• 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.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.60
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• pp.37-46
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• 2000

A biomechanical model of lower extremity in seated postures was developed to assess muscular activities of lower extremity involved in a variety of foot pedal operations. The model incorporated four rigid body segments with the twenty-four muscles to represent lower extremity This study deals with quasi-static movement to investigate dynamic movement effect in seated foot operation. It is found that optimization method which has been used for modeling the articulated body segments does not predict the forces generated from biarticular muscles and antagonistic muscles reasonably. So, the revised nonlinear optimization scheme was employed to consider the synergistic effects of biarticular muscles and the antagonistic muscle effects from the stabilization of the joint. For the model validation, three male subjects performed the experiments in which EMG activities of the nine lower extremity muscles were measured. Predicted muscle forces were compared with the corresponding EMG amplitudes and it showed no statistical difference. For the selection of optimal seated posture, a physiological meaningful criterion was developed for muscular load sharing developed. For exertion levels, the transition point of type F motor unit of each muscle is inferred by analyzing the electromyogram at the seated postures. Also, for predetermined seated foot operations exertion levels, the recruitment pattern is identified in the continuous exertion, by analyzing the electromyogram changes due to the accumulated muscle fatigue.

• Safety and Health at Work
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• v.6 no.2
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• pp.128-133
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• 2015

Background: To investigate the relationship between musculoskeletal disorders and comorbid health problems, including depression/anxiety disorder, insomnia/sleep disorder, fatigue, and injury by accident, and to determine whether certain physical and psychological factors reduce comorbid health problems. Methods: In total, 29,711 employees were selected from respondents of the Third Korean Working Conditions Survey and categorized into two groups: Musculoskeletal Complaints or Musculoskeletal Sickness Absence. Four self-reported health indicators (overall fatigue, depression/anxiety, insomnia/sleep disorder, and injury by accident) were selected as outcomes, based on their high prevalence in Korea. We used multiple logistic regression analysis to determine the relationship between comorbid health problems, musculoskeletal complaints, and sickness absence. Results: The prevalence of musculoskeletal complaints and musculoskeletal sickness absence due to muscular pain was 32.26% and 0.59%, respectively. Compared to the reference group, depression/anxiety disorder and overall fatigue were 5.2-6.1 times more prevalent in the Musculoskeletal Complaints Group and insomnia/sleep disorder and injury by accident were 7.6-11.0 times more prevalent in the Sickness Absence Group. When adjusted for individual and work-related physical factors, prevalence of all four comorbid health problems were slightly decreased in both groups. Conclusion: Increases in overall fatigue and depression/anxiety disorder were observed in the Musculoskeletal Complaints Group, while increases in insomnia/sleep disorder and injury by accident were observed in the Sickness Absence Group. For management of musculoskeletal complaints and sickness absence in the workplace, differences in health problems between employees with musculoskeletal complaints and those with sickness absence as well as the physical and psychological risk factors should be considered.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.12 no.1
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• pp.16-26
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• 2006

The purpose of this study was to investigate the influence of the various knee angles and ground state on the muscular activities and fatigue of the ankle muscles by integrated electromyograms (iEMG) and median frequency of tibialis anterior (TA), peroneus longus (PL), flexor digitorum longus (FDL) and gastrocnemius (GC). Ten healthy male subjects were participated into stable and balance ball sessions at four angles of knee joint. The surface electromyograms (sEMG) were recorded from the TA, PL, FDL and GC on stable and balance ball with full weight bearing at four knee angles of $0^{\circ}$, $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$. The time serial data of the surface electromyographic signals were transformed into integrated and frequency serial data by fast fourier transformation. On the stable ground, the iEMG signals of the TA, PL, FDL and GC were significantly higher at $45^{\circ}$ and $30^{\circ}$ of knee angles than $0^{\circ}$ and $15^{\circ}$ of knee flexion (p<0.05). On the balance ball, the iEMG of the TA, PL, FDL and GC were significantly higher at $45^{\circ}$ and $30^{\circ}$ of knee angles than $0^{\circ}$ and $15^{\circ}$ of knee flexion (p<0.05). The median frequency of the TA, PL, FDL and GC were significantly lower at $45^{\circ}$ and $30^{\circ}$ of knee angles than $0^{\circ}$ and $15^{\circ}$ of knee on the stable ground (p<0.05). On the balance ball, also the median frequency of the TA, PL, FDL and GC were significantly lower at $45^{\circ}$ and $30^{\circ}$ of knee angles than $0^{\circ}$ and $15^{\circ}$ of knee flexion (p<0.05). The iEMG of the TA, PL, FDL and GC were significantly higher on the balance ball at $0^{\circ}$, $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$ of knee angles compared with stable ground. The median frequency of the TA, PL, FDL and GC were significantly lower on the balance ball at $0^{\circ}$, $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$ of knee angles compared with stable ground. These results indicate that the ground conditions and angles of the knee joint involved to muscular activities and fatigue of ankles muscles, may performed at first on stable ground and then balance ball in order to $0^{\circ}$, $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$ of knee flexion.

