• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.147-154
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• 2007

This study's purpose is to investigate the effects on leg muscle activity caused by perturbation, using a trapdoor system during the support phase of gait for healthy adults (n = 6, height $177.5{\pm}5.5cm$, weight $81.0{\pm}9.5kg$, age $30.0{\pm}3.3yrs$). The trapdoor had the functional ability of causing inversion or eversion. The release time for the trapdoor was specified for two times, 0.3 and 0.5 seconds after heel contact. While altering these variables, EMG was recorded for the leg muscles (rectus femoris, biceps femoris, vastus lateralis, tibialis anterior, gastrocnemius, soleus). The following conclusions were derived. The steptime was longer for the 0.5s eversion than 0.3s inversion condition. So in order to regain stability after the perturbation the unsupporting leg reached forward rapidly. This quick reflex can be observed through the center of pressure (COP) and its rapid change in direction. The gastrocnemius was activated throughout the total experiment. There was a low amount of activity recorded in the rectus femoris, vastus lateralis and tibialis anterior except for the condition of inversion 0.3s. For most of the conditions, the highest average EMG peak values were recorded during the condition of inversion 0.3s. The iEMG patterns were similar for the conditions of inversion 0.3s and eversion 0.3s. To cope with the rapid change in these conditions, the biceps femoris was activated. During the experiment except for the condition of normal gait, the activity of the soleus and gastrocnemius was relatively high. Therefore, to prevent injury from perturbation of the lower leg strengthening of the soleus and gastrocnemius is required. Likewise to prevent injury to the thigh strengthening for the biceps femoris.

• Journal of The Korean Society of Integrative Medicine
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• v.5 no.3
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• pp.57-61
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• 2017

Purpose : The purpose of study was to find out the environmental risk factor that can be easily occurred imbalance muscle activities according to direction for using the ramp during one legged standing. Method : The subjects were 20 normal adults with a mean age of $23.15{\pm}2.14years$ and a Body Mmass Index (BMI) of $22.74{\pm}1.07$. Participants were measured muscle activities on vastus medialis, vastus lateralis, tibialis anterior, peroneus longus during one legged stance at four conditions ramp (down ramp, up ramp, medial ramp, lateral ramp). The statistical analyses were performed using IBM SPSS(Ver. 23) and p-value less than .05 were considered statistically significant for all cases. Result : In this study, the activity of the lower extremity muscle and the ratio of the vastus medial and lateral muscles according to the direction of use of the ramp were investigated. The changes in the muscle activity of the lower limbs along the direction of the ramp were significantly different between the vastus medial muscle and the peroneus longus muscle. Conclusion : For a short time on a ramp or a pedestrian crossing, a clerk in a ramp can move or stand by placing the lower limbs in various directions, but if performed in consideration of the individual's disease characteristics or unstable foot position, It is thought that there will be an effect to prevent on the ankle and knee unstability.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.3
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• pp.131-140
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• 2022

Purpose : Although many studies have explored the effect of seating side angles on the spinal curve and surrounding muscles during seating, only a few studies have investigated the effect of different seating face angles on different lower limb and deep trunk muscles. Therefore, this study investigated the effects of seating surface angles (0 degrees, 10 degree anterior, and 10 degree rear) on lower extremity and deep trunk muscles in healthy adults. Methods : Thirty people were asked to sit once on each seating surface three times during the day, and their muscle thicknesses were measured by ultrasound while sitting. The method of sitting was the same when sitting on the three seating surfaces. Results : From the comparison results of the muscle thicknesses according to the seating surface angles, a significant difference existed in the muscle thicknesses of the vastus medialis, vastus medialis oblique, vastus intermedius, soleus and gastrocnemius (p<.05). However, no significant difference was found in the transversus abdominis, internal obliques, rectus femoris and vastus lateralis (p>.05). Conclusion : Our findings revealed that the lower back load decreases, the leg load increases, and the legs specific muscles are affected as the body tilts forward when sitting on the seating surface inclined forward. Therefore, it is possible to suggest a forwardly inclined seating surface that reduces lower back loads and utilizes the posture-maintaining muscles of the legs when sitting in a person with a poor sitting posture or lower back pain at ordinary times.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.3
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• pp.93-98
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• 2017

