• The Research Journal of the Costume Culture
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• v.21 no.4
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• pp.606-611
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• 2013

It has been reported that tight sportswear could have complicated influence on physiological function of human body. The purpose of this present study was to investigate the effect of wearing gradient compression tights (GCT) on muscle strength and EMG activity during repeated isokinetic muscle contractions. Four healthy male undergraduate students performed maximal voluntary isokinetic concentric muscle contractions on biomechanical test and training systems with GCT and loose pants as control (Cont) respectively. During each test, the peak torque of extensor and flexor contractions and the surface electromyography (sEMG) of the rectus femoris and medial gastrocnemius was recorded simultaneously, the peak torque was recorded as an indicator of muscle strength, and the average amplitude and mean power frequency of sEMG were calculated as indicators of EMG activity. The results showed that: the peak torque decreased gradually during continuous muscle contractions both when the Cont and GCT were worn, average sEMG and mean power frequency declined along with the repetitions of muscle contractions for both wearing conditions, and the change tendency was consistence with that of peak torque. There was no obvious difference between the peak torque recorded wearing the Cont or wearing GCT, but when GCT were worn, average sEMG was lower and mean power frequency was higher than the Cont condition. In 24 samples obtained from four subjects, 80% of results showed the same trend. So we could make a conclusion that wearing GCT had no obvious effect on the improvement of muscle strength, but it would affect the EMG activity positivly.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.8 no.2
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• pp.7-12
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• 2010

Purpose : The purpose of this study was to determine the effects of hip adduction using a ball on the activation of the vastus medialis oblique (VMO) and the vastus lateralis (VL) during dynamic semisquat exercises. Methods : Twenty seven participants performed three repetitions of a double-leg semisquat and squeeze semisquat (semisquat with hip adduction using a ball) at $60^{\circ}$ knee flexion. The activation of the VMO and the VL was recorded at dominant leg during both semisquat exercises using surface electromyography (MP 100). EMG data were normalized to the maximal voluntary isometric contraction (MVIC) of the quadriceps produced during seated, isometric knee extension. Results : Results of paired t-test analyses revealed that there were no differences between activity of the VMO and the VL in both double-leg semisquat and squeeze semisquat. The activity of the VMO was significantly increased in squeeze semisquat whereas there was no difference in activity of the VL between double-leg semisquat and squeeze semisquat. Conclusion : Combining hip adduction using a ball with semisquat at $60^{\circ}$ knee flexion preferentially increases the activity of the VMO. We can conclude that semisquat at $60^{\circ}$ knee flexion with hip adduction using a ball selectively recruits the VMO. Rehabilitation for quadricep imbalance should consider these findings when selecting exercises which could preferentially activate the VMO.

• Physical Therapy Korea
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• v.15 no.2
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• pp.54-63
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• 2008

The purpose of this study was to examine the effect of the hip internal rotation on knee extensor and hip abductor electromyographic (EMG) activity during stair up and stair down mobility. Eighteen healthy subjects were recruited. All subjects performed stair up and down movements on a step of 30cm height while maintaining the hip in neutral (condition 1) and hip in internal rotation (condition 2). Surface EMG activity was recorded from five muscles (gluteus maximus, vastus lateralis (VL), vastus medialis oblique (VMO), posterior gluteus medius (Gmed), and tensor fascia latae (TFU)) and hip internal rotation angle was measured using a three dimensional motion analysis system The time period for stair up and down was normalized using the MatLab 6.5 program, and EMG activity was normalized to the value of maximal voluntary isometric contraction (%MVIC). The EMG activities according to the hip rotation (neutral or internal rotation) during the entire time period of stair up and down in each phase were compared using a paired t-test. During the entire period of stair up, the EMG activities of VL and TFL in condition 2 were significantly greater than in condition 1 (p<.05). During the entire period of stair down, the EMG activities of VL and TFL in condition 2 were significantly greater than in condition 1 (p<.05). However, the EMG activities of the other muscles were not significantly different between the conditions (p>.05). These results suggest that the stair up and down maintaining hip internal rotation was could be a contributing factor on patellar lateral tracking.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.4
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• pp.33-41
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• 2019

