• Physical Therapy Korea
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• v.14 no.4
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• pp.50-57
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• 2007

The purpose of this study was to investigate the relationship between delays in initiation and termination of tibialis anterior contraction through surface electromyographic (sEMG) analysis in adults with hemiplegia and healthy subjects and clinical assessment of lower-limb mobility. EMG activity of 6 long-term survivors of stroke and 5 healthy subjects was recorded during maximal isometric ankle dorsiflexion in 3 seconds beeper signals. It must be done as fast and forcefully as possible. Lower limb mobility was assessed with Modified Emory Functional Ambulation Profile (mEFAP). Delay in initiation and termination of muscle contraction was significantly prolonged in the affected lower limb relative to the unaffected limb. Termination of muscle contraction in the hemiplegic lower limb was significantly delayed than the initiation on the affected sides. Delay in initiation and termination of muscle contraction correlated significantly with a few range of mEFAP. Abnormally delayed initiation and termination of muscle contraction may contribute to hemiparetic lower limb mobility in hemiparetic patients. Consequently, this study showed that abnormal delay of initiation and termination of muscle contraction may contribute to hemiparetic lower limb mobility in adults with hemiplegia. Further studies are needed to demonstrate a treatment effect.

• PNF and Movement
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• v.21 no.3
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• pp.281-289
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• 2023

Purpose: This study investigated the effects of the non-elastic taping method for controlling internal hip joint rotation on internal and external hip rotator muscle activity in healthy people. Methods: In this study, 18 healthy volunteers were instructed to perform the small knee bending (SKB) test. All participants completed the test following two methods (using non-elastic taping and not using taping). Muscle activation during the two methods was measured using a surface electromyography (EMG) device. Surface EMG data were collected from the gluteus medius, gluteus maximus, and tensor fasciae femoris muscles while performing the SKB test with and without non-elastic taping. Results: Muscle activity in the gluteus maximus was significantly higher during the SKB test with non-elastic taping than during the conventional SKB test with taping (p < 0.05). Tensor fasciae latae muscle activity was lower during the SKB test with non-elastic taping than during the conventional SKB test (p < 0.05). Conclusion: The findings suggest that the non-elastic taping method for controlling internal hip joint rotation effectively activates the hip's external rotator muscles and minimizes unwanted internal rotator muscle use during the SKB test. Therefore, the non-elastic taping method for controlling internal hip joint rotation could be an effective intervention for those who cannot control the internal rotation of their hips.

• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.301-309
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• 2015

Objective : The purpose of this study was to describe the correlation between the activity of the muscles of upper and lower limbs of a golf driver swing according to shoulder injury. Method : The subjects were 18 professional golfers (7 male in KPGA and 11 female in KLPGA). Using surface electromyography, we evaluated muscle activities during the golf drive swing. Surface electrodes were used to record the level of muscle activity in the left Deltoid(MD), Triceps Brachii(TB), Pectoralis(PM), Trapezius(UT), Rectus Femoris(RF), Vastus Medialis Obilique(VMO), Biceps Femoris(BF), Gastrocnemius(GCM) muscles during the golfer's swing. The golf swing was divided into five phases: take away, forward swing, acceleration, early follow through, late follow through. Results : The results can be summarized as follows: MD, VMO had statistically significant difference in take away phases, GCM had statistically significant difference in acceleration phases, MD, PM, VMO had statistically significant difference in early follow through phases, PM had statistically significant difference in late follow through phases, Conclusion : Muscle activity of the 8 muscles(Deltoid, Triceps Brachii, Pectoralis, Trapezius, Rectus Femoris, Vastus Medialis Obilique, Biceps Femoris, Gastrocnemius) along the shoulder damage or absence of has shown that they are organically connected to each of the phases.

• Physical Therapy Korea
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• v.19 no.2
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• pp.29-38
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• 2012

This study aimed to identify the asymmetry observed in the electromyography (EMG) activity patterns of selected trunk and thigh muscles between the affected and unaffected sides during the sit-to-stand movement in ambulatory patients with post-stroke hemiparesis. This study included 20 patients with post-stroke hemiparesis. The differences between stroke fast walkers (${\geq}8m/s$, 11 subjects) and stroke slow walkers (<8 m/s, 9 subjects) were compared. The activation magnitude and onset time of the multifidus, lumbar erector spinae, hamstrings, and quadriceps during the sit-to-stand movement were recorded through surface EMG. Moreover, the EMG activation magnitude and onset time ratios of each bilateral corresponding muscle from the trunk and leg were measured by dividing the relevant values of the unaffected side by those of the affected side. In all the subjects, the activation magnitudes of the multifidus, hamstring, and quadriceps on the affected side significantly decreased compared to those on the unaffected side (p<.05). The onset time of muscle activity in the affected side was markedly delayed for the multifidus and quadriceps during the task (p<.05). The activation magnitude ratios of the quadriceps were markedly decreased in the stroke slow walkers as compared to those in the stroke fast walkers. These findings indicate that the asymmetry in the multifidus, hamstring, and quadriceps muscle activation patterns in patients with post-stroke hemiparesis may be due to the excessive muscle activation in the unaffected side to compensate for the weakened muscle activity in the affected side. Our findings may provide researchers and clinicians with information that can be useful in rehabilitation therapy.

