• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.1
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• pp.13-19
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• 2013

The aim of this study was to investigate difference of the muscle activation patterns of the upper body during wheelchair cycle ramps ascent of different slopes for disabled with spinal cord injury. Three subjects who is disabled with spinal cord injury participated in this study. Surface electromyography (EMG) data (reaction time [RT], onset-offset time, and peak value of muscle activation) were collected biceps, triceps, upper trapezius, anterior deltoid, latissimus dorsi, and upper rectus abdominal muscles during wheelchair cycle ramps ascent ($0^{\circ}$, $3^{\circ}$, and $6^{\circ}$). For latissimus dorsi muscle, RT and peak value of muscle activation was were increased and offset time was delayed as the slope increased (p < 0.05). These results indicate that wheelchair cycle ramps ascent might cause excessive overuse of latissimus dorsi muscle.

• Journal of the Ergonomics Society of Korea
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• v.32 no.5
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• pp.413-420
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• 2013

Objective: The objective of this study was to compare one-hand and two-hands lowering activity in terms of biomechanical stress for the range of lowering heights from knuckle height to 10cm above floor level. Background: Even though two-hands lifting/lowering activity of manual materials handling tasks are prevalent at the industrial site, many manual materials handling tasks which require the worker to perform one-hand lifting/lowering are also very common at the industrial site and forestry and farming. Method: Eight male subjects were asked to perform lowering tasks using both a one-handed as well as a two-handed lowering technique. Trunk muscle electromyographic activity was recorded while the subjects performed the lowering tasks. This information was used as input to an EMG-assisted free-dynamic biomechanical model that predicted spinal loading in three dimensions. Results: It was shown that for the left-hand lowering tasks, the values of moment, lateral shear force, A-P shear force, and compressive force were increased by the average 6%, as the workload was increased twice from 7.5kg to 15kg. For the right-hand lowering task, these were increased by the average 17%. For the two-hands lowering tasks, these were increased by the average 14%. Conclusion: Even though the effect of workload on the biomechanical stress for both one-hand and two-hands lowering tasks is not so significant for the workload less than 15kg, it can be claimed that the biomechanical stress for one-hand lowering is greater than for two-hands lowering tasks. Therefore, it can be concluded that asymmetrical lowering posture would give greater influence on the biomechanical stress than the workload effect for one-hand lowering activity. Application: The result of this study may be used to provide guidelines of recommended safe weights for tasks involved in one-hand lowering activity.

• Physical Therapy Korea
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• v.20 no.4
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• pp.32-39
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• 2013

Abdominal curl-up exercise may excessively increased superficial neck flexor such as sternocleidomastoid (SCM) muscle. Also, the muscle activity of the abdominal muscles haven't investigated during abdominal curl-up with craniocervical flexion (CCF). Therefore, the purpose of our study was to determine the effect of CCF on the muscle activity of the abdominal and SCM muscles during abdominal curl-up. Twelve healthy subjects (six men and six women) with no history of abdominal or lower back pain within 6 weeks were recruited. Surface electromyographic signals were collected on SCM, rectus abdominis (RA), internal oblique (IO), and external oblique (EO) muscles bilaterally during performing the traditional abdominal curl-up and the abdominal curl-up with CCF. Paired t-tests were used to compare the differences in the muscle activity of the bilateral SCM, RA, EO, and IO muscles between the traditional abdominal curl-up and the abdominal curl-up with CCF (p<.05). There was significantly lower electromyogram (EMG) activity of the both SCMs during the abdominal curl-up with CCF (Right SCM, $39.50{\pm}15.29%MVIC$; Left SCM, $38.24{\pm}17.31%MVIC$) than with the traditional abdominal curl-up (Right SCM, $54.85{\pm}20.05%MVIC$; Left SCM, $53.18{\pm}26.72%MVIC$) (p<.05). The activity of abdominal muscles were not significantly different between the traditional abdominal curl-up and the abdominal curl-up with CCF. The abdominal curl-up with CCF requires significantly less muscle activity of SCM. Consequently, the abdominal curl-up with CCF is recommended to prevent excessive activation of superficial cervical flexors during abdominal curl-up exercise.

