• The Journal of Korean Physical Therapy
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• v.31 no.1
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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.

• Journal of the Korea Society of Computer and Information
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• v.26 no.2
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• pp.125-132
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• 2021

In this paper, We propose a study on the construction of an environment for collaboration in mixed reality and a method for working with wearable IoT devices. Mixed reality is a mixed form of virtual reality and augmented reality. We can view objects in the real and virtual world at the same time. And unlike VR, MR HMD does not occur the motion sickness. It is using a wireless and attracting attention as a technology to be applied in industrial fields. Myo wearable device is a device that enables arm rotation tracking and hand gesture recognition by using a triaxial sensor, an EMG sensor, and an acceleration sensor. Although various studies related to MR are being progressed, discussions on developing an environment in which multiple people can participate in mixed reality and manipulating virtual objects with their own hands are insufficient. In this paper, We propose a method of constructing an environment where collaboration is possible and an interaction method for smooth interaction in order to apply mixed reality in real industrial fields. As a result, two people could participate in the mixed reality environment at the same time to share a unified object for the object, and created an environment where each person could interact with the Myo wearable interface equipment.

• Korean Journal of Applied Biomechanics
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• v.33 no.1
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• pp.10-16
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• 2023

Objective: The purpose of this was to find out the muscle activity of the quadriceps femoris by gender when sitting on a chair while performing stairs gait (US; Up-stairs, DS; Down-stairs). Method: 13 male subjects (age: 22.00 ± 1.68 yrs, height: 174.85 ± 6.10 cm, weight: 68.15 ± 9.83 kg) and 15 female subjects (age: 21.17 ± 1.58 yrs, height: 168.20 ± 5.55 cm, weight: 55.73 ± 6.94 kg) participated in this study. The study used wireless three channel EMG. Results: In this study, there was no gender difference in quadriceps femoris activity during the US and DS periods, and there was no significant difference between the male group before and after postural maintenance during the US and DS periods. The quadriceps muscle of the female group also did not show a significant difference before and after US sitting. However, the vastus medialis muscle activity during DS in the female group was significantly lower after application than before application of maintaining a sitting posture (p<.05). There was no interaction effect between the 15-minute sitting position application and gender. Conclusion: Our results demonstrate that sitting in a chair affects the transient functioning of the quadriceps muscle in women. Therefore, emphasize the need for active rest when sitting in a chair for long periods of time.

• Korean Journal of Applied Biomechanics
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• v.34 no.1
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• pp.25-33
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• 2024

Objective: The purpose of this study was to compare the lower extremity muscle activity and knee joint load according to movement speed conditions during the barbell back squat. Method: Nine males with resistance training experience participated in this study. Participants performed the barbell back squat in three conditions (Standard, Fast, and Slow) differing movement speed. During the barbell back squat, muscle activity of the rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM), biceps femoris long head (BFL), semitendinosus (ST), gluteus maximus (GM), gastrocnemius (GCN), and tibialis anterior (TA) was collected using an 8 channel wireless EMG system. The peak flexion angle of the lower extremity joints and the peak resultant joint force in each direction of the knee joint were calculated using eight motion capture cameras and ground reaction force plates. This study was to used the Friedman test and the Wilcoxon signed rank test, to compare lower extremity muscle activity and peak resultant joint force at knee joint according to movement speed conditions during the barbell back squat, and the statistical significance level was set at .01. Results: In the downward phase of the barbell back squat, the RF and TA showed the higher muscle activity in the fast condition, and in the upward phase, RF, VL, VM, BFL, ST, GM, and TA showed the higher muscle activity in the fast condition. As a results, analyzing of the load on the knee joint, in the downward phase, and in the upward phase, the higher peak compressive force of the knee joint was showed in the fast condition. Conclusion: The barbell back squat with fast movement speed was more effective due to increased muscle activity of lower extremity, but one must be careful of knee joint injuries because the load on the knee joint may increase during the barbell back squat with fast movement speed.

• Journal of The Korean Society of Integrative Medicine
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• v.12 no.2
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• pp.177-186
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• 2024

Purpose : The purpose of this study was to use oral instruction and taping to induce abdominal draw-in in the previous study, but there is a lack of research on the comparison of effects. Therefore, in this study, we would like to study how the effect of oral instruction, taping, and no feedback can affect muscle activity when performing abdominal draw-in pier exercises. Methods : Before the experiment, group A trained piers and applied only draw-in piers, group B applied taping feedback, and group C were divided into three groups per week for six weeks, and three sets of contractions for five seconds per group were performed five times, and a minute break was provided between each exercise. As a measurement tool, a wireless surface electromyography (EMG) was used to measure surface electromyography (Telemyo-DTS, NORAXON, USA) that derives a synthetic unit of muscle using a surface electrode. For statistical processing of data, the analysis is performed using the SPSS/PC Version 25.0 statistical program for Windows, and the statistical significance level is a=.05 Results : First, the duration was somewhat shorter in order to more accurately compare the muscle activity of the core muscles. Therefore, future research needs to be research that can be exercises with precise biofeedback and taping applied over a longer period of time. Secondly, it is believed that there is no significant difference, since the subjects were studied in healthy young adult men and women, not patients. Thirdly, they could not control the daily life of the subjects. Through future research, it is necessary to analyze the correlation between muscle activity and abdominal muscle thickness by adding ultrasound in addition to muscle activity in various age groups. Conclusion : During draw-in bridge exercise according to feedback, the muscle activity of the back muscle increased, and there was no significant difference in the muscle activity of the back muscle according to each feedback. Therefore, both the feedback applied during the draw-in pier exercise and the control group are effective in changing the thickness of the abdominal muscles.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5B
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• pp.502-510
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• 2011

