• Journal of International Academy of Physical Therapy Research
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• v.10 no.3
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• pp.1840-1848
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• 2019

Background : There is lack of studies on the effects of the bag-carrying style on the shoulder muscles and body alignment in adults with rounded shoulder posture (RSP). Objective: The purpose of this study was to investigate the effects of various bag-carrying styles on muscle tone, muscle stiffness and spinal alignment in 20 adults with RSP as they were walking on a treadmill. Design : Crossover Study Design. Methods: A subject performed treadmill walking for 15 minutes at a speed of 4 ㎞/ｈ while carrying three different types of bags: a backpack, a cross bag, and a shoulder bag. Results : The results showed that the main effect of timing was observed in the muscle tone for all the variables and in muscle stiffness only for the upper and lower trapezius muscles. As for the main effect of timing, the muscle tone of the upper trapezius and the pectoralis major significantly increased in all conditions, while the muscle tone of the lower trapezius significantly decreased in all conditions. The muscle stiffness of the upper trapezius significantly increased in all conditions, while the muscle stiffness of the lower trapezius significantly decreased in all conditions. As for the spinal alignment, the dimple distance data values significantly decreased for the cross-bag style. Conclusions : This study demonstrated that walking with a heavy bag, regardless of the bag-carrying style, increased muscle stiffness around the shoulders in adults with rounded shoulder posture, and walking with a cross-bag also induced changes in spinal alignment.

• International Journal of Contents
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• v.7 no.2
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• pp.59-63
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• 2011

The aim of our study was to evaluate the immediate effects of an 830-nm Aluminium gallium arsenide (GaAlAs) laser, by examining the changes, in pressure-pain threshold (PPT) and tenderness at 3 kg of the myofascial trigger point (MTrP) of the upper trapezius muscle in visual display terminal (VDT) workers in comparison with placebo treatment. Thirty VDT workers (13 males, 17 females) with complaints of upper trapezius muscle were recruited. All participants were given either active GaAlAs laser (830 nm wavelength, 450 mW, 9 J at point) or placebo GaAlAs laser, according to the double-blinded and placebo-controlled trial. Both active and placebo low-level laser therapy (LLLT) treatments showed no significant effect on PPT and tenderness at 3 kg. These results suggest that a higher dosage may be necessary to produce immediate effects when applying LLLT to the MTrP of relatively large muscles such as the upper trapezius muscle.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.6 no.1
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• pp.103-114
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• 2008

The purpose of this study is to use standard and downward slope of the keyboards with taping to influence electromyography of upper trapezius. The effect of taping raise a medical criticism, but we do an experiment on two kind of keyboards with taping in order to decrease stress of shoulder. Subjects are in Seonam university whose are twelve healthy adults in their twenties. This experiment used two kind of keyboards. Standard keyboard's degree is $0^{\circ}$ and another keyboard's degree is $-7.5^{\circ}$. Application of Kinesio taping attached belly of upper trapezius tightly. Measurement of electromyography attached posterior of acromion process go by spinous process of 7th cervical vertebra and upper trapezius. Method of analysis used Repeated measure two-way ANOVA. Result of this experiment, both shoulder's muscle activity increased(p<.05) when used standard keyboard and downward keyboard with taping used. We compared muscle activity that used downward keyboard than standard keyboard. Statistically, it dosen't increase in neck and shoulder(p>.05). Therefore, using a keyboard with upper trapezius's taping in order to decrease muscle activity isn't influenced.

• Physical Therapy Korea
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• v.19 no.1
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• pp.46-55
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• 2012

The purpose of this study was to investigate the effect of the two different types of chairs on trapezius muscle activation during dictation tasks. Seventeen university students, each of whom were within ${\pm}1$ standard deviation of the mean Korean standard body size, voluntarily participated in this study. Surface electromyography was used to collect electrical signals from both the upper and lower trapezius muscles. Amplitude Probability Distribution Function (APDF) was performed to analyze the muscle activity. The findings of this study were 1) The backrest-point height of the auditorium chair and the height, length and width of the connected desk were shorter than what was suggested by the KS. Another difference was that the auditorium chair had a bigger angle of the backrest compared to the classroom chair. 2) Regarding within-subject effect the sole statistically significant difference was found between activation of the upper trapezius muscle. The upper trapezius muscle's %RVC in the APDF 10th-50th-90th percentile was statistically higher for participants sitting in the auditorium chair than for participants sitting in the classroom chair (p<.05). 3) There was an interaction effect between the 'two chair-types' and the 'two muscle-sides' in the APDF 10th-50th percentile (p<.05). 4) There was an interaction effect between the 'two chair-types' and the 'three gaze-direction' in the APDF 90th percentile (p<.05). The findings of this study indicated that maintaining a writing posture for a prolonged period of time in an auditorium chair significantly increased the left upper trapezius muscle activation compared to a classroom chair.

