• Animal cells and systems
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• v.16 no.6
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• pp.431-437
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• 2012

Calpains are a class of proteins that belong to the calcium-dependent, non-lysosomal cysteine proteases. There are three major types of calpains expressed in the skeletal muscle, namely, ${\mu}$-calpain, m-calpain, and calpain 3, which show proteolytic activities. Skeletal muscle fibers possess all three calpains, and they are $Ca^{2+}$-dependent proteases. The functional role of calpains was found to be associated with apoptosis and myogenesis. However, calpain 3 is likely to be involved in sarcomeric remodeling. A defect in the expression of calpain 3 leads to limb-girdle muscular dystrophy type 2A. Calpain 3 is found in skeletal muscle fibers at the N2A line of the large elastic protein, titin. A substantial proportion of calpain 3 is activated 24 h following a single bout of eccentric exercise. In vitro studies indicated that calpain 3 can be activated 2-4 fold higher than normal resting cytoplasmic [$Ca^{2+}$]. Characterization of the calpain system in the developing muscle is essential to explain which calpain isoforms are present and whether both ${\mu}$-calpain and m-calpain exist in differentiating myoblasts. Information from such studies is needed to clarify the role of the calpain system in skeletal muscle growth. It has been demonstrated that the activation of ubiquitous calpains and calpain 3 in skeletal muscle is very well regulated in the presence of huge and rapid changes in intracellular [$Ca^{2+}$].

• Korean Journal of Exercise Nutrition
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• v.25 no.2
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• pp.15-19
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• 2021

[Purpose] Skeletal muscle glycogen is a determinant of endurance capacity for some athletes. Ginger is well known to possess nutritional effects, such as anti-diabetic effects. We hypothesized that ginger extract (GE) ingestion increases skeletal muscle glycogen by enhancing fat oxidation. Thus, we investigated the effect of GE ingestion on exercise capacity, skeletal muscle glycogen, and certain blood metabolites in exercised rats. [Methods] First, we evaluated the influence of GE ingestion on body weight and elevation of exercise performance in rats fed with different volumes of GE. Next, we measured the skeletal muscle glycogen content and free fatty acid (FFA) levels in GE-fed rats. Finally, we demonstrated that GE ingestion contributes to endurance capacity during intermittent exercise to exhaustion. [Results] We confirmed that GE ingestion increased exercise performance (p<0.05) and elevated the skeletal muscle glycogen content compared to the nonGE-fed (CE, control exercise) group before exercise (Soleus: p<0.01, Plantaris: p<0.01, Gastrocnemius: p<0.05). Blood FFA levels in the GE group were significantly higher than those in the CE group after exercise (p<0.05). Moreover, we demonstrated that exercise capacity was maintained in the CE group during intermittent exercise (p<0.05). [Conclusion] These findings indicate that GE ingestion increases skeletal muscle glycogen content and exercise performance through the upregulation of fat oxidation.

• International Journal of Contents
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• v.5 no.4
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• pp.35-39
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• 2009

The purpose of this study was to evaluate the changes in skeletal muscle architecture and qualitative properties by muscle contraction force when neuromuscular electrical stimulation (NMES) of 50% MVIC was applied. Sixteen subjects (8 male, 8 female) without neuromuscular disease volunteered to participate in the study. All subjects were divided into two subgroups: control (no electrical stimulation) group and 50% maximal voluntary isometric contraction (MVIC) group. NMES training program was performed in the calf muscle three times a week for 10 weeks. Before and after the experiments, the MVIC of ankle plantar flexor was measured by the use of dynamometer, and the ultrasonography in the gastrocnemius medialis muscle was measured. The following results were obtained; MVIC was significantly increased in the electrical stimulation groups. Pennation angle, muscle density, and white area index also considerably changed in the electrical stimulation groups. In conclusion, the NMES training of 50% MVIC, comparative low level, improved the skeletal muscle architecture and the qualitative properties as well as the muscle contraction force.

• PNF and Movement
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• v.2 no.1
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• pp.35-47
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• 2004

Purpose : The purpose of this article was to review the literature on contractile properties of skeletal muscle with reference to its molecular and functional diversity. Method : This review outlines scientific findings regarding different contractile properties in skeletal muscle fibers, and discusses their involvement in functional diversity. Result & Conclusions: Muscle fibers possess distinct mechanical and energetic properties. Myosis, one of the primary contractile muscle proteins, displays structural, functional variability and plays the role of the molecular motor of muscle contraction. Muscle satellite cells are normally mitotically quiescent, but initiate proliferation and give rise to daughter myogenic precursor cells as required for the postnatal growth and regeneration of adult muscle. Passive extensibility is an important component of total muscle function because it allows for the maximal length of skeletal muscles. Proprioceptive neuromuscular facilitation(PNF) stretching can help to restore or improve flexibility and coordination, thereby improving overall muscle function.

• The Journal of the Korean dental association
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• v.12 no.6
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• pp.419-423
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• 1974

The authors have investigated the roles of cortisone and calcium on the depressive effects of local anesthetics on the acetylcholine-induced skeletal muscle contraction in frog. The results are as follows. 1. Tetracaine, cocaine, lidocaine and procaine decreased the acetylcholine-induced skeletal muscle contraction. 2. Cortisone increased the depressive effects of local anesthetics on the acetyl-choline-induced skeletal muscle contraction. 3. There was a tendency that in high calcium concentration, the depressive effects of cocaine and lidocaine on acetylcholine-induced skeletal muscle contraction were increased.

