• Title/Summary/Keyword: Biceps brachii

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Effects of Box Color and Precision Demand on the Muscles' Recruitment Pattern in Repetitive Lifting Tasks (대칭형 들기 작업에서 사회심리적 요인이 근육 동원 형태에 미치는 영향 분석)

  • Song, Young-Woong;Lee, Wook-Gee;Kim, Sang-Ho
    • Journal of the Korea Safety Management & Science
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    • v.11 no.3
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    • pp.79-85
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    • 2009
  • In this study, the effects of psychosocial stress (box color and precision demand) on muscle activity were evaluated in laboratory setting. Eight subjects performed sagittally symmetric lifting tasks. Box color (yellow, black), precision demand (yes, no), and box weight (5%MVC, 10%MVC, 15 %MVC) were varied and surface EMG signals from seven muscles(medial deltoid right, biceps brachii right, lateral triceps right, latissimus dorsi right, erector spinae right, external oblique right, internal oblique right) were recorded. EMG signals were band-pass filtered($10{\sim}400\;Hz$), rectified, RMS smoothed and normalized (NEMG). Analysis of variance tests were conducted on the total NEMG (TNEMG: the sum of the seven muscles' NEMGs) and on the individual muscle's NEMGs. Box color had no effect on the TNEMG and on the seven muscles activities(p>0.05). When precision demand was required at the end point of lifts, the mean NEMG showed higher values than no precision demand conditions: TNEMG (14% increase) and medial deltoid(40% increase), biceps brachii(10% increase), lateral triceps(26% increase), latissimus dorsi(25% increase) muscles. Those increases showed more conspicuous as the box weight increased in the muscles of medial deltoid, lateral triceps, and latissimus dorsi.

Comparison of Muscle Onset Times During Perturbation Between Subjects With and Without Work-Related Chronic Low Back Pain (직업성 만성요통 환자와 정상성인에서 동요 유발 시 근 수축 개시시간 비교)

  • Roh, Kyung-Sun;Kwon, Oh-Yun;Yi, Chung-Hwi;Jeon, Hye-Seon
    • Physical Therapy Korea
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    • v.14 no.2
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    • pp.21-28
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    • 2007
  • The purpose of this study was to compare the onset times of muscle activities and the order of muscle firing in erector spinae, multifidus, rectus abdominis and biceps brachii during perturbation between subjects with and without work-related chronic low back pain (LBP). Twenty-nine subjects, 14 with and 15 without LBP, participated in this study. The muscle responses were measured by surface EMG (electromyography) during perturbation in eye opened and eye closed conditions. The EMG onset times of the erector spinae, multifidus, rectus abdominis and biceps brachii were similar between groups in eye closed condition. But the onset times of the erector spinae, multifidus, rectus abdominis were significantly delayed in subjects with LBP in eye opened condition. The results provide an evidence for impaired feed-forward control of the trunk muscles in subjects with LBP. Further studies are needed to identify whether the impaired feed-forward control of the trunk muscles is the contributing factor to LBP.

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Are Lighter Smartphones Ergonomically Better?

  • Yoon, Jangwhon;Kim, Kisong;Yoon, Taelim
    • Journal of the Ergonomics Society of Korea
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    • v.34 no.1
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    • pp.11-18
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    • 2015
  • Objective: The aim of this study was to understand the effects of phone weight on the typing performance and muscle recruitment in the neck and upper extremity while typing a text message with dominant hand. The iPhone4 and iPhone5 were compared due to their 28-gram differences in weight. Background: Too much use of a cellular phone can lead the musculoskeletal disorders in the upper extremity. Phone makers tend to make their new models bigger, lighter, faster and smarter. Method: Fourteen healthy volunteers without any history of neuromuscular disorders or ongoing pain who used their smartphone more than one year were recruited. A 112g phone (iPhone5) and a 142g phone (iPhone4) were used for typing the lyric of the Korean national anthem with their dominant hand. Typing duration, the typing error, the perceived fatigue, and preference was investigated. Muscle recruitment and the resting gap of neck (middle trapezius and levator scapula), shoulder (infraspinatus and mid deltoid), elbow (biceps brachii and brachioradialis), thumb (extensor and abductor policis brevis) were collected using surface electromyography. Typing error was counted and typing speed was calculated in characters per min. The data were analyzed using a paired t-test and chi-square (${\chi}^2$) analysis for the effects of phone weight on the typing performance parameters and muscle recruitment. Results: Typing text message with iPhone5 took longer but had less muscle recruitment in brachioradialis, and extensor policis brevis muscles. Lighter weight of iPhone5 made biceps brachii to rest less without increasing the mean %EMG. Conclusion/Application: Findings of this study can be valuable information for phone designers to develop more productive device and for smartphone users to prevent the musculoskeletal disorders in the upper extremities.