• Journal of the Korea Convergence Society
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• v.11 no.1
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• pp.83-88
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• 2020

The purpose of this study was to investigate the optimal position among three manual muscle tested positions for upper trapezius in which to obtain an isolated upper trapezius EMG signal for the normalization of upper trapezius muscle EMG activity. A total of 28 healthy adult men participated in the experiment. The UT (upper trapezius) and LS (levator scapulae) muscle activities were measured using the TeleMyo 2400T and analyzed using MyoResearch software. The muscle activity of the US and LS was measured by performing three manual muscle test positions for the upper trapezius. The UT/LS ratio during the S-MVIC was 80.25 and was significantly higher than that during the T-MVIC (76.50; p = 0.011) and the C-MVIC (60.95; p < 0.001). And, the UT/LS ratio during the T-MVIC and was significantly higher than that during the C-MVIC (p < 0.001). Based on the results of present study, we suggest a switch from T-MVIC to S-MVIC for the independent normalization reliability of upper trapezius EMG activity. The UT muscle strength or normalization test using S-MVIC will be able to measure muscle strength or activity of UT compared to previous measurement methods.

• Physical Therapy Korea
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• v.20 no.3
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• pp.19-26
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• 2013

The smart-phone has become a necessity for most people. In this study, we determined that using a smart-phone for 20 minutes can cause increased neck and shoulder muscle activities and fatigue. Seventeen healthy male smart-phone users who attended Yonsei University played a smart-phone game for 20 minutes and changes in their bilateral cervical erector spinae and upper trapezius muscle activities and fatigue were measured. To assess muscle activities and fatigue, we used the following variables: the median frequency, the 50th percentile Amplitude probability distribution function (APDF) value (median load), and the discrepancy in the 90th percentile APDF value and the 10th percentile APDF value (APDF range). A paired t-test was used to compare pre-smart-phone-use status with post-smart-phone-use-status. The median frequency of the bilateral cervical erector spinae and the upper trapezius decreased significantly after 20 minutes of smart-phone use (p<.05). In addition, the 50th percentile APDF value of the bilateral cervical erector spinae and the right upper trapezius increased significantly (p<.05). The APDF range of the bilateral cervical erector spinae and the upper trapezius also increased significantly (p<.05). However, the 50th percentile APDF range of the left upper trapezius was not significantly different (p>.05). These findings suggest that using smart-phones for 20 minutes can induce muscle fatigue and increased neck and shoulder muscle activities.

• PNF and Movement
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• v.19 no.2
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• pp.269-278
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• 2021

Purpose: This study aimed to investigate effective cueing methods for selective muscle activation of the serratus anterior. Methods: Based on the inclusion criteria, 26 healthy adults, both males and females, were recruited for the measurement of muscle activation of the upper trapezius and serratus anterior muscles while performing basic movements in knee push-up plus (KPP) and dynamic hug (DH) positions using five different cueing methods. An electromyogram was used to measure muscle activation, and both muscle activation and muscle ratio (serratus anterior/upper trapezius) were compared during the basic movements and different cueing methods. The cueing methods were trapezius verbal cueing, trapezius verbal cueing + trapezius tactile cueing, emphasis verbal cueing, serratus anterior tactile cueing, and trapezius verbal cueing + trapezius tactile cueing + serratus anterior tactile cueing. Results: The results of the study showed that there was a significant difference in the muscles for the two exercises (p < 0.05). There was also a significant difference between the cueing methods (p < 0.05). The correlative effect between the muscles and cueing methods was also significant (p < 0.05). The muscle ratio in trapezius verbal cueing + trapezius tactile cueing + serratus anterior tactile cueing during KPP and DH was higher than in basic movements and other cueing methods. This confirms that trapezius verbal cueing + trapezius tactile cueing + serratus anterior tactile cueing is an effective cueing method for selective activation of the serratus anterior during KPP and DH. This study also demonstrated that cueing by a therapist may both increase and decrease selective muscle activation. Conclusion: Through this study, an effective cueing method to selectively activate the serratus anterior may be suggested, and the results of this study may provide basic information regarding future studies and clinical practice.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.25 no.1
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• pp.29-36
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• 2019