Purpose : The muscle strength of iliopsoas (IL) was measured commonly in sitting position with hip and knee flexed 90°. However, there is no study to determine the muscle strength of IL in various test positions. Therefore, the purpose of this study was to compare the muscle strength of IL and muscle activity of rectus femoris (RF) according to test position and knee flexion angle. Methods : Twenty healthy subjects were participated for this study. The muscle strength of IL and muscle activity of RF were measured by hand-held dynamometer and surface electromyography during maximum voluntary isometric contraction (MVIC) of IL, respectively. The muscle strength of IL and muscle activity of RF was measured in 4 conditions as follows; 1) knee flexion angles 90 ° in supine, 2) 130 ° in supine position, 3) 90 ° in sitting, 4) 130 ° in sitting. Each condition were performed randomly by three repetitions. Results : The muscle strength of the IL was the main effect on the test position and knee flexion angle (p<.05), and the muscle activity of RF was the main effect only on the knee flexion angle (p<.05). There was also no interaction between the factors (p>.05). In supine position, the muscle strength of IL in knee flexion 130 ° was significantly less than that in knee flexion 90 ° (p<.0125). In knee flexion 90 °, the muscle strength of IL in supine position was significantly greater than that in sitting position (p<.0125). The muscle activity of RF in knee flexion 130 ° was significantly less than that in knee flexion 90 ° in supine and sitting positions (p<.0125). Conclusion : When the muscle strength of IL was measured in clinic and sports fields, the supine position with knee flexion 130 ° was recommended to prevent the muscle activation of RF and to maintain the trunk stability.

• Physical Therapy Korea
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• v.23 no.2
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• pp.75-83
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• 2016

Background: Several studies have discussed diverse exercise methods considered to be useful for the selective contraction of the vastus medialis oblique (VMO) muscle for the treatment of patellofemoral pain syndrome. Some studies have reported that exercise methods, including hip adduction, in closed kinetic chain exercises are more effective in terms of the muscle activation of the VMO and the timing of the muscle's initial contraction. We focused on isometric contraction during a closed kinetic chain exercise with hip adduction. Objects: The purpose of this study was to examine muscle activation in the VMO and the vastus lateralis (VL) and the onset time difference between their initial contractions via closed kinetic chain isometric quadriceps femoris exercises including hip adduction. Methods: In total, 36 healthy subjects adopted two hip positions during isometric contraction of the quadriceps femoris in a closed kinetic chain exercise (hip neutral and hip adduction position). Statistical analyses were conducted using a paired t-test (${\alpha}=.05$). Results: Isometric contraction of the quadriceps femoris in a closed kinetic chain exercise caused a greater increase in VMO muscle activity in the hip adduction position [$52.68{\pm}22.21$ percentage of maximal voluntary isometric contraction (%MVIC)]than the hip neutral position ($43.43{\pm}19.85%MVIC$). The onset time difference (VL-VMO) decreased more in the hip adduction position ($-82.14{\pm}34.2ms$) than the hip neutral position ($73.94{\pm}2.94ms$). Conclusion: We recommend this exercise as a clinically useful therapeutic method for patients with patellofemoral pain syndrome due to weakening of the VMO muscle and lateral inclination of the patella.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2632-2640
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• 2012

The purpose of this study was to investigate whether medial gastrocnemius ultrasound imaging of the Delayed Onset Muscle Soreness (DOMS) has the possibilities as a measurement method. This study was conducted from April 21th 2011 to April 30th 2011. Thirty-five healthy subjects were included based on the absence of regular physical activity, and no history of recent trauma, musculoskeletal pathology, cardiovascular disease or drug intake. All subjects induced DOMS through climbing for 5 hours and we measured the visual analogue scale (VAS), creatine kinase (CK) and maximal voluntary isometric contraction (MVlC) of ankle plantar flexor prior to DOMS and at 24, 48 and 72 hours post DOMS and these measurements were compared with pennation angle of medial gastrocnemius measured by ultrasound imaging. Results of this study were as following. VAS, CK, and MVIC of ankle plantar flexor were found significant difference related measurement period (p<0.05) and pennation angle of medial gastrocnemius were found significant difference related measurement period (p<0.05). Furthermore, we confirmed that the flow of change between variables related measurment period was consistent. Through this study, we think that measuring the changes in pennation angle of medial gastrocnemius over time using ultrasound imaging will be able to be used as a new method measuring DOMS.

• Physical Therapy Rehabilitation Science
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• v.5 no.2
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• pp.95-100
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• 2016

Objective: The purpose of this study was to investigate effects of hand grip strength on the muscle activation of shoulder joint in breast cancer patients. Design: Cross-sectional study. Methods: Ten breast cancer patients who agreed to active participation were included. These patients were operated with either conservative surgery or segmental mastectomy, and then were treated with radiation therapy and chemotherapy. The activity of the upper trapezius, lower trapezius, supraspinatus and serratus anterior muscle were measured using surface electrodes during 4 hand gripping tasks (lowered their arms in standing position, 0%, 30%, and 50% of maximum voluntary contraction) in the scapular abduction plane. Results: The results were analyzed using a one-way repeated measures ANOVA. There was a significant difference in the lower trapezius and supraspinatus muscles according to grip strength, lower trapezius and supraspinatus muscles showed significantly difference according to grip strength (p<0.05). The result of the muscle activation according to hand strength (0%, 30%, and 50%) it showed a significant difference between the upper trapezius and supraspinatus in 0% grip strength (p<0.05). In addition, it did not show a significant difference between muscles in 30%, 50% hand strength. Conclusions: This study showed an increase in shoulder muscle activation with increasing hand grip strength with the upper trapezius muscle being more activated than other muscles in 0% grip strength. The finding of this study suggests usefulness for development of preventative measures and rehabilitation strategies for increasing shoulder motor function in patients with breast cancer.

