• Korean Journal of Acupuncture
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• v.28 no.3
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• pp.13-23
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• 2011

Objectives : The aim of this study was to develop the combined medical stimulus system consisted of the PEMFs (Pulsed electromagnetic fields) and LED which are able to stimulate local point such as acupoints and trigger points. Methods : To evaluate the therapeutic effect on the musculoskeletal disorders and the possibility of alternative method on manual acupuncture, we compared the fatigue recovery of two groups by analyzing the EMG and peak torque (non-stimulation and, stimulation group) after strenuous knee exercise. We chose the LR9 as a stimulation point. Results : The median frequency (MF) and fatigue index (F.I) of the stimulation group were recovered faster than those of the non-stimulation group. Also the peak torques of both groups were not restored until after 20 minutes. However, the peak torque of the stimulation group was regained higher than that of the non-stimulation group. Conclusions : We confirmed that the proposed combined stimulus system had useful effects as treatment instrument of musculoskeletal disorder using non-invasive method of PEMFs and LED.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.5 no.2
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• pp.95-105
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• 2007

The purpose of this study is to define the effect of taping and icing on muscle fatigue at knee joint of ordinary adult. The 30 adults meeting research standard were chosen to be observed. The period of the research was 9 days and N-K table was used as equipment to measure position sense of knee joint. Heart rate monitor was also used to measure heart beat during both when in comfortable state and in exercises. For the method of this study, error in position sense of knee joint was measured right before fatigue occurs. Then volunteers were to be exercised for 10 minutes in treadmill aiming to raise the heart beat to 90%. If muscle fatigue occurs after the exercise, let the comparative group rest for 20 minutes while applying taping for group 1 and icing for group 2. For the icing, it was applied for 3 minutes followed by 1 minute rest. 5 sets of icing were applied on thighs and calf each, Then error of position sense of knee joint was measured same way it was done before muscle fatigue. As the result, there were similar differences among comparative group(p<.05), group 1 and group 2 before the muscle fatigue and after the muscle fatigue. There were similar differences in comparative group with muscle fatigue, group 1 and group 2 as the result of one-way ANOVA and with further examination, similar differences were only found in between comparative group and group 2(p<.05). With the result, we can see there wasn't clear effect of rest, icing or taping, however, group 2 with icing showed better condition compared to comparative group who have rested without any application.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.10
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• pp.2317-2323
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• 2010

When the muscle is contracted by continuous and same, the force takes fatigue and stiffness. The aim of this study was to know how the fatigue and muscle stiffness change during an isometric contraction. Surface Electro myography(EMG) signal monitoring system and ultrasonic transducer set up the same muscle stem, subjects contract his right femoris muscle by submaximal isometric contraction(50% of MVC) until exhaustion. Before and after the test, muscle stiffness was measured and EMG was measured during the contraction. As time goes by, muscle fatigue was increased. and the stiffness was shown strongly after the contraction. These results show if the muscle becomes more and more fatigued, the circulation of muscle is delayed although the contraction doesn't happen. So muscle stiffness is increased.

• The Journal of Korean Obstetrics and Gynecology
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• v.20 no.2
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• pp.155-163
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• 2007

Purpose: This study was conducted to investigate the muscle anti-fatigue effects of Morindae officinalis Radix liquid extract. Methods: 4-6 weeks old ICR rats are used in the study, and we administered the extracts powder of Morinda officinalis concentration of 1, 10, 100mg/0.3 ml to each to rats(MO group) once a day for each 30 and 60 days. After 30 and 60 days, we examined the plasma concentraion of lactate dehydrogenase, glucose. And we measured the persistent time of swimming exercise test and conducted grip strength test Results: We found that there are no significantly differences between the control and the treatment group in the plasma concentration of activity level of lactate dehydrogenase. And we found that in 30days group, level of glucose concentration is significant. In swimming exercise test, as administration time and concetration growed up, swimming time is increased. And in grip strength test, as concentraion is growed up, grip strength is increased. Conclusion: This study show that Morinda officinalis is effective against muscle fatigue.