• The Journal of Korean Physical Therapy
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• v.2 no.1
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• pp.35-46
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• 1990

The right hip adbuctor musculature has been reported to demonstrate 'stretch weakness' attributable to chronic elongation imposed by standing posture common to right-handed healthy persons. Kendall and associates have described the concept of 'stretch weakness'. The purpose of this study was to assess isometric hip abduction torque and surface electro-myographic activity (using MYOMED 432) in a sample of 40 healthy right-handed persons (20 male, 20 female), all of whom agreed to participate in the study, and compare side difference in the hip abductor musculature. In order to assure the statistical significance of the results, the paired t-test was applied at the .05 level of significance. The results were as follows : 1. The difference in apparent leg length of right and left legs was significant at the .05 leve1. 2. There was a significant difference between right and left pelvic height (standing position) at the .005 level measurements, and scapula height at the .05 level. 3. Power measurements and action potentials of right hip adbuctor were greater than the left hip adbuctor regardless of the range of joint motion (inner range, outer range). 4. The difference in muscle power and action potentials according to inner or outer range of both hip abductor were significant at the .05 level. 5. In supine during active left hip abduction, the appearance of action potentials in the right hip abductors is indicative of contra-lateral effect (p<.005). These results suggest : In healthy right-handed persons. the apparent leg length on the right is longer than on the left, and pelvic height is elevated on the right side. Muscle torque and muscle action potentials of the right hip adbuctor art higher than those of the hip abductor in the lengthened position. Therefore, the results in this study are contrary to Kendall's. This type of study should be carried out in many physical therapy departments.

• PNF and Movement
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• v.3 no.1
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• pp.1-15
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• 2005

Objective : The purpose of this study was to evaluate the influence of a community based group exercise intervention on motor functional capacity. To evaluate the immediate(post-treatment) effects after 6-weeks exercise program on the group exercise intervention(PNF and Circuit exercise). Methods : Subjects-Included persons with stroke who were living in the community. Thirty-seven subjects were randomly assigned to the PNF, Circuit exercise and control group participated in a repeated measures design that evaluated the subjects with pre-treatment, post-treatment(6 weeks). Functional ability outcome measures assessed the motor assessment scale(MAS) and EMG. Both treatment groups participated in exercise cJass three times a week for 6 weeks. Group programs focused on balance, functional motor capacity and walking ability. The PNF program was modified PNF pattem and techniques with emphasis on functional tasks when possible, as well as stretching of the more affected limb particularly in the more affected shoulder. The Circuit program with subjects completing practice at a selies of work station as well as participating in walking races and relay with other members of the group. Results : Compared with the control group, the treatment group had larger improvements in the motor function ability after 6 weeks treatment and Post-treatment test scores were more significant than the pre-treatment score. 1. Motor function were assessed by using MAS, sit to stand, walking and upper function were assessed pre-treatment versus post-treatment measures revealed a statically significant(p<.05). There were significant differences between the groups. Compared with the control group, the treatment group had larger improvements. 2. In the treatment groups, demonstrated difference in the electromyographic activation of biceps, triceps, quadriceps and tibialis anterior muscles on the paretic side in the response to the reaching arm movement and stepping motion in stance. The difference in muscle activation improvement were not statically significant. Conclusion : The results of this study showed that the PNF and Circuit group exercise intervention can improve motor functional ability. This study suggests that the PNF and Circuit exercise programs is appropriate for community-based group exercise principles. It leads to gain and maintain potential function for disabled persons after stroke in the community.

• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.385-391
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• 2018

The purpose of this study was to examine the lower-extremity muscle activation of flat-footed and normal-footed subjects descending stairs while wearing high-heels, thereby identifying any imbalance between the medial and lateral muscles.Thirty female students volunteered to participate in this study. The navicular drop test (NDT) was applied to the selection criteria for the flat-footed group and the normal-footed group. Surface electromyographic data was collected from the medial and lateral quadriceps, hamstrings, and gastrocnemius. Activation of MG and LG was significantly lower in the flat-footed group than in the normal-footed group. Both groups showed significant increases in MQMH and MHMG, but the co-activation in the medial and lateral muscles was lower in the flat-footed group. The co-activation ratios showed a significantly greater MQMH/LQLH in the flat-footed group. Flat-footed subjects who wear high-heels are more likely to experience impaired knee joint alignment than normal-footed subjects. Therefore, flat-footed subjects should use caution when descending stairs while wearing high-heels.

