• The Journal of Korean Physical Therapy
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• v.34 no.4
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• pp.175-180
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• 2022

Purpose: Leg length discrepancy causes the posture deformation, gait asymmetry, and lower back pain. The purpose of this study is to investigate the correlation among functional leg length discrepancy (FLLD), muscle activity, muscle contraction onset time and vertical ground reaction force (vGRF) during simple lifting task. Methods: Thirty-nine subjects participated in this study. FLLD was measured from the umbilicus to medial malleolus of left and right leg using a tape. The subjects performed to lift a 10 kg box from the floor to chest. The muscle activity and muscle contraction onset time of rectus abdominis, erector spinae and rectus femoris was measured using EMG system and vGRF was measured by two force plate. Pearson correlation was used to fine out the correlation among FDDL, muscle activity, muscle contraction onset time and vGRF during simple lifting task. Results: Correlation between FLLD and difference of muscle activity of short-long side was very high (r>0.9) during simple lifting task. Correlation between FLLD and difference of muscle contraction onset time of short-long side was very high (r>0.9) during simple lifting task. And correlation between FLLD and difference of vGRF of short-long side was high (r>0.7) during simple lifting task. Conclusion: This study suggests that there is high correlation between FLLD and muscle activity, muscle contraction onset time, and ground reaction force during simple lifting task. Therefore, FLLD could negatively affect the postural balance.

• Journal of Korean Physical Therapy Science
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• v.27 no.1
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• pp.34-42
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• 2020

Background: The purpose of this study was to investigate the effects of ipsilateral and contralateral load changes during single-leg standing on the leg muscle activities of healthy people. Design: Randomized controlled trial. Methods: For all the subjects, a load was randomly applied to the ipsilateral or the contralateral side. While the load was applied, the subject raised a hand and then performed single-leg standing for 10 seconds using the dominant side. Results: During single-leg standing, the muscle activity of the gluteus medius, peroneus longus on the supporting side increased statistically significantly when an upper limb load was applied contralaterally, but no statistically significant differences were detected in the muscle activities of the tibialis anterior and the gastrocnemius using a test of within-subjects effects. Conclusion: It can be seen that muscle activities increase during exercise when the amount and frequency of a load are increased and when the same load is applied to different sides of the body. Such muscle activity increases may be applied to change the intensity of exercise when one is in a static posture, such as during single-leg standing.

• 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.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.3
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• pp.249-253
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• 2014

PURPOSE: This study intends to examine the effects of change of anatomical position of the ankle joint in open kinematic chain, an appropriate position for selective muscle training, on vastus lateralis obliques, rectus femoris, vastus medilais obliques, and rectus abdominalis muscle activation and to present an effective method of muscle training for patients and normal people. METHODS: The participants of this study were Korean healthy adult in their 20s. The 8 channel surface electromyography was used to measure muscle activation while the subjects raised their legs under each condition. Under each condition, while the subjects raised the leg to hip joint flexion at $60^{\circ}$ along the arch. RESULTS: The analysis result of muscle activation by each section and position during leg rising. There were significant differences. CONCLUSION: For independent strengthening of each muscle, muscle activation was measured according to leg raising angles and the result differed according to each section and position. If this study result is applied to muscle training for patients who need selective muscle training, more effective muscle strengthening will be made possible.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.4
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• pp.533-538
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• 2013

PURPOSE: This study was performed to investigate the effect of Low-dye Taping on muscle activity during single-leg standing in subjects with flexible flatfoot. METHODS: Thirteen able-body volunteers who had flexible flatfoot were recruited for this study. Subjects were measured navicular drop test to evaluate pronation of foot and muscle activity during single-leg standing before and after taping. The muscle activity was recorded using surface EMG from the tibialis anterior and the peroneus longus during single-leg standing on stable and unstable surface. RESULTS: The results show that the navicular drop height and the tibialis anterior muscle activity were significantly decreased after Low-dye taping. CONCLUSION: The results suggest that Low-dye taping could be useful in managing overuse of the tibialis anterior by reducing their level of activation during single-leg standing.

• The Journal of Korean Physical Therapy
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• v.29 no.2
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• pp.91-94
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• 2017

Purpose: This study investigated the effects of trunk muscle activity with power grasping during one leg stance. Methods: Twenty-eight subjects participated in this study. Subjects were divided into two groups, one that performed power grasping, and another that did not. An investigator measured the activities of a subject's trunk muscle such as internal oblique (IO), external oblique (EO), erector spinae (ES), and gluteus medius (GM) while a subject was doing one leg stance. Results: An independent t-test was used to analyze trunk muscle activities with power grasping during one leg stance between the experimental group and the control group. Only the EO activity differed significantly between groups (p<0.05). Conclusion: The results indicate that one leg stance with power grasping affected trunk muscle activity. Therefore, this is a useful method for providing lumbar spine stability.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.3
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• pp.67-71
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• 2017

