• Physical Therapy Korea
• /
• v.29 no.2
• /
• pp.165-170
• /
• 2022

Background: The serratus anterior (SA) muscle prevents scapular winging (SW) by stabilizing the medial border of the scapula during arm movement. The upper trapezius (UT) and lower trapezius (LT) muscles may compensate for the weak SA muscle in individuals with SW during shoulder flexion. However, there is no study to examine whether compensation by UT and LT occurs in individuals with SW. Objects: This study compared the muscle activities of UT, LT, and SA as well as the SA/UT activity ratio between individuals with and without SW during shoulder flexion with load. Methods: This study recruited 27 participants with SW (n = 14) and without SW (n = 13). Electromyography data of the SA, UT, and LT muscles and SA/UT activity ratio were recorded and analyzed during shoulder flexion with 25% load of the maximal shoulder flexion force. Independent t-test was used to compare the UT, LT, and SA muscle activities and SA/UT ratio between the groups with and without SW; statistical significance was set at α of 0.05. Results: SA activity was significantly lesser in the group with SW than in the group without SW. However, there were no significant differences in the UT and LT activities and SA/UT activity ratio between the two groups. Conclusion: The SA activity was lesser in the group with SW than in the group without SW with 25% load of the maximal shoulder flexion force, but there was no compensatory muscle activity of the UT and LT observed. Therefore, further studies are warranted to clarify the compensatory strategy of scapular stabilization in individuals with SW during shoulder flexion under other heavy load conditions.

• Journal of the Ergonomics Society of Korea
• /
• v.32 no.5
• /
• pp.437-442
• /
• 2013

Objective: The objective of this study was to investigate the effects of drive-assisting system in a shower carrier on the upper body muscle activities of caregivers through drivability tests. Background: In care facilities, one of the major ADL (Activities of Daily Living) factors is bathing/showering. Recently, bath/shower-assisting equipment is actively being introduced in care facilities to reduce caregivers' muscle burden. In particular, it is desirable to utilize a shower carrier equipped with drive-assisting system to effectively care for the elderly. However, there were few systematic studies on the relationship between muscle activities and drive-assisting speeds. Method: For the drivability tests to study the effects on the muscle activities according to the drive-assisting speeds(corresponding drive-voltages: 0.0V, 2.0V, 2.1V, 2.3V), 6 females in their 40s($43{\pm}4yrs$, $157{\pm}5cm$, and $54.5{\pm}1.5kg$) were selected. To measure muscle activities of caregivers through drivability tests, 7 muscles in the upper body(TM/Trapezius Muscle, DM/Deltoid Muscle, BBM/Biceps Brachii Muscle, TBM/Triceps Brachii Muscle, ECRLM/Extensor Carpi Radialis Longus Muscle, FCUM/Flexor Carpi Ulnaris Muscle, and ESM/Erector Spinae Muscle) were selected. Results: In the TM, muscle activities were decreased as 21% compared to 0.0V, when drive-voltage 2.0V was applied, as 57% by 2.1V, and 62% by 2.3V(p<0.05), whereas 40%, 56%, and 69% of muscles activities were decreased respectively from the DM(p<0.05). Also, from the UL(BBM+TBM+ECRLM+FCUM), muscle activities were decreased by 17% with 2.0V as against 0.0V, by 47% with 2.1V, and 52% with 2.3V, whereas decreases in muscle activities from the ESM were found by 20%, 34%, and 42% respectively by 2.0V, 2.1V, and 2.3V(p<0.05). Conclusion: The muscle activities were decreased in the order of the DM, TM, ESM, and UL. As muscle activities were remarkably reduced as drive voltage were increased, it was expected to reduce the upper body muscle burden on the caregivers when using shower carriers equipped with driving-assist system. Applications: The results from this study can be applied for the development of a shower carrier including other equipment to possibly reduce the muscle burden of the caregivers.

