scholarly journals The new "Tehran Back Belt": Design then testing during a simulated sitting task improved biomechanical spine muscle activity

2019 ◽  
Vol 9 (2) ◽  
pp. 115-122 ◽  
Author(s):  
Hamidreza Mokhtarinia ◽  
Javad Ghamary ◽  
Azam Maleki-Ghahfarokhi ◽  
Morteza Asgari ◽  
Charles Philip Gabel ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Large Scale ◽  
Ease Of Use ◽  
Emg Activity ◽  
Activity Levels ◽  
Flexor Muscle ◽  
Sitting Posture ◽  
Back Belts ◽  
Occupational Low Back Pain ◽  
Spinal Load

Background: Spinal load and muscle activity in occupation settings is an area of increasing concern. Regarding technological advancements, in diverse occupations the spinal loads have increased through constrained seated postures. Back belts are consequently used in prophylactic and conservative management of occupational low back pain (LBP) in two distinct settings, prevention in industry, and treatment in LBP management. Industrial sites utilize belts for LBPprophylaxis on a large scale with their design and user experience (UE) influencing both the effectiveness and the workers’ compliance. This pilot study aims at determining the effectiveness of the new Tehran Back Belt (TBB) and assesses both UE and biomechanical effect (BE) on paraspinal muscle activity in healthy subjects. Methods: A pretest-posttest study. Stage-1, design and fabrication of the TBB. Stage-2, the UE of the designed belt evaluated in healthy volunteers (n=30) via a checklist. The BE was determined from the level of lumbar extensor and trunk flexor muscle activity gauged during two test conditions of sitting posture (with and without belt) over 35-minute periods. Results: Most subjects (>90%) reported high ‘ease of use’ and ‘comfort’ while wearing the TBB.The BE statistical analysis showed significantly reduced EMG activity levels for the longissimus(P = 0.012, η2=0.24), rectus abdominis (P=0.024, η2=0.18) and internal oblique (P=0.001,η2=0.44) muscles in belt-use conditions. Conclusion: Decreased muscle activity while using the TBB is potentially advantageous for workers as spinal muscle activity is significantly reduced. Further investigations for longer duration effects and during real work office-based activities are warranted.

Head Movements and Neck Muscle Activity During Air Combat Maneuvering

2020 ◽  
Vol 91 (1) ◽  
pp. 26-31 ◽  
Author(s):  
Roope Sovelius ◽  
Maunu Mäntylä ◽  
Heini Huhtala ◽  
Juha Oksa ◽  
Rasmus Valtonen ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Muscular Activity ◽  
Head Movements ◽  
Neck Muscle ◽  
Activity Levels ◽  
Sitting Posture ◽  
Field Of Vision ◽  
Air Combat ◽  
The Difference ◽  
Neutral Posture

BACKGROUND: The aim of the study was to determine the characteristics of cervical muscle activity in different head movements when using helmet mounted display in air combat maneuvering.METHODS: Cervical EMG was measured with eight F/A-18 pilots using the Joint Helmet Mounted Cueing System (JHMCS) during air combat maneuvering. In-flight Gz acceleration and continuous head position were recorded. Muscular activity was compared between head movements in isolation and combined with torso movement. In addition, the effect of the direction of head movements and the use of head support of the ejection seat on muscle activity was determined.RESULTS: Muscular loading increased in the cervical flexors and extensors when using the torso during targeting beyond the field of vision in the neutral sitting posture; the difference was significant in the flexors, but activity levels were higher in the extensors. Cervical muscles are loaded to a lesser extent if the head is kept in a stable position during Gz loading. Muscular activity in the neck muscles was higher when the pilot was moving the head out of neutral posture rather than toward neutral posture. The use of the headrest as a support decreased muscle activity in the extensors, but resulted in higher activity in the flexor muscles.DISCUSSION: All analyzed conditions were significantly affected by an increase in Gz. An increase of muscle activity with torso movements is considered as a positive factor as it reflects maintained muscular support for the cervical spine. Presented results may be helpful when specific conditioning programs and cockpit ergonomics are developed for fighter pilots.Sovelius R, Mäntylä M, Huhtala H, Oksa J, Valtonen R, Tiitola L, Leino T. Head movements and neck muscle activity during air combat maneuvering. Aerosp Med Hum Perform. 2020; 91(1):26–31.

scholarly journals Triceps surae torque-length relationships relevant for walking activity levels with and without an ankle exoskeleton