Electromyographical Analyses of Muscle Activities of Upper Trunk for Ssireum Dutguri Technique (Electromyography 기법을 이용한 씨름 덧걸이 기술의 상체 근 동원 비교분석)

  • Shin, Sung-Hyu;Lim, Young-Tae;Kim, Tae-Hwan;Park, Ki-Ja;Kwon, Moon-Suk
    • Korean Journal of Applied Biomechanics
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    • v.13 no.1
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    • pp.95-108
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    • 2003
  • The purposes of this study were to analyze the muscle activities and the characteristics of muscle recruiting patterns of upper trunk for Ssirum dutguri technique using three top-ranked elite Ssirum players. The EMG technique was used to record muscle activities of both right and left sides of latissimus dorsi, biceps brachii, and erector spinae. Six surface electrodes were placed on the surface of the selected muscles and one ground electrode was also attached on the back of neck(C7). One video camera was also used to record the Ssirum motion to define 4 events and 3 phases for further analysis. The raw EMG data were filtered with band pass filter (50-400 Hz) to remove artifacts and then low pass filtered (4 Hz) to find the linear envelope which resemble muscle tension curve. This filtered EMG data were normalized to MVIC for the purpose of comparion between the subjects. The results were indicated that each subject with different physical characteristics showed very different muscle activity patterns. Although Ssirum dutguri is considered as foot technique the player grasped opponent's satba(belt) with both hands when they play. Because of this reason, activities of upper trunk muscles were relatively high. However, direct comparison between upper and lower body muscles was not possible due to the lack of the data in present study. Interestingly, all threes subjects showed that erector spinae muscle activity was comparatively higher than those of latissimus dorsi and biceps brachii. This implies to reinforce back muscle as a routine of training to improve performance or to prevent back injury.

A study on upper extremity muscle fatigue changes of train driver (기관사 상지 근육의 피로도 변화에 대한 연구)

  • Jang, Hye-Yoen;Lee, Yung-Gi;Jang, Jae-Ho;Kim, Tae-Sik;Hong, Sung-Jun;Han, Chang-Soo;Han, Jung-Soo;Ahn, Jae-Yong
    • Journal of the Korean Society for Railway
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    • v.10 no.5
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    • pp.576-581
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    • 2007
  • The purpose of this study is to investigate changes in the forearm-muscle fatigue of a train driver operating the MasCon by using EMG (electromyogram) measurement technique. Train drivers usually use their forearm 4hours/day for normal operation. Accordingly, few different EMG signals of deltoid, biceps brachii, brachioradialis, flexor carpi ulnaris muscle of upper extremity have been measured and analyzed. The raw EMG Signals have been converted into median frequency using spectrum analysis. As the result, 80% of 10 subjects (real train drivers) showed that median frequency value of all four muscles has been reduced after 30 minutes of train operation. This results demonstrated that operating MasCon for 30 minutes could induce muscle fatigue.

