are regulated by the activity of the midbrain, the vestibular system, which obey the cerebellum. The cerebellum coordinates the proportionality of movement. To perform movement in space, it is necessary to combine all types of sensitive sphere (afferentation). This process occurs at the level of the diencephalon and subcortical nuclei. It is proved that part of the vestibular signals must be registered and modulated by the brain. The lack of modulation of vestibular stimuli will be noticeable in bilateral reactions, coordination of the two sides of the body. The postural response may go unnoticed because it is difficult for the child to adopt a particular posture. Sensorimotor development affects the functioning of the body of a child with violation of intellectual development.

Assessment of muscular effort in workers performing an actual use-case manual material handling with and without the assistance of Bazar robot

Human-robot collaboration (HRC) technologies represent one of the new options for the prevention of work-related musculoskeletal disorders (WMDs) [1]. They share the workspace with workers, communicate with them, manage the human partner's flexibility and ergonomics and physically interact, to work together on a common goal [2]. Reconfigurable collaborative robots adapt to the workers’ intentions and task variations, offloading them from external loads and keeping them in ergonomic working circumstances, to improve efficiency and quality of the task execution. Although collaborative work is a widespread method for lowering WMDs, the scientific literature reveals conflicting findings on its efficacy, due to factors affecting team capacity, autonomy, and coordination [3]. To measure motor coordination during dynamic tasks, a common approach is muscle co-activation that may become functionally unfavorable [3]. Therefore, this research aims to evaluate upper limb muscle coactivation in workers performing an industrial use case manual material handling (MMH), proposed by the SME HANKAMP (Netherlands), by comparing a scenario where the workers are helped by a dual-arm cobot BAZAR [4] with a scenario without BAZAR. This cobot BAZAR is being assessed in the context of SOPHIA (http://www.project-sophia.eu) project funded by the European Union's Horizon 2020 (grant agreement No. 871237). Eleven participants (5 females and 6 males; 27.73±5.99 years; BMI: 23.06±3.93 kg/m2) took part in the study carried out at the University of Montpellier in accordance with the Helsinki Declaration and authorized by the local Ethics Committee (Protocol number IRB-EM 2103 A). Six bipolar electrodes (FreeEMG300 System, BTS, Italy, sampling rate at 1000 Hz) were placed on the flexors and extensors muscles of the shoulder (anterior and posterior deltoideus), elbow (biceps and triceps brachii caput longum) and wrist (flexor and extensor carpi radialis) joints. The experiments are shown in the video available at: https://youtu.be/vul8iLO0Sdw. Each participant, after being instructed, completed the task 3 times without BAZAR and 3 with BAZAR (Fig. 1A). We randomly ordered the 2 conditions for each subject. Furthermore, participants performed a specific exercise twice with each muscle to obtain the isometric maximal voluntary contractions (iMVCs) [1,3]. The envelope of each task's sEMG signals was then extracted, normalized respect to the average iMVC peak value for each muscle, time-normalized and then interpolated according to the brushing sub-task duration (400 samples) [1,3]. The time-varying multi-muscle coactivation function (TMCf) [3] was estimated and the mean and maximum values were calculated. A statistical analysis was carried out to evaluate whether the help of the cobot had determined significant changes in each parameter (p-value < 0.05). Fig. 1 B show the mean and standard deviation of mean and max values of evaluated TMCf for each condition. Significant effects of the presence of BAZAR were found for mean (p<0.001) and max (p=0.001) values of TMCf: the values significantly decrease when the task is performed with BAZAR. The results showed a reduction in upper limb co-activation when the specific MMH was performed with BAZAR. Therefore, HRC technologies, which share the workspace with workers, not only offload workers from external loads and improve the task execution efficiency and quality. They also allow a better coordination and reduce the worker’s physical effort while she/he physically interacts with the robot, and positively affect her/his physiological motor strategy.

Effect Of Transcutaneous Electrical Spinal Cord Stimulation On The Functional Activity Of Reciprocal And Presynaptic Inhibition In Healthy Subjects

