• Elastomers and Composites
• /
• v.40 no.3
• /
• pp.181-187
• /
• 2005

Changes of physical properties or NR vulcanizates with different cure systems by thermal aging were investigated. Two sulfur cure systems and one resole cure system were employed, and total contents of the curatives were varied. For the NR vulcanizates with sulfur cure systems, hardness and modulus after the thermal aging at $90^{\circ}C$ for 3 days were increased, but elongation at break and tensile strength were decreased. For the NR vulcanizates with resloe cure system, the physical properties after the thermal aging were decreased. The change of physical properties by the thermal aging was explained with the crosslink density change. The crosslink densities or the NR vulcanizates with sulfur cure systems were increased after the thermal aging, but those with resole cure system were decreased. Influence of the migration of antidegradant on the changes of physical properties was also investigated. However, the changes of physical properties by the thermal aging were not explained sufficiently with the migration of antigradant.

• Journal of The Korean Society of Integrative Medicine
• /
• v.10 no.1
• /
• pp.109-118
• /
• 2022

Purpose : The study to verify the effectiveness of the Soomchi combined marine healing program by analyzing the physical composition of the subjects, their blood lipids, and the effects of the program on their lung health-related variables, and heart rate variability variables. Methods : In the experiment, the Soomchi combined marine healing program was conducted for 5 hours a day, 5 days a week. on 15 participants. The results of their body composition, blood lipids, lactic acid, blood pressure, PEF, FEV1 and maximum oxygen intake were analyzed before and after the subjects completed the Soomchi program. For the statistical analysis, the mean and standard deviation (M±SD) of each variable were calculated using SPSS version 20 and an independent t-test was conducted to test for the amount of change in the participants before and after the Soomchi combined marine healing program. All significant levels were set to α=.05. As a result of the experiment Results : First, no statistically significant differences were found in the changes in body composition after the 5-day combined marine healing program was completed. Second, regarding the changes in blood component after the program was conducted, statistically significant differences were found in the lactic acid (p<.05). That is, the experimental group showed a significant decrease in lactic acid after the program whereas the control group showed a significant increase. Third, systolic blood pressure decreased significantly and while in PEF and FEV1 increased significantly in the experimental group after the program. Fourth, the LF of the control group significantly decreased after 5 days. Conclusion : After the Soomchi Lung Health Ocean Healing Program, positive physical changes were observed in the lung health variables and heart rate variability of the participants.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.1
• /
• pp.198-208
• /
• 2010

This study intends to evaluate the impacts of traditional recreations on children's physical strength and self-ego on a group of 40 seven-year-old children observed twice per week for a ten week period. The results of the research are as follows. First, in the changes of the infant's basic physical strength, according to the traditional playground program, low factors like muscular strength, agility, quickness, and flexibility shows higher in experimental group comparing to control group. Statically between two groups, there was a significant difference. Second, in the changes of the infant's physical self-concept, according to the traditional playground program, low factors like, appearance, fitness ability, and physical strength Shows higher in experimental group comparing to control group, but statically, two groups there wasn't any significant differences. So according to the results of the research, it clearly shows that traditional playground program has positive effects to the infant's basic physical strength, and physical self-concepts.

• Journal of The Korean Society of Integrative Medicine
• /
• v.7 no.4
• /
• pp.53-59
• /
• 2019

Purpose : The purpose of this study was to determine the influence of the elastic-band exercise program for elderly who over 65 years old in terms of depression and physical self efficacy. We aim to suggest interventions with an elastic-band exercise program for elderly. Methods : The study subjects selected were females or males 65 years old or more who could walk without assistance and could talk about daily living without mental or physical disorders. A total of eight subjects understood the purpose of this study and agreed to participate. Before and after the exercise program, the subjects were monitored for changes in their physical self-efficacy and depression. To measure the physical self-efficacy, we used a perceived physical ability scale and physical self-presentation confidence scale (Cronbach α =0.942). To measure depression, we used the geriatric depression scale short form (Korea version, Cronbach α =0.969). The data obtained from each measure were analyzed using the Wilcoxon signed rank test to determine changes from before and after the exercise program. The program consisted of three parts (warm-up, main exercise and cool-down) and included the upper extremities, the lower extremities and trunk exercises with an elastic band (yellow and red). The program lasted for 15 weeks, once a week, with each session lasting for 60 minutes. Results : After 15 weeks of the elastic-band exercise program, there was a significant decrease on the depression scale (p<0.05) and significant improvements on the physical self-efficacy scale (p<0.05). Conclusion : Based upon our results, we demonstrated that the exercise program using the elastic band was effective in improving the depression and physical self-efficacy of the elderly.