The Study on Analysis of Muscle Activity during Sling Squat Exercise according to Rope Type (로프 타입에 따른 슬링을 이용한 스쿼트 운동 시 근육의 활성화 비교 분석)

  • Woo, Hyun Ji;Kwon, Tae Kyu
    • Korean Journal of Applied Biomechanics
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    • v.30 no.4
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    • pp.311-319
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    • 2020
  • Objective: The purpose of this study was to examine of this study is to study the effect of squat exercise on muscle activation in a sling device using various types of ropes and to propose an effective sling exercise method for strengthening the lower extremity strength. Method: 20 adult male subjects (age: 25.2±2.4 yrs, height: 176.5±3.2 cm, weight: 77.2±4.5 kg) participated in this study. In the experiment, a total of four squats were conducted: squat [SE], sling squat using inelastic rope [IR], sling squat using elastic rope [ER], and sling squat using two elastic ropes [TER]. Squats were performed 5 times for each condition, and a 60-second break was given for each condition to minimize muscle fatigue. The activation of biceps brachii, rectus femoris, gastrocnemius, and tibialis anterior muscles was measured. Results: It was found that the activation of all muscles was the lowest during the squat exercise [SE]. During the sling squat using inelastic rope [IR], the muscle activation of the biceps brachii was the highest. During the sling squat using elastic rope [ER], the activation of the rectus femoris, gastrocnemius, and tibialis anterior muscles was found to be the highest. In the sling squat using two elastic ropes [TER], most of the muscle activation was similar to that of the sling squat using inelastic rope [IR]. Conclusion: Our results of the experiment, it was found that sling squat exercise using elastic rope had a positive effect on the activation of all muscles. It is thought that performing a squat exercise under moderate weight load and unstable conditions, such as sling squat exercise using elastic rope, can increase the muscle activity of the lower limbs and perform more effective exercise effect than performing a conventional squat exercise under stable conditions. In the future, if research is conducted not only on adult men, but also on various ages and patients, it will be able to provide positive help in improving balance, stability and stamina through squat exercise.

Association of functional sequence variants of the myosin heavy chain 3 gene with muscle collagen content in pigs

  • Yong-Jun Kang;Sang-Hyun Han;Sang-Geum Kim;Su-Yeon Kim;Hyeon-Ah Kim;Yoo-Kyung Kim;Ji-Hyun Yoo;Moon-Cheol Shin;Byoung-Chul Yang;Hee-Bok Park;Jun Heon Lee;In-Cheol Cho
    • Journal of Animal Science and Technology
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    • v.65 no.3
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    • pp.511-518
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    • 2023
  • This study examined the association between functional sequence variants (FSVs) of myosin heavy chain 3 (MYH3) genotypes and collagen content in a Landrace and Jeju native pig (JNP) crossbred population. Four muscles (Musculus longissimus dorsi, Musculus semimembranosus, Musculus triceps brachii, and Musculus biceps femoris) were used for the analysis of meat collagen content, and the same animals were genotyped for the FSVs of the MYH3 gene by using PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism). Three FSVs of MYH3 genotypes were identified and had genotype frequencies of 0.358, 0.551, and 0.091 for QQ, Qq, and qq, respectively. QQ animals for the FSVs of the MYH3 genotypes showed higher collagen content in their M. longissimus dorsi (p < 0.001), M. semimembranosus (p < 0.001), M. triceps brachii (p < 0.001), and M. biceps femoris (p < 0.001) than qq homozygous animals. After the validation of this result in other independent populations, the FSVs of MYH3 genotypes can be a valuable genetic marker for improving collagen content in porcine muscles and can also be applied to increase the amount of collagen for biomedical purposes.

Effects of Pre-slaughter Fasting and Chiller Ageing on Objective Meat Quality in Longissimus Dorsi, Biceps Femoris, and Triceps Brachii Muscles of Korean Native Black Pigs (도축전 절식과 냉장숙성이 재래돼지 Longissimus Dorsi, Biceps Femoris와 Triceps Brachii의 육질에 미치는 영향)