2019 ◽  
Author(s):  
Anthony L. Hessel ◽  
Brent J. Raiteri ◽  
Michael J. Marsh ◽  
Daniel Hahn
Keyword(s):  
Muscle Activity ◽  
Metabolic Cost ◽  
Activity Levels ◽  
Plantar Flexor ◽  
Plantar Flexors ◽  
Flexor Muscle ◽  
Fascicle Length ◽  
Lateral Gastrocnemius ◽  
Work Requirements ◽  
Ankle Exoskeleton

AbstractAnkle exoskeletons have been developed to assist walking by offloading the plantar flexors work requirements, which reduces muscle activity level. However, reduced muscle activity alters plantar flexor muscle-tendon unit dynamics in a way that is poorly understood. We therefore evaluated torque-fascicle length properties of the soleus and lateral gastrocnemius during voluntary contractions at simulated activity levels typical during late stance with and without an ankle exoskeleton. Soleus activity levels (100, 30, and 22% maximal voluntary activity) were produced by participants via visual electromyography feedback at ankle angles ranging from −10° plantar flexion to 35° dorsiflexion. Using dynamometry and ultrasound imaging, torque-fascicle length data of the soleus and lateral gastrocnemius were produced. The results indicate that muscle activity reductions observed with an exoskeleton shift the torque-angle and torque-fascicle length curves to more dorsiflexed ankle angles and longer fascicle lengths where no descending limb is physiologically possible. This shift is in line with previous simulations that predicted a similar increase in the operating fascicle range when wearing an exoskeleton. These data suggest that a small reduction in muscle activity causes changes to torque-fascicle length properties, which has implications for the design and testing of future ankle exoskeletons for assisted walking.Significance StatementAssistive lower-limb exoskeletons reduce the metabolic cost of walking by reducing the positive work requirements of the plantar flexor muscles. However, if the exoskeleton reduces plantar flexor muscle activity too much, then the metabolic benefit is lost. The biological reasons for this are unclear and hinder further exoskeleton development. This research study is the first to directly evaluate if a reduction in plantar flexor muscle activity similar to that caused by wearing an exoskeleton affects muscle function. We found that reduced muscle activity changes the torque-length properties of two plantar flexors, which could explain why reducing muscle activity too much can increase metabolic cost.

scholarly journals Happy Enough to Relax? How Positive and Negative Emotions Activate Different Muscular Regions in the Back - an Explorative Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Clara Scheer ◽  
Simone Kubowitsch ◽  
Sebastian Dendorfer ◽  
Petra Jansen
Keyword(s):  
Muscle Activity ◽  
Negative Emotions ◽  
Activity Patterns ◽  
Large Body ◽  
Reciprocal Relationship ◽  
Emg Activity ◽  
Sitting Posture ◽  
Elevated Activity ◽  
Resting Period ◽  
Positive And Negative Emotions

Embodiment theories have proposed a reciprocal relationship between emotional state and bodily reactions. Besides large body postures, recent studies have found emotions to affect rather subtle bodily expressions, such as slumped or upright sitting posture. This study investigated back muscle activity as an indication of an effect of positive and negative emotions on the sitting position. The electromyography (EMG) activity of six back muscles was recorded in 31 healthy subjects during exposure to positive and negative affective pictures. A resting period was used as a control condition. Increased muscle activity patterns in the back were found during the exposure to negative emotional stimuli, which was mainly measured in the lumbar and thorax regions. The positive emotion condition caused no elevated activity. The findings show that negative emotions lead to increased differential muscle activity in the back and thus corroborate those of previous research that emotion affects subtle bodily expressions.

EMG activity of slow and fast ankle extensors following spinal cord transection

1984 ◽  
Vol 56 (6) ◽  
pp. 1608-1613 ◽  
Author(s):  
M. A. Alaimo ◽  
J. L. Smith ◽  
R. R. Roy ◽  
V. R. Edgerton
Keyword(s):  
Spinal Cord ◽  
Muscle Activity ◽  
Total Duration ◽  
Spinal Cord Transection ◽  
Emg Activity ◽  
Activity Levels ◽  
Virtual Absence ◽  
Contraction Times ◽  
Slow Twitch ◽  
Slow Twitch Fibers

Transformations of slow-twitch fibers to the fast-twitch type following spinal cord transection are thought to be related to a substantial decrease or virtual absence of neuromuscular activity. In this experiment, spontaneous activity levels in spinalized and normal cats, raised under similar conditions, were assessed by integrated electromyography (I-EMG) recorded for 240 min over 24 h from the slow-contracting soleus (SOL) and the fast-contracting lateral gastrocnemius (LG). In the SOL of the spinalized cats, there was a 75% reduction in total I-EMG and a 66% reduction in the total duration of muscle activity. Conversely, the LG showed no significant change in total I-EMG, but there was a 66% reduction in the total duration of muscle activity. Based on muscle property data published in companion studies, there was no significant correlation between the SOL total I-EMG and the reduction in contraction times or the decrease in the percentage of slow-twitch fibers determined histochemically. We conclude that transformations of slow-twitch fibers following spinal transection may be regulated by several factors, among which is the total level of spontaneous daily activity.