• Physical Therapy Korea
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• v.26 no.3
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• pp.91-98
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• 2019

Background: The bridge exercise targets the gluteus maximus (Gmax) and gluteus medius (Gmed). However, there is also a risk of dominant hamstring (HAM) and erector spinae (ES) muscles. Objects: To analyze the muscle activity the of Gmax, Gmed, HAM and ES during the bridge exercise with and without hip external rotation in different degrees of knee flexion. Methods: Twenty-three subjects were participated. The electormyography (EMG) activity of the Gmax, Gmed, HAM and ES muscles was recorded during the exercise. The subjects performed the bridge exercise under four different conditions: (a) with $90^{\circ}$ knee flexion, without hip external rotation (b) with $90^{\circ}$ knee flexion, with hip external rotation (c) with $135^{\circ}$ knee flexion, without hip external rotation (d) with $135^{\circ}$ knee flexion, with hip external rotation. Results: There was no significant interaction effect between the degree of knee flexion and hip external rotation. There was a significant main effect for degree of knee flexion in Gmax, HAM muscles activity. Gmax muscle activity was significantly greater in the $135^{\circ}$ knee flexion position than in the $90^{\circ}$ knee flexion position (p<.001). While HAM muscle activity was significantly less in $135^{\circ}$ knee flexion position than in the $90^{\circ}$ knee flexion position (p<.001). ES muscle activity was significantly less in the $135^{\circ}$ knee flexion position than in the $90^{\circ}$ knee flexion position (p=.002). The activity of both the Gmax and Gmed muscles was significantly greater with hip external rotation (p<.001 and p=.005, respectively). Conclusion: For patients performing the bridge exercise, positioning the knee in $135^{\circ}$ of flexion with hip external rotation is effective for improving Gmax and Gmed muscle activity while decreasing HAM, and ES muscle activity.

• Sleep Medicine and Psychophysiology
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• v.4 no.1
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• pp.107-119
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• 1997

Objectives: The psychophysiologic response pattern between healthy subjects and patients with generalized anxiety disorder, and the relationship among anxiety rating scales and those patterns in patients were examined. Methods: Twenty-three patients with generalized anxiety disorder(AD) and 23 healthy subjects were evaluated by Hamilton Rating Scale for Anxiety(HRSA) and State-Trait Anxiety Inventory before baseline stressful tasks. Subjective Units of Distress were evaluated just before baseline period, immediately after stressful tasks, at the end of the entire procedure, and psychophysiologic measures, i.e., skin temperature(ST), electromyographic activity(EMG), heart rate(HR), electrodermal response(EDR) during baseline & rest and during two psychologically stressful tasks (mental arithmetic, TM; talk about a stressful event, TT) were also evaluated. Results: 1) AD group showed significantly higher EMG level during rest after stressful tasks and higher HR level during all period except TM compared to control group. 2) AD group showed lower change in the startle response(SR) of ST, in the SR & the recovery response(RR) of EMG during TM, and in the RR of EDR immediately after TM than control group. AD group showed that the RR of EDR was significantly lower than the SR during stressful tasks. 3) We found that there was significantly negative correlation between state anxiety and the RR of EDR after TT in AD group. We also found that there were significantly positive correlations between HRSA score and the SRs of EDR during stressful tasks, and between state anxiety and the SR of EDR during TT. Conclusion: Our results suggest that patients with generalized anxiety disorder show higher autonomic arousal than healthy subjects and decreased physiologic flexibility or reduced autonomic flexibility.

