• Journal of Korean Physical Therapy Science
• /
• v.31 no.2
• /
• pp.30-40
• /
• 2024

Background: The purpose of this study is to identify the difference in muscle activity and muscle contraction onset time according to a LLD and object weight When subjects performed a lifting task. Design: Repeated measure design Methods: 15 male adults participated in this study. When subjects performed a lifting task, we measured a difference of muscle activity and muscle contraction onset time in the rectus abdominis(RA), the erector spinae(ES), and the rectus femoris(RF) between both legs using the surface electromyogram (Telemyo DTS, Noraxon Inc., USA). When subjects performed a lifting task, the weight of the object was set to 0% kg, 10% kg, and 20% kg of the subject's body weight, excluding the weight of the box. Results: The difference in muscle activity in the RA, the ES, and the RF between both legs when lifting an object was larger in LLD condition than in non-LLD condition(p<0.05). In all of muscles, the difference of contraction onset time was generally increased as the object's weight increased. Specially, the difference in muscle contraction onset time in the RA, the ES between both legs was larger in the LLD condition than in the non-LLD condition(p<0.05). Conclusion: This study suggests that LLD affects the muscle activity and muscle contraction onset time during lifting objects. It can be used as data to prevent joint damage and muscle due to the LLD during work and movements of daily living.

• Journal of Biomedical Engineering Research
• /
• v.10 no.2
• /
• pp.109-111
• /
• 1989

An electrical stimulator was designed to induce locomotion for paraplegic patients caused by central nervous system injury. Optimal stimulus parameters, which can minimize muscle fatigue and can achieve effective muscle contraction were determined in slow and fast muscles in Sprague-Dawley rats. Stimulus patterns of our stimulator were designed to simulate electromyographic activity monitored during locomotion of normal subjects. Muscle types of the lower extremity were classified according to their mechanical property of contraction, which are slow muscle (msoleus m.) and fast muscle (medial gastrocneminus m., rectus femoris m., vastus lateralis m.). Optimal parameters of electrical stimulation for slow muscles were 20 Hz, 0.2 ms square pulse. For fast muscle, 40 Hz, 0.3 ms square pulse was optimal to produce repeated contraction. Higher stimulus intensity was required when synergistic muscles were stimulated simultaneously than when they were stimulated individually. Electrical stimulation for each muscle was designed to generate bipedal locomotion, so that individual muscles alternate contraction and relaxation to simulate stance and swing phases. Portable electrical stimulator with 16 channels built in microprocessor was constructed and applied to paraplegic patients due to lumbar cord injury. The electrical stimulator restored partially gait function in paraplegic patients.

• Journal of The Korean Society of Integrative Medicine
• /
• v.6 no.2
• /
• pp.117-123
• /
• 2018

Purpose : The purpose of this study was to investigate the effect of increased brain activity on the muscle endurance and the effect of brain activation through the combination of transcranial direct current stimulation and aerobic exercise on elderly woman. Methods : To investigate the effect of the muscle endurance on right leg, muscle endurance was evaluated by measuring the surface EMG of the muscles of the rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius muscle. Results : There was a significant difference in the pre and post comparisons of muscle endurance on rectus femoris, biceps femoris, tibialis anterior muscle (p<.05). Difference of Combination of transcranial direct current stimulation and aerobic exercise group median frequency was smaller than control group (p<.05). There was not a significant difference in the pre and post comparisons of muscle endurance on biceps femoris, and gastrocnemius muscle. Difference of Combination of transcranial direct current stimulation and aerobic exercise group median frequency was showed a similar pattern. Conclusion : Through these results, It was found that increasing the brain activity by the transcranial direct current stimulation improves the exercise capacity on the elderly women. Combination of transcranial direct current stimulation and aerobic exercise maybe applied as an effective treatment for improving muscular endurance.

• Korean Journal of Applied Biomechanics
• /
• v.24 no.3
• /
• pp.287-293
• /
• 2014

The purpose of this study was to investigate the effects of Hoehn-Yahr scale on the activation of lower-extremity muscles during walking. Electromyography (EMG) analysis was carried out on 36 patients with Parkinson's disease in the off phase of the medication cycle. We recorded EMG signals of the tibialis anterior (TA), medial gastrocnemius (MG), lateral gastrocnemius (LG), soleus (SOL), rectus femoris (RF), vastus lateralis (VL), semitendinosus (ST) and biceps femoris (BF) using Noraxon 16 channels EMG system during walking at preferred speed. Rectified EMG signals were normalized to reference voluntary contractions (RVC) over a gait cycle at the preferred speed, allowing for an assessment of how the activity was distributed over the gait cycle. Compared to the H & Y Scale 1, H & Y Scale 3 exhibited greater activation of the vastus lateralis during mid-stance and greater activation of the medial gastrocnemius during terminal swing. Compared to the H & Y Scale 1, H & Y Scale 2 and 3 exhibited less activation of the tibialis anterior during initial swing. We conclude that the more Hoen & Yahr Scale increase, the more abnormal lower-extremity muscles activation.

• The Journal of Korean Physical Therapy
• /
• v.35 no.2
• /
• pp.53-57
• /
• 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.

