• PNF and Movement
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• v.22 no.2
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• pp.181-189
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• 2024

Purpose: This study aimed to identify the effect of sling-applied plank exercise on the frequency, stiffness, and decrement of the rectus abdominis and longissimus muscles of the trunk according to the stability of the base of support. Methods: Thirty-three young adults volunteered to participate and were randomly assigned to one of three groups (SS, stable support; LES, lower extremity support; and ULES, upper and lower extremity support) according to the stability of the base of support. The muscular properties of the rectus abdominis and longissimus muscles during sling-assisted plank exercise according to the stability of the base of support. were measured by using Myoton PRO (Myoton AS, Tallinn, Estonia). Statistical analysis was performed MANOVA to determine the effect of sling-assisted plank exercise on the muscular properties of the rectus abdominis and longissimus muscles according to the stability of the base of support. Post hoc analysis was conducted using Bonferroni. The level of statistical significance was set at α = 0.05. Results: When comparing the muscular properties, the muscle frequency and stiffness of the left rectus abdominis of ULES were significantly decreased compared to that of SS (p < 0.05). In the measurement time, the muscle frequency and the muscle stiffness of the right rectus abdominis increased significantly after the intervention (p < 0.05). Conclusion: It was concluded that the more unstable the base of support (ULES), the higher the exercise strength, and the muscle frequency and stiffness decreased on the rectus abdominis at rest.

• Electronics and Telecommunications Trends
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• v.34 no.4
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• pp.108-116
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• 2019

Electro-active polymers and dielectric elastomers have many intriguing properties that enable smart interfaces and electrically tunable optical systems, such as haptic feedback devices, artificial muscles, and expansion-tunable optical elements. These device classes are of great interest owing to their promising roles in next-generation technologies including virtual or augmented reality, human sensing and muscular enhancement, and artificial skins. In this report, we review basic principles, current state-of-the-art techniques, and future prospects of electro-active and dielectric elastomer technology. We describe chemical and physical properties of the most promising polymer substances, essential elementary architectures for artificial muscle-like functionalities, and their applications to haptic interfaces, muscular enhancement, and focus-tunable optical elements.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.4
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• pp.29-35
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• 2020

PURPOSE: This study examined the immediate effects of Graston instrument-assisted soft-tissue mobilization (GIASTM) and self-stretching on the muscular properties of the gastrocnemius in athletes. METHODS: Thirty subjects (All in their 20 s) were distributed randomly and evenly into two groups of 15 each: GIASTM and stretching. The subjects had no history of gastrocnemius damage in the previous three months. The muscle tone, stiffness, elasticity, and mechanical stress relaxation time (MSRT) of the gastrocnemius were blind-tested. RESULTS: The GIASTM group showed significant changes in all categories, while only MSRT changed significantly in the self-stretching group after intervention. A comparison of the two groups revealed significant differences in stiffness, elasticity, and MSRT (Time required for the muscle to recover after distortion after intervention in the GIASTM group. CONCLUSION: In this study, significant decreases in muscle tone and stiffness, as well as significant increases in elasticity, were observed in the gastrocnemius of the GIASTM group. On the other hand, sSelf-stretching showed significant differences in MSRT. Therefore, GIASTM is more effective in the recovery of the gastrocnemius muscle from fatigue than self-stretching. This study suggests that GIASTM can help prevent damage to the gastrocnemius in athletes and contribute to their training and rehabilitation programs.

• Physical Therapy Korea
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• v.22 no.2
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• pp.70-80
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• 2015

The spinal cord is highly complex, consisting of a specialized neural network that comprised both neuronal and non-neuronal cells. Any kind of injury and/or insult to the spinal cord leads to a series of damaging events resulting in motor and/or sensory deficits below the level of injury. As a result, muscle paralysis (or paresis) leading to muscle atrophy or shrinking of the muscle along with changes in muscle fiber type, and contractile properties have been observed. Traditionally, histology had been used as a gold standard to characterize spinal cord injury (SCI)-induced adaptation in spinal cord and skeletal muscle. However, histology measurements is invasive and cannot be used for longitudinal analysis. Therefore, the use of conventional magnetic resonance imaging (MRI) is promoted to be used as an alternative non-invasive method, which allows the repeated measurements over time and secures the safety against radiation by using radiofrequency pulse. Currently, many of pathological changes and adaptations occurring after SCI can be measured by MRI methods, specifically 3-dimensional MRI with the advanced diffusion tensor imaging technique. Both techniques have shown to be sensitive in measuring morphological and structural changes in skeletal muscle and the spinal cord.