The objective of our research was to examine an effect of 20-minute electrical stimulation session of the spinal cord (tESCS) on the manifestation of reciprocal and presynaptic inhibition in the system of shin antagonist muscles in healthy individuals in a state of a relative muscle rest and weak muscle effort, along with possible physiological mechanisms of these manifestations. Material and Methods — The study involved 10 healthy men 27 to 35 years of age. Reciprocal and presynaptic inhibition was evaluated by suppressing the amplitude of testing H-reflex of m. soleus under conditions of conditioning stimulation of n. peroneus profundus and testing stimulation of n. tibialis with interstimulus intervals of 3 ms and 100 ms, respectively. Reciprocal inhibition and presynaptic inhibition were recorded during a 20-minute tESCS in the area of T11-T12 thoracic vertebrae at rest, in combination with voluntary muscular effort (5% of the maximum voluntary contraction), and after the stimulation. Results — During 20-minute electrical stimulation of the spinal cord at rest, the severity of reciprocal inhibition decreased, inverting to reciprocal facilitation, while presynaptic inhibition weakened only at the twentieth minute of stimulation; and in the postactivation period, the activity of spinal inhibition processes in the antagonist muscle system corresponded to background values. The most pronounced effect of prolonged tESCS was observed when performing a weak isometric contraction, which was accompanied by an increase in reciprocal inhibition activity during 10 minutes of exposure and 10 minutes after the end of stimulation. The severity of presynaptic inhibition during and after the spinal cord stimulation remained unchanged and complied with background values. The presynaptic inhibition activity was expressed to a greater extent during prolonged stimulation of the spinal cord at rest, and when performing a weak voluntary effort, as well as during the postactivation period. Conclusion — Changes in the spinal inhibitory interactions in the system of antagonist muscles on the basis of tESCS effects during arbitrary muscle tension could probably be explained by the fact that in this case, the inhibitory interneuron circuits of spinal cord were exposed to a wider range supraspinally descending and ascending peripheral effects, compared with spinal cord stimulation in a state of a relative muscle rest.

Effect of low-cost automation on labor productivity and labor fatigue for corrugated boxes flaps twisting.

Flaps of the corrugated box folded inversely while manual packing of goods initiative this will cause tearing of the box at creased positions. To avoid tearing, it is required to twist each box along creased positions as soon as it is manufactured and in wet condition due to liquid gum application. To apply and evaluate the effect of Low-Cost Automation on labor productivity and labor fatigue for corrugated boxes flaps twisting. Low-Cost Automation solution is applied to overcome low labors' productivity and excessive labors' fatigue problems in the manual box twisting work. Productivity need analysis is performed to identify the key productivity measures. Three automated mechanisms are developed for box stopping, clamping, and twisting activities. Reduction in labors muscular efforts requirement is confirmed through surface electromyography technique. It is observed that the average actual time required for twisting one box reduced from 34 seconds to 17 seconds, and labor productivity almost doubled. The muscular efforts required for twisting of flaps of the boxes are reduced significantly. The developed low-cost automation solution is unique and found worthy for small scale corrugated box manufacturers.

Inspiratory threshold loading negatively impacts attentional performance.

RationaleThere are growing concerns over the occurrence of adverse physiologic events (PEs) occurring in pilots during operation of United States Air Force and Navy high-performance aircraft. We hypothesize that a heightened inspiratory work of breathing experienced by jet pilots by virtue of the on-board life support system may constitute a “distraction stimulus” consequent to an increased sensation of respiratory muscle effort. As such, the purpose of this study was to determine whether increasing inspiratory muscle effort adversely impacts on attentional performance.MethodsTwelve, healthy participants (age: 29 ± 6 years) were recruited for this study. Participants completed six repetitions of a modified Masked Conjunctive Continuous Performance Task (MCCPT) protocol while breathing against four different inspiratory threshold loads to assess median reaction times (RTs). A computer-controlled threshold loading device was used to set the inspiratory threshold loads. Repeated measures analysis of variances (ANOVAs) were performed to examine: (i) the efficacy of the threshold loading device to impose significantly higher loading at each loading condition; (ii) the effects of loading condition on respiratory muscle effort sensation; and (iii) the influence of hypercapnia on MCCPT scores during inspiratory threshold loading. Generalized additive mixed effects models (GAMMs) were used to examine the potential non-linear effects of respiratory muscular effort sensation, device loading, and hypercapnia, on MCCPT scores during inspiratory threshold loading.ResultsInspiratory threshold loading significantly augmented (P < 0.05) inspiratory effort sensation and the inspiratory pressure-time product (PTP). Our analyses also revealed that median hit RT was positively associated with inspiratory effort sensation during inspiratory loading trials.ConclusionThe findings of this work suggest that it was not increasing inspiratory muscle effort (i.e., PTP) per se, but rather participant’s subjective perception of inspiratory “load” that impacts negatively on attentional performance; i.e., as the degree of inspiratory effort sensation increased, sotoo did median hit RT. As such, it is reasonable to suggest that minimizing inspiratory effort sensation (independent of the mechanical output of the inspiratory muscles) during high-performance flight operations may prove useful in reducing pilot RTs during complex behavioral tasks.

In-toeing gait requires less muscular effort and reduces lower limb joint loads in people with internal torsional deformities

In-toeing gait requires less muscular effort and reduces lower limb joint loads in people with internal torsional deformities