scholarly journals A Study on the Upper Limb Muscles Load in Various Surface Heights of the Working and in Various Working Postures

Sangyo Igaku ◽  
1982 ◽  
Vol 24 (7) ◽  
pp. 886
Author(s):  
M. KONISHI ◽  
Y. MINAGAWA
Keyword(s):  
Upper Limb ◽  
Working Postures ◽  
Limb Muscles

Reflex Responses in Upper Limb Muscles to Cutaneous Stimuli

1993 ◽  
Vol 20 (04) ◽  
pp. 271-278 ◽  
Author(s):  
R. Chen
Keyword(s):  
Stimulus Intensity ◽  
Upper Limb ◽  
Healthy Subjects ◽  
Voluntary Contraction ◽  
Cutaneous Reflexes ◽  
Focal Lesions ◽  
Normal Ranges ◽  
Conduction Velocities ◽  
Limb Muscles ◽  
Biphasic Responses

ABSTRACT:Cutaneous reflexes in the upper limb were elicited by stimulating digital nerves and recorded by averaging rectified EMG from proximal and distal upper limb muscles during voluntary contraction. Distal muscles often showed a triphasic response: an inhibition with onset about 50 ms (Il) followed by a facilitation with onset about 60 ms (E2) followed by another inhibition with onset about 80 ms (12). Proximal muscles generally showed biphasic responses beginning with facilitation or inhibition with onset at about 40 ms. Normal ranges for the amplitude of these components were established from recordings on 22 arms of 11 healthy subjects. An attempt was made to determine the alterent fibers responsible for the various components by varying the stimulus intensity, by causing ischemic block of larger fibers and by estimating the afferent conduction velocities. The central pathways mediating these reflexes were examined by estimating central delays and by studying patients with focal lesions

Effect of Computer Keyboard Slope on Upper Limb Postures at Sitting and Standing ComputerWorkstations : A Pilot Study

2021 ◽  
Vol 65 (1) ◽  
pp. 1235-1239
Author(s):  
Howraa Nash ◽  
Gourav Kumar Nayak ◽  
Jashwant Thota ◽  
Mohammed Alsowaidi ◽  
Hashem Alsowaidi ◽  
...  
Keyword(s):  
Upper Limb ◽  
User Preference ◽  
Positive Slope ◽  
Standing Posture ◽  
Support Design ◽  
Wrist Extension ◽  
Sitting Posture ◽  
Working Postures ◽  
Computer Workstation ◽  
Computer Keyboard

A user’s posture at a computer workstation, especially wrist posture, is determined by the keyboard angle. Most commercially available computer keyboards have a built-in positive slope that requires the user to extend their wrist approximately 20° when typing. The purpose of this study is to find the negative keyboard angles that minimize wrist extension for both sitting and standing workstations. In this study, we compared upper limb working postures, including those of the wrist, elbow and shoulder, at 5 different keyboard angles between −16° and +6° in sitting and standing postures. Based on our results, we can conclude that the optimal range of keyboard slope is from −4° to −12° in sitting posture and −8° to −12° in the standing posture in terms of minimum wrist extension, typing performance, and user preference. We also propose a universal keyboard support design as an attachment to currently available keyboards.

Validity of Skeletal Muscle Ultrasound in Assessment of Suspected Limb Girdle Muscular Dystrophy Patients

QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Rasha M Ibrahim ◽  
Haitham M Hamdy ◽  
Amr A Mohammed ◽  
Ahmed M Elsadek ◽  
Ahmed M Bassiouny ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Upper Limb ◽  
Lower Limb ◽  
Limb Girdle Muscular Dystrophy ◽  
Ultrasound Images ◽  
General Electric ◽  
Cross Sectional ◽  
Lower Limb Muscles ◽  
Limb Muscles ◽  
Muscle Ultrasound

