• Journal of Biomedical Engineering Research
• /
• v.29 no.1
• /
• pp.8-16
• /
• 2008

The aim of this study was to evaluate the motor recovery in 4 chronic hemiparetic patients with Fugl-Meyer (FM) and EMG characteristics before and after the training program. The training was performed at 1hr/day, 5days/week during 6 weeks in 4 chronic stroke patients. Electromyographic activities of the affected hand were recorded during isometric wrist flexion/ extension movements. In all patients, FM was significantly improved after the 6-week training. Onset/offset delay of muscle contraction significantly decreased in the affected wrist after the training. The co-contraction ratio of flexor/extensor muscles decreased significantly. Also, onset/offset delay of muscle contraction and co-contraction ratio correlates significantly with upper limb motor impairment and motor recovery. This EMG technique allows an objective evaluation of changes in muscle activity in post-stroke patients, providing easily measurable, quantitative indices of muscle characteristics.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.246-249
• /
• 2004

The purpose of this study was to investigate the characteristics between EMG timing of muscle contraction and motor impairment in chronic hemiplegic stroke patients. Delay time and co-contraction of 4 patients who had stroke less than 3 years were measured during isometric wrist flexion and extension along the 3 seconds beep signal. Onset and offset of muscle contraction were significantly delayed on the more affected sides than control sides. Offset was significantly delayed than the onset on the affected sides in wrist flexion. Also, recruitment of antagonist was larger than agonist on the affected sides. Co-contraction ratio on the affected side was significantly smaller than control sides in wrist flexion. In affected sides, Fugl-Meyer motor assessment(FMA) shows the correlation of onset delay in wrist flexion and extension. However, co-contraction ratio correlated with FMA in wrist flexion. EMG assessment is likely to be useful outcome measure and provide insights into mechanism for motor recovery in stroke patients.

• Physical Therapy Korea
• /
• v.12 no.1
• /
• pp.91-99
• /
• 2005

We assessed whether the use of a symmetrical upper limb motion trainer in daily repetitive training for a 6-week period reduced spasticity and improved motor function in three chronic hemiparetic patients. Upper limb motor impairment and disability were measured by the Fugl-Meyer Assessment (FMA), Modified Ashworth Scale (MAS) and Manual Muscle Test (MMT), respectively. The electromyography (EMG) of the affected hand was recorded during isometric wrist flexion and extension. In all patients, FMA and MMT scores were significantly improved after the 6-week training. However, MAS scores of the affected wrist spasticity did not change considerably. Onset and Offset delays in muscle contraction significantly decreased in the affected wrist. The co-contraction ratio of flexor and extensor muscles significantly increased after the 6-week training. Onset and offset delays of the muscle contraction and co-contraction ratio correlated significantly with the patients' FMA. This study showed that repetitive, symmetric movement training can improve upper limb motor functions and abilities in chronic hemiparetic patients. Also, the EMG assessment of motor response is likely to provide insights into mechanisms and treatment strategies for motor recovery in chronic hemiparetic patients.

• Journal of the Korean Society of Physical Medicine
• /
• v.7 no.3
• /
• pp.275-282
• /
• 2012

Purpose : Bridge exercise has been commonly used in clinical rehabilitation settings to improve trunk control, and hip adductor muscles were a related muscle that may affect trunk muscle activation. The aim of this study was to investigate whether the co-contraction of hip adductor muscles may affect trunk muscle activation during bridge exercises. Methods : Thirty-eight healthy young subjects (19 men and 19 women) performed bridge exercises (with and without hip adduction movement). Surface electromyography (EMG) data were collected from the dominant-side internal oblique (IO), rectus abdominis (RA), multifidus (MF) and erect spine (ES) during bridge exercises to compare trunk muscles activation patterns. Result : The EMG activities of IO and RA appeared to be significantly higher during bridge exercise with hip adductor co-contraction than during bridge exercise alone (p<.01), but there were no significant differences in those of MF and ES. Furthermore, there were significant differences in the IO:RA EMG ratio during bridge exercise with hip adductor co-contraction (p<.05). Conclusion : These findings suggest that integration of hip adduction during bridge exercise may be beneficial in increasing deep muscles' activity for trunk stabilization.