In this research, a wireless movable systems is introduced that is applicable for real-world clinical examination in order to resolve the inconvenience of wired motion analysis system which uses markers by measuring more accurately the angle of the 3D motion. The system is composed of bluetooth data transmission and 6 DOF inertial measurement system that is composed of 3-axis acceleration and 3-axis gyroscope. The samples were collected from 10 feet of 5 young children who were confirmed as patients having flat feet and achilles tendonitis by podiatric expert in pediatrics, and the validity of the system was evaluated by comparison with the opinion by the expert using the EMG data and the data measured by the developed system. ROM of ankle was measured by the difference between the maximum and the minimum peaks of 3-axis values (pitch, roll and yaw) measured at lateral malleolus bone, and based on this measured value, the eversion rate became relatively higher as flat feet state become worse, which is equivalent to the opinion from the podiatric experts. It was shown that there is a relation between the certain muscle activities and the abnormal motion of foot caused by disease.

• 한국체육학회지인문사회과학편
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• v.57 no.3
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• pp.345-356
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• 2018

Objective: The purpose of this study was to investigate the local stability of the lower extremity joints and muscle activation patterns of the lower extremity during walking between falling and non-falling group in the elderly women. Method: Forty women, heel strikers, were recruited for this study. Twenty subjects (age:72.55±5.42yrs; height:154.40±4.26cm; mass:57.40±6.21kg; preference walking speed:0.52±0.17m/s; fall frequency=1.70±1.26 times) had a history falls(fall group) within two years and Twenty subjects (71.90±2..90yrs; height:155.28±4.73cm; mass:56.70±5.241kg; preference walking speed: 0.56±0.13m/s) had no history falls(non-fall group). While they were walking on a instrumented treadmill at their preference speed for a long while, kinematic and EMG signals were obtained using 3-D motion capture and wireless EMG electrodes, respectively. Local stability of the ankle and knee joint were calculated using Lyapunov Exponent (LyE) and muscles activation and their co-contraction index were also quantified. Hypotheses were tested using one-way ANOVA and Mann-Whitey. Spearman rank was also used to determine the correlation coefficients between variables. Level of significance was set at p<.05. Results: Local stability in the knee joint adduction-abduction was significantly greater in fall group than non-fall group(p<.05). Activation of anterior tibials that acts on the foot segment dorsal flexion was greater in non-fall group than fall group(p<.05). CI between gastrocnemius and anterior tibials was found to be significantly different between two groups(p<.05). In addition, there was significant correlation between CI of the leg and LyE of the ankle joint flexion-extention in the fall group(p<.05). Conclusion: In conclusion, muscles that act on the knee joint abduction-adduction as well as gastrocnemius and anterior tibials that act on the ankle joint flexion-extention need to be strengthened to prevent from potential fall during walking.

• Journal of Korean Physical Therapy Science
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• v.29 no.3
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• pp.12-20
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• 2022

Background: The purpose of this study was to investigate the changes of trunk and lower extremity muscle activity according to the compensation of arm during bridge movement of healthy subject. Design: Cross-sectional Study. Methods: Twenty healthy subjects participated in this study. The subjects performed bridge exercise with 3 different arm positions(arm abduction 45°, 90° and cross-arms) and measured the muscle activity of the trunk and lower extrimity. During bridge exercise with 3 different arm positions, trunk (rectus abdominis, erector spinae) and lower extrimity muscle activity (gluteus medius, biceps femoris, tibialis anterior) were measured using wireless surface EMG. Results: Rectus abdominis and gluteus medius muscle were most activated during bridge exercise with arm abduction 90° and erector spinae and biceps femoris muscle were most activated during bridge exercise with arm abduction 45°. In addition, tibialis anterior muscle was most activated during bridge exercise with arm cross. However, these difference in muscle activity according to the arm position was not statistically significant. Conclusion: As a result of this study, we think that the change in arm position does not induce sufficient instability to increase the muscle activity of the trunk and lower extremity muscles. Therefore, various approaches for inducing instability of the support surface for increasing muscle activity when applying bridge movement in clinical practice should be explored.