• Korean Journal of Applied Biomechanics
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• v.17 no.2
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• pp.239-245
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• 2007

The purpose of this study was to compare the electromyography signal's power spectrum mean and median tendencies appearing in the lower extremity during walking while wearing roller shoes. 9 male subjects volunteered who have no experience riding inline-skate or roller-skate, and have no record of musculoskeletal disorder. Subjects walked on treadmill twice for an hour (Once a week, one trial with the roller on and the other without roller, Walking velocity = 1.39 m/s). Electromyography was measured every 15 minute (0, 15, 30, 45, 60 minutes). Surface electrode sticked muscle at rectus femoris(R.F.), vastus lateralis(V.L.), vastus medialis(V.M.), biceps femoris(B.F.), tibialis anterior(T.A.), gastrocnemius lateralis(G.L.), gastrocnemius medialis(G.M.). At Rectus femoris, Vastus Lateralis, Vastus medialis, and Biceps femoris showed no statistically significant decrease of median frequency or mean edge frequency as time passes. Also, between two treatments (wearing the roller shoes vs not wearing the roller shoes), no statistically significant difference. After 60 minutes, mean edge frequency showed statistically significant decrease at tibalis anterior and after 45 minutes, mean edge frequency showed statistically significant decrease compared to wearing roller shoes without the wheels at gastrocnemius lateralis. At gastrocnemius medialis after 30 minutes, median frequency showed statistically significant decrease, and showed statistically significant difference compared to the control group. Wearing the roller shoes with wheels for a long time resulted in statistically significant decrease of mean edge frequency and median frequency in lower extremity, especially in shank muscles. Increase of wearing time of roller shoes and walking on a bumpy road wearing roller shoes with wheels result fatigue and thus, danger of injury.

• Journal of Biomedical Engineering Research
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• v.43 no.3
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• pp.177-184
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• 2022

The purpose of this study was to present the IMU sensor based trunk stabilization exercise and to evaluate the changes in the muscle activity and thickness with non-specific low back pain patients (N=30). They were classified into two groups; lumbar stabilization exercise using IMU sensor (ILS), (n₁=20) and general lumbar stabilization exercise (GLS), (n₂=10). By comparing the difference between pre and post intervention via trunk muscle activity and muscle thickness, the significant differences were identified. Muscle activity was measured on external oblique (EO), internal oblique (IO), and multifidus (MF) by using surface electromyography (sEMG). Muslce thickness was measured on external oblique, internal oblique, transverse abdominis (TrA), and multifidus (MF) by using ultrasonography. sEMG activity was recorded at right side-bridge position. Each group performed the proposed lumbar stabilization exercise for 30 minutes a day, 5 times a week for 4 weeks. Trunk muscle activity was observed with a significant increase in the IO of ILS (p<.05) and a decrease in the MF of GLS (p<.05). Trunk muscle thickness was significantly increased in left EO and both IO of GLS (p<.05), and also significant increased right EO, both IO, both TrA, and both MF of the ILS (p<.05). In the future, a convergence approach of rehabilitation and engineering is needed to select a sensor suitable for rehabilitation purposes, study the validity and reliability of data, and produce appropriate rehabilitation contents.

• Physical Therapy Korea
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• v.30 no.3
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• pp.221-229
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• 2023

Background: In modern society, the use of computers accounts for a large proportion of our daily lives. Although substantial research is being actively conducted on musculoskeletal diseases resulting from computer use, there has been a recent surge in interest in improving the working environment for prevention. Objects: This study aimed to examine the effects of posture correction feedback (PCF) on changes in neck posture and muscle activation during computer typing. Methods: The participants performed a computer typing task in two sessions, each lasting 16 minutes. The participant's dominant side was photographed and analyzed using ImageJ software to verify neck posture. Surface electromyography (EMG) was used to confirm the participant's cervical erector spinae (CES) and upper trapezius muscle activities. The EMG signal was analyzed using the percentage of reference voluntary contraction and amplitude probability distribution function (APDF). In the second session, visual and auditory feedback for posture correction was provided if the neck was flexed by more than 15° in the initial position during computer typing. A 20-minute rest period was provided between the two sessions. Results: The neck angle (p = 0.014), CES muscle activity (p = 0.008), and APDF (p = 0.015) showed significant differences depending on the presence of the PCF. Furthermore, significant differences were observed regarding the CES muscle activity (p = 0.001) and APDF (p = 0.002) over time. Conclusion: Our study showed that the feedback system can correct poor posture and reduces unnecessary muscle activation during computer work. The improved neck posture and reduced CES muscle activity observed in this study suggest that neck pain can be prevented. Based on these results, we suggest that the PCF system can be used to prevent neck pain.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.2
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• pp.1-9
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• 2020

