• 한국전문물리치료학회지
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• 제29권2호
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• pp.106-116
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• 2022

Background: Shoulder external rotation exercises are commonly used to improve the stabilizing ability of the infraspinatus. However, during exercise, excessive activation of the posterior deltoid compared to the infraspinatus causes the humeral head to move anteriorly in an abnormal position. Many researchers have emphasized selective activation of the infraspinatus during shoulder external rotation exercise. Objects: This study aims to delineate the optimal exercise method for selective activation of infraspinatus by investigating the muscle activities of the infraspinatus and posterior deltoid according to the four shoulder exercise methods and two forearm positions. Methods: Thirty healthy individuals participated in this study. The participants were instructed to perform shoulder external rotation exercises following four exercise methods: sitting external rotation (SIER); standing external rotation at 90° abduction (STER); prone external rotation at 90° abduction (PRER); side-lying external rotation (SLER), and two forearm positions (neutral, supinated). The electromyography (EMG) signal amplitude was measured during each exercise. Surface EMG signals were recorded from the posterior deltoid, infraspinatus, and biceps brachii. Results: EMG results of the infraspinatus and posterior deltoid in PRER, were significantly higher than that of the other exercises (p < 0.01). The EMG ratio (infraspinatus/posterior deltoid) in SIER was significantly higher than that of the other exercises. EMG activation of the posterior deltoid in SIER, PRER, and SLER was significantly higher in neutral than in supinated (p < 0.01). Furthermore, the EMG of the infraspinatus in SIER was significantly higher in neutral than in supinated (p < 0.01). The EMG ratio (infraspinatus/ posterior deltoid) in SIER was significantly higher in neutral than in supinated (p < 0.05.) Contrarily EMG ratios in PRER and SLER were significantly higher in supinated than in neutral (p < 0.05). Conclusion: The results show that clinicians should consider these exercise methods and forearm positions when planning shoulder external rotation exercises for optimal shoulder rehabilitation.

• Journal of Biosystems Engineering
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• 제29권6호
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• pp.531-538
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• 2004

This study examined the muscle fatigue of the erector spinae according to box size during lifting activity. Ten healthy adult man participated in the experiment for lifting the boxes 10 times with 0.2 lift/s frequency. Bilateral surface EMG (Electomyogtamphy) recordings were made regarding M. (Muscle) Longissimus, M. Iliocostal and M, Multifidus activity throughout lifting working. The median frequency in back muscle fatigue was investigated using power spectral analysis of surface EMG. When the box larger than shoulder width was lifted, the muscle fatigue of M, Multifidus was shown larger than one of the other muscles. Accordingly, the result far M. Multifidus can be applied in optimizing design parameter of box. Also, the standard of box width for box makers have to be below about 420 mm, being average shoulder width of adult male.

• 한국전문물리치료학회지
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• 제23권4호
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• pp.55-62
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• 2016

Background: The functioning of the serratus anterior (SA) muscle is essential to normal scapulohumeral rhythm during forward flexion (FF) of the shoulder. Also, SA weakness and overuse of the upper trapezius (UT) is observed in patients with shoulder dysfunction and trapezius myalgia. We designed a combination exercise involving FF and scapular protraction with resistance (CFFSP) to activate the SA muscle and to deactivate the UT muscle. Objects: The purpose of this study was to determine whether or not CFFSP would be more effective in activating the SA muscle than FF alone and FF with scapular protraction (FFP). Methods: Nineteen subjects (12 men and 7 women) participated in this study and performed FF, FFP, and CFFSP at $120^{\circ}$. Surface electromyography was applied to the SA, UT, and pectoralis major (PM) muscles, as was one-way analysis of variance (ANOVA) with repeated measures. Statistical significance was set at .05. Bonferroni adjustment was used to counteract the problem of multiple comparisons, with a statistical level of significance of .017 (.05/3). Results: A statistically significant difference was found in relation to the three positions for the SA muscle (p<.001) and the SA/UT ratio (p=.005) using ANOVA. Significantly different results, depending on the position, were also demonstrated using the Bonferroni post-hoc test for the SA muscle ($FF=28.27{\pm}16.20$, $FFP=45.66{\pm}15.81$, and $CFFSP=62.4{\pm}27.21$) and for the SA/UT ratio ($FF=3.04{\pm}2.14$, $FFP=3.61{\pm}2.38$, and $CFFSP=5.95{\pm}3.01$). Significant differences between the three positions was not found regarding the average amplitude of SA/PM muscle ratio (SA/PM: p=.060). Conclusion: We recommend the use of CFFSP to strengthen the SA muscle at $120^{\circ}$.

• The Journal of Korean Physical Therapy
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• 제25권2호
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• pp.56-63
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• 2013

Purpose: This study was conducted in order to examine how an effective rehabilitation exercise program influences the activity of shoulder muscles, and to help the clinical application of a rehabilitation program, for prevention and relief of pain, adhesion, and joint stiffness of patients who undergo rotator cuff repair. Methods: Nine test subjects were placed randomly into each group for a total of 27 subjects and exercise program interventions according to the group were conducted for six weeks, after which maximum voluntary isometric contraction (%MVIC) value was re-measured for supraspinatus muscle, infraspinatus muscle, serratus anterior muscle, and middle deltoid muscle in all groups in order to compare changes in muscle activity before and after the experiment in order to perform comparative analysis of changes in muscle activity between groups, based on which four experimental hypotheses were confirmed. Results: Changes in muscle activity according to %MVIC showed a statistically significant difference (p<0.01) (p<0.001) in all muscles, except the middle deltoid muscle, and post-verification results showed that changes in muscle activity according to %MVIC were greater in test groups I and II, compared with the control group, for the supraspinatus muscle, infraspinatus muscle, and serratus anterior muscle. Conclusion: Therefore, rehabilitation through use of the methods described above should be applied efficiently in clinical settings and more research in development of much more efficient rehabilitation program interventions must be conducted.

