• Journal of International Academy of Physical Therapy Research
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• v.11 no.4
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• pp.2173-2177
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• 2020

Background: Shoulder horizontal abduction in the prone position (SHAP) has been reported as an effective exercise to strengthen the lower trapezius. However, the effects of pre-emptive scapular posterior tilt on scapular muscle activity and scapulohumeral movements during SHAP have not been examined. Objectives: To examine the effect of the addition of scapular posterior tilt on muscle activity of the trapezius and posterior deltoid, and scapular posterior tilt and shoulder horizontal abduction, during SHAP. Design: Cross-sectional study. Methods: Fifteen healthy male subjects performed two types of SHAP: general and modified SHAP (SHAP combined with pre-emptive scapular posterior tilt). To perform modified SHAP, pre-emptive scapular posterior tilt training was performed prior to the modified SHAP. Muscle activity of the middle and lower trapezius and posterior deltoid, and the amount of scapular posterior tilt and shoulder horizontal abduction, were measured during two types of SHAP. Results: Muscle activity of the lower trapezius and scapular posterior tilt was significantly increased during the modified SHAP, while muscle activity of the posterior deltoid and the amount of shoulder horizontal abduction were significantly decreased. However, the middle trapezius muscle activity did not change during the modified SHAP. Conclusion: The SHAP with pre-emptive scapular posterior tilt can be useful to strengthen the lower trapezius.

• Journal of The Korean Society of Integrative Medicine
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• v.5 no.2
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• pp.19-23
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• 2017

Purpose: The purpose of this study was to determine the muscle activity ratio according to the shoulder abduction angle by identifying the mean muscle activities and calculating the muscle ratios for use in developing strengthening methods. Methods: The participants were healthy adults in their 20s (n=19). The activity of the deltoid middle, upper trapezius, middle trapezius, and lower trapezius muscles was measured by 8-channel surface electromyography. Muscle activity was measured during 4 conditions of angle of shoulder abduction: $30^{\circ}$, $60^{\circ}$, $90^{\circ}$, and $120^{\circ}$. The data used in the analysis were the root mean square and % total muscle activity values. Results: The root mean square values for the deltoid middle, upper trapezius, middle trapezius, and lower trapezius muscles showed significant differences. No significant differences were detected in the % total muscle activity of the deltoid middle, upper trapezius, middle trapezius, or lower trapezius muscles. Conclusion: Future studies aimed at developing selective shoulder abductor muscle strengthening methods are likely to provide more effective results by using muscle activity ratios.

• Physical Therapy Korea
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• v.18 no.1
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• pp.47-56
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• 2011

The purpose of this study was to compare electromyography (EMG) activity for the middle and lower trapezius muscle according to various shoulder abduction angles. Thirty healthy male subjects were recruited for this study. Each subject performed three repetitions of horizontal abduction at $75^{\circ}$, $90^{\circ}$, $125^{\circ}$, $160^{\circ}$, and $180^{\circ}$ of shoulder abduction angle in a prone position. Surface EMG activity was recorded from the middle and lower trapezius while the subjects held for five seconds at a predetermined position. The EMG activity was normalized using the maximal voluntary isometric contraction (MVIC) elicited using a manual muscle testing technique. A repeatedly measured ANOVA was performed by Bonferroni's post hoc test. The EMG activity of the middle and lower trapezius was significantly different among shoulder abduction angles (p<.05). The greatest level of muscle activity for the middle and lower trapezius were demonstrated at $90^{\circ}$ and $160^{\circ}$ of shoulder abduction angle, respectively. These results suggest that middle and lower trapezius strengthening exercise and manual muscle testing should be performed at different shoulder abduction angles.