• Physical Therapy Korea
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• v.9 no.3
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• pp.125-135
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• 2002

In most of the medical literature that discusses the common problem of movement in patients with cerebral lesions. This critical problem is ascribed to a mechanism involving uninhibited neural activity. The goals of neurological physical therapy are focus on reduce of muscle hypertonicity, facilitates muscle activities, and improve of performance in living environment. A variety of studies suggest that spasticity is a distinct problem and separate from the muscle weakness. It has become increasingly recognized that the major functional deficits following brain damage are largely due to negative features such as muscle weakness and loss of performance rather than spasticity. Adequate recruitment of prime mover, not release was able to carry out the movement tasks well. The strengthening exercise of spastic limbs on changes in muscle properties and performance skill, the repeated motor practice has been identified as crucial for motor recovery. This article support the concept that strengthening is an appropriate intervention to improve the quality of physical function in patients with central nervous system lesions. Further studies and therapeutic approaches should be efforts at improving motor neuron recruitment in agonist rather than reducing activity in antagonists while retraining muscle strengthening.

• Journal of Embryo Transfer
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• v.23 no.4
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• pp.283-289
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• 2008

Lepidium meyenii, known as Maca, is traditionally employed in the Andean region for its supposed properties to improve energy and fertility. In the present study, we investigated the effects of gelatinized and fermented Maca on improvement of physical stamina and epididymal sperm counts, and on blood biochemical parameters related to fatigue and tissue injury: creatine phosphokinase, aspartate transaminase, lactate dehydrogenase, blood urea nitrogen, glucose, total cholesterol and total proteins. Adult male mice was divided at random into two main groups (resting and excercise groups). The excercise group was separated into three subgroups (exercise only, exercise with gelatinized Maca and fermented Maca-treatment groups). Gelatinized or fermented Maca (800 mg/kg) were orally administered for 30 days. All animals in exercise groups were subjected to daily 30-min swimming for 28 days 30 min after Maca treatment. Daily exercise decreased the body weight gain, and fermented Maca further attenuated the body weight increase. Gelatinized and fermented Maca significantly increased the maximum swimming time on 14 and 28 days of treatment (p<0.05), respectively, suggestive of a long-term stamina-enhancing effect of fermented Maca. Both Maca fully or significantly recovered blood parameters of energy as well as muscular and hepatocytic injuries changed by repeated exercise and maximum swimming performance (p<0.01). Moreover, gelatinized and fermented Maca increased epididymal sperm counts 22.0% and 32.0%, respectively. In conclusion, the results indicate potential benefits of Maca for improving both physical stamina by minimizing muscular and hepatic damage and preserving energy during swimming exercise and male reproductive function by increasing epididymal sperm counts.

• Applied Microscopy
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• v.42 no.1
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• pp.17-26
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• 2012

Histologic and microstructural changes during the postembryonic development of the wolf spider Arctosa kwangreungensis were studied using light and scanning electron microscopy to examine the relationship between a morphological differentiation and behavioral properties. The postembryo with abdominal yolk sac was stayed inactive in the egg case because its muscular and visual systems were not fully developed to a functional level. The first instar spiderlings, developed from the postembryo by a first molting process, started to exhibit its pigmentation on their body cuticles. In particular, undifferentiated cell clusters of central nervous system (CNS) were densely distributed within the cephalothorax, and highly differentiated abdominal ganglion was observed. They had a characteristic visual system looks more like its adult counterpart, and had segmented appendages looks more like the tiny spiders containing well oriented muscular system. After 3rd instar, spiderlings grew more rapidly with accordance to their consistent growth and periodical molting processes. Thus, the relative area of CNS with respect to cephalothorax was gradually decreased, instead a pair of venom glands, musculature, and connectives occupied the residual area. It has been revealed that the early development of spider can be controled by the feeding condition of larval period, since histologic and microstructural differentiations in both appendages and optic system were completed at the second instar. In particular, behavioral properties of the wandering spiders that depend on vision and their running ability were deeply related to physiological differentiation of the microstructural development.