PURPOSE: Muscle fatigue is a cause to change proprioception. The purpose of this study was to investigate the effects of calf muscle fatigue and visual control on postural balance during single-legged standing in healthy adults. METHODS: Nineteen healthy adults (male) were participated in this study (mean age: 24.36 years; mean height: 171.32 cm; mean weight: 64.58 kg). The postural balance (sway length, sway area, sway velocity of COG displacement) was measured by Balance Trainer System (BT4) in before and after calf muscle fatigue feeling in single legged stance. In this study, repetitive single-legged heel rise test was used to induce fatigue of the calf muscle. Paired t- test was used to compare the postural balance between before and after calf muscle fatigue. Data of subjects were analyzed using SPSS 22.0 (SPSS Inc., Chicago, IL, USA). Level of significance was set to .05. RESULTS: The sway length, sway area, sway velocity of COG (center of gravity) displacement after calf muscle fatigue feeling was significantly increased compared to before calf muscle fatigue feeling during single leg standing both eye open and close conditions (p<.05). CONCLUSION: This study suggested that calf muscle fatigue feeling has affected on postural balance when standing one leg both eye open and close conditions and postural control was disturbed by muscle fatigue and visual feedback in single leg standing.

• Korean Journal of Applied Biomechanics
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• v.31 no.2
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• pp.104-112
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• 2021

Objective: This study aimed to analyze the effects of consecutive whole body vibration through heel raise posture on the center of pressure and electromyography of anterior tibial muscle, lateral gastrocnemius and soleus muscles during single-leg stance. Method: The subjects of this study included 30 healthy males in their 20's, with the following inclusion criteria: no history of orthopaedic medical history, no participation in regular exercises, no history of whole body vibration exercise, and right leg being the dominant leg. The experimental procedure involved pretreatment measurement of eye open single-leg stance, application of whole body vibration for 30 seconds, post-treatment measurement (3 measurements in total). Static and dynamic movements have been measured over 2 separate experiments, with 72 hours gap between the experiments. Static movement involved maintaining single-leg heel raise posture for 30 seconds while applying whole body vibration, and dynamic movement involved heel raise (15 repetitions over 30 seconds) while applying whole body vibration. The strength of applied whole body vibration was 35 Hz frequency and 2~4 mm amplitude. Results: As the single-leg posture after static heel raise posture, mediolateral velocity of the center of pressure at post 2 and post 3 were significantly reduced compared to the pre-treatment measurement. In addition, the percentage for reference voluntary contraction in anterior tibial muscle and soleus and median frequency at anterior tibial muscle and lateral gastrocnemius muscle at post 3 were significantly decreased compared to the pre-treatment value. As the single-leg posture after dynamic heel raise posture, the mediolateral 95% edge frequency of the center of pressure and median frequency at anterior tibial muscle, lateral gastrocnemius muscle, and soleus muscle at post 3 were significantly reduced compared to the pre-treatment value. Conclusion: Acute whole body vibration via static and dynamic heel raise posture have positive effect on mediolateral posture control during single-leg stance.

• Journal of the East Asian Society of Dietary Life
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• v.16 no.4
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• pp.453-457
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• 2006

This study investigated the extractability, solubility, Mg$^{2+}$-, Ca$^{2+}$- and EDTA-ATPase activity of actomyosin prepared from leg and breast muscle of dog meat. The actomyosin extractability of breast muscle(2,100.6 mg/l00 g) was higher than that of leg muscle(500.8 mg/l00 g). The Mg$^{2+}$-ATPase activity of actomyosin had a high ionic strength of 0.02$\sim$0.05 M KCI and did not differ between leg and breast muscle. The Ca$^{2+}$-ATPase activity of actomyosin had a high ionic strength of 0.02$\sim$0.10 M KCI and leg muscle had a higher level of Ca$^{2+}$-ATPase activity than breast muscle did. The EDTA-ATPase activity was lower in low ionic strength and showed higher in high ionic strength, and increased sharply with increasing ionic strength up to 0.3 M KCI. The solubility of actomyosin did not differ between leg and breast muscle, and the solubility started and ended at KCI concentrations of 0.35 M and 0.4 M, respectively.

• PNF and Movement
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• v.15 no.2
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• pp.177-183
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• 2017

Purpose: This study compared and analyzed the effect of the proprioceptive neuromuscular facilitation (PNF) arm extension pattern and leg flexion pattern on the contralateral lower extremity muscles when the patterns were applied to the same subject. Methods: In the study, 35 healthy men and women who understood the PNF patterns were selected as participants. The participants completed the PNF arm extension-abduction-internal rotation pattern and leg flexion-adduction-external rotation with knee flexion pattern in the supine position. While the patients' completed each pattern, the contralateral leg muscle activity was measured to examine the irradiation effect. The maximum isometric contraction time of the muscles to be measured was kept for 5 seconds, and the mean value was obtained by repeating the pattern three times. Results: When the leg flexion-adduction-external rotation with knee flexion pattern was completed, the muscle activity in the vastus lateralis, vastus medialis, biceps femoris, tibialis anterior, and gastrocnemius of the contralateral lower extremity was significantly greater than that found in the PNF arm extension-abduction-internal rotation pattern. Conclusion: The PNF leg flexion pattern showed greater muscle activity on the contralateral lower extremity than the arm extension pattern. Thus, the PNF leg extension pattern is more effective in the activation of the muscles associated with weight-bearing activity.