• 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

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.4
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• pp.213-220
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• 2023

Purpose : The purpose of this study is to investigate the effect of each lower trapezius muscle exercise performed according to the abduction position (Y type - shoulder joint abduction 145 °, T type - shoulder joint abduction 90 °, and MPC type - shoulder joint 45 ° abduction) of the shoulder joint on the muscle activity of the round shoulder and lower trapezius muscle. Methods : This study was conducted on 31 adult men and women. Through random assignment, they were assigned to the Y group, T group, and MPC group. A 4-week intervention was performed for each group of 31 subjects who participated in the experiment, and shoulder height and lower trapezius muscle activity were measured before and after the intervention. Shoulder height measurement is a test to measure rounded shoulder posture. When the value is low, it means that rounded shoulder posture is improved. The muscle activity of the lower trapezius muscle was measured using the %MVIC method, and when the value is high, it means that the lower trapezius muscle is active. All measured data were verified using dependent t-tests for before and after comparisons and one-way analysis of variance for comparisons between groups. Results : The results of this study showed a significant decrease after intervention only in shoulder height. Muscle activity of the lower trapezius muscle decreased after intervention, but did not show a significant difference. Both variables showed no significant differences between groups. Conclusion : The results of this study show that three lower trapezius muscle exercises were performed on subjects in rounded shoulder posture. All three groups showed a significant decrease in the shoulder height value, a method of measuring rounded shoulder posture, and no significant differences between groups could be confirmed. Therefore, all three exercises can be considered effective in reducing shoulder posture.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.3
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• pp.109-115
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• 2019

Purpose : The purpose of this study was to investigate the activity of muscles around the scapulothoracic muscles according to the angle of shoulder joint abduction in the prone position. Methods : The participants included 15 adult males who had not undergone orthopedic surgery and did not have shoulder joint impairments. We measured the muscle activity of the upper trapezius, middle trapezius, lower trapezius, and serratus anterior at $120^{\circ}$, $90^{\circ}$, and $60^{\circ}$ shoulder joint abduction angles. Results : There was a significant difference in the comparison of muscle activity in the upper trapezius, middle trapezius, and serratus anterior muscles according to the shoulder joint abduction angle (p<.05). The results of the post test showed that the upper trapezius was significantly different between $120^{\circ}$ and $60^{\circ}$ (p<.01), and the middle trapezius was significantly different between $90^{\circ}$ and $120^{\circ}$, and between $90^{\circ}$ and $60^{\circ}$ (p<.05). There was a significant difference in the serratus anterior between $120^{\circ}$ and $90^{\circ}$ (p<.01), and $120^{\circ}$ and $60^{\circ}$ (p<.01). Conclusion : The results of this study could be used to determine an effective shoulder joint abduction angle to reduce muscle activity of the upper trapezius and increase muscle activity of the middle trapezius, lower trapezius, and serratus anterior.

• Journal of The Korean Society of Integrative Medicine
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• v.1 no.4
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• pp.85-92
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• 2013

PURPOSE : The purpose of this study was to determine the effects of the length of the pectoralis minor on muscle activity of trapezius and pectoralis major in subjects in subjects with shortened pectoralis minor muscle. METHOD : The subjects was participated in 36 with shortened pectoralis minor muscle. All subjects was examined the length test of pectoralis minor muscle. we divided by 3 groups. group I(n=12) was for 4~5cm of length of pectoralis minor muscle, group II(n=12) was for 5~6cm, group III(n=12) was for above 6cm. The EMG activity of upper trapezius, middle trapezius, lower trapezius and pectoralis major muscle activity was measured by surface EMG while elevationg the right arm in sitting postion with head to the neutral, shoulder elevation $135^{\circ}$ with scaption. Data were analyed using one-way ANOVA with a Tukey post hoc test. RESULT : The EMG activity differed significantly among the three groups(p<.05). The group III had significantly greater EMG activity of upper trapezius and pectoralis major muscles than group I and II(p<.05). Also, The group III had significantly smaller EMG activity of lower trapezius muscle than group I and II(p<.05). But, these was no significant difference in the EMG activity of the middle trapezius muscle among the groups (p.05). CONCLUSION : Therefore, the result of this study should be suggested that the shortened pectoralis minor muscle was affected the EMG activity of the upper trapezius, lower trapezius and pectoralis major. Ultimately the length of the pectoralis minor muscle leads to the muscle imbalance in shoulder girdle.