Abstract Background Limb-girdle muscular dystrophies (LGMDs) are a clinically and genetically heterogeneous group of disorders characterized by progressive muscle weakness and degenerative muscle changes. Studies have shown that ultrasound can be useful both for diagnosis and follow-up of LGMDs patients. Objectives This study aims to measure the sensitivity and the specificity of muscle ultrasound in assessment of suspected limb girdle muscular dystrophy patients. Subjects and Methods This cross-sectional descriptive study was conducted on Fifty-five patients with suspected LGMD from neuromuscular unit, myology clinic, Ain Shams University hospitals and eight healthy subjects. Age was above 2 years. Both sexes were included in the study. They underwent real-time B-mode ultrasonography performed with using Logiq p9 General Electric ultrasound machine and General Electric 7-11.5 MHZ linear array ultrasound probe. All ultrasound images have been obtained and scored by a single examiner and muscle echo intensity was visually graded semiquantitative according to Heckmatt's scale. The examiner was blinded to the muscle biopsy results and clinical evaluations. Results Statistical analysis revealed that the diagnostic performance of muscle US (Heckmatt’s score) in LGMD is most sensitive when calculated in all examined upper limb and lower limb muscles, followed by lower limb muscles alone. US of upper limb was found to be the least sensitive. Conclusions Muscle ultrasound is a practical and reproducible and valid tool that can be used in assessment of suspected LGMD patients.

62. Effects of leg pedaling on the cutaneous reflexes in the upper limb muscles

2008 ◽  
Vol 119 (6) ◽  
pp. e90
Author(s):  
Syusaku Sasada ◽  
Toshiki Tazoe ◽  
Tsuyoshi Nakajima ◽  
Tomoyoshi Komiyama
Keyword(s):  
Upper Limb ◽  
Cutaneous Reflexes ◽  
Limb Muscles

scholarly journals Correlation between Age, Nutritional Status, and Working Posture and Musculoskeletal Disorders in PT ARPS

2019 ◽  
Vol 8 (3) ◽  
pp. 283
Author(s):  
Mufidha Khoirul Umami
Keyword(s):  
Nutritional Status ◽  
Musculoskeletal Disorders ◽  
Upper Limb ◽  
Risk Level ◽  
Physical Endurance ◽  
Cross Sectional ◽  
Significance Level ◽  
Physical Strength ◽  
Working Postures ◽  
Body Map

Introduction: Musculoskeletal disorders occur due to various factors: main factors, such as extortion of the muscles, repetitive activities, non-ergonomic working postures; secondary factors (pressure, vibrant, microclimate), and individual factors (age, years of service, sex, nutritional status, physical endurance, smoking habits, physical strength and anthropometry). The workers in the Injection Department at PT. ARPS mostly work with non-ergonomic working postures. The aim of this study is to analyze the correlation between age, nutritional status, and working postures and the complaints on musculoskeletal disorders among the workers in the Injection department at PT. ARPS. Metods: This study applies analytic observational method with a cross-sectional design. The sample is chosen by implementing simple random sampling with a total of 52 respondents. The data collection to measure the ratio risk level of the working postures of the injection workers is completed by using Rapid Upper Limb Assessment (RULA) measurement method, while Nordic Body Map (NBM) questionnaire form is used to measure risk level of the disorder, and anthropometry measurement is applied to evaluate the nutritional status of the workers, such as their height and weight. The data are analyzed using Spearman Rho’s Correlation (significance level α = 5%). Results: The percentage of injection workers are <35 years old (76.9%), have normal nutritional status (59.6%), 27 workers (51.9%) have low musculoskeletal disorders and 19 others (36.5%) have low-risk postures. Concluded: That there is a correlation between age (ρ-value = 0.005), nutritional status (ρ-value = 0.003) and working postures (ρ-value = 0.036) and musculoskeletal disorders on the injection workers at PT. ARPS. Keywords: injection worker, musculoskeletal disorders, Nordic Body Map, Rapid Upper Limb Assessement, working postures

scholarly journals Effects of Focal Vibration over Upper Limb Muscles on the Activation of Sensorimotor Cortex Network: An EEG Study

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Wei Li ◽  
Chong Li ◽  
Quan Xu ◽  
Linhong Ji
Keyword(s):  
Upper Limb ◽  
Sensorimotor Cortex ◽  
Biceps Brachii ◽  
Central Area ◽  
Therapeutic Effects ◽  
Relative Power ◽  
Alpha Band ◽  
Beta Band ◽  
Muscle Belly ◽  
Limb Muscles

