• Journal of Korean Physical Therapy Science
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• v.25 no.2
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• pp.55-61
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• 2018

Purpose: This study is to compare muscle activation of leg muscles with forward and backward gait and treadmill speed. Method: The experimenter is a healthy ten male and female. They practice walking on the treadmill for 2 minutes and then walk 2km/h and 4km/h in front and back for 3 minutes. Muscle activities were recorded from the lower limb muscles (rectus femoris [RF], biceps femoris [BF], gastrucnemius [GCM]). Results: According to the study, lower extremity muscles have higher backward gait than forward gait. Conclusion: Muscle activity at the speed indicated that the muscular activity of the lower limbs was 4.0km/h, which is higher than 2.0km/h.

• The Journal of Korean Physical Therapy
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• v.34 no.5
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• pp.267-271
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• 2022

Purpose: This study examined the effects of a kettlebell and aqua bag on the gluteus maximus, gluteus medius, and vastus medialis lower extremity muscle strength during a one-leg deadlift, a top-down exercise. Methods: Twenty healthy adults were enrolled in the one-leg deadlift exercise under two conditions. The muscle activity of the gluteus maximus, gluteus medius, and vastus medialis was measured by surface electromyography (S-EMG). A paired t-test was used for statistical analysis, and the statistical significance criteria were set to p<0.05. Results: A comparison of the muscle activity according to the degree of contraction of the gluteus maximus revealed low muscle activity in AD exercise compared to KD exercise (p<0.05), and there was no significant difference in the gluteus medius and vastus medialis (p<0.05). Conclusion: These results suggest that when the one-leg deadlift exercise is performed according to the weight characteristics, the gluteus maximus is suitable for intervention using a kettlebell, and the gluteus medius and vastus medialis are more suitable for intervention by providing instability using an aqua bag.

• Korean Journal of Applied Biomechanics
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• v.18 no.1
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• pp.63-72
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• 2008

The purpose of this study was to compare and analyze the effects of exercise types on lower extremity muscle activity in stroke patients. For the purpose, the subjects of this study were classified into three groups such as therapeutic exercise group(n=7), elastic band group(n=7), and stretch reflex group(n=7). The three exercise programs were 5 times a week for 8 weeks. The stretch reflex group revealed higher in iliopsoas and biceps femoris %MVIC than the therapeutic exercise group and elastic band group, whereas elastic band group revealed lower in tibialis anterior %MVIC than therapeutic exercise group in the primary single-limb support. The stretch reflex group revealed higher in iliopsoas %MVIC than the therapeutic exercise group and elastic band group, whereas stretch reflex group revealed lower in medial gastrocnemius %MVIC than therapeutic exercise group in the secondary double support phase.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4459-4466
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• 2011

The purpose of this study was to compare the lower extremity muscle activities according to the different longitudinal arch and treadmill inclination and to provide basic data on treadmill walking exercise. The selected 17 subjects who had not lower extremity injury and ROM limitation were recruited in this study. The longitudinal arch was divided into normal foot and flat foot. The inclinations of the treadmill were $0^{\circ}$, up hill $5^{\circ}$, $10^{\circ}$, $15^{\circ}$, down hill $5^{\circ}$, $10^{\circ}$ and $15^{\circ}$. The electromyography was used to analyze the muscle activity of rectus femoris, biceps femoris, tibialis anterior, gastrocnemius lateralis and medialis. There were significant differences between the inclination $0^{\circ}$ and down hill $15^{\circ}$. There was no interactive effect of treadmill inclination on the longitudinal arch. The activity difference of lower extremity muscle was not conspicious. There existed the interactive effect between the longitudinal arch and muscle activity. The contrast test within subjects showed positively in the rectus femoris and gastrocnemius medialis, biceps femoris and gastrocnemius medialis. The different longitudinal arch did not influence on the effect(p>.05). There was significant difference between the normal foot and the flat foot. So it is necessary to carry out the long term study.