• Journal of Life Science
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• v.27 no.9
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• pp.1070-1077
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• 2017

Chondrocyte apoptosis induced by reactive oxygen species (ROS) plays an important role in the pathogenesis of osteoarthritis. Schisandrin A, a bioactive compound found in fruits of the Schisandra genus, has been reported to possess multiple pharmacological and therapeutic properties. Although several studies have described the antioxidant effects of analogues of schisandrin A, the underlying molecular mechanisms of this bioactive compound remain largely unresolved. The present study investigated the cytoprotective effect of schisandrin A against oxidative stress (hydrogen peroxide [$H_2O_2$]) in SW1353 human chondrocyte cells. The results showed that schisandrin A preconditioning significantly inhibited $H_2O_2-induced$ growth inhibition and apoptotic cell death by blocking the degradation of poly (ADP-ribose) polymerase proteins and down-regulating pro-caspase-3. These antiapoptotic effects of schisandrin A were associated with attenuation of mitochondrial dysfunction and normalization of expression changes of proapoptotic Bax and antiapoptotic Bcl-2 in $H_2O_2-stimulated$ SW1353 chondrocytes. Furthermore, schisandrin A effectively abrogated $H_2O_2-induced$ intracellular ROS accumulation and phosphorylation of histone H2AX at serine 139, a widely used marker of DNA damage. Thus, the present study demonstrates that schisandrin A provides protection against $H_2O_2-induced$ apoptosis and DNA damage in SW1353 chondrocytes, possibly by prevention of ROS generation. Collectively, our data indicate that schisandrin A has therapeutic potential in the treatment of oxidative disorders caused by overproduction of ROS.

• Korean Journal of Applied Biomechanics
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• v.24 no.1
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• pp.1-9
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• 2014

The purpose of this study was to investigate the muscle mechanical properties of the pelvic axial pre-rotational movement for the Jireugi in the Taekwondo Juchumseogi stance. Eleven elite Taekwondo Poomsae athletes participated. Each participant performed 5 right hand Jireugi in Juchumseogi stance as fast and strong as possible while their motion was recorded by a 3D motion analysis system and the ground reaction forces by two force plates. The power and work of the muscular group surrounding the waist were analyzed to verify the effect of the stretch-shortening cycle (SSC) theory. The cause of the greater power seems to be the application of the SSC by the muscles surrounding the waist during the preparation phase of the pre-rotation group. For the none pre-rotation group, they only used the concentric contraction of the muscles surrounding the waist. Because the pre-rotation group used the SSC theory, they had the effect of shortening of the range of movement, creating a fast and more powerful rotation, thus anticipating the increase the magnitude of impact.

• The Korean Journal of Physiology
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• v.23 no.1
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• pp.129-138
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• 1989

In an attempt to characterize the ventral root afferent fibers, arterial blood pressure responses to stimulation of the ventral root (VR) were observed in anesthetized cats. Effects of the morphine administered either intravenously or direct spinally and of the spinal lesions on the pressor responses were compared. Followings are the results obtained. 1) Stimulation of the VR with C-strength, high frequency stimuli evoked a marked pressor response. No depressor response, which had been reported during peripheral nerve stimulation, was observed during VR stimulation with low frequency. 2) Acute cervical spinalization abolished the pressor response, indicating the involvement of supraspinal mechanism. 3) The ascending spinal pathways of the pressor response were located in the dorsolateral funiculus bilaterally. 4) Intravenously administered morphine exaggerated the pressor response to VR stimulation, while direct spinally administered morphine suppressed it. From the above results it was concluded that the ventral root afferent fibers have more similar properties to muscular C-afferent fibers than to cutaneous C-fibers.