• The Journal of Korean Physical Therapy
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• 제31권2호
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• pp.76-81
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• 2019

Purpose: This study examined the effects of squatting with different foot positions on the muscle activation of the vastus medialis oblique (VMO) and vastus lateralis (VL) muscles in subjects with genu varum. Methods: Thirty four subjects participated in this study. Surface electromyography was used to measure the muscle activation of the VMO and VL muscles at the knee angles ($15^{\circ}$, $60^{\circ}$) at three foot positions (internal rotation, neutral position, external rotation) during squatting. Results: Muscle activation differences at different knee angles and foot positions differed significantly between the VMO and VL muscles in both the varus and normal groups. In addition, there was a significant difference according to the knee angles with the foot in external rotation in the VMO and VL ratio. In the varus group, however, the VMO and VL ratio were significantly different only with the feet in internal rotation. In the muscle activation changes of the knee angle differences in the foot position, there was no significant difference in the varus group, but both the VMO and VL muscles were significant different in the normal group. Conclusion: In both groups, regardless of the foot position, muscle activation of the VMO and VL muscles increased with increasing knee flexion angle. In the normal group, when squatting with the feet in external rotation, the VMO and VL muscles activations increased with increasing knee angle. In the varus group, however, the foot position did not affect the VMO or VL muscle activation. This study shows that subjects with genu varum and normal subjects have different VMO and VL muscle activation patterns during squat exercises.

• The Journal of Korean Physical Therapy
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• 제23권5호
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• pp.1-5
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• 2011

Purpose: This study was designed to investigate the changes of postural sway and muscle activation while standing upright and performing a dual task. Methods: Nine healthy adults were recruited and provided their written informed consent. They performed a balance task with and without a cognitive task on a force flatform (Good balance, Metitur Ltd., Filand). Postural sway was measured as medio-lateral and anterior-posterior distance and the velocity of the center of pressure and muscle activations of the ankle dorsi- and plantar-muscle was measured. The recruits completed three trials and the data was analyzed by a paired t-test. Results: There were significant differences in the medio-lateral and anterior-posterior distance and the velocity of the center of pressure, and significant increases in the muscle activities of the tibialis anterior. Conclusion: These findings revealed that performing a dual task increases postural sway and muscle activation of the ankle when simultaneously maintaining balance and performing another cognitive task. Future studies should focus on balance training with a dual task for patients.

• 대한물리의학회지
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• 제7권3호
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• pp.275-282
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• 2012

Purpose : Bridge exercise has been commonly used in clinical rehabilitation settings to improve trunk control, and hip adductor muscles were a related muscle that may affect trunk muscle activation. The aim of this study was to investigate whether the co-contraction of hip adductor muscles may affect trunk muscle activation during bridge exercises. Methods : Thirty-eight healthy young subjects (19 men and 19 women) performed bridge exercises (with and without hip adduction movement). Surface electromyography (EMG) data were collected from the dominant-side internal oblique (IO), rectus abdominis (RA), multifidus (MF) and erect spine (ES) during bridge exercises to compare trunk muscles activation patterns. Result : The EMG activities of IO and RA appeared to be significantly higher during bridge exercise with hip adductor co-contraction than during bridge exercise alone (p<.01), but there were no significant differences in those of MF and ES. Furthermore, there were significant differences in the IO:RA EMG ratio during bridge exercise with hip adductor co-contraction (p<.05). Conclusion : These findings suggest that integration of hip adduction during bridge exercise may be beneficial in increasing deep muscles' activity for trunk stabilization.

• 대한물리치료과학회지
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• 제27권1호
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• pp.51-55
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• 2020

Background: A typical plank exercise (PE) strengthens the core muscles, stabilizes the spinal column, and provides stability around the pelvis and trunk when the trunk is aligned. However, because PE require that the hip joint be kept straight, they can activate the hamstring (HAM). Excessive HAM activation can induce tightness, which may cause low back pain. Therefore, it is necessary to explore PE methods that can minimize HAM activity while maximizing core muscle activity. Design: Cross-sectional study. Methods: This study included 30 healthy adults as subjects. We measured the activity of the HAM and the erector spinae (ES), rectus abdominis (RA), and external oblique (EO) muscles using surface electromyography during three PEs (typical PE, PE with balance pad, and PE with sling). Results: The RA, EO, and ES showed the highest muscular activity during PE with balance pad and the lowest during PE with sling; however, the differences were not significant. The HAM showed lower activity during PE with sling than during the other two PEs; however, these differences were also not significant. Conclusion: Although HAM activation was not significantly difference among PE positions, we should recognize altering activation of core and hamstring muscle according to PE postures.

