• PNF and Movement
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• v.17 no.3
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• pp.401-409
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• 2019

Purpose: This study investigated the muscular activity of abdominal muscles during a variety of plank exercises following changes in the leg and head positions. Methods: Thirty healthy individuals participated in this study. They performed six variations of plank exercises, including three changes in head position and two changes in leg position. Each plank was defined as head neutral-leg neutral, head up-leg neutral, head down-leg neutral, head neutral-leg wide, head up-leg wide, and head down-leg wide. During the plank excises, the muscle activities of the rectus abdominis, internal oblique, erector spinae, and upper trapezius were measured. Results: The head down position significantly increased the rectus abdominis activity compared to other head positions (p<0.05). On the other hand, the upper trapezius muscle activity was significantly higher with the head up position compared to other head positions (p<0.05). Regardless of head positions, both the rectus abdominis and internal oblique muscles were significantly activated with leg wide position compared to the leg neutral position (p<0.05). Conclusion: Head and leg positions could change the muscular activities of abdominal muscles during plank exercises. For example, the head down position is effective for activating the rectus abdominis while the leg wide position could be advantageous for enhancing the internal oblique and rectus abdominis.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.4
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• pp.569-575
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• 2018

Objective: This experiment was conducted to investigate the effects of chromium picolinate (CrP) on fat deposition, genetic expression and enzymatic activity of lipid metabolism-related enzymes. Methods: Two hundred forty one-day-old Ross broilers were randomly divided into 5 groups with 4 replicates per group and 12 Ross broiler chicks per replicate. The normal control group was fed a basal diet, and the other groups fed the same basal diet supplemented with 0.1, 0.2, 0.4, and 0.8 mg/kg CrP respectively. The experiment lasted for 21 days. Results: Added CrP in the basal diet decreased the abdominal fat, had no effects on subcutaneous fat thickness and inter-muscular fat width; 0.2 mg/kg CrP significantly decreased the fatty acid synthase (FAS) enzymatic (p<0.05); acetyl-CoA carboxylase (ACC) enzymatic activity decreased in all CrP groups (p<0.05); hormone-sensitive lipase (HSL) enzymatic activity also decreased, but the change was not significant (p>0.05); 0.4 mg/kg CrP group significantly decreased the lipoprotein lipase (LPL) enzymatic activity. FAS mRNA expression increased in all experimental groups, and the LPL mRNA expression significantly increased in all experimental groups (p<0.05), but not 0.2 mg/kg CrP group. Conclusion: The results indicated that adding CrP in basal diet decreased the abdominal fat percentage, had no effects on subcutaneous fat thickness and inter-muscular fat width, decreased the enzymatic activity of FAS, ACC, LPL and HSL and increased the genetic expression levels of FAS and LPL.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.1
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• pp.53-71
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• 1991

This study was performed to investigate the muscular activity of the complete denture wearers compare with subjects with natural teeth. For the study, 10 subjects with natural dentition and 18 upper and lower complete denture wearers selected and the Bio-electric Processor EM2(Myo-tronics Reaserch, Inc., U.S.A.) with the surface electrodes was used to record electromyographic activity from the right and left middle of masseter and anterior temporal muscles of each subject during mandibular postural rest position, tapping of teeth from postural rest position, maximal clench, and right and left gum and raw carrow chewing. This results of this study were as follows : 1. In mandibular postural rest position, the denture wearers produces high muscular activity in contrast to natural objects(P<0.05) but, there was no difference between the state of denture removal and insertion, and the muscle activity of the anterior temporal muscle was high than the middle of masseter muscle in natural objects and denture wearers. 2. In tapping of teeth, there was no difference in muscle activity between natural objects and the state of denture removal of denture wearers. 3. In maximal clench, there was markedly lower denture wearers than natural objects in muscle activity, and the ratio of mean voltages was about 36 percentages. 4. In gum and raw carrow chewing, the activity was lower than natural object, the ratio was about 59 percentages. 5. In chewing, the mean voltages of the middle of masster muscle on the chewing side was highest, followed by the anterior temporal on the chewing side, the anterior temporal and masster muscles on the non-chewing side.

