• 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 Korean Society of Physical Medicine
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• v.12 no.4
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• pp.123-132
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• 2017

PURPOSE: This study aimed to examine the effects of lumbar stabilization exercise during abdominal hollowing with conscious contraction of the pelvic floor muscles on trunk muscle in healthy twenties subjects. METHODS: The participants were randomly allocated to an experimental group (n=15) and a control group (n=15). The experimental group received lumbar stabilization exercise combined with conscious contraction of the pelvic floor muscles during abdominal hollowing. The control group received lumbar stabilization exercise with abdominal hollowing. Both groups trained with the respective exercise for 30 minutes a day, 3 times a week for 6 weeks. Muscle activation of the external oblique and erector spinae muscles, thickness of the transversus abdominis and multifidus, and contraction holding time of tranversus abdominis were measured before and after exercise. RESULTS: Activations of both the external oblique muscles were significantly decreased, and thickness of both the transversus abdominis and multifidus muscles, and contraction holding time of the transversus abdominis muscle were significantly increased in the experimental group (p<.05). The thickness of the left transversus abdominis and right multifidus muscles, and the contraction holding time of the transversus abdominis muscle significantly increased in the control group (p<.05). On comparing both groups, the activations of both external oblique muscles were significantly reduced and the contraction holding time of the transversus abdominis muscle was significantly increased in the experimental group (p<.05). CONCLUSION: These results suggest that lumbar stabilization exercise by abdominal hollowing and conscious contraction of the pelvic floor muscles is suitable and efficient for healthy twenties subjects.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.2
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• pp.33-41
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• 2018

PURPOSE: Femur and tibia alignment in the knee joint is important to the biomechanics of lower limb movement. The purpose of this study was to compare vastus medialis oblique (VMO) and vastus lateralis electromyographic muscle activities according to tibial rotation taping methods. METHODS: Twenty-nine healthy subjects (13 males and 16 females) in the 20s, without knee joint-related diseases or disorders, participated in our study. After identifying each subject's dominant foot, the maximal voluntary isometric contraction (MVIC) was determined using a manual muscle tester. The activity of each target muscle was measured at 50% MVIC in isometric muscle contraction and at a $30^{\circ}$ knee flexion position before and after applying internal and external rotation taping by the Mulligan concept and in the neutral position. Non-elastic tape was used to stabilize the tibia rotation position. RESULTS: In the males, VMO muscle activity was significantly increased in the tibia internal rotation position ($47.2{\pm}14.6$, $mean{\pm}SD$) than in the neutral position ($39.3{\pm}14.9$) (p<.05). CONCLUSION: The results of this study indicate that when applying tibia internal rotation taping in healthy males, VMO muscle activity significantly increases during isometric extension of the knee. Therefore, this study provides a basis for selecting the appropriate taping method, in consideration of the available treatments in clinical practice for patients with knee problems.

• Physical Therapy Rehabilitation Science
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• v.9 no.1
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• pp.18-24
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• 2020

Objective: The purpose of this study was to compare the activities of the abdominal muscles according to trunk stabilization exercises using Swiss ball in normal individuals. Design: Cross-sectional study. Methods: Ten healthy university students participated in this study. The subjects were required to complete the following three exercise positions: Exercise position 1, sitting on a Swiss ball and lifting the legs; Exercise position 2, pushing to a plank position from an ending position; and Exercise position 3, push-up posture with the legs on a Swiss ball. Changes in the trunk muscle activities were estimated using Biometric electromyography (EMG). Activities of the dominant side internal oblique muscle (IOM) and external oblique muscle (EOM) were estimated in all participants. The maximal voluntary isometric contraction (MVIC %) was measured to standardize the EMG signals for the IOM and EOM during maximum resistance when sitting up with each shoulder pointing towards the contralateral pelvis with knees bent and both arms crossed on the chest for 5 seconds. Results: There was a significant difference in the activity of the internal and external oblique muscles between Exercises 1 and 2 and Exercises 1 and 3 (p<0.05). Furthermore, the IOM/EOM activity ratio was the greatest during Exercise 3 and the smallest during Exercise 1. IOM and EOM activities were the greatest during Exercise 2 with greater EOM activity. Conclusions: In future studies, it will be necessary to investigate muscle activities by supplementing the above-mentioned limitations during the stabilization exercise. The results of this study may be used as a basis for controlling the intensity and frequency of exercise while prescribing trunk stabilization exercises.

• Physical Therapy Rehabilitation Science
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• v.7 no.2
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• pp.72-77
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• 2018

Objective: This study aimed to compare the effects of core exercise methods on muscle activation and muscle thickness in healthy young adults and to propose effective core exercise methods. Design: Three-group pretest-posttest design. Methods: A total of 30 healthy young adults (14 males, 16 females) voluntarily participated in the study. Subjects were randomized to the prone plank exercise (n=10), reverse plank exercise (n=10), or bridge exercise (n=10) groups. Muscle activity and thickness of the rectus abdominis (RA), multifidus (MF), external oblique (EO), and internal oblique (IO) muscles were measured using surface electromyography and ultrasound. Subjects from each group participated in the exercises five times a week, with five 20-second sets during week 1. The set time was increased by 10 seconds per week. Results: Muscle activity and thickness in the prone plank, reverse plank, and bridge exercise group were statistically significant different for RA, MF, EO, and IO changes over time, and interaction between time and groups were also significantly different (p<0.05). We analyzed statistically significant differences between groups using a one-way analysis of variance for each period. A significant difference was observed after 4 weeks of exercise (p<0.05). Conclusions: The results suggest that the prone plank exercise is a beneficial method for enhancing muscle activation and thickness of the RA, EO, and IO compared to the reverse plank and bridge exercises. On the other hand, the reverse plank and bridge exercises are effective methods for enhancing the MF compared to the prone plank exercise.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.2
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• pp.49-56
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• 2020