  • Hwang, I.H.;Park, B.Y.;Cho, S.H.;Kim, M.J.;Lee, J.M.
    • Journal of Animal Science and Technology
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    • v.46 no.3
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    • pp.405-414
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    • 2004
  • This study evaluated the effects of preslaughter feed withdrawal and chiller ageing on objective meat quality traits in longissimus dorsi (LD), biceps femoris(BF), and triceps brachii(TB) muscles of Korean native black pigs. Twenty males were assigned into a 2(pre-slaughter feeding) ${\times}$ 2(pre-slaughter stress) ${\times}$ 4(chiller ageing) factorial. Pre-slaughter fasting for 18 h resulted in significantly(P < 0.05) higher pHs at 1.5 h for both LD and BF. On the other hand, muscle temperature did not differ between the fasted and fed animals. The result implied that pigs with different pre-slaughter feedings experienced different pH-temperature profiles during rigor development. This was reflected by the significan(P < 0.05) increase in cooking loss and hunter $L^*$ for LD of the fed pigs. However, WB-shear force of LD was not affected by the treatment. Furthermore, objective meat quality of BF and TB did not differ between the treatments. Hunter $L^*$ value and cooking loss for LD were constant for 7 d, followed by a significant(P < 0.05) increase at 14 d. BF and TB had significantly(P < 0.05) higher hunter $L^*$ value and cooking loss at 14 d than at 1 d. Significant(P < 0.05) linear reductions in LD WB-shear force took place from 1 to 7 d, while BF and TB WB-shear forces were significantly (P < 0.05) reduced at 14 d. Simple correlation for WB-shear force between LD and BF, and between LD and TB indicated that 6 kg of shear force for LD was equivalent to approximately 3.5 and 6 kg for TB and BF, respectively. On the basis of the current result, feeding until the morning of slaughter appeared to contribute to favourable meat color for LD. However, negative effect on palatability due to increase in cooking loss should be taken into account. A 7-d chiller ageing was likely the best practice for LD, while TB appeared not to require chiller ageing. A 14-d ageing could improve the tenderness of BF, but could likely reduce juiciness.

The Correlation of the Area of the Base of Support with the Maximal Voluntary Isometric Contraction of Upper Limb Muscles (기저면의 넓이와 상지 근육의 최대 수의적 등척성 수축의 상관관계)

  • Lee, Sang-Yeol;Jo, Marg-Eun
    • PNF and Movement
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    • v.14 no.1
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    • pp.49-52
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    • 2016
  • Purpose: The purpose of the present study was to examine the effects of the area of the base of support formed by the human body on the maximal voluntary isometric contraction of upper limb muscles. Methods: The study was conducted with 20 normal adults. To identify changes in the base of support, the maximal voluntary isometric contraction of the biceps muscle was measured in a standing position, a sitting position, and a lying position for each subject. The sizes of the base of support formed in the standing, sitting, and lying positions were set to 1, 2, and 3 respectively, based on the sizes, to analyze the correlations. The maximal voluntary isometric contraction of the biceps muscle was measured using surface electromyograms (EMGs) (Noraxon DTS, Germany). Results: The results showed negative correlations in which, as the size of the base of support increased, the maximal voluntary isometric contraction of the biceps muscle decreased. Conclusion: Changes in the base of support of the body affect the maximal voluntary isometric contraction of the upper limbs. Therefore, when resistance exercises are applied for muscle strengthening, the positions should be changed considering the changes in muscle activity according to those positions. In addition, when EMGs are used to measure the maximal voluntary isometric contraction, the measurements should be conducted in the same positions, considering muscle activity that changes according to the base of support and positions, for data quantification.

A Study Median Frequency Analysis of Surface EMG on Gender Differences (성별에 따른 표면근전도의 중앙주파수 분석에 관한 연구)

  • Lee, Sang-Sik;Lee, Ki-Young;Go, Jae-Wook;Park, Won-Yeop
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.5 no.1
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    • pp.20-25
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    • 2012
  • Gender differences have been studied by using spectral features such as median frequency (MDF) respectively. MDF is the most commonly used as a feature to describe muscle conduction velocity. The aim of this paper is to detect gender differences from surface EMG signals during isotonic contractions of the bicep Brachii. Eight volunteers participated in surface EMG recordings placed on the biceps brachii and each recording experiment continued until their exhaustion. We used feature values and regressive slopes and compared the feature changes from the onset to the endurance time to find gender differences. The result of experiments shows that the regressive slope of these features is valid to measure gender differences.