Studying the therapeutic effects of focal vibration (FV) in neurorehabilitation is the focus of current research. However, it is still not fully understood how FV on upper limb muscles affects the sensorimotor cortex in healthy subjects. To explore this problem, this experiment was designed and conducted, in which FV was applied to the muscle belly of biceps brachii in the left arm. During the experiment, electroencephalography (EEG) was recorded in the following three phases: before FV, during FV, and two minutes after FV. During FV, a significant lower relative power at C3 and C4 electrodes and a significant higher connection strength between five channel pairs (Cz-FC1, Cz-C3, Cz-CP6, C4-FC6, and FC6-CP2) in the alpha band were observed compared to those before FV. After FV, the relative power at C4 in the beta band showed a significant increase compared to its value before FV. The changes of the relative power at C4 in the alpha band had a negative correlation with the relative power of the beta band during FV and with that after FV. The results showed that FV on upper limb muscles could activate the bilateral primary somatosensory cortex and strengthen functional connectivity of the ipsilateral central area (FC1, C3, and Cz) and contralateral central area (CP2, Cz, C4, FC6, and CP6). These results contribute to understanding the effect of FV over upper limb muscles on the brain cortical network.

EMG activation of trunk and upper limb muscles following experimentally-induced overpronation and oversupination of the feet in quiet standing

2013 ◽  
Vol 37 (2) ◽  
pp. 190-194 ◽  
Author(s):  
Theodoros Ntousis ◽  
Dimitris Mandalidis ◽  
Efstathios Chronopoulos ◽  
Spyros Athanasopoulos
Keyword(s):  
Upper Limb ◽  
Quiet Standing ◽  
Limb Muscles ◽  
Experimentally Induced

Heteronymous reflex connections in human upper limb muscles in response to stretch of forearm muscles

2011 ◽  
Vol 106 (3) ◽  
pp. 1489-1499 ◽  
Author(s):  
Curtis D. Manning ◽  
Parveen Bawa
Keyword(s):  
Upper Limb ◽  
Biceps Brachii ◽  
Monosynaptic Reflex ◽  
Electromyographic Activity ◽  
Response Patterns ◽  
Triceps Brachii ◽  
Limb Muscles ◽  
Abductor Digiti Minimi ◽  
Human Upper Limb ◽  
Wrist Flexors

Torque motor produced stretch of upper limb muscles results in two distinct reflex peaks in the electromyographic activity. Whereas the short-latency reflex (SLR) response is mediated largely by the spinal monosynaptic reflex pathway, the longer-latency reflex (LLR) is suggested to involve a transcortical loop. For the SLRs, patterns of heteronymous monosynaptic Ia connections have been well-studied for a large number of muscles in the cat and in humans. For LLRs, information is available for perturbations to proximal joints, although the protocols for most of these studies did not focus on heteronymous connections. The main objective of the present study was to elicit both SLRs and LLRs in wrist flexors and extensors and to examine heteronymous connections from these muscles to elbow flexors (biceps brachii; BiBr) and extensors (triceps brachii; TriBr) and to selected distal muscles, including abductor pollicis longus (APL), first dorsal interosseous (FDI), abductor digiti minimi (ADM), and Thenars. The stretch of wrist flexors produced SLR and LLR peaks in APL, FDI, ADM, Thenars, and BiBr while simultaneously inducing inhibition of wrist extensors and TriBr. When wrist extensors were stretched, SLR and LLR peaks were observed in TriBr, whereas the primary wrist flexors, APL and BiBr, were inhibited; response patterns of FDI, ADM, and Thenars were less consistent. The main conclusions from the observed data are that: 1) as in the cat, afferents from wrist flexors and extensors make heteronymous connections with proximal and distal upper limb muscles; and 2) the strength of heteronymous connections is greater for LLRs than SLRs in the distal muscles, whereas the opposite is true for the proximal muscles. In the majority of observations, SLR and LLR excitatory peaks were observed together. However, on occasion, LLRs were observed without the SLR response in hand muscles when wrist extensors were stretched.

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