• 대한물리치료과학회지
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• 제10권2호
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• pp.96-103
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• 2003

The purpose of this study was to assess the effect of applied pressure to abdomen on lumbar and abdominal muscle activation during upper limb exercise. The experimental group consisted of twenty-seven healthy male subjects (mean age=$22.40{\pm}2.19years$, mean height=$175.30{\pm}2.19cm$, mean weight= $67.67{\pm}7.44kg$, RM=$8.43{\pm}2.76kg$). In each different pressure condition (OmmHg, 30mmHg, 70mmHg, 100mmHg), upper limb exercise was performed in total of 10 trials with 10 RM dumb-bell exercise. Lumbar and abdominal muscle activity was measured using surface bipolar electrode electromyography(EMG). EMG activity was measured from upper rectus abdominis, external oblique abdominis, internal oblique abdominis, and elector spinae. The raw EMG signal was processed into the root mean square(RMS). All RMS EMG data were normalized and express as a percentage of the EMG(%EMG). Collected data were statistically analyzed by SPSS/PC Ver 10.0 using two-way analysis of variance for repeated measures($4{\pm}3$) and Bonferroni post hoc, test. Lumbar and abdominal muscle activation was significantly increased when 100 mmHg was applied(p<.05). Upper rectus abdominis activation was significantly increased compared as other muscles activation(p<.05). However, there were no interaction between pressure and muscles(p>.05). The findings of this study can be used as a fundamental data when lumbar orthosis is applied and external pressure can be used as a therapeutic tool.

• The Journal of Korean Physical Therapy
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• 제31권1호
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• pp.62-66
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• 2019

Purpose: This study examined the most efficient exercise position to activate the gluteus medius (GM) and tensor fascia latae (TFL) in hip abduction in side-lying (HA-SL), clam in side-lying (CL-SL), and sling bridging in side-lying (SB-SL), which are the most representative GM exercises. Methods: Twenty-four healthy male adults aged from 20 to 40 years, whose body mass index was under 25, participated in this experiment. While all participants conducted three different positions with a counterbalanced manner, such as in AB, CL, and BR, activation of the GM and TFL was measured using 8-channel wireless EMG. Exercise was performed for 10 seconds three times in total with a five minute-break session. Results: Significant differences in GM and TFL activation were observed among the three positions (p<0.05). The highest activation of 60.69 was observed in BR followed in order by 46.03 and 12.92 in HA-SL and CL, respectively. TFL activation in HA-SL was 42.01, followed in order by 35.98 and 14.01 in BR and CL, respectively. On the other hand, there was no significant difference in TFL muscle activation between BR and HA-SL. Conclusion: These findings suggest that both BR and HA-SL in GM can be done selectively. CL has remarkably low muscle activation in GM and TFL, which makes it less valuable in GM and TFL exercise. In conclusion, selective BR and HA-SL exercise should be applied to maximally and effectively activate the GM.

• The Journal of Korean Physical Therapy
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• 제35권6호
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• pp.167-176
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• 2023

Purpose: Due to the high incidence of shoulder injuries, including shoulder impingement syndrome (SIS), among CrossFit practitioners due to frequent overhead movements, serratus anterior exercises are considered crucial for scapular stabilization in both intervention and prevention. Objective: The objective of this study is to compare the muscle activity and ratios of scapular stabilizing and shoulder girdle muscles between individuals with and without SIS during serratus punch and wall slide exercises, both targeting the serratus anterior muscle, in CrossFit training practitioners. Methods: Surface electromyography was used to compare the muscle activity and activity ratio of scapular stabilizing muscles and shoulder muscles during serratus punch and wall slide exercises in two groups of 20 CrossFit practitioners: ten with SIS and ten without symptoms. Results: The group with SIS showed higher activation of the pectoralis major, upper trapezius, and a higher pectoralis major/serratus anterior and upper trapezius/serratus anterior muscle activation ratio during the serratus punch exercise compared to the group without SIS. Similarly, during the wall slide exercise, the group with SIS exhibited higher activation of the upper trapezius and a higher upper trapezius/serratus anterior muscle activation ratio compared to the group without SIS. However, no significant difference in serratus anterior muscle activation was observed between the two groups. Conclusions: This study highlights the higher activation of the pectoralis major and upper trapezius muscles in CrossFit practitioners with SIS during the serratus anterior exercise, suggesting the importance of minimizing the overactivation of these muscles to prevent impingement syndrome in this population.