PURPOSE: This study investigated the activities of lower limb muscles according to the angle of a medio-lateral ramp while walking to promote awareness of the risks associated with a medio-lateral ramp. METHODS: This study was conducted on 20 healthy male adults. The muscle activities of the vastus medialis oblique (VMO), vastus lateralis oblique (VLO), tibialis anterior (TA) and peroneus longus (PL) were measured while the subjects were walking on a 3 m medio-lateral ramp. Five angles (flat, $2^{\circ}$, $5^{\circ}$, $10^{\circ}$, and $15^{\circ}$) were selected for the angle conditions of the experiment on a medio-lateral ramp. The activities were measured during the stance phase only in the middle cycle of a three-cycle walking experiment. The mean value obtained from the three walking tests was used for the analysis. RESULTS: Results showed that walking on a mediolateral ramp required more muscle activities than walking on a flat surface, through which balanced walking was achieved. CONCLUSION: Walking on a medio-lateral ramp requires proper muscle activation and control, without which the risks of injury to the joints of the lower limbs and falls are likely to increase. Therefore, special attention should be given to older people and the disabled under the condition of traversing a ramp.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.17 no.1
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• pp.29-34
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• 2011

Background: The purpose of this study was to investigate the effect of a Kinesio taping on muscle power and fatigue index in quadriceps femoris (vastus medialis, vastus lateralis, rectus femoris.). Methods: 15 male (heathy collegiate students) was enrolled from Kyungwoon university, Gumi. Kinesio tape was applied on quadriceps femoris muscle of subjects. Muscle power and fatigue index was measured by Wingate ergometer (warm-up was 30sec in 60W, maximum power test was 30sec in 100W, recovery was 30sec in 60W) in pre- and post applied taping. Results: As a results, there showed statistically significant improvement in mean power, peak power, mean power/kg, peak power/kg, fatigue index (p<.05). Conclusions: The study of Wingate test by applying Kinesio taping was significantly effected in mean power, peak power, mean power/kg, peak power/kg.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.26 no.1
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• pp.47-54
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• 2020

Background: This study examined the changes in the leg muscle activities of 30 healthy subjects according to different pressures caused by isometric hip adduction during squat exercise. Methods: With their knee flexed at 60°, the subjects performed isometric hip adduction with a pressure of 0, 20, 40, and 60mmHg. Surface electromyography was used to measure their muscle activities. Changes in the activities of the muscles, such as the gluteus maximus (GMAX), Gluteus medius (GM), vastus medialis oblique (VMO), vastus lateralis oblique (VLO), biceps femoris (BF), and Tensor fasciae latae (TFL) muscles, were analyzed. Results: The activities of the VMO, VLO, GM, BF, and GMAX muscles were significantly different after exercise compared to that before exercise (p<.05). The activities of all the leg muscles measured were highest at a pressure of 60mmHg during isometric hip joint adduction. Conclusion: The pressure produced by isometric hip joint adduction during squat exercise increased the leg muscle activities of the subjects. These results will provide basic data on effective squat exercise to alleviate knee joint diseases.

• Physical Therapy Korea
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• v.4 no.2
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• pp.66-76
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• 1997

The purpose of this study was to compare the integrated electromyographic activity ratios of vastus lateralis(VL); rectus femoris lateral portion (RFL); rectus femoris medial portion(RFM); and vastus medialis(VM) muscles of 30 healthy subjects under three proprioceptive neuromuscular facilitation(PNF) techniques. Each subject was randomly assigned to one of 3 PNF techniques groups : slow reversal(SR), slow reversal hold(SRH) and rhythmic stabilization (RS). Each person was positioned in supine with the right hip flexed to $45^{\circ}$ and the knee fully extended and received a total of 6 sessions. Each technique was applied to the right lower extremity in two diagonal patterns while electrical activity was monitored from the ipsilateral muscles VL, RFL, RFM, and VM, respectively. Comparison of normalized mean EMG magnitudes from VL, VM showed that RS demonstrated significantly greater activity than that of SR or SRH and that RFL and RFM did not demonstrate any greater relative EMG activity with the three PNF techniques than did VL or VM.