• Korean Journal of Community Nutrition
• /
• v.21 no.6
• /
• pp.533-544
• /
• 2016

Objectives: We aimed to examine levels of physical activity, anthropometric features, and health-related quality of life (HRQoL) among Korean breast cancer survivors who reported changes in their diet after diagnosis. Methods: A total of 380 women who had been diagnosed with stage I to III breast cancer and had breast cancer surgery at least six months before the interview were included. Participants provided information on dietary change after diagnosis, post-diagnostic diet, physical activity, anthropometric measures, and HRQoL through face-to-face interview. We assessed HRQoL levels of breast cancer survivors using a validated Korean version of European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) and Breast Cancer Module (BR23). We used the logistic regression and generalized linear models to identify the associations of dietary changes in relation with physical activity, anthropometry, and HRQoL. Results: The majority of participants (72.6%) reported that they have changed their diet to a healthier diet after diagnosis. Breast cancer survivors who reported to have change to a healthy diet had higher intakes of vegetables and fruits and lower intakes of red and processed meats, and refined grains than those who did not. Also, survivors with a healthy change in their diet were more likely to engage in physical activity (top vs. bottom tertile: odds ratio [OR], 1.85; 95% confidence interval [95% CI], 1.02-3.36) and have lower body mass index (BMI) (OR, 0.90; 95% CI, 0.82-0.98 for one $kg/m^2$ increment in BMI) compared to those who did not. We found that a healthy change in diet was associated with higher scores of physical functioning (p=0.02) and lower scores of constipation (p=0.04) and diarrhea (p=0.006) compared to those who did not. Conclusions: Healthy changes in diet after breast cancer diagnosis may be associated with lower levels of BMI, and higher levels of physical activity and HRQoL.

• Physical Therapy Rehabilitation Science
• /
• v.8 no.1
• /
• pp.45-51
• /
• 2019

Objective: The purpose of this study was to investigate the muscle activity ratio of the lower limb according to changes in straight leg raise (SLR) test angles on hamstring muscle shortening during squat exercises. Design: Randomized controlled trial. Methods: The subjects were 14 healthy adults who were informed of and agreed to the method and purpose of the study. The participants were classified into SLR groups according to two angles (over $80^{\circ}$ or under $80^{\circ}$) assessed using the SLR tests. After training and practicing the wall squat posture to be applied to the experiment, electromyography (EMG) was used to measure changes in muscle activity during the performance of a wall squat. After stretching, a sequence of pre-stretch tests were performed again, and the active and passive SLR tests were also reconducted; thereafter, a wall squat was performed again by attaching EMG electrodes. The EMG results before and after stretching were compared. Results: The muscle activity of the vastus lateralis oblique muscle increased in both groups. The muscle activity of the vastus medialis oblique muscle decreased in over both group. Rectus femorus activity increased in the under 80-degree groups but decreased in the over 80-degree group. The muscle activity of the biceps femoris muscle decreased after stretching in the over 80-degree group and increased in the under 80-degree group, and the semitendinosus muscle activity after stretching was decreased. The quadriceps-to-hamstring muscle (Q:H) ratio before and after stretching between groups showed that the hamstring muscle ratio decreased after stretching in both groups. Conclusions: The results of this study showed that the Q:H ratio before and after stretching between groups was not significantly different.

• Journal of the Korean Society of Physical Medicine
• /
• v.14 no.2
• /
• pp.137-144
• /
• 2019

PURPOSE: The continued use of smartphones has resulted in an abnormal body posture and neck alignment changes. Maintaining this posture for a long time weakens the flexor muscles in the neck and shortens the extensor muscles in the neck. This study examined the correlation between the suboccipital muscle tension and deep neck flexor muscle physical endurance according to the craniovertebral angles. METHODS: The craniovertebral angle, tension of the suboccipital muscle and endurance of the deep neck flexor muscle were measured in 58 healthy 20-year-old male and female college students. The tension of suboccipital muscle and endurance of the deep neck flexor muscle were then divided according to the body mass index (BMI). Their correlation with the craniovertebral angle was then examined. Each parameter was measured three times to determine the interrater reliability. RESULTS: The craniovertebral angle and suboccipital muscle tension showed differed significantly. On the other hand, the craniovertebral angle and deep neck flexor muscle physical endurance showed no significant differences. CONCLUSION: The results show that the craniovertebral angle and deep neck flexor muscle physical endurance were not correlated, but a smaller craniovertebral angle resulted in a higher suboccipital muscle tension.

• Journal of Preventive Medicine and Public Health
• /
• v.57 no.5
• /
• pp.443-450
• /
• 2024

Objectives: Lack of physical activity has a critical effect on the physical and mental health of adolescents. This study examined the influence of family adversities on the longitudinal changes in physical inactivity among adolescents during the coronavirus disease 2019 (COVID-19) pandemic. Methods: The study used multi-wave data from the Korean Children and Youth Panel Survey, including 2590 Korean adolescents aged 12-14 years. The longitudinal trajectory of physical inactivity among adolescents and the effects of related factors were estimated using a latent growth modeling method. Results: Our results revealed a significant increase in physical inactivity among adolescents over time. At the onset of the pandemic, approximately one-seventh of Korean middle schoolers reported a lack of physical activity. However, 3 years later, during the quarantine, nearly one-fifth of these adolescents reported a significant increase in their physical inactivity. Initially, low level parental education was predictive of adolescents' physical inactivity, but this effect diminished over time, becoming statistically insignificant by the end of the 3-year period. Moreover, the increase in physical inactivity over the 3 years was significantly influenced by parental rejection. Conclusions: These findings suggest that adolescents who experience parental rejection are more likely to report an increase in sedentary behaviors in contexts such as the COVID-19 pandemic.