PURPOSE: This study examined the effects of different external loads on the muscle activities around the hip during prone hip extension with knee flexion (PHEKF) exercise in healthy young men. METHODS: Sixteen healthy adult males participated in the study. A pressure biofeedback unit was used to provide feedback to the participants during the abdominal drawing-in maneuver (ADIM) with PHEKF. Sandbags (0 kg, 1 kg, 2 kg, and 3 kg) were used to provide external resistance. The quadriceps was contracted to maintain knee flexion 90° against resistance. Each resistance condition using a sandbag weight was given in random order. Surface electromyography (sEMG) was used to measure the electrical activity of the gluteus maximus, biceps femoris, and erector spinae during PHEKF. RESULTS: The muscle activity of the gluteus maximus was highest with the 3 kg resistance and lowest with 0 kg (F = 128.46, P = .00). The muscle activities of the biceps femoris and erector spinae were highest with 0 kg and lowest with 3 kg (F = 29.49, P = .00). The muscle activity rate of the gluteus maximus/biceps femoris was highest with 3 kg and lowest with 0 kg (F = 37.49, P = .00). CONCLUSION: The activity of the gluteus maximus was increased using a higher external weight load during PHEKF, while the activity of the biceps femoris decreased. These findings suggest that an external weight is needed during hip extensor exercise to strengthen the gluteus maximus and inhibit the biceps femoris.

• Physical Therapy Rehabilitation Science
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• v.4 no.1
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• pp.44-48
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• 2015

Objective: The purpose of this study was to investigate the relationship between anticipatory postural adjustment (APA), single task, dual tasks and physical performances. The trunk muscles of APA consist of bilateral erector spinae (ES) and bilateral internal oblique (IO) adnominal muscles, during rapid stepping with the affected or unaffected leg in a sitting posture. Design: Cross-sectional study. Methods: In patients with chronic stroke, electrodes of surface electromyography (EMG) were attached on the bilateral erector spinae (ES), bilateral internal oblique adnominal (IO), and bilateral rectus femoris (RF) muscles. RF acts as the prime mover. The stroke patients performed hip flexion until $20^{\circ}$ as fast as possible at each leg in a sitting posture according to a visual cue. The visual cue unexpectedly appeared on monitor in front of the stroke patient. The single task was the Timed Up and Go (TUG) test. The dual tasks were the TUGconitive, which increased cognitive capacity, and the TUGmanual task, which had an external focus. Results: All EMG data showed earlier onset latency before the prime mover. In affected leg raising, the onset time of unaffected ES muscle of the stroke patients was correlated with the single and dual tasks (p<0.05). In unaffected leg raising, the onset time of the affected IO muscle was related to all the tasks (p<0.05). Gait speed showed a relationship with the unaffected ES muscle only. Conclusions: The trunk muscles of the bilateral ES and bilateral IO play an important role in APA. The single and dual tasks using TUG test were correlated with the APA s of ES and IO muscles. Dual task by the TUG test is a good measuring tool for reflecting the real life in patients with chronic stroke.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.3
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• pp.99-111
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• 2023

PURPOSE: This study examined the effects of pelvic compression methods on the muscle activities of the trunk muscles during plank exercises in individuals with and without low back pain. METHODS: Individuals who experienced back pain for three or more days within the last six months (low back pain group, LBPG; n = 15) and those who did not (non-experienced low back pain group, NLBPG; n = 15) were instructed to perform plank exercise without pelvic compression or while wearing a ReaLine or Com-pressor belt. The electromyography (EMG) data was measured during each session of exercise. Surface EMG signals were collected for the rectus abdominis (RA), external oblique (EO), erector spinae (ES), and gluteus maximus (GM) muscles. The data were collected during three 5-s exercises with a 1-min rest period between the three sets. RESULTS: During the plank exercise, the muscle activity of the RA in the LBPG was significantly higher than that in the NLBPG (p < .05), and greater muscle activity was observed in the LBPG even when two pelvic compression methods were applied (p < .05). The muscle activity of RA was decreased significantly during pelvic compression according to the pelvic compression methods in both groups (p < .05). No significant interaction was observed between the groups or the pelvic compression methods for the RA, EO, ES, or GM muscle activities during plank exercises. CONCLUSION: Both pelvic compression methods reduced the RA muscle activity during plank exercises in individuals who had not experienced back pain within the last six months.