• Journal of The Korean Society of Integrative Medicine
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• v.2 no.3
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• pp.57-63
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• 2014

Purpose : The purpose of this study was to identify the muscle activity of leg during stair down in the subjects with flatfoot and normal foot. Methods : The fourteen subjects with the flatfoot group and the fifteen subjects with the normal foot group volunteered for this study. All subjects descended the stairs that the height was 20cm and consisted 25 stairs. The target muscles for recording muscle activity were posterior fiber of gluteus medius, vastus medialis and vastus lateralis oblique, semitendinosus and biceps femoris, tibialis anterior, and medial and lateral fiber of gastrocnemius muscles. The muscle activity was recorded using the wireless EMG system. Results : The flatfoot group had significantly lower the muscle activity of posterior fiber of gluteus medius than the normal foot group in stance phase during stair down(p<.05). The flatfoot group had significantly higher the muscle activity of biceps femoris and tibialis anterior than the normal foot group in swing phase during stair down(p<.05). Conclusions : This study proposed that the subject with flatfoot should train the strengthening exercise for posterior fiber of gluteus medius.

• Journal of Society of Preventive Korean Medicine
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• v.11 no.2
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• pp.121-132
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• 2007

The purpose of this study is to find out the effects of taping therapy on muscle activities between the group of taping therapy treatment and control group before or after exercises. The subjects are 18 S college's healthy male students who do not have any problems in the legs and could bend the knee joint normally. Considering physique, condition of health and capacity for locomotion, 3 groups of each 6 persons for the experimentation were classified. Three groups composed of control group without taping therapy treatment for control group, group I with taping therapy treatment only before the experimentation and group II with taping therapy treatment during 24 hour. before and after the experimentation. EMG MP150 was used to evaluate the parameter of the lower leg's muscle activities the exercise before 5 min. after 10 min. and after 24 hour. for the experimentation. Compared with control group, group I and group II had more increased muscle activities in vastus lateralis and rectus femoris and was statistically significant. And group I and group II also had more increase in muscle activities than control group in vastus medialis, although there was no statistically significant. We found that taping therapy increased muscle activity positively. The application of taping therapy could be used not only for preventive effects for sports man but also therapeutic effects for general people.

• The Journal of Korean Physical Therapy
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• v.32 no.5
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• pp.273-276
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• 2020

Purpose: The purpose of this study was to investigate the effects of the resistance conditions on the electromyography (EMG) activity ratio of vastus medialis oblique (VMO) and vastus lateralis (VL) muscle during partial lunge exercise in healthy subjects in order to suggest the basic data of exercise intervention for such as patients with patellofemoral pain syndrome (PFPS). Methods: The participants of this study were healthy twenty two people with no knee pain, limitation of motion and past history of operation at lower extremity. The participants performed three types of lunge 1) no resistance, 2) anterolateral 45° resistance and 3) lateral 90° respectively. The EMG activity of the VMO and VL were recorded by surface EMG and the measured data normalized by the %MVIC value was analyzed by repeated measured ANOVA. Results: The results showed that the VMO/VL EMG activity ratio during lunge with anterolateral 45° resistance was significantly higher than with no resistance and lateral 90° resistance (p<0.05). There was no significant difference in VMO, VL, and VMO/VL muscle activity between male and female subjects (p>0.05). Conclusion: This study suggests that partial lunge exercise with anterolateral 45° resistance can increase the VMO/VL muscle activity in healthy subjects. This result could be used as basic data to develop therapeutic exercise programs such as PFPS patients.