• The Journal of Korean Obstetrics and Gynecology
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• v.20 no.2
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• pp.60-70
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• 2007

Purpose: This study was conducted to investigate the muscle anti-fatigue effects of Allii tuberosi semen after short term administration. Methods: 4-6 weeks old ICR mice were used in this study and we administered the water soluble extracts of Allii tuberosi semen in the concentration of 1, 10 and 100mg/0.3ml to each 5 mice (ATS group) and same volume of normal saline was administered to 5 mice (control group) once a day for 30 or 60 days. After the administration we performed the swimming exercise test and the grip strength test. And we measured the concentration of glucose and the activity of lactate dehydrogenase in plasma regarded as biochemical indicator related with the muscular fatigue.. Results: In swimming exercise test. 10 and 100mg/0.3ml ATS groups showed increased time compared with relative control group after 30 days administration. But after 60 days adminstration all ATS groups showed increased results. In grip strength test, 100mg/0.3ml ATS group increased grip strength after 30days administration and 10mg/0.3ml ATS group showed increased result after 60days administration. All the results of plasma glucose and lactate dehydrogenase didn't showed statistically significant difference after 30 and 60 days administration. Conclusion: From this study we could find the anti-fatigue effect of Allii tuberosi semen in the muscle strength related test.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.3
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• pp.305-310
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• 2007

This study was designed to investigate the effects of KH-305 on erectile dysfunction in young rats, via nitric oxide (NO)-cGMP pathways. After oral administration of the KH-305 mixture (50, 100, 200, 300 mg/kg) to young rats for 10 days, NOS and SOD protein expressions in penile tissue and testosterone in plasma were measured. cGMP degradation was also investigated using bovine vascular smooth muscle cells pretreated with an NO donor, S-nitroso-N-Acetylpenicillamine (SNAP). The penile expression levels of nNOS and eNOS-dependent NOS activities as well as SOD preventing oxidative stress by overproduction of NO were increased significantly. Also, the concentration of testosterone in the plasma was increased. In vitro, cGMP concen-trations were decreased dose dependently in the KH-305. These results suggest that KH-305 may be useful in erectile dysfunction.

• Physical Therapy Korea
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• v.20 no.3
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• pp.36-44
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• 2013

This study aimed to investigate the influence of shoe heel height and muscle fatigue on static and dynamic balance in young women. Thirty women who were used to wearing high heels volunteered to participate in this study. The shoe heel heights were 0 cm and 7 cm. And ankle plantar flexor fatigue was experimentally induced. Static and dynamic balance were measured using the one leg standing test (OLST) and the star excursion balance test (SEBT) in anterior, posteromedial, and posterolateral directions, respectively. Values in the OLST (shoe heel height 0 cm, $28.83{\pm}3.24$ sec to $26.12{\pm}6.13$ sec; and 7 cm, $24.75{\pm}7.09$ sec to $16.86{\pm}9.32$ sec) and the SEBT in anterior (shoe heel height 0 cm, $71.02{\pm}4.57%$ to $69.50{\pm}3.66%$; and 7 cm, $64.17{\pm}3.53%$ to $59.61{\pm}4.06%$) and posteromedial (shoe heel height 0 cm, $92.01{\pm}5.61%$ to $90.38{\pm}7.10%$; and 7 cm, $83.09{\pm}7.29%$ to $76.83{\pm}9.28%$) directions were significantly reduced when fatigue-inducing exercise was performed (p<.05). Furthermore, within these parameters, there were significant interaction effects between shoe heel height and fatigue condition (p<.05). These findings suggest that shoe heel height and muscle fatigue contribute to some changes in static and dynamic balance in young women, probably leading to negative effects on physical function during a variety of activities of daily living.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.4
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• pp.565-572
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• 2010