• Journal of Biomedical Engineering Research
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• v.9 no.2
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• pp.211-214
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• 1988

As a muscular contraction is sustained, the power spectrum of the myoelectric signal is compressed into lower frequencies. The median frequency appears to be the prefered parameters to monitor this compression. This paper describes a technique and a device which provide an estimate of the median frequency using a TMS32020 DSP chip and IBM PC for tracking of this parameter. Results obtained from myoelectric signal are presented and discussed.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.714-717
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• 1988

As a muscular contraction is sustained, the power spectrum of the myoelectric signal is compressed into lower frequencies. The median frequency appears to be the prefered parameters to monitor this compression. This paper describes a technique and a device which provide an estimate of the median frequency using a TMS32020 DSP chip and IBM PC for tracking of this parameter. Results obtained from myoelectric signal are presented and discussed.

• Journal of the Ergonomics Society of Korea
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• v.31 no.3
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• pp.469-474
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• 2012

The aim of this study is to develop an ergonomic design of magic saw handle considering user experiences. Background: Frequent use of hand tool can cause musculoskeletal disorders by inadequate wrist posture, excessive strength, repetitiveness, friction and pressure, vibration, etc. A hand tool that is inappropriately designed has higher risk causing musculoskeletal disorders. Complaints for the design of magic saw handle has been raised by many users according to the increasing use of magic saw. Method: Hand tool has to be designed considering worker's characteristics and task condition to prevent worker's musculoskeletal disorders. For this, user experiences for magic saw handle were measured through questionnaire survey and observation. Results: An ergonomic design of magic saw handle considering user experiences was proposed and then its design suitability was evaluated in comparison with the existing handle design using EMG and subjective evaluation. Conclusion: The proposed handle design showed higher satisfaction and lower muscular fatigue. Application: The results of this study can be effectively used to develop a new magic saw.

• Journal of Chest Surgery
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• v.42 no.5
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• pp.674-676
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• 2009

Isolated stress fracture of the first rib is rare, and repeated muscular pulling and fatigue of bone is thought to be responsible for this fracture. The diagnosis can be made by taking a thorough history and performing chest roentgenography, computed tomography or magnetic resonance imaging. Conservative treatment generally cures this condition. We report here on a case of exercise-induced isolated stress fracture of the first rib in a non-athlete college student and we review the related articles.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.165-166
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• 1998

A multi-parameter neuro muscular electrical simulator (NMES) system was developed to be used to find the optimal parameter condition in obtaining maximum muscle power and minimal fatigue. Since the performance of NMES is mainly determined by the characteristic of its output-stage circuit, we implemented 3 different circuits and compared output characteristics of them. Three amplifier circuits are; 1) a resonant switching converter, 2) a linear amplifier with a transformer, and 3) a step-up DC/DC converter with a high-voltage linear amplifier. Experimental results showed that the step up DC/DC converter with a high-voltage linear amplifier has the best performance.

• Annals of Clinical Neurophysiology
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• v.5 no.2
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• pp.202-209
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• 2003

Postpolio syndrome (PPS) refers to a constellation of neuromuscular and orthopedic symptoms and signs that have been noted to occur in patients with remote antecedent poliomyelitis. It has been increasingly recognized that individuals recovering from acute poliomyelitis develop new symptoms, most commonly weakness, fatigue, and pain that develops decades after initial disease in the region previously affected. Associated symptoms may include dysphagia, respiratory insufficiency, new muscular atrophy, dysarthria, muscle cramps, fasciculations, sleep abnormalities, and cold intolerance. Although the concepts of PPS was first described in the late 1800s, it was not until nearly 100 years later that the concept of PPS was more widely recognized and defined. This was due largely to the polio epidemic of the 1940s and 1950s that left many survivors in the world. The virtual epidemic of PPS that occurred among these polio survivors in the 1980s and 1990s has served as a catalyst to attract medical attention to this syndrome.