• Journal of Korean Medicine Rehabilitation
• /
• v.20 no.1
• /
• pp.119-132
• /
• 2010

Objectives : The purpose of this study is to compare interrelations between stress and muscles of neck through stress response inventory(SRI), 7 zone diagnostic system and surface electromyography(sEMG). Methods : This study was carried out with the data from SRI, 7 zone diagnostic system and sEMG. First subjects were divided into two group according to the SRI points. subjects in group A had points of SRI in which lower than 30 points. Subjects in group B had points of SRI in which higher than 30 points. And subjects were divided into nonstress group(Group C) and stress grouop(Group D) according to the result of 7 zone diagnostic system. Then we investigated how to differentiate the muscle contraction, fatigue, recovery and asymmetry ratio on sEMG for each groups. Results : In this study, the muscle contraction of both upper trapezius muscle and left sternocleidomastoid muscle and left scalene muscle in stress group were higher than nonstress group significantly. And the muscle recovery of left sternocleidomastoid muscle and left scalene muscle in stress group were higher than nonstress group significantly. Conclusions : This results show that the stress was associated with muscle condition.

• The Journal of Korean Physical Therapy
• /
• v.35 no.3
• /
• pp.83-88
• /
• 2023

Purpose: This study was to investigate the effect of forward head posture (FHP) and round shoulder posture (RSP) on changes in muscle activities according to shoulder flexion and abduction tasks. Methods: Twenty-two male subjects with no history of neurological, musculoskeletal surgery or injuries, or pain in the spine region within the previous 3-month periods were recruited for this study. Craniovertebral angle (CVA) and Scapula Index were measured before performing 90° abduction and flexion tasks holding a 3kg dumbbell. Muscle activities were measured during the tasks. All measurements except height of the acromion were carried out in a sitting position at the height of the subject's knee angle of 90 degrees, and two tasks were randomly performed with the arm that the subject mainly use to throw the ball. The abduction and flexion angles were checked by the examiner using a goniometer beside the subject. Results: Correlation coefficient analysis between Scapular Index and upper trapezius muscle activity during shoulder abduction task showed significant positive correlation. No significant correlation was observed between CVA, Scapular Index, and other muscle activities. Conclusion: FHP showed increased muscle activation, making it difficult to change muscle activity under lower loads, and RSP was correlated with UT activation in shoulder abduction. Therefore, in the RSP, the loaded shoulder abduction is considered a potential risk factor for increasing shoulder muscle tension. This paper proposes an approach to treating RSP before FHP.

• The Journal of Korean Physical Therapy
• /
• v.13 no.3
• /
• pp.829-837
• /
• 2001

Using Video Display Terminals(VDT) in the working environment often causes health complaints in the neck and shoulder region. This study was conducted on ten subjects, in order to investigate the change of electromyographic activities in the neck region(sternocleidomastoid muscle, upper trapezius muscle and erector muscle of cervical spine)with regards to the screen height and document holder position. A total of six different conditions of screen height and document holder position were measured during subjects performed a text-entry task for a duration of 10min. The raw EMG signal was transmuted into the root mean square(RMS). Two-way ANOVA for repeated measures was used to analyse the effects of the two factors. As a result, changing the screen height and document holder position has no effect on electromyographic activities in the neck region.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.30 no.1
• /
• pp.15-27
• /
• 2024

Background: This study examined the effects of the muscle energy technique and cervical traction after applying conservative physical therapy to patients with cervical radiculopathy. Methods: Twenty-six patients with cervical radiculopathy were randomized into two groups: the experimental group (n=13) and the control group (n=13). The two groups performed the muscle energy technique and for 4 weeks, 3 times a week, in 70-minute sessions. Pain, range of motion, function, and muscle performance were assessed using the visual analogue scale (VAS), cervical range of motion (CROM) goniometer, neck disability index (NDI), and stabilizer pressure biofeedback, before and after training. Results: After four weeks of therapy, the VAS (p<.001), NDI (p<.01), and the maximum strength of the deep neck flexion muscles significantly decreased (p<.01) and CROM significantly increased in both groups (p<.05). Conclusion: The muscle energy technique and therapeutic modalities such as cervical traction are effective in reducing VAS and NDI and increasing CROM and muscle performance in patients with cervical radiculopathy.