Myoelectric Activity Differences in Three Learning Sessions

2002 ◽  
Vol 16 (2) ◽  
pp. 92-96
Author(s):  
Tiina Ritvanen ◽  
Reijo Koskelo ◽  
Osmo H„nninen
Keyword(s):  
High School Students ◽  
Muscle Activity ◽  
Muscle Tension ◽  
Emg Activity ◽  
Traditional Learning ◽  
Myoelectric Activity ◽  
School Students ◽  
Language Laboratory ◽  
Upper Trapezius ◽  
Muscle Groups

Abstract This study follows muscle activity in three different learning sessions (computer, language laboratory, and normal classroom) while students were studying foreign languages. Myoelectric activity was measured in 21 high school students (10 girls, 11 boys, age range 17-20 years) by surface electromyography (sEMG) from the upper trapezius and frontalis muscles during three 45-min sessions. Root mean square (RMS) average from both investigated muscles was calculated. The EMG activity was highest in both muscle groups in the computer-aided session and lowest in the language laboratory. The girls had higher EMG activity in both investigated muscle groups in all three learning situations. The measured blood pressure was highest at the beginning of the sessions, decreased within 10 min, but increased again toward the end of the sessions. Our results indicate that the use of a computer as a teaching-aid evokes more constant muscle activity than the traditional learning situations. Since muscle tension can have adverse health consequences, more research is needed to determine optimal classroom conditions, especially when technical aids are used in teaching.

Simulate and sense force exertions during virtual patient transfer tasks

2020 ◽  
Vol 64 (1) ◽  
pp. 2092-2096
Author(s):  
Ken Chen ◽  
Rebecca Widmayer ◽  
Karen B. Chen
Keyword(s):  
Muscle Activity ◽  
Fine Tuning ◽  
Activity Levels ◽  
Patient Lifting ◽  
Perceived Workload ◽  
Specific Muscle ◽  
Muscle Groups ◽  
Forceful Exertion ◽  
Lifting Task ◽  
Transfer Tasks

Virtual reality (VR) is commonplace for training, yet simulated physical activities in VR do not require trainees to engage and contract the muscle groups normally engaged in physical lifting. This paper presents a muscle activity-driven interface to elicit the sensation of forceful, physical exertions when lifting virtual objects. Users contracted and attained predefined muscle activity levels that were calibrated to user-specific muscle activity when lifting the physical counterpart. The overarching goal is to engage the appropriate muscles, and thereby encourage and elicit behaviors normally seen in the physical environment. Activities of 12 key muscles were monitored using electromyography (EMG) sensors while they performed a three-part patient lifting task in a Cave Automatic Virtual Environment. Participants reported higher task mental loads and less physical loads for the virtual lift than the physical lift. Findings suggest the potential to elicit sensation of forceful exertion via EMG feedback but needed fine-tuning to offset perceived workload.

scholarly journals Back-Support Exoskeleton Control Strategy for Pulling Activities: Design and Preliminary Evaluation

Designs ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 39
Author(s):  
Maria Lazzaroni ◽  
Tommaso Poliero ◽  
Matteo Sposito ◽  
Stefano Toxiri ◽  
Darwin G. Caldwell ◽  
...  
Keyword(s):  
Control Strategy ◽  
Muscle Activity ◽  
Material Handling ◽  
Ease Of Use ◽  
Biomechanical Analysis ◽  
Perceived Support ◽  
Preliminary Evaluation ◽  
Subjective Measurements ◽  
Spinal Muscles ◽  
Forearm Muscle