• Journal of the Ergonomics Society of Korea
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• v.26 no.2
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• pp.35-44
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• 2007

Work-related musculoskeletal disorders (WMSDs) are a major problem in industries in which manual materials handling is performed by workers. To prevent these WMSDs, it is necessary to understand the muscular strength capability and use this knowledge to design job and selection and assignment of workers. Even though two-hands lifting activity of manual materials handling tasks are prevalent at the industrial site, many manual materials handling tasks which require the worker to perform one-hand lifting are also very common at the industrial site and forestry and farming. However, a few researches have been done for one-hand lifting activity of manual materials handling tasks. The objective of this study is to compare one-hand and two-hands lifting strength in terms of static and dynamic strength of the lifting activity for the ranging from the height of knuckle to elbow. It is shown in this study that the isometric lifting strength of one-hand is ranging from 54.7 to 63.3% of the one of two-hands. However, it is found that there is no significant difference between a person's isometric lifting strength for left-hand and right-hand. It is also shown that there is no significant difference between the peak force under the dynamic sub-maximal loading with one-hand and two-hands lifting activity. Similar results were obtained for the peak acceleration and peak velocity under the dynamic sub-maximal loading with one-hand and two-hands lifting activity. Isometric lifting strength at the height of knuckle was ranging from 2 to 3 times of the dynamic peak force during sub-maximal lifting. It is concluded that the dynamic peak forces under the sub-maximal loading are not highly correlated with the isometric lifting strength in similar postures.

• Journal of the Ergonomics Society of Korea
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• v.20 no.2
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• pp.71-82
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• 2001

Twisting posture in lifting tasks has been identified as a risk factor of low back pain. However, it has been usually estimated in terms of compressive stress or muscular activity. Thus, this study was conducted to predict the influence on muscular fatigue during lifting simulation. Fifteen young and healthy subjects were recruited and performed isometric trunk exertions during upright standing, two-level flexions and five-level asymmetric twisting conditions. EMG signals from five primary trunk muscles in right part of body were collected during 20sec for 45 different lifting conditions. RMS(root mean square) and MPF(mean power frequency) parameters were used to analyze the EMG signals. Twisting postures were significant in right erector spinae(ERSR), right latissimus dorsi(LATR), right internal oblique(INOR) for muscular activities. Especially, when trunk was $30^{\circ}$ CCW twisting posture. ERSR and INOR activities increased respectively by 11% and 3%. Regarding the trunk muscle fatigue, we found that MPF shifts in twisting posture increased 2.3 and 2.6 times for ERSR and INOR muscles respectively. Therefore, It is probable for workers to suffer from low back disorders when they were exposed to a extreme twisting posture during prolonged lifting. This study suggests NIOSH(National Institute for Occupational Safety and Health) lifting equation needs the time-duration multiplier in addition to asymmetric multiplier.

• Korean Journal of Exercise Nutrition
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• v.24 no.2
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• pp.38-46
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• 2020

[Purpose] This study aimed to investigate the effects of leucine-enriched essential amino acid (LEAA) supplementation on muscle fatigue and the level of inflammatory cytokines in wheelchair basketball players after a basketball game and interval training. [Methods] Of the ten recruited wheelchair basketball players (aged 34.5±8.9 years; lean body mass of 34.3±10.0 kg) who had spinal cord injury (SCI) and had undergone amputation, nine participated in the final test. These nine athletes received LEAA supplements (3 times 4.0 g/day) or placebo treatment in a double-blind, randomized, crossover study. We measured variables related to muscular fatigue and inflammatory response before the intense exercise and 4 days after recovery. [Results] The significant effect of LEAA supplementation was inhibition of circulating IL-6 levels in the LEAA-treated group compared with the placebo group (P < .05). However, no changes were observed in the TNF-α and creatinine kinase levels. Moreover, analysis of variance analysis showed no significant difference in the relative values of muscle soreness. However, the effect size analysis with Cohen's d reported a significant improvement in the relative values of whole body and back muscle soreness. [Conclusion] Our results revealed that LEAA supplementation before and after intense exercise could help reduce muscle soreness and IL-6 levels in wheelchair basketball players.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.6
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• pp.678-682
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• 2007