• Biomedical Science Letters
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• v.10 no.3
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• pp.259-262
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• 2004

The aim of present study was to examine the effect of carrageenan on the tendon of skeletal muscle of rat. The tendon damage was induced by injection of carrageenan into skeletal hind muscle of rats. Rats were killed on 48 hours after carrageenan injection. The resulting tendons were fixed with 10％ neutral buffered formalin (NBF), dehydrated, embedded, sectioned by 4 μm, and stained by phosphotungstic acid hematoxylin (PTAH) or hematoxylin-eosin (H-E). Carrageenan induced the segregation of tendon fibers, intratendinous cleft, segregation of muscle cell group, wave arrangement of tendon fiber. The results suggest that carrageenan induced tendon damage of rat's skeletal muscle by morphological changes.

• Journal of Biomedical Engineering Research
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• v.17 no.2
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• pp.155-164
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• 1996

In the clinical environment, measurements of some characteristics of the skeletal muscle are currently used to assess the severity of a neuromuscular disease or in some cases to assist in making a diagnosis. But a quantitative method of evaluation has not yet been introduced satisfactorily. In this paper, the skeletal EMG(biceps muscle, masseter muscle) analysis has been processed both in the time and in the frequency domain by designing the digital signal processing system based on pentium PC and transputer (IMS 7805). The experiment have been performed in five normal subjects, and various parameters have been statistically tested and compare4 As a results, the effective parameters obtained for the evaluation of skeletal EMG electrical activity are turn analysis, MiTi, MiTa, IEMG, PDF in the time domain, and are mean frequency, median frequency, skewness, kurtosis, muscle fatigue slope in the frequency domain. The designed H/W and S/W in this study can be used effectively for the establishment of EMG data base and for clinical research.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.4
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• pp.37-45
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• 2023

PURPOSE: The coexistence of age-related skeletal muscle mass loss and obesity poses a substantial health risk for individuals because it combines the detrimental effects of muscle mass reduction associated with aging and the health complications from obesity. This study aimed to identify the incidence rate and key influencing elements among Korean men in their thirties. METHODS: A cross-sectional study involving 934 male participants was performed using complex sampling analysis. Various influencing elements were investigated, including age, height, weight, body mass index, waist circumference, skeletal muscle mass index, smoking and drinking behaviors, systolic and diastolic blood pressure, fasting glucose levels, triglyceride, and cholesterol levels. RESULTS: The incidence rate was 2.90%. The key influencing elements were age, height, weight, body mass index, waist circumference, skeletal muscle index, systolic blood pressure, fasting glucose, triglyceride, and total cholesterol (p < .05). CONCLUSION: This study identified the incidence rate and key influencing element for CALSMO among Korean younger community-dwelling men.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.3
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• pp.313-320
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• 2020

Objectives: The aim of this study is to evaluate the association between vibration exposure and skeletal muscle mass index through a single university health check-up. Methods: We used data from 134,067 male subjects who received a general health check-up or vibration exposure health check-up out of the 1,515,322 people who underwent medical check-up at a local university hospital from 2002 to 2018. Pearson correlation analysis was conducted for comparing the association between skeletal muscle mass index and demographic and hematological variables in both groups. Mixed linear model analysis after controlling demographic and hematological variables was used to analyze the differences in skeletal muscle mass index between groups at every visit over 10 years. Results: In the Pearson correlation test, the variables that showed different results when comparing the two groups were C-reactive protein (p=0.001) and glycated hemoglobin (p=0.002) in the vibration exposure group and erythrocyte sedimentation rate (p<0.001) and vitamin D (p<0.001) in the general group. After the adjustment of demographic and hematologic variables, the skeletal muscle mass index at every visit was markedly decreased in the vibration exposure group (p<0.001). Conclusions: In the vibration exposure group, the skeletal muscle mass index showed a tendency to decrease markedly over time compared to the general health check-up group, which showed that C-reactive protein and glycated hemoglobin would have an influence on skeletal muscle index in male workers exposed to vibration.

• Journal of Life Science
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• v.22 no.6
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• pp.713-722
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• 2012

When proteins extracted from longissimus dorsi muscles of Landrace and Berkshire at the finishing stage were compared by 2-DE, the Landrace demonstrated a quantitative increase in proteins related to slow skeletal muscle function, such as serum albumin precursor, troponin T (slow skeletal muscle; sTnT) and myoglobin. In contrast, the Berkshire exhibited comparatively elevated enzymes involved in metabolic pathways, fast skeletal muscle function, and energy production, such as heat shock 27-kDa protein (HSP27)-1, TnT (fast skeletal muscle; fTnT), muscle creatine kinase, phosphoglucomutase 1 (PGM1), triosephosphate isomerase (Tpi1) and adenylate kinase isoenzyme 1 (AK1). When compared to growing Berkshire, finishing Berkshire showed increased levels of aldehyde dehydrogenase 1 family, member L1 (ALDHL1), and muscle creatine kinase. In contrast, the growing Berkshire muscle had elevated levels of HSP27-1, sTnT, fTnT, serum albumin precursor, PGM1, AK1, and Tpi 1 as compared to the finishing Berkshire. The Landrace longissimus dorsi muscle may be composed of slower skeletal muscle, whereas Berkshire is composed of a faster skeletal muscle. The uniquely elevated quantities of proteins involved in skeletal muscle function, energy metabolism, and cytoskeleton function in the growing Berkshire indicate that these factors support growth and maintenance during the growing stage when compared with the finishing Berkshire.