The execution of manual material handling activities in the workplace exposes workers to large lumbar loads that increase the risk of musculoskeletal disorders and low back pain. In particular, the redesign of the workplace is making the execution of pulling activities more common, as an alternative to lifting and carrying tasks. The biomechanical analysis of the task revealed a substantial activation of the spinal muscles. This suggests that the user may benefit from the assistance of a back-support exoskeleton that reduces the spinal muscle activity and their contribution to lumbar compression. This work addresses this challenge by exploiting the versatility of an active back-support exoskeleton. A control strategy was specifically designed for assisting pulling that modulates the assistive torques using the forearm muscle activity. These torques are expected to adapt to the user’s assistance needs and the pulled object mass, as forearm muscle activity is considered an indicator of grip strength. We devised laboratory experiments to assess the feasibility and effectiveness of the proposed strategy. We found that, for the majority of the subjects, back muscle activity reductions were associated with the exoskeleton use. Furthermore, subjective measurements reveal advantages in terms of perceived support, comfort, ease of use, and intuitiveness.

scholarly journals Rostrocaudal Distribution of the C-Fos-Immunopositive Spinal Network Defined by Muscle Activity during Locomotion

2021 ◽  
Vol 11 (1) ◽  
pp. 69
Author(s):  
Natalia Merkulyeva ◽  
Vsevolod Lyakhovetskii ◽  
Aleksandr Veshchitskii ◽  
Oleg Gorskii ◽  
Pavel Musienko
Keyword(s):  
Spinal Cord ◽  
Locomotor Activity ◽  
Control Systems ◽  
Muscle Activity ◽  
Knee Extensors ◽  
Emg Activity ◽  
Lumbosacral Spinal Cord ◽  
Adductor Muscles ◽  
Spinal Network ◽  
Hip Flexor

The optimization of multisystem neurorehabilitation protocols including electrical spinal cord stimulation and multi-directional tasks training require understanding of underlying circuits mechanisms and distribution of the neuronal network over the spinal cord. In this study we compared the locomotor activity during forward and backward stepping in eighteen adult decerebrated cats. Interneuronal spinal networks responsible for forward and backward stepping were visualized using the C-Fos technique. A bi-modal rostrocaudal distribution of C-Fos-immunopositive neurons over the lumbosacral spinal cord (peaks in the L4/L5 and L6/S1 segments) was revealed. These patterns were compared with motoneuronal pools using Vanderhorst and Holstege scheme; the location of the first peak was correspondent to the motoneurons of the hip flexors and knee extensors, an inter-peak drop was presumably attributed to the motoneurons controlling the adductor muscles. Both were better expressed in cats stepping forward and in parallel, electromyographic (EMG) activity of the hip flexor and knee extensors was higher, while EMG activity of the adductor was lower, during this locomotor mode. On the basis of the present data, which showed greater activity of the adductor muscles and the attributed interneuronal spinal network during backward stepping and according with data about greater demands on postural control systems during backward locomotion, we suppose that the locomotor networks for movements in opposite directions are at least partially different.

Respiratory Activity of the Rat Posterior Cricoarytenoid Muscle

1997 ◽  
Vol 106 (11) ◽  
pp. 897-901 ◽  
Author(s):  
Robert G. Berkowitz ◽  
John Chalmers ◽  
Qi-Jian Sun ◽  
Paul M. Pilowsky
Keyword(s):  
Phrenic Nerve ◽  
Muscle Activity ◽  
Electrophysiological Study ◽  
Emg Activity ◽  
Diaphragmatic Muscle ◽  
Posterior Cricoarytenoid Muscle ◽  
Inspiratory Activity ◽  
Intramuscular Nerve ◽  
Posterior Cricoarytenoid ◽  
Nerve Discharge

An anatomic and electrophysiological study of the rat posterior cricoarytenoid (PCA) muscle is described. The intramuscular nerve distribution of the PCA branch of the recurrent laryngeal nerve was demonstrated by a modified Sihler's stain. The nerve to the PCA was found to terminate in superior and inferior branches with a distribution that appeared to be confined to the PCA muscle. Electromyography (EMG) recordings of PCA muscle activity in anesthetized rats were obtained under stereotaxic control together with measurement of phrenic nerve discharge. A total of 151 recordings were made in 7 PCA muscles from 4 rats. Phasic inspiratory activity with a waveform similar to that of phrenic nerve discharge was found in 134 recordings, while a biphasic pattern with both inspiratory and post-inspiratory peaks was recorded from random sites within the PCA muscle on 17 occasions. The PCA EMG activity commenced 24.6 ± 2.2 milliseconds (p < .0001) before phrenic nerve discharge. The results are in accord with findings of earlier studies that show that PCA muscle activity commences prior to inspiratory airflow and diaphragmatic muscle activity. The data suggest that PCA and diaphragm motoneurons share common or similar medullary pre-motoneurons. The earlier onset of PCA muscle activity may indicate a role for medullary pre-inspiratory neurons in initiating PCA activity.

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