• Physical Therapy Korea
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• v.16 no.2
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• pp.67-76
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• 2009

In order to prevent upper extremity musculoskeletal disorders, effective keyboard selection is an important consideration. The aim of this study was to compare upper extremity muscle activity according to transverse plane angle changes during vertical keyboard typing. Sixteen healthy men were recruited. All subjects had a similar typing ability (rate of more than 300 keystrokes per minute) and biacromion and forearm-fingertip lengths. Four different types of keyboard (vertical keyboard with a transverse plane angle of $60^{\circ}$, $96^{\circ}$, or $120^{\circ}$, and a standard keyboard) were used with a wrist support. The test order was selected randomly for each subject. Surface electromyography (EMG) was used to measure upper extremity muscle activity during a keyboard typing task. The collected EMG data were normalized using the reference contraction and expressed as a percentage of the reference voluntary contraction (%RVC). In order to analyze the differences in EMG data, a repeated one-way analysis of variance, with a significance level of .05, was used. Bonferroni correction was used for multiple comparisons. There were significant differences in the EMG amplitude of all seven muscles (upper trapezius, middle deltoid, anterior deltoid, extensor carpi radialis, extensor carpi ulnaris, flexor carpi radialis, and flexor carpi ulnaris) assessed during the keyboard typing task. The mean activity of each muscle had a tendency to increase as the transverse plane angle increased. The mean activity recorded during all vertical keyboard typing was lower than that recorded during standard keyboard typing. There was no significant difference in accuracy and error scores; however, there was a significant difference between transverse plane angles of $60^{\circ}$ and $120^{\circ}$ with regard to comfort. In conclusion, a vertical keyboard with a transverse plane angle of $60^{\circ}$ would be effective in reducing muscle activity compared with vertical keyboards with other transverse plane angles.

• Physical Therapy Korea
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• v.10 no.1
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• pp.51-62
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• 2003

The purpose of this study was to compare the relative accuracy of a range of computer-based analysis with respect to EMG onset determined visually by an experienced examiner. Ten healthy students (6 male, 4 female) were recruited and three times randomly selected trials of isometric contraction of wrist flexion and extension were evaluated using four technique. These methods were compared which varied in terms of EMG processing, threshold value and the number of samples for which the mean must exceed the defined threshold, and beyond 7% of maximum amplitude. To identify determination of onset time, ICCs(Intraclass Correlation Coefficients) was used and inter-rater arid intra-rater reliability ranged good in visually derived onset values. The results of this study present that in wrist flexion and extension, the reliability of the inter and intra-examiner muscle contraction onset times through visual analysis showed beyond .971 with ICCs. The reliability of the muscle contraction onset time decision through visual reading, tested with computer analysis, showed a relationship of all the selected analysis methods with ICCs .859 and .871. The objective computer-based analysis comparing with visual reading at the same time is the effective and qualitative data analysis method, considering the specificity of each study method.

• Journal of Biomedical Engineering Research
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• v.38 no.4
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• pp.143-152
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• 2017

The main purpose of this research was to examine the EMG characteristics of driver's upper limb and driving performance for operating accelerator and brake pedal by using four types of left hand control devices(Push/Pull, Push/Right angle, Push/Rock, Push/Twist) during simulated driving. The persons with disabilities in the lower extremity have problems in operation of the vehicle because of functional impairments for controlling accelerator and brake pedal. Therefore, if hand control device is used for adaptive driving controls in persons with lower extremity loss, the disabled people could improve their quality of mobility life by driving a car. Twenty subjects were involved in this research to assess driving performance and EMG activities for operating accelerator and brake pedal by using four types of left hand controls in driving simulator. We measured EMG responses of six muscles(posterior deltoid, middle deltoid, biceps, triceps, extensor carpi radialis, and flexor carpi radialis) during pulling and pushing movement with four types of left hand controls for acceleration and braking. STISim Drive 3 program was used for evaluation test of four types of left hand control devices in straight lane course for time to reach target speed and brake reaction time. While operating the four types of left hand controls for acceleration, EMG activities of posterior deltoid in normal subjects were significantly increased(p < 0.05) compared to the disabled subjects. It was also found that EMG responses of triceps and posterior deltoid were significantly increased(p < 0.05) when using the Push/Right angle type than Push/Pull type. While operating the four types of left hand controls for braking, EMG activities of flexor carpi radialis and triceps in subjects with disability were significantly increased(p < 0.05) compared to the normal subjects. It was shown that muscle responses of posterior deltoid, middle deltoid and triceps were significantly increased when using the Push/Right angle type than Push/Rock type. Time to reach target speed and brake reaction time in subjects with disability was increased by 2.5% and 4.6% on average compared to normal subjects. The person with disabilities showed a tendency to relatively slow performance in acceleration at the straight lane course.