Effects of medicinal herbs on the improvement of muscular strength along with the related fatigue factors were evaluated in SD rats. Nine types of treatment groups were fed diets supplemented with 1% herb hot-water extracts (Liriope spicata (LS), Schizandra chinensis (SC), Acanthopanax sessiliflorus (AS), Saliconia herbacea (SH), Eucommia ulmoides (EU), Lycium chinensis (LC), Panax ginseng (red ginseng) (PG), Polygonum multifloum (PM), Glycyrrhizae uralensis (GU)) for 4 weeks. The muscular strength of all groups were measured weekly for 4 weeks. After 4 weeks serum was collected and liver dissected out for the analysis of glycogen and fatigue factors. The liver glycogen contents of all treatment groups ($21.0{\sim}25.9mg/g$) were higher than that of control group (18.1 mg/g). A significantly increase of muscular strength in the fourth week were found in the AS (282.5 gf), SH (277.4 gf), PG (287.2 gf) groups (p<0.05). LS (7.88 mg/dL), SC (7.85 mg/dL), AS (7.64 mg/dL), EU (7.54 mg/dL), LC (7.81 mg/dL) and PG (7.75 mg/dL) groups were significantly reduced in serum inorganic phosphorus concentration measured after 4 weeks (p<0.05). Serum lactate levels of treatment groups ($8.61{\sim}12.18{\mu}g/dL$) were significantly lower than that of control group ($17.45{\mu}g/dL$). These results suggest that medicinal herbs enhanced muscular strength of rats by delaying accumulation of muscular fatigue factor.

• Journal of Oral Medicine and Pain
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• v.21 no.2
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• pp.293-304
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• 1996

The purpose of this study was to investigate the peak electromyographic activity(EMG) and time intervals in firing sequence of Anterior temporalis(TA) and Masseter(MM) on clenching, the number of tender points in the head and neck muscles, the occlusal contact state on clenching, and their relationship. 78 patients with Temporomandibular Disorders(TMDs) participated and were classified into articular or muscular group by clinical signs and symptoms. BioEMG$\textregistered$ of integrated masticatory function analyzer, Biopak$\textregistered$ system(Bioresearch Inc., USA), was used to measure EMG and related items, and T- Scan$\textregistered$(Tekscan, USA), computerized occlusal analyser, was used to record occlusal contact state on maximum voluntary clenching. EMG and occlusal contact were synchronously recorded and analysed with SAS Statistical program. The results of this study were as follows : 1. In total subjects, EMG of TA was lower than that of MM in articular group but in muscular group, vice versa, As a result, the ratio TA to MM was significantly different between the two groups. no significant differece. 3. The number and force of occlusal contact were more in articular group, but there was no significant difference in Total Left-Right statistics(TLR) between the two groups. 4. In unilaterally affected subjects for muscle function, no significant difference was observed between the affected side and the contralateral side in articular group, but in muscular group, the item of the number of tender points showed significant difference. However, for occlusal contact items, contact force in articular group shows significant difference between the two sides. 5. Rate of coincidence of the first firing side of TA with affected side or preferred chewing side was higher and not different between the two groups, but no significant correlation was showed between the first firing side and the first occlusal contact side.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.195-196
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• 2008

• Korean Journal of Applied Biomechanics
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• v.22 no.3
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• pp.365-371
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• 2012

We aimed to analyze the muscle activity of adolescent patients with idiopathic scoliosis during gait and develop the wearing of musculo-skeletal functional garment by applying the principle of sports taping based on the result of the analysis. We selected 20 male students between the ages of 13 and 18 and divided them into 2 groups: one group consisted of 10 patients with idiopathic scoliosis <20 degrees of Cobb's Angle: the other group had 10 normal students. Using, we measured and analyzed the muscle activity of 8 different regions: left and right latissimus dorsi, left and right thoracolumbar fascia, left and right gluteus medius, and left and right biceps femoris during gait. Our results can be summarized as follows: Firstly, in patients with idiopathic scoliosis, the gait showed a significantly low activity of the right latissimus dorsi muscle when the left foot was supported on the ground(p<.05). Secondly, in the overall gait cycle, the patients showed a higher activity of the right thoracolumbar fascia and right gluteus medius than that seen in the normal students: however, this difference was not statistically significant. Thirdly, by applying sports taping on the bisis of the results, this study developed the wearing of musculo-skeletal functional garment that could maximize the stimuli of the right latissimus dorsi and alleviate muscle contraction of the right thoracolumbar fascia and right gluteus medius, while expanding the spinal line upward and downward, by focusing on the difference between left and right muscular strength of the muscle activity of the bright latissimus dorsi. Overall, we expect that by wearing of musculo-skeletal functional garment, the muscular functions in adolescents with idiopathic scoliosis.