• Physical Therapy Rehabilitation Science
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• v.8 no.2
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• pp.61-66
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• 2019

Objective: The purpose of this study was to investigate the effects of resistance applied in various directions on lower extremity muscle activity and balance during squat exercise performance. Design: Cross-sectional study. Methods: Forty-one adults (19 males and 22 females) agreed to the study purpose and procedures. All subjects randomly performed squat exercises with an intensity of overcoming 10% of body weight resistance pulled forward, backward and general squats with $60^{\circ}$ of knee joint flexion. Electromyography was used to measure muscle activity of the vastus medialis oblique (VMO), rectus femoris (RF), vastus lateralis oblique (VLO), biceps femoris (BF), and semitendinosus (ST) muscles. The Wii Balance Board was used to assess balance during the three-method squat operation. Each operation was measured three times for 10 seconds. Results: There were significant differences in muscle activities of the VMO, RF, VLO, ST and balance ability with the application of three directions of resistance (p<0.05). Post hoc comparisons revealed that squats performed with resistance pulled in the backward direction resulted in higher VMO, RF and VLO activity than with the resistance placed in a pulled forward direction (p<0.05). In the ST, resistance applied in the pulled forward direction showed greater muscle activity compared to the pulled backward direction (p<0.05). With balance, squats performed with resistance pulled in the forward direction showed greater muscle activity than with resistance applied in the pulled backward direction and during general squat performance (p<0.05). Conclusions: In this study, squat exercises performed with resistance applied in the direction of pulling backwards was found to be the most effective in improving quadriceps muscle strength and balance. It is effective to provide resistance that is placed in the forward when it is difficult to perform a general squat due to weakness of the quadriceps.

• Korean Journal of Applied Biomechanics
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• v.17 no.4
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• pp.141-148
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• 2007

Falls associated with tripping over an obstacle can be dangerous, yet little is known about the strategies used for stepping over obstacles in older Parkinson disease. The purpose of this study was to investigate the lower extremity muscle activity on the obstacle gait according to obstacle height in older Parkinson diseases. The obstacle gait of 7 older Parkinson disease was examined during a 5.0 m approach to, and while stepping over, obstacles of 0, 25, 52, and 152mm. Seven pairs of surface electrodes(Noraxon MyoResearch, USA) were attached to the right-hand side of the body to monitor the adductor longus(AL), gluteus medius(GME), gluteus maximus(GMA), biceps femoris(BF), rectus femoris(RF), gastrocnemius(GA), tibialis anterior(TA). Electromyography data were filtered using a 10Hz to 350 Hz Butterworth band-pass digital filter and normalized to the maximum value in the analyzed phases. A one-way ANOVA for repeated measures was employed for selected electromyography variables to analyze the differences of the height of four obstacles. The results showed significant differences between 0.0mm and 25, 52, and 152mm obstacle height in TA and GA activities during the second phase(swing phase). But the more increase obstacle height, the more not increase the muscle activities. This means that the Parkinson disease stepping over obstacle inefficiency. To prevent and reduce the frequency of falls, elderly Parkinson disease maintained and improved their balance, muscular strength, neuromuscular control and mobility.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.13 no.1
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• pp.44-57
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• 2007

Purpose: The objective of this study is to analyze the activities of muscles importantly functioning when walking with different inclinations and speeds of a treadmill, in order to provide basic data on walking exercise using a treadmill. Method: The selected subjects of this study were 16 men and women who had lower extremity injury. A treadmill was used to provide the activation of muscle, and the electromyography was used to analyze the muscle activity variables. The Biodex was used to measure the value of maximum isometric contraction. The inclinations of the treadmill were 0%, 5% and 10%, respectively, and its speeds were 2Km/h. 3Km/h, 4Km/h, 5Km/h, and 6Km/h, respectively. Result: For quadriceps femoris muscle and trunk muscle, there were significant differences in muscle activity when different speeds were applied at 0%, 5% and 10% inclinations.(p<0.05) The activity of vastus medialis muscle was 9.78% at 0% inclination and 2km/h speed, whereas it was 9.32% at 0% inclination and 3km/h, which was slightly lower. The activity of erector spinae muscle was 24.93% at 0% inclination and 2km/h speed, whereas it was 24.84% at 0% inclination and 3km/h, whereas it was 23.99% at 0% inclination and 4km/h, which was slightly lower. The activity of vastus medialis muscle was 11.89% at 10% inclination and 2km/h speed, whereas it was 10.65% at 10% inclination and 3km/h, which was slightly lower. The activity of rectus femoris muscle was 10.26% at 10% inclination and 2km/h speed, whereas it was 9.77% at 10% inclination and 3km/h, which was slightly lower. Conclusion: It was found that the activities of trunk muscle and quadriceps femoris muscle increase as the inclination and the speed of a treadmill increase during treadmill walking.