• Journal of the Ergonomics Society of Korea
• /
• v.34 no.1
• /
• pp.11-18
• /
• 2015

Objective: The aim of this study was to understand the effects of phone weight on the typing performance and muscle recruitment in the neck and upper extremity while typing a text message with dominant hand. The iPhone4 and iPhone5 were compared due to their 28-gram differences in weight. Background: Too much use of a cellular phone can lead the musculoskeletal disorders in the upper extremity. Phone makers tend to make their new models bigger, lighter, faster and smarter. Method: Fourteen healthy volunteers without any history of neuromuscular disorders or ongoing pain who used their smartphone more than one year were recruited. A 112g phone (iPhone5) and a 142g phone (iPhone4) were used for typing the lyric of the Korean national anthem with their dominant hand. Typing duration, the typing error, the perceived fatigue, and preference was investigated. Muscle recruitment and the resting gap of neck (middle trapezius and levator scapula), shoulder (infraspinatus and mid deltoid), elbow (biceps brachii and brachioradialis), thumb (extensor and abductor policis brevis) were collected using surface electromyography. Typing error was counted and typing speed was calculated in characters per min. The data were analyzed using a paired t-test and chi-square (${\chi}^2$) analysis for the effects of phone weight on the typing performance parameters and muscle recruitment. Results: Typing text message with iPhone5 took longer but had less muscle recruitment in brachioradialis, and extensor policis brevis muscles. Lighter weight of iPhone5 made biceps brachii to rest less without increasing the mean %EMG. Conclusion/Application: Findings of this study can be valuable information for phone designers to develop more productive device and for smartphone users to prevent the musculoskeletal disorders in the upper extremities.

• Safety and Health at Work
• /
• v.11 no.1
• /
• pp.80-87
• /
• 2020

Background: Residential and commercial cleaning is a part of our daily routine to maintain sanitation around the environment. Health care of professionals involved in such cleaning activities has become a major concern all over the world. The present study investigates the risk of musculoskeletal disorders in professional cleaners involved in floor mopping tasks. Methods: A cross-sectional study was performed on 132 mopping professionals using a modified Nordic questionnaire. The Pearson correlation test was implemented to study the association of perceived pain with work experience. The muscle strain and postural risk were evaluated by means of three-channel electromyography and real-time motion capture respectively of 15 professionals during floor mopping. Results: Regarding musculoskeletal injuries, risk was reported majorly in the right hand, lower back, left wrist, right shoulder, left biceps, and right wrist of the workers. Work experience had a low negative association with MSDs in the left wrist, right wrist, right elbow, lower back, and right lower arm (p < 0.01). Surface EMG showed occurrence of higher muscle activity in upper trapezius and biceps brachii (BB) muscles of the dominant hand and flexor carpi radialis and BB muscles of the nondominant hand positioned at the upper and lower portion of the mop rod, respectively. Conclusion: Ergonomic mediations should be executed to lessen the observed risk of musculoskeletal injuries in this professional group of workers.

• Journal of the Korea Society of Computer and Information
• /
• v.25 no.1
• /
• pp.125-130
• /
• 2020

This study is to investigate the effects of stretching of hospital office employees on muscle stiffness. A total of 40 healthy young women voluntarily participated in the study. The participants were randomized to the stretching groups and control groups. Before stretching, the participants measured muscle stiffness of sternocleidomastoid muscle, upper trapezius muscle suboccipital muscles and pectoralis minor. And then applied stretching to stretching group. Muscle stiffness remeasured five minutes later in each group. In all muscles, muscle stiffness of stretching group were significant decreased(p<.05), but control group were no significant difference between pre and post. therefore appropriate stretching is expected to prevent and reduce musculoskeletal diseases caused by increased muscle stiffness in hospital office employees.

• Physical Therapy Rehabilitation Science
• /
• v.13 no.1
• /
• pp.124-133
• /
• 2024

Objective: This study aims to investigate the immediate effects of myofascial release and Duoball assisted self-relaxation (DASR) techniques on pain and muscle tension in patients experiencing chronic cervical pain. Design: A randomized controlled trial. Methods: This study is a randomized controlled experimental study. Eighteen patients with chronic neck pain who met the selection criteria were randomly assigned to myofascial release group and myofascial release group using Duoball. Results: The frequency results for assessment muscle tension showed a decrease of about 10% in the suboccipital muscle, SCM, Pect m, UT, and LS in both the MFR and DASR groups, and the stiffness results showed a decrease in all muscles except the upper trapezius in the MFR group and the DASR group. All were found to decrease by about 10% in the suboccipital muscle, SCM, Pect m, UT, and LS, and the decrement results showed an increase of about 15% in the suboccipital muscle, SCM, Pect m, UT, and LS in both the MFR and DASR groups(p<0.05). Conclusions: In patients experiencing chronic neck pain, application of MFR and duoball assisted self relaxion was shown to be effective on pain and muscle tension. MFR is a non-pharmacological intervention method with few potential side effects and is considered a universal and easily applicable treatment method.