• The Journal of Korean Physical Therapy
• /
• v.12 no.2
• /
• pp.121-132
• /
• 2000

This study was carried out to determine the influencing of electrical stimulation to cervicothoracic sympathetic ganglion(CTSG; stellate ganglion) u the sympathetic tone. For the purpose of this study. the stimulation was given to both the interferential current stimulation(ICS: AMF 100Hz) group consisting of 10 person(males 8, females 2) and the transcutaneous nerve electrical stimulation(TENS: 100 Hz) group of 10(males 7, females 3) in the right side of the trachea with probe electrodes. Then. the temperature changes on the surfaces of the forehead. cheek, neck and internal ear of cephalocervix, which is subject to the influence of the cervicothoracic sympathetic ganglion, and the palm. which is the end of the upper limbs. measured before. immediately alter. 10 minutes after and 20 minutes after experiment. The results are summarized as follows. 1. The emergence of remarkable Horner's symptoms which appear due to the changes of the tone of cervicothoracic sympathetic ganglion was not seen. However, in the interferential current stimulation group there were two felt the sense of warmth in the facial region and one person who felt it in the upper limbs, and in the transcutaneous nerve electrical stimulation group there was each one person who felt the sense of warmth in the facial region and in the upper limbs, respectively. Both groups have each one person who felt the sense of oppression in the eyelids. Three persons of the interferential current stimulation group and two persons of the transcutaneous nerve electrical stimulation group have the sense of hoarse voice or numbness in the neck. These are the symptoms that appeared during stimulation, so it is difficult for them to be considered as the direct effects of the changes of the tone of cervicothoracic sympathetic ganglion. 2. The t-test was performed to determine the significance between the right, which is the experimental side, and the left, which is the non-experimental side. Significance between the right, which is the experimental side, and the left, which is the non-experimental side. Significant changes were seen in the necks of the interferential current stimulation group and in the cheeks and internal ears of the transcutaneous nerve electrical stimulation immediately after experiment(P<.05). And the interferential current stimulation group showed a very high significance in the cheeks immediately after experiment and in the necks ten minutes after experiment(p<.01). Therefore, it could be seen that the electrical stimulation had an influencing on the changes of body temperature of the cephalocervix. 3. In both the interferential current stimulation group and the transcutaneous nerve electrical stimulation group, the forecheads, checks and necks of the cephalocervix in the experimental side(right) rather than the non-experimental side(left) had mostly a statistically significant rise in temperature immediately after experiment. The one-way ANOVA was carried out to determine the temperature change of on the surface of the body with the lapse of time; before, immediately after, ten minutes after and tewenty minutes after experiment. But no statistical significance was found from both the right and left sides.

• Physical Therapy Korea
• /
• v.18 no.3
• /
• pp.26-37
• /
• 2011

Although there have been various studies related to the body's movement from a sitting to a standing position (sit-to-stand task), there is limited information on the kinematic changes on the frontal and transverse planes. The purpose of this study was to ascertain how pelvic tilt affects kinematic changes in the frontal and transverse planes in the hip and knee joints during a sit-to-stand task. For this study, 33 healthy participants (13 female) were recruited. Each participant rose from a sitting to a standing posture at his or her preferred speed for each of three different pelvic tilt trials (anterior, posterior, and neutral), and the measured angles were analyzed using a 3-D motion analysis system. A one-way repeated measure analysis of variance was performed with Bonferroni's post hoc test. In addition, an independent t-test was carried out to determine the sex differences in hip and knee joint kinematic changes during the sit-to-stand tasks. The results were as follows: 1) The hip and knee joint angle in the frontal and transverse planes showed a significant difference between the different pelvic tilt postures during sitting in the pre-buttock lift-off phase (pre-LO) (p<.05). Compared to the posterior pelvic tilt posture, the anterior pelvic tilt posture involved significantly greater hip joint adduction and internal rotation, knee joint adduction, and reduced internal rotation of the knee joint. 2) Sex differences were found with significant differences for males in the initial and maximal angles in the frontal plane of the hip and knee joint (p<.05). Females had a significantly smaller initial abduction angle of the hip joint and a significantly greater maximal angle of the hip adduction joint. These results suggest that selecting a sit-to-stand exercise for pelvic tilt posture should be considered to control abnormal movement in the lower extremities.