• Physical Therapy Rehabilitation Science
• /
• v.11 no.2
• /
• pp.145-153
• /
• 2022

Objective: The purpose of this study was to evaluate the Electromyography (EMG) of the upper limb during reaching tasks according to two heights in the sitting position. Design: Cross sectional design Methods: Fifteen hemiplegia, fifteen elderly, and fifteen healthy subjects have participated in this study. The targets (90% length of the subject's arm) were located at the two heights (the eye and xiphoid process). We have recorded EMG signals of seven upper limb muscles (anterior deltoid (AD), posterior deltoid (PD), pectoralis major (Pec), infraspinatus (Inf), supraspinatus (Sup), biceps brachii (Bi), triceps brachii (Tri)). The dependent variables were movement time(s), modulation ratio, working ratio, and the co-contraction ratio of the hemiplegia, elderly, and healthy at the reaching task. Two-way repeated-measures ANOVA (2-heights) was analyzed with the LSD post hoc test. Results: The study results were as follows: (1) The movement time to the target during reaching movement was significantly longer for the hemiplegia and elderly groups compared to the healthy group. (2) The modulation rate was significantly higher at eye height than the xiphoid height in AD, PD, Pec, Inf, Bi muscles, and the hemiplegia group and elderly group were significantly lower than the healthy group. Additionally, the modulation ratio showed a significant interaction between heights and groups. Conclusions: It is expected that the variables using the muscle contraction characteristics, the evaluation method of this study, can be used as an electromyography-based feedback method that can be objectively evaluated and quantified in clinical practice.

• Journal of Korea Water Resources Association
• /
• v.31 no.5
• /
• pp.529-538
• /
• 1998

The flow configurations at open channel junctions are analyzed by 2-D depth averaged mathematical model. The governing factors of the flow at the junction are found to be discharge ratio between tributary flow and the post confluence combined flow, and confluence angle. Analyzed by these two factors are flow patterns and flow depth variation at the confluence, discharge ratio above which the flow upstresm from the junction is affected by the tributary flow and the geometries of a recirculation region. Further, the flow contraction in the downstream region and the deflection of the tributary flow in the main channel were investigated. The numerical results are compared with the existing experimental data fairly well.

• Korean Journal of Applied Biomechanics
• /
• v.27 no.2
• /
• pp.83-90
• /
• 2017

Objective: To investigate the effect of short-term vibration frequencies on muscle force generation capabilities. Method: Six healthy participants were recruited for this study and only their dominant leg was tested. The subjects were tested under five conditions of vibration frequencies with constant amplitude: 0 Hz (no vibration), 30 Hz, 60 Hz, and 90 Hz, and the vibration amplitude was 10 mm for all frequency conditions. The vibration was applied to the rectus femoris (RF). The subjects were then instructed to maintain a steady-state isometric knee joint torque (100 Nm) for the first 6 s. After the steady-state torque production, the subjects were required to produce isometric knee joint torque by leg extension as hard as possible with a start signal within the next 3 s. The vibration was applied for ~4 s starting from 1 s before initiation of the change in the steady-state knee joint torque. Results: The results showed that the maximum voluntary torque (MVT) of the knee joint increased with the vibration frequencies. On average, the MVTs were 756.47 Nm for 0 Hz (no vibration) and 809.61 Nm for 90 Hz. There was a significant positive correlation (r = 0.71) between the MVTs and integrated electromyograms (iEMGs). Further, the co-contraction indices (CCIs) were computed, which represent the ratio of the iEMGs of the antagonist muscle to the iEMGs of all involved muscles. There was a significant negative correlation (r = 0.62) between the CCIs and MVTs, which was accompanied by a significant positive correlation (r = 0.69) between the iEMGs of the vibrated muscle (RF). There was no significant correlation between the MVTs and iEMGs of the antagonist muscle. Conclusion: The results of this study suggest that the short-term vibration on the muscle increases the level of muscle activation possibly owing to the increased Ia afferent activities, which enhances the muscle force generation capability.