• Journal of the Korean Society of Physical Medicine
• /
• v.13 no.2
• /
• pp.137-145
• /
• 2018

PURPOSE: The purpose of this study was to investigate the effect of action observational physical training with rhythmic auditory stimulation on muscle activity and gait ability in patients with stroke. METHODS: Twenty-six chronic stroke patients participated in this study were assigned into three groups, experimental group 1 (10% faster tempo rhythmic auditory stimulation with action observation training) n=8, experimental group 2 (average tempo rhythmic auditory stimulation with action observation training) n=9, and control group (action observation training) n=9. In this experiment, the corresponding exercise were applied into the subjects of three group for 30 minute a day, 3 time a week during 4 weeks. All participants were measured to muscle activity of lower limb, 10 meter walking test, Figure of 8 walk test, Dynamic gait Index. The collected data were analyzed by using SPSS (version 18.0 for window) and verified that each data was a normal distribution based on Shapiro-Wilk test. Between-group and within-group comparison was analyzed by using One-way ANOVA test, Paired t-test respectively. In all statistical analyses, significance level, ${\alpha}$ was set by .05. RESULTS: The above results revealed that the all experimental group 1 and experimental group 2 and control group were all effective to improve the lower limb muscle activities, gait ability. However more positive effects shown action observational physical training with rhythmic auditory stimulation experimental group. CONCLUSION: This study suggest that action observation physical training with rhythmic auditory stimulation is effective intervention for improvement of muscle activity and walking ability in chronic stroke patients.

• Physical Therapy Rehabilitation Science
• /
• v.9 no.1
• /
• pp.36-42
• /
• 2020

Objective: Many caregivers often carry infants using baby carriers until they are approximately 36 months old. The purpose of this study was to compare the muscular activity of the trunk and lower leg muscles during trunk flexion-extension movements in correspondence to various wearing methods of a baby carrier blanket. Design: Cross-sectional study. Methods: Sixteen healthy adult women were to wear baby carrier blankets in five different ways in terms of direction and height, followed by flexion-extension of the trunk. Erector spinae (ES), rectus abdominis, rectus femoris (RF), biceps femoris (BF) muscle activities and triaxial acceleration of trunk were investigated. Results: The front-wearing method of the baby carrier blanket increased the muscular activity of the ES muscle, and wearing the baby carrier blanket at waist height in the same direction was significantly higher than wearing it at pelvic height (p<0.05). As the angle of flexion increased during trunk flexion-extension, the muscle activity of the ES, BF, and the RF increased. There was a greater increase in muscle activity of the ES and the BF during extension compared to flexion (p<0.05). Conclusions: If it is difficult to wear a baby carrier blanket due to lumbar pain, it is recommended to lower the wearing height of the baby carrier to the pelvic level so that the external load can be transferred to the lower extremity. In addition, it appears to be necessary to hold the baby and distribute the load onto the waist through proper body control when performing flexion-extension movements of the trunk. More objective and scientific research that includes various daily tasks and evaluation methods are needed.

• Physical Therapy Rehabilitation Science
• /
• v.13 no.2
• /
• pp.163-170
• /
• 2024

Objective: The purpose of this study was to compare the muscle activity of the vastus lateralis, vastus medialis, rectus femoris, and gluteus medius muscles according to the medial/lateral bias of the knee during lunge exercise. Design: Crossed-control group study Methods: This study recruited 20 healthy men and women in their 20s who were capable of lunge exercise and had no musculoskeletal or neurological abnormalities. All three postures were performed three times each during lunge exercise. In each posture, surface electromyography (EMG) equipment was used to measure muscle activity of the vastus lateralis, vastus medialis, rectus femoris, and gluteus medius during lunge exercise. Results: As a result of comparing lower extremity muscle activity in normal, medial and lateral knee-deviation postures according to lunge exercise, the muscle activity of the vastus medialis was 107.09±13.90% in the normal posture, 79.24±5.26% in the medial- deviation posture and 125.73±14.30% in the lateral- deviation posture, which was a statistically significant difference (p<0.05). However, In the case of the vastus lateralis, rectus femoris and gluteus medius there was no statistically significant difference in muscle activity in the medial and lateral deviation positions(p>0.05). Conclusions: As a result, it was found that the muscle activity of the vastus medialis during lunge exercise significantly increased in the lateral deviation posture compared to the normal and medial deviation postures. In the case of the vastus lateralis, rectus femoris and gluteus medius there was no significant difference in muscle activity for medial and lateral knee deviation.

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

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.9 no.1
• /
• pp.73-80
• /
• 2015

In this paper, we propose the robotic arm control method based on upper extremity electromyogram for lower upper extremity amputation patient. The muscle activity of the forearm flexor, forearm extensor and biceps was analyzed to utilize distribution of muscle activity to a specific position in order to the control input. This control input is converted into a control command for controlling the robotic arm through the algorithm. For the experiment and verify the proposed method, 5DoF robotic arm control system was constructed with 1 channel EMG Module and PC applications through the interworking with each module to perform a three-channel EMG analysis. For accuracy and performance evaluation of control, Experiments were performed with robotic arms moving objects. As a result of experiments which after training for 10 hours by middle 20's man, Validity of the proposed method was evaluated based an average accuracy of 92.5%.