• Korean Journal of Acupuncture
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• v.22 no.1
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• pp.67-74
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• 2005

Objectives : This study was carried to identify the component of the Pericardium Meridian Muscle in human. Methods : The regional muscle group was divided into outer, middle, and inner layer. The inner part of body surface were opened widely to demonstrate muscles, nerve, blood vessels and to expose the inner structure of the Pericardium Meridian Muscle in the order of layers. Results We obtained the results as follows; He Perfcardium Meridian Muscle composed of the muscles, nerves and blood vessels. In human anatomy, it is present the difference between terms (that is, nerves or blood vessels which control the muscle of the Pericardium Meridian Muscle and those which pass near by the Pericardium Meridian Muscle). The inner composition of the Pericardium Meridian Muscle in human is as follows ; 1) Muscle P-1 : pectoralis major and minor muscles, intercostalis muscle(m.) P-2 : space between biceps brachialis m. heads. P-3 : tendon of biceps brachialis and brachialis m. P-4 : space between flexor carpi radialis m. and palmaris longus m. tendon(tend.), flexor digitorum superficialis m., flexor digitorum profundus m. P-5 : space between flexor carpi radialis m. tend. and palmaris longus m. tend., flexor digitorum superficialis m., flexor digitorum profundus m. tend. P-6 : space between flexor carpi radialis m. tend. and palmaris longus m. tend., flexor digitorum profundus m. tend., pronator quadratus m. H-7 : palmar carpal ligament, flexor retinaculum, radiad of flexor digitorum superficialis m. tend., ulnad of flexor pollicis longus tend. radiad of flexor digitorum profundus m. tend. H-8 : palmar carpal ligament, space between flexor digitorum superficialis m. tends., adductor follicis n., palmar interosseous m. H-9 : radiad of extensor tend. insertion. 2) Blood vessel P-1 : lateral cutaneous branch of 4th. intercostal artery, pectoral br. of Ihoracoacrornial art., 4th. intercostal artery(art) P-3 : intermediate basilic vein(v.), brachial art. P4 : intermediate antebrachial v., anterior interosseous art. P-5 : intermediate antebrarhial v., anterior interosseous art. P-6 : intermediate antebrachial v., anterior interosseous art. P-7 : intermediate antebrachial v., palmar carpal br. of radial art., anterior interosseous art. P-8 : superficial palmar arterial arch, palmar metacarpal art. P-9 : dorsal br. of palmar digital art. 3) Nerve P-1 : lateral cutaneous branch of 4th. intercostal nerve, medial pectoral nerve, 4th. intercostal nerve(n.) P-2 : lateral antebrachial cutaneous n. P-3 : medial antebrachial cutaneous n., median n. musrulocutaneous n. P-4 : medial antebrachial cutaneous n., anterior interosseous n. median n. P-5 : median n., anterior interosseous n. P-6 : median n., anterior interosseous n. P-7 : palmar br. of median n., median n., anterior interosseous n. P-8 : palmar br. of median n., palmar digital br. of median n., br. of median n., deep br. of ulnar n. P-9 : dorsal br. of palmar digital branch of median n. Conclusions : This study shows some differences from already established study on meridian Muscle.