• Physical Therapy Rehabilitation Science
• /
• v.11 no.4
• /
• pp.400-408
• /
• 2022

Objective: The purpose of this study is to compare EMG activity during horticulture motion and upper limb rehabilitation motion, to confirm whether horticulture motion is suitable for upper extremity rehabilitation of hemiparesis. Design: Three-group cross-sectional design. Methods: The 45 subjects were divided into three groups: hemiparesis (n=15), elderly (n=15) and healthy (n=15). We have recorded EMG signals of six upper limb muscles Upper trapezius (UT), Middle deltoid (MD), Anterior deltoid (AD), Biceps brachii (BB), Triceps brachii (TB), Brachioradialis (BR) during horticultural motions and three upper limb rehabilitative motions. The dependent variables were peak EMG, integral EMG, co-contraction ratio. A two-way repeated measures ANOVA was used to compare the horticultural motion and rehabilitation motion of the three groups. Results: The peak EMG was significantly different in MD, AD, BB, TB according to the motion(p<0.05), and the UT, BB were significant differences according to the group(p<0.05). The integral EMG was significantly different in MD, AD, BB, TB, BR according to the motion(p<0.05), and the BB were significant differences according to the group(p<0.05). The co-contraction ratio was significantly different in TB/BB according of the motion, and there was no difference between the groups. Conclusions: As a result of this study, horticultural motion alone was insufficient for upper arm rehabilitation, and horticultural motion alone was insufficient to induce continuous activity of the forearm.

• Journal of Korea Water Resources Association
• /
• v.48 no.8
• /
• pp.625-634
• /
• 2015

The diverse patterns of separation zone according to the marked bed discordance by dredging at confluence in addition to the confluence angle of tributary and discharge ratio between tributary and main channels have been analyzed by CCHE2D model simulation. The separation zone is defined by inside of zero velocity boundary at down-stream of confluence. The separation zone dose not formed at the $30^{\circ}$ of confluence angle of tributary. The size of separation zone increases as the discharge ratio and confluence angle increase in general. The separation zone decreases as the dredging depth increases which shows the relative momentum reduction compared by the flow volume increasing by dredging at confluence. The contraction factor with the variation of confluence angle and discharge ratio has been investigated and confirmed the corresponding conveyance decreasing results in backwater effect. The regression equation of shape factor with confluence angle and discharge and dredging depth ratios has been suggested.

• Journal of the Korean Society of Physical Medicine
• /
• v.5 no.3
• /
• pp.405-412
• /
• 2010

Purpose : The purpose of this study was to assess the effects of the trunk muscle activity on bridging exercise according to the knee joint angle. Methods : Twenty-five healthy adults volunteered to participate in this study. Subjects were required to complete following four bridging exercises; knee joint flexion $120^{\circ}$, $90^{\circ}$, $60^{\circ}$, $45^{\circ}$. Surface electromyography from selected trunk muscles was normalized to maximum voluntary isometric contraction. Muscle activity was measured by QEMG-4 system(LXM 3204, Laxtha Korea). A repeated measures of one-way ANOVA with post-hoc Bonferroni's correction was used to determine the influence of bridging exercise on muscle activity for each muscle and descriptive statistics was used to determine local/global muscle ratio. Results : The internal oblique of bridging exercises $120^{\circ}$, $90^{\circ}$ showed significantly(p<.05). The erctor spinae of all bridging exercises showed significant excepted between $60^{\circ}$ and $45^{\circ}$(p<.05). Median of internal oblique/rectus abdominis ratio of $120^{\circ}$ was 4.41, $90^{\circ}$ was 3.94, $60^{\circ}$ was 3.58, $45^{\circ}$ was 3.39. Median of internal oblique/external oblique ratio of $120^{\circ}$ was 2.66, $90^{\circ}$ was 2.43, $60^{\circ}$ was 2.87, $45^{\circ}$ was 2.64. Conclusion : Angular motion decreasing with knee joint flexion made erector spinae activation increase. on the other hand, as decreasing abdomen muscle activation, the more performing motor learning is required for abdomen muscle strength and co-contraction for the trunk stabilization.