• Physical Therapy Rehabilitation Science
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• v.10 no.4
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• pp.487-492
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• 2021

Objective: This study aimed to identify the effects of assuming two types of posture (standing and kneeling) during squat exercise on lower body muscle activity. Design: Cross-sectional study Methods: Twenty-five healthy adults (18 men and 7 women) were instructed to perform the squat exercises while assuming two types of posture (standing and kneeling). EMG (Electromyography) data (% maximum voluntary isometric contraction) were recorded three times from the rectus femoris (RF), gluteus maximus (GMax), gluteus medius (GMed) and biceps femoris (BF) of participant's dominant side and the mean values were analyzed. Results: During the squat exercise with all postures, there was statistically significant difference on rectus femoris, gluteus maximus, gluteus medius, and biceps femoris muscle activity (p<0.05). The results showed that, there was significantly greater rectus femoris, gluteus medius, and biceps femoris muscle activity in standing posture than in kneeling position (p<0.05). However, the gluteus maximus muscle activity was significantly greater with kneeling posture compared to standing posture (p<0.05). Conclusions: With standing posture, it is showed that rectus femoris, gluteus medius, and biceps femoris muscle activity was greater than kneeling position. While the gluteus maximus muscle activity with standing posture was less than with kneeling posture. Therefore, it is considered that this study can be used as a selective indicator of exercise posture for strengthening specific muscle or weakness caused by paralysis.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.9 no.2
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• pp.7-12
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• 2011

Purpose : We studied the correlation between reference voluntary contraction (% RVC) of vastus lateralis (VL) and vastus medialis (VM), Berg balance scale (BBS), and timed-up & go (TUG) test. Methods : We recruited 30 stroke patients from a rehabilitation center at a hospital.? All subjects could walk with or without an assisting device. Subjects were evaluated with % RVC of VL and VM, BBS, and TUG. The data were analyzed using a Pearson correlation coefficient. Results : The % RVC of VL and VM and BBS (p<0.01) showed a significant positive correlation. TUG negatively correlated with % RVC of VL and VM and BBS (p<0.01). Conclusion : Lower extremity muscle activity increases balance and walking ability. We recommend the implementation of lower extremity strength exercises in the rehabilitation of stroke patient.

• PNF and Movement
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• v.17 no.2
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• pp.207-214
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• 2019

Purpose: Although multi-directional reaching exercises are commonly used clinically, the effects of specific movement directions on the muscle systems of the lower extremities have not been explored. We therefore investigated lower extremity muscle activity during reaching exercises with different sagittal and horizontal plane movements. Methods: The surface electromyography responses of the bilateral rectus femoris, tibialis anterior, peroneus longus, and gastrocnemius muscles were measured during reaching exercises in three directions in the horizontal plane (neutral, $45^{\circ}$ horizontal shoulder adduction, and $45^{\circ}$ abduction) and three directions in the sagittal plane (neutral, $120^{\circ}$ flexion, and $60^{\circ}$ flexion). A total of 20 healthy, physically active participants completed six sets of reaching exercises. Two-way repeated ANOVA was performed: body side (ipsilateral and contralateral) was set as the intra-subject factor and direction of reach as the inter-subject factor. Results: Reaching at $45^{\circ}$ horizontal shoulder adduction significantly increased the activity of the contralateral rectus femoris and gastrocnemius muscles, while $45^{\circ}$ horizontal shoulder abduction activated the ipsilateral rectus femoris and gastrocnemius muscles. The rectus femoris activity was significantly higher with reaching at a $120^{\circ}$ shoulder flexion compared to the other conditions. The gastrocnemius activity decreased significantly as the shoulder elevation angle increased from $60^{\circ}$ to $120^{\circ}$. Conclusion: Our results suggest that multi-directional reaching stimulates the lower extremity muscles depending on the movement direction. The muscles acting on two different joints responded to the changes in reaching direction, whereas the muscles acting on one joint were not activated with changes in reaching direction.