• The korean journal of orthodontics
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• v.26 no.1 s.54
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• pp.65-82
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• 1996

This study was carried out to study the changing patterns in muscle activities in Angle's II and Class III malocclusion patients following activator therapy, To study the activities of anterior temporal(T.A.), masseter(M.M.), posterior temporal(T.P.), and anterior belly of digastric(D.A.) muscles, surface electrodes were placed on 15 Angle's Class II and 17 Angle's Class III malocclusion patients and following conclusions were obtained after electromyographic recordings were taken at prior to the activator therapy and at some time between 6 -12 month after the start of activator therapy. 1. Class II and Class III malocclusion groups, when compared to normal occlusiongroup, showed no significant differences during resting and swallowing. But significant differences were observed in masseter and posterior temporal muscles during clenching. 2. Most of the muscles studied showed a certain pattern, that is those groups whose pre-treatment E.M.G. were lower than the normal value showed significant increase after activator therapy, whereas those groups whose pre-treatment E.M.G. were higher than the normal value showed significant decrease after activator therapy. This pattern was observed in all of the muscle groups studied except T.A.(swallowing), T.P.(clenching) and D.A.(swallowing, clenching) in Angle's Class III malocclusion group and in Angle's Class II malocclusion group, above tendency were observed only in T.A.(swallowing), M.M.(resting, swallowing) and T.P.(clenching). This pattern was less obvious during clenching. 3. When E.M.G. activity after activator therapy between Angle's Class II and Class III malocclusion group was compared, Class III malocclusion group showed more increase during resting, and Class II malocclusion group showed more increase during swallowing and clenching excepting M.M. and D.A. respectively.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.8 no.1
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• pp.18-26
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• 1997

There are two types of phonetic study, acoustic and physiologic, for differentiating the three manner categories of Korean stop consonants. On the physiologic studies, there are endoscopic, electromyographic(EMG), electroglottographic(EGG) and aerodynamic studies. In this study, I tried to investigate general features of Korean stops using EGG study for the open quotient of vocal fold and baseline shift during speech, and aerodynamic characteristics for e subglottal air pressure, air flow and glottal resistance at consonants. On the aerodynamic study, the glottalized and aspirated stops may be characterized by e increasing subglottal pressure comparing with lenis stop at consonants. The airflow is largest in the aspirated stops followed by lenis stops and glottalized. The glottal airway resistance (GAR) showed highest in the glottalized followed by the lenis, but lowest in e aspirated during e production of consonants, and showed highest in e aspirated, but low in the glottalized and lenis during the production of vowel. The glottal resistance at consonant showed significant difference among consonants and significant interaction between subject and types of consonant. The glottal resistance at vowel showed significant difference among consonants, and e interaction occured between subject and types of consonant. The electroglottography(EGG) has been used for investigating e functioning of e vocal folds during its vibration. The EGG should be related to the patterns of the vocal fold vibration during phonation in characterizing the temporal patterns of each vibratory cycle. The purpose of this study is to investigate the dynamic change of EGG waveforms during continuous speech. The dynamic changes of EGG waveforms fir the three-way distinction of Korean stops were characterized that the aspirated stop appears to be characterized by largest open quotient and smallest glottal contact area of the vocal folds in e initial portion of vocal fold vibration ; the lenis stop by moderate open quotient and glottal contact area ; but the glottalized stop by smallest open quotient and largest glottal contact area. There may be close relationship between the OQ(open quotient) in the initial voice onset and the glottal width at the time of consonant production, the larger glottal width just before vocal fold vibration results in the smaller OQ of the vocal fold vibration in the initial voice onset. The EGG changes of baseline shift during continuous speech production were characterized by the different patterns for the three types of Korean consonants. The small and less stiffness change of baseline shift was found for the lenis and the glottalized, and the largest and stiffest change was found for the aspirated. On the baseline shift for the initial voice onset, they showed so similar patterns with for the consonant production, larger changed in the aspirated. for the lenis and the glottalized during the initial voice onset, three subjects showed individual difference each other. I suggest at s characteristics were strongly related with articulatory activity of vocal tract for the production of consonant, especially for the aspirated stop. The suspecting factors to affect EGG waveforms are glottal width, vertical laryngeal movement and the intrapharyngeal pressure to neighboring tissue during connected spech. So the EGG may be an useful method to describe laryngeal activity to classify pulsing conditions of the larynx during speech production, and EGG research can be controls for monitoring the vocal tract articulation, although above factors to affect EGG would have played such a potentially role on vocal fold vibratory behavior obtained using consonant production.