It is difficult to predict the accurate fatigue life of the ship structure because of load uncertainty and load redistribution at the ship structure members. As one of studies for accurate evaluation and prediction of fatigue life, it is a promising way to detect the crack previously by attaching the Fatigue Indicator Sensor (FIS) at the crack prediction region. In order to predict the fatigue life of the ship structure by using FIS, it is required to know previously the crack propagation characteristics according to pre-notch shapes. In this study, we obtained the stress distribution phase, stress concentration factors and stress intensity factor of various pre-notch shapes through FEA. Additionally, we conducted the fatigue test and obtained the characteristics of crack propagation according to the pre-notch shapes through comparison between the fatigue test and the FEA. Consequently, we classified the pre-notch shape into 3 categories: Long, Medium, and Short life type. On the basis of the numerical and experimental results, the FIS can be developed.

• Journal of the Ergonomics Society of Korea
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• v.14 no.1
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• pp.9-23
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• 1995

The objectives of the study were twofole: (1) to investigate effects of rhythmic contraction and sustained contraction methods on recovery rate of isometric endurance capacity and (2) to compare aptterns of muscle recruitment of both arms observed during each contraction period. In the experiment, each of two subjects performed five successive rhythmic or sustained isometric contractions at 50% MVC with both arms to the point of fatigue, which was the failure to maintain the required tension. In making the contractions, the subjects stood erect with upper arms held at an angle of approximately 90 .deg. to the forearm. The interval between the successive contractions was kept constant at 3, 7, 20, or 40 minutes. Regardless of the contraction methods, the recovery rate was least at the shortest interval and was highest at the longest interval. However, a statistical analysis showed that the recovery rates for the rhythmic contractions were significantly lower than those for the sustained contractions throughout 4 different intervals. Furthermore, as the frequency of the rhythmic contractions per min, increased 4 to 6 times, the recovery rate of isometric endurance capacity decreased. From an EMG anglysis, recruitment pattern of the muscules of both arms was found to be common between two different contraction methods. The biceps muxcles of the upper arms played a major role in exerting 50% MVC, while the brachioradialis muscles of the forearms acted as synergists. As the contraction proceeded, the role of the biceps muscles as a prime mover lessened due to the fatigue. Then, the brachioradialis muscles exerted more strength to sustain 50% MVC. The implications of these finding were discussed.

• The Journal of Korean Physical Therapy
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• v.18 no.1
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• pp.53-64
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• 2006

Purpose: The present study purposed to examine the effects of massage and stretching on the recovery of muscle contraction force for muscle fatigue caused by sustained isometric contraction. Methods: The subjects of this study Were 64 healthy men and women (women: 30, men: 34). They Were divided into massage group (23), stretching group (21) and rest group (20), and using Biodex System we observed the pattern of changes in maximal voluntary contraction force (MVC) after causing muscle fatigue in quadriceps femoris muscle through sustained isometric contraction. Results: We measured the point of fatigue occurrence by sustained isometric contraction with 50% MVC and changes in isometric contraction force at 0, 10, 20 and 30 minutes after fatigue and compared them according to gender and treatment group. Conclusion: 1. According to the result of measuring the point of time when fatigue occurred, a difference was observed in time to task failure between men and women. It was significantly longer in women. 2. By gender, MVC changed significantly in all time frames in women, but it showed significant increases only at 10 minutes after fatigue in men. 3. In the comparison of MVC among the treatment groups, it showed significant differences among the groups at 10 minutes after fatigue. 4. In the comparison of changes in MVC among the time frames for each group, the rest group showed significant differences in MVC between 0 and 10 minutes after fatigue and between 20 and 30 minutes after fatigue. The massage group showed significant differences in MVC between 0 and 10 minutes after fatigue and between 10 and 20 minutes after fatigue. The stretching group showed a significant difference in MVC between 10 and 20 minutes after fatigue and between 20 and 30 minutes after fatigue.