• Journal of Biomedical Engineering Research
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• v.44 no.6
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• pp.482-487
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• 2023

The purpose of this study was to investigate changes in wrist extensor activity, pain, and grip strength before and after wearing a forearm strap in their 20s who complained of chronic lateral epicondylitis for more than 6 weeks. As a result of the study, there was an increase in wrist extensor activity on both the injured and non-injured sides after wearing the forearm strap, but this was not statistically significant. There was a statistically decrease in pain after wearing the forearm strap on the injured side, and a statistically significant increase in grip strength on both. After applying the forearm strap with pad, there was an increase in muscle activity of ECRB (extensor carpi radialis brevis) on both the injured and non-injured sides. This is thought to be due to the strap pad acting as a compressive force, reducing pain, and increasing muscle recruitment ability due to stability in wrist extension. However, considering that the number of study subjects is insufficient to generalize the results, additional supplementary research is deemed necessary.

• Physical Therapy Korea
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• v.20 no.2
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• pp.28-37
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• 2013

This study examined differences in the activity of upper limb muscles according to how an ultrasound head is gripped. Twenty-two adult males were participated in the study. Each participant was asked to apply ultrasound treatment on to a lump of pork meat by two different ultrasound head grip patterns: spherical and cylindrical grips. Muscle activity was measured in the extensor carpi radialis longus (ECRL), flexor carpi ulnaris (FCU), and pronator teres (PT), triceps brachii (TB), middle deltoid (MD), and upper trapezius (UT) muscles. There were no significant differences in the EMG signals of any muscle according to the ultrasound head grip pattern (p>.05). There were significant differences in the EMG signal of each type of muscle (p<.05). The EMG signal of UT was the lowest and that of TB was lower than ECRL and FCU. There were interactions between ECRL and FCU, between ECRL and PT, between FCU and ECRL, and between FCU and MD. The EMG signal of ECRL using the cylindrical head was low and that of FCU with the cylindrical head was high, while the opposite was the case with the spherical head ($p_{adj}$ <.05/15). The results of this study indicate that the wrist muscles worked actively when the participants applied ultrasound therapy using both spherical and cylindrical heads. A spherical head might induce imbalanced muscle activity among the wrist muscles, leading to deviation of the wrist joint. Therefore, the cylindrical head is recommended for ultrasound therapy because it produced a constant, repeated force.

• Korean Journal of Applied Biomechanics
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• v.25 no.1
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• pp.21-28
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• 2015

Objectives : The purpose of this study was to compare differences in muscle activities according to distance changes, and success or failure in relation to approaches during a round of golf in order to obtain basic data on golf swings. Methods : To achieve our research goal, we asked eight professional golfers playing for the Korea Professional Golfers' Association (height: $1.76{\pm}0.05m$, weight: $73.87{\pm}9.21kg$, career duration: $12.87{\pm}4.48yr$) to perform approach swings at distances of 30, 50, and 70 m. Results : No differences were observed in the muscle activity of the extensor carpi radialis that were caused by the distance changes. In addition, we found that the wrist extensors seemed unaffected by the increase in approach distance. Also, we found that the powers of the approach shots were driven by efficient movements rather than by the strength of the arms. We confirmed that when the distance of the approach increased, the golfers should perform their back-swing tops and follow-through right from the right to the left pelvic limb. To achieve successful approach swings despite distance changes, golfers should first work on the activity of the erector spinae to prepare for rotatory power in the P1 section. Moreover, golfers should increase the activity of the erector spinae on the left when they need to deal with the distance improvements in the P2 and P3 sections. Conclusion : In the light of the discussion above, we may infer that despite approach distance changes during a round of golf, ideal swings can be realized by consistent activities of the wrist extensor muscles and improved performances of the pelvic limb muscles. Furthermore, this study suggests that golfers should improve the consistency of muscle activities in all the other body parts to achieve the ideal swing.