PURPOSE: This study examined the difference in muscle activity of the trunk and legs during flat walking with or without an abdominal drawing-in maneuver. METHODS: This study was conducted on 15 healthy males and eight females who were attending D University in Busan. This experiment was conducted after 15 minutes of abdominal drawing-in training using a pressure biofeedback unit before the experiment, and the difference in the muscle activity of the trunk and legs during flat walking with or without an abdominal drawing-in technique was investigated. Surface electromyography was used, and the electrode attachment site was the right sternocleidomastoid muscle, splenius capitis muscle, rectus abdominis muscle, external abdominal oblique muscle, transverse abdominis muscle, erector spinae muscle, vastus medialis muscle, and vastus lateralis muscle (TM DTS, Noraxon, USA). The data were analyzed statistically using a paired t-test on SPSS version 18.0 (IBM). RESULTS: The muscle activity of the rectus abdominis muscle, external abdominal oblique muscle, transverse abdominis muscle, vastus medialis muscle were increased significantly and maintained more than walking without maintaining an abdominal drawing-in maneuver (p < .05). Moreover, muscle activity of the erector spinae muscle was decreased significantly and maintained more than walking without maintaining an abdominal drawing-in maneuver (p < .05). CONCLUSION: Maintaining an abdominal drawing-in maneuver during flat walking is more effective during walking training.

• The Journal of Korean Physical Therapy
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• v.29 no.2
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• pp.80-84
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• 2017

Purpose: This study was conducted to examine the effects of different sizes of blood flow restriction areas on the thickness of the external oblique and biceps brachii. Methods: The study subjects were 52 adults who were divided into four groups that performed plank exercises over a six-week period after blood flow restriction. Changes in the thickness of the external oblique and biceps brachii were measured using ultrasonography before the experiment, then three and six weeks after the experiment. The changes in each variable over time were evaluated by repeated-measures analysis of variance (ANOVA). Results: The external oblique and biceps brachii showed significant differences in muscle thickness with regard to time and the interaction between time and each group (p<0.01), but no significant differences with regards to changes between groups (p>0.05). Conclusion: A larger blood flow restriction area resulted in a statistically significant increase in muscle thickness. The results of this study may be used as the basis for future studies and for rehabilitation in clinical practice.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.20 no.1
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• pp.39-45
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• 2014

Background: The purpose of this study is to identify effects of neuro-muscular control training on vastus medialis oblique (VMO) after menisectomy of the knee. Methods: The subjects of this study are women aged 42 and 39 each who did menisectomy. Case 1 was applied quadriceps setting exercise and neuro-muscular contrlol training and case 2 was applied quadriecps setting. Intervention was done 5 times a week for 2 weeks. Measurement of muscle activity on VMO and vastus lateralis (VL) was standardized signals of each muscle to %RVC using surface EMG. Results: On comparison of exercise before and after on VMO and VL, VL activation of case 2 was increased more than case 1. Conclusion: Quadriecps-setting exercise and selective neuro-muscular control training of VMO is effective intervention on VMO activity and muscle activity ratio of VMO to VL.

• Journal of muscle and joint health
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• v.18 no.2
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• pp.249-256
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• 2011

Purpose: The purpose of this study was to investigate electromyographic(EMG) activity of vastus medialis oblique(VMO) and vastus lateralis(VL) following the application of patellar taping during stair stepping. Methods: Both VMO-VL onset timing and VMO/VL ratio of 15 participants with patellofemoral pain syndrome (PFPS) were measured using an surface EMG uint(Myosystem 1400A, Noraxon Inc., USA). The measurements were taken under three conditions in random order of patellar taping, placebo taping, and no-taping. Data were analysed using $1{\times}3$ repeated measures ANOVA. Results: There was a significant difference with patellar taping on VMO/VL amplitude compared with the placebo taping and no-taping conditions during stair stepping, but no significant difference on VMO-VL onset timing. Conclusion: These result indicate that patellar taping on the vastus medialis oblique has effect on the VMO/VL ratio. Increased values of VMO/VL ratio may contribute to patellar realignment and explain the mechanism of pain reduction following patellar taping in participants with PFPS.

• Journal of muscle and joint health
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• v.17 no.2
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• pp.142-150
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• 2010

Purpose: The purpose of this study was to examine EMG activities and VMO/VL ratio of the vastus medialis oblique, vastus lateralis, and rectus femoris during squat exercise (knee angle: 15, 45, and 60 degrees; tibial rotation: internal rotation, neutral, and external rotation). Methods: Twelve subjects performed squat exercise at each knee angle and tibial rotation while electromyographic (EMG) activity was collected. Statistical analysis consisted of two-way repeated measures analysis of variance with post hoc analysis. Results: There were significant main effects of knee angles and foot positions and interaction effect on EMG activities of vastus medialis oblique and vastus lateralis. VMO/VL ratios were significantly different by tibial rotations and there was an interaction effect. A neutral position produced significantly more VMO/VL activity ratio than that from internally rotated position and externally rotated position at 60 degrees. Conclusion: Considering the interaction effects for EMG activity across quadriceps muscles tested, the 60 degrees knee angle with a neutral foot position may provide the most effective condition for patients with acute patellofemoral syndrome.