• 대한물리의학회지
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• 제7권2호
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• pp.199-203
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• 2012

Purpose : Bridging exercise was used most frequently of lumbar stabilization exercise. There has been no reserch regarding the bridging exercise according to hip abductor activation or hip adductor activation. The purpose of this study is to determine correlation of hip abductor, adductor and abdominal muscles, lower limb muscle. Methods : Participants who met the criteria for this study (n=45). Participants performs bridging exercise on three types (normal bridging exercise, bridging exercise with hip abductor contraction, bridging exercise with hip adductor contraction) for evaluate correlation of each muscles. Results : There was a significant negative correlation between adductor magnus and gluteus medius, adductor magnus and rectus femoris. And there was a positive correlation between gluteus medius and rectus femoris on normal bridging exercise (p<0.05). There was a significant positive correlation between adductor magnus and gluteus medius, transverse abdominis, and between gulteus medius and transverse abdominis on bridging exercise with adductor magnus activation (p<0.05). There was a significant positive correlation between adductor magnus and gluteus medius, rectus femoris, and between gulteus medius and rectus femoris on bridging exercise with gluteus medius activation (p<0.05). Conclusion : When we perform bridging exercise for transverse abdominis activation and increase pressure in the abdmen, bridging exercise with hip adductor contraction is more effective than normal bridging exercise and bridging exercise with hip abductor contraction.

• The Journal of Korean Physical Therapy
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• 제15권1호
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• pp.26-37
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• 2003

This study was to investigate the effect of 10th weeks Exercise of Different Intensity on the activation of antioxidation enzyme and lipid peroxidation. 15 subjects were divided into the 65$\%$ running exercise(EG; 5), 85$\%$ running exercise(EG: 5), and the control(CG: 5) groups. The exercise group had 10 week of running exercise 4 times a week with ACSM(1995) protocol, 65$\%$ of HRmax from the beginning to 5th week, 85$\%$ of HRmax from 6th to 10th week. The subjects had 60 min exercise for each day. After extracting the blood sample, the activation of antioxidation enzyme and lipid peroxidation were compared between the groups. The one way ANOVA was conducted about pretest, 5th week, and 10th week of the subject data. The results obtained from this study were as follows; 1. The 65$\%$ exercise group showed the significantly greater increase in the activation of SOD after 10 weeks for the rest and all-out exercise. (p < .05). 2. The 65$\%$ exercise group displayed the significantly higher increase in the activation of CAT after 10th weeks for the rest exercise. (p < .05). 3. The 65$\%$ exercise group had the significantly greater decrease in the activation of MDA after 10 weeks for the all-out exercise. (p < .05).

• The Journal of Korean Physical Therapy
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• 제35권2호
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• pp.53-57
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• 2023

Purpose: The purpose of this study was to compare the changes in the muscle activation of the quadriceps muscle (rectus femoris, vastus lateralis, vastus medialis) during the stand-to-sit (StandTS) movement according to the plantar flexion angle of the ankle joint. Methods: A total of 22 healthy young females participated in this study. During the StandTS under the three conditions (plantarflexion angle 0°, 20°, and 45° of the ankle), electromyography (EMG) data (% maximum voluntary iso¬metric contraction) of the rectus femoris, vastus lateralis, and vastus medialis were recorded using a wireless surface EMG system. Results: There was a significant difference in the muscle activation of rectus femoris, vastus lateralis, and vastus medialis according to the plantar flexion angle (0°, 20°, and 45°) of the ankle. The muscle activation of the quadriceps was the highest at a 45° angle of plantarflexion and the lowest at 0°. One-way repeated ANOVA was used to analyze the muscle activation data of the lower extremity muscles according to the angle of the ankle joint. Conclusion: Based on the results of our study, it was confirmed that the muscle activity of the quadriceps can be increased even in the StandTS movement, which involves the eccentric contraction of the quadriceps muscle. This suggests that maintaining a plantar flexion posture for a long time, say by wearing high-heeled shoes, can quickly cause muscle fatigue in the lower-limb muscles, which can cause a decrease in balance ability leading to falls.