• Therapeutic Science for Rehabilitation
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• v.9 no.4
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• pp.7-20
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• 2020

Objective : This study aimed to investigate the effect of simultaneous application of peripheral nerve sensory stimulation and task-oriented training on the improvement of upper extremity motor function after stroke. Methods : This study included 29 patients with hemiplegia. The 14 subjects were in the peripheral nerve sensory stimulation and task-oriented training group for 4 weeks (30 min/d, 5 d/wk), while the 15 control group subjects underwent only task-oriented training for the same duration. The outcome measures were the percentage of voluntary baseline muscle contractions of the wrist and shoulder and Box and Block Test, grip and pinch strength, and Action Research Arm Test. Results : After 4 weeks, muscle activity of extensor carpi radialis, flexor carpi radialis and grip strength and Action Research Arm Test were significantly higher in the experimental group. Conclusion : Simultaneous application of the peripheral nerve sensory stimulation and task-oriented training was found to be superior to task-oriented training for improving upper extremity motor function of adults with stroke.

• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.347-357
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• 2009

The purpose of this study was to compare EMG and GRF during a free throw. Seven pairs of surface electrodes were attached to the right-hand side of the body to monitor the flexor carpi radialis (FC), extensor carpi radialis longus (EC), biceps brachii (BB), triceps brachii (TB), rectus femoris (RF), tibialis anterior (TA) and medial gastrocnemius (GM). GRF data from two force platform were collected during a free throw. The results showed that the muscle activities in the unskilled group must be highly activated prior to the moment of release. This means that a skilled participant can shoot a free throw more efficiently while producing less muscle activeness than an unskilled participant. The DCP of unskilled group in the medio-lateral direction were greater than the corresponding values in skilled group. This showed that the unskilled group were not able to shoot the free throws stably. Thus, when a teacher or instructor teaches students how to shoot free throw, it is considered that the teacher show the learner how to use not only the upper limbs but also lower limbs on the basis of the efficent connecting movement and the flexibility in a stable procedure.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.1
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• pp.2012-2020
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• 2020

Background: Multifaceted approaches will be needed, such as global synkinesis (GS) achieve functional improvements in the arms of stroke patients from involuntary movements during exercise. Objective: To identify changes in arm GS and muscle activity, functional evaluation and the correlation with variables through action observation training, combined with functional electrical stimulation (FES), thereby verifying the effect on stroke patients. Design: A quasi-experimental study. Methods: The subjects of this study were 20 stroke patients who were divided into two groups: Control group (n=10) and experimental group (n=10). Before the intervention, arm GS and muscle activity were measured using surface electromyography (EMG), and arm function was evaluated using the Fugl-Meyer Assessment (FMA) scale. At the end of the intervention, which lasted 4-wk, arm GS and muscle activity were measured again using the same scale. Results: There was a decrease statistically significant difference in GS during the bending action in experimental group (P<.01). Both groups showed a significant difference increased only in the activity of the anterior deltoid (AD) and biceps brachii (BB) (P<.05). The results of the arm functional assessment revealed a significant difference increase in both groups (P<.05). In the between-group comparison, there was a significant difference decrease in GS during the bending action (P<.05). Only the muscle activity of the AD and BB were significantly increase different (P<.05). There was a significant between-group difference increase in the arm functional assessment (P<.05). There was a positive correlation between GS and muscle activity on the FMA in the control group (r=.678, P<.05). In experimental group, GS during the bending arm action exhibited a negative correlation (r=-.749, P<.05), and the muscle activity of the AD and BB showed a positive correlation (r=.701, P<.05). Furthermore, in experimental group, the activity of the extensor carpi radialis increased, and the activity of the flexor carpi radialis decreased, which exhibited a negative correlation (r=-.708, P<.05). Conclusion: These results suggest that brain plasticity could be more efficiently stimulated by combining surface stimulation in the affected arm of stroke patients.