Background: This study was conducted to investigate the effect of leg lift difference on the serratus anterior muscle and the upper trapezius muscle when a subject with winged scapula performs a scapula protraction exercise in a four-leg crawling posture. Method: Twenty normal adults and 20 subjects with winged scapula participated in the experiment. Surface EMG recordings were collected from serratus anterior muscle and back trapezius muscle during scapula protraction exercises. Scapular winging is measured with the lifting distance of scapula retraction to the back using an electronic digital caliper. In two groups of four-leg crawling posture, the two legs support, the dominant leg lifting, and the non-dominant leg lifting, including the scapula protraction, were performed. To examine the difference between groups in the variance analysis, the Bonferroni correction was used (significance level ${\alpha}=.017$). Statistical significance level ${\alpha}$ was .05. Results: There was a significant difference in serratus anterior muscle and upper trapezius muscle during push-up plus exercise in leg lifting in four-leg crawling posture, but there were no significant differences in muscle activity between serratus anterior muscle and upper trapezius muscle, and there was no significant difference according to the presence or absence of scapular winging. Conclusion: For the shoulder stability of the ipsilateral side with the serratus anterior muscle, the leg-lifting posture is effective in the four-leg crawling, and also when a subject with winged scapula chooses an exercise, lifting the ipsilateral side of leg with scapula protraction exercises at the same time may have a positive effect on scapula dysfunction.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.30 no.2
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• pp.1-12
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• 2024

Background: This study aimed to determine the effects of pectoralis minor stretching, lower trapezius strengthening exercise with serratus anterior strengthening exercise to find an effective therapeutic exercise for alignment, shoulder range of motion, muscle imbalance of rounded shoulder patient. Methods: This study targeted on a total of 28 male subjects, aged 20s and 30s, and randomly divided the subjects into each group, with 14 subjects each. The experimental group performed pectoralis minor stretching, lower trapezius strengthening exercise, and serratus anterior strengthening exercise, while the control group performed pectoralis minor stretching and lower trapezius strengthening exercise. Results: both group showed an increase in active range of motion for shoulder flexion, a muscle activity of the serratus anterior muscle and the lower trapezius muscle, a decrease in muscle activity of the upper trapezius muscle, and a significant improvement in scapular alignment after the intervention. In the comparison between group, the experimental group showed greater increased shoulder joint flexion range of motion, serratus anterior muscle activity, and decreased upper trapezius muscle activity than the control group. Conclusion: Performing serratus anterior strengthening exercises with pectoralis minor stretching and lower trapezius strengthening exercises is effective for improving the active range of motion in shoulder joint flexion and muscle imbalance

• The Journal of Korean Physical Therapy
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• v.35 no.6
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• pp.167-176
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• 2023

Purpose: Due to the high incidence of shoulder injuries, including shoulder impingement syndrome (SIS), among CrossFit practitioners due to frequent overhead movements, serratus anterior exercises are considered crucial for scapular stabilization in both intervention and prevention. Objective: The objective of this study is to compare the muscle activity and ratios of scapular stabilizing and shoulder girdle muscles between individuals with and without SIS during serratus punch and wall slide exercises, both targeting the serratus anterior muscle, in CrossFit training practitioners. Methods: Surface electromyography was used to compare the muscle activity and activity ratio of scapular stabilizing muscles and shoulder muscles during serratus punch and wall slide exercises in two groups of 20 CrossFit practitioners: ten with SIS and ten without symptoms. Results: The group with SIS showed higher activation of the pectoralis major, upper trapezius, and a higher pectoralis major/serratus anterior and upper trapezius/serratus anterior muscle activation ratio during the serratus punch exercise compared to the group without SIS. Similarly, during the wall slide exercise, the group with SIS exhibited higher activation of the upper trapezius and a higher upper trapezius/serratus anterior muscle activation ratio compared to the group without SIS. However, no significant difference in serratus anterior muscle activation was observed between the two groups. Conclusions: This study highlights the higher activation of the pectoralis major and upper trapezius muscles in CrossFit practitioners with SIS during the serratus anterior exercise, suggesting the importance of minimizing the overactivation of these muscles to prevent impingement syndrome in this population.