• Journal of International Academy of Physical Therapy Research
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• v.5 no.2
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• pp.757-763
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• 2014

The purpose of this study is to observe the effect of elasticity of taping on ankle muscles'activity and endurance after plyometric training that easily causes ankle injury, and provide baseline data for physical therapy intervention methods. The study subjects are 24 male students in their 20s who attend N University in Choongnam. They were divided into three groups; 8 subjects in the elastic taping group, 8 in the non-elastic taping group, and 8 in the non-taping group(control group). They had plyometric training for 6 weeks. After the training, this study measured their maximum voluntary isometric contraction(MVIC) and muscle endurance of the muscles around ankle joint. The experiment result is as follows. After the training, all three groups showed improvement in muscle strength and endurance. The elastic taping group showed insignificant improvement in muscle strength but significant increase in muscle endurance in plantarflexion. In dorsiflexion, both muscle strength and endurance increased significantly. The non-elastic taping group showed insignificant improvement in muscle strength but significant increase in muscle endurance in plantarflexion. Taping during plyometric training had a little or insignificant effect on muscle endurance and strength compared to the non-taping group.

• The Journal of Korean Physical Therapy
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• v.23 no.4
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• pp.37-44
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• 2011

Purpose: The aim of this study was to investigate the effects of an exercise program using a virtual reality game and a gait exercise program using a treadmill on % maximum voluntary isometric contraction (%MVIC) and static and dynamic balancing capabilities. Methods: A total of 26 elderly women were included in the study. 13 women were assigned to an exercise program using a virtual reality game, and 13 to a gait exercise program using a treadmill. The subjects performed the exercise for 40 min per session, three sessions per week, for eight weeks. Results: The %MVIC of the vastus medialis was significantly increased from $28.91{\pm}2.03%$ to $32.98{\pm}2.6%$ in the virtual reality game exercise group (p<0.00). The %MVIC of the vastus lateralis was significantly increased from $27.17{\pm}1.93%$ to $31.50{\pm}2.18%$ (p<0.00) in the gait exercise program group. The whole path length with both feet on the floor and eyes open was significantly decreased from $1570.92{\pm}820.6mm$ to $1343.62{\pm}242.41mm$ (p<0.00). The whole path length with both feet on the floor and eyes closed was significantly decreased from $1819.85{\pm}361.14mm$ to $1581.05{\pm}285.11mm$ (p<0.00). The length of a functional reach was significantly increased from $25.2{\pm}4.23cm$ to $27.68{\pm}4.04cm$ (p<0.00). Conclusion: The exercise program using a virtual reality game is effective for improving the %MVIC and static and dynamic balancing capabilities in elderly women aged 65 years and more.

• The Journal of Korean Physical Therapy
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• v.36 no.2
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• pp.71-77
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• 2024

Purpose: The prolonged use of digital devices has led to the widespread adoption of poor postures, particularly rounded shoulder posture (RSP), associated with shoulder impingement and pain. This study investigates the effects of neuromuscular electrical stimulation (NMES) on RSP in healthy adults. Methods: Thirty adults with RSP were randomly assigned to NMES only, exercise only, or NMES with exercise groups. NMES was applied to the lower trapezius, which was the target muscle in this study, for a total of 2 weeks, 5 times per week, 20 minutes per session. The exercise program included pectoralis minor stretching, wall-slide exercise, dynamic hug exercise with band, and Brugger stretching for upper body with band, which were performed for a total of 2 weeks, 5 times per week, 20 minutes per session. Outcome measures, including the Supine Method (SM) for posture and surface electromyography (EMG) of the lower trapezius for muscle activity, were assessed before the intervention, after 5 sessions, and after 10 sessions. Results: All the groups showed significant changes in the SM and % maximal voluntary isometric contraction (%MVIC) over time (p<0.05). The NMES group had significantly reduced SM at 1 week, while the exercise and combined groups had reduced SM at 2 weeks (p<0.017). All the groups had increased %MVIC at 2 weeks (p<0.017), with no significant differences observed between groups. Conclusion: NMES alone can be as effective as exercise in improving RSP. NMES combined with exercise also showed positive outcomes, thus offering diverse treatment options for this condition.