• Journal of The Korean Society of Integrative Medicine
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• v.12 no.3
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• pp.143-153
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• 2024

Purpose : Forward head posture (FHP), characterized by the anterior positioning of the head relative to the spine, is a common postural deviation that can lead to neck pain, reduced mobility, and muscle imbalances. Recently, high-frequency deep heat therapy (HFDT) has been gaining attention for the intervention of FHP. This research aims to investigate the efficacy of HFDT in comparison to instrument assisted soft-tissue mobilization (IASTM) for treating FHP among 30 young adults. Methods : Participants were randomly assigned to either the HFDT or IASTM group. The study focused on examining changes in neck joint mobility, pain thresholds, rounded shoulder distance, lower trapezius muscle strength, and neck dysfunction. Measurements were taken before and after the interventions. Paired t-tests were used for within-group analyses, and independent t-tests were employed for between-group comparisons. The statistical significance level α was set to .05. Results : Statistically significant improvements were observed across all measured parameters in both groups (p<.05). The HFDT group showed significantly greater enhancements in neck joint mobility, pain thresholds, rounded shoulder distance, lower trapezius muscle strength, and neck dysfunction parameters. Specifically, HFDT was more effective than IASTM in improving neck joint mobility, right upper trapezius pain threshold, left rounded shoulder distance, and right lower trapezius strength. The only exceptions were neck flexion range of motion, left upper trapezius pain threshold, right rounded shoulder distance, and left lower trapezius strength, where no significant differences were found between the groups. Conclusion : The findings suggest that HFDT, by combining the benefits of high-frequency therapy and manual therapy, effectively alleviates upper trapezius muscle pain and tension, enhances neck mobility, and strengthens lower trapezius muscles. Thus, HFDT could be considered a valuable intervention for clinicians aiming to address FHP and associated musculoskeletal problems.

• Physical Therapy Korea
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• v.19 no.2
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• pp.12-19
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• 2012

The purpose of this study was to assess the influence of scapular alignment on the electromyographic (EMG) activity of the trapezius in people with a short pectoralis minor muscle. For the study, we recruited 15 volunteers who had positive results for short on a pectoralis minor muscle length test. We measured the EMG activity of the upper, middle and lower trapezius muscles. The participants lifted their dominant arm to ear level with the thumb up toward the ceiling in the prone position on a table with the shoulder at a flexion angle of 180 degrees and a horizontal abduction angle of 120 degrees. Scapula was manually aligned by an experienced physical therapist prior to arm lift for the scapular alignment condition. A paired t-test was used to compare the effects of scapular alignment on the EMG activity of the trapezius muscles. The EMG activity of the lower trapezius muscle was significantly increased during the test with the scapular alignment compared to that without scapular alignment (p<.05), while the upper trapezius and middle trapezius exhibited no significant difference between the two conditions (p>.05). The findings of this study suggest that a scapular alignment may alter the recruitment of the lower trapezius muscle during arm lifting in the prone position in people with a short pectoralis minor muscle.

• Physical Therapy Korea
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• v.20 no.3
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• pp.27-35
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• 2013

The aim of this study was to compare the electromyographic (EMG) activity levels of the scapular upward rotators [upper trapezius (UT), lower trapezius (LT), and serratus anterior (SA)] and other scapular muscles [posterior deltoid (PD), levator scapulae (LS), and infraspinatus (IS)] during isometric lower trapezius exercises. Twenty males with no medical history of shoulder pain or upper extremity disorders were recruited for this study. EMG activity was recorded from the UT, LT, SA, PD, LS, and IS while subjects performed three different exercises: Prone arm lift (PAL), Backward rocking diagonal arm lift (BRDAL), Modified Prone Cobra (MPC). One-way analysis of variance (ANOVA) was used to determine any significant differences among the three exercises. A lower relative activation of UT, LT, and SA was seen with the MPC than with the other exercises (p<.05). The relatively lower activation of the UT identified, the MPC exercise as the preferred choice for preferential strengthening the LT (p<.05). However, a higher activation in the PD, LS, and IS occurred with the MPC than with the other exercises (p>.05). The recruitment pattern of synergist varied depending on the exercise posture. These findings suggest that exercise posture is an important factor in the selection of strengthening exercise for weak muscle.