• The Journal of Korean Physical Therapy
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• 제31권4호
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• pp.199-203
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• 2019

Purpose: This study investigated the effects of shoulder protraction exercise according to weight by examining the surface electromyography (EMG) amplitude in the serratus anterior (SA), upper trapezius (UT), and pectoralis major (PM) as well as the activity ratio of each muscle. Methods: Twenty three winging scapula subjects participated in the study. The subjects performed scapula protraction at shoulder $90^{\circ}$ flexion and $60^{\circ}$ horizontal abduction with up to four (none, 1kg, 1.5kg, and 2kg) dumbbells in the supine position. The EMG data were collected from the dominant side muscles during a shoulder protraction exercise according to weight in the supine position. One way repeated measures analysis of variance (ANOVA) was used to compare the normalized activities of the SA, UT, and PM and the ratios of PM/SA and UT/SA. Results: The results showed that the activities of both the SA and UT were highest for the shoulder protraction exercise at 2kg in the supine position. The UT/SA ratio also was the lowest for exercise at 2kg. On the other hand, the activities of both the UT and PM/SA ratio were similar under all conditions. Conclusion: These results show that there is a need to selectively strengthen the SA muscle in the case of patients with the shoulder dysfunction. In particular, it is necessary to weigh 2kg when performing shoulder protraction exercises in the supine position to activate the SA muscle in patients with a winging scapula.

• 대한물리의학회지
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• 제11권2호
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• pp.25-31
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• 2016

PURPOSE: The purpose of this study was to compare the trunk muscle activity according to the direction of upper extremity lifting using elastic band. METHODS: Thirty three healthy individuals participated in this study. Each subject performed upper extremity lifting using elastic band on two different directions (straight and diagonal). And then we compared the muscle activity of respective trunk muscles of both directions. In order to examine the muscle activity of trunk muscle, we used the electromyogram to measure peak and mean torque in shoulder 90 degree flexion with sitting position. Electromyographic activities were recorded from the external oblique, internal oblique, rectus abdominis, and erector spine muscles during upper extremity lifting. RESULTS: As a result, first, there was significant difference between two directions. The muscle activity of ipsilateral external oblique and contralateral internal oblique is significantly increased in both straight and diagonal directions (p<0.05). Second, the muscle activities of external oblique and internal oblique of both side showed significant difference in diagonal direction (p<0.05). Third, the muscle activity of erector spine of both side showed significant difference in straight direction (p<0.05). CONCLUSION: Through this study, it is important that implement diagonal direction exercise at sitting positions to help increasing muscle activity of ipsilateral external oblique and contralateral internal oblique on patients when activating the trunk muscle or stabilizing the trunk.

• The Journal of Korean Physical Therapy
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• 제13권3호
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• pp.769-776
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• 2001

This study were to review of muscle imbalance of head, cervical and shoulder region. Head, cervical and shoulder region is a complicated mechanical unit. interconnected by numerous soft tissue links. These links, or articulation are functionaly and reflexly interdependent on one another. The line of gravity falls anterior to the transverse axis of rotation for flexion and extension of the head and creates a flexion moment. which tends to tut the head forward, is counteracted by tension in the tectorial membrane, and ligamentum nuchae, and by activity of the neck extensors. Therefore, the flexion moment equilibrate with the extension moment. Changing of the equilibrium will make mid cervical straight. It will make forward head posture(FHP) also. FHP makes imbalance of suboccipital muscles, suprahyoid muscles and infrahyoid muscles. It has some relationship with temporomandibular joint, spine and equilibrium of pelvis.

• 한국전문물리치료학회지
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• 제24권4호
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• pp.77-83
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• 2017

Background: Shoulder external rotation exercises are commonly used to improve the stabilizing ability of the infraspinatus. Although the side-lying wiper exercise (SWE) is the most effective shoulder external rotation exercise to maximize infraspinatus activity, the effect of adduction force on the infraspinatus and posterior deltoid has not been demonstrated. Objects: This study was conducted to investigate whether horizontal adduction force increases infraspinatus activity and decreases posterior deltoid activity. Methods: Twenty-eight healthy subjects (male: 21, female: 7; $age=23.5{\pm}1.8years$; $height=170.1{\pm}7.4cm$; $weight=69.4{\pm}9.6kg$) were recruited. Subjects were asked to perform the SWE under two conditions: (1) general SWE and (2) SWE with adduction force using pressure biofeedback. Surface electromyography (EMG) signals of the infraspinatus and posterior deltoid were recorded during SWE. Paired t-tests were used to compare the EMG activity of the infraspinatus and posterior deltoid between the two conditions. Results: Posterior deltoid muscle activity was significantly decreased following SWE with adduction force ($7.53{\pm}4.52%$) relative to general SWE ($11.68{\pm}8.42%$) (p<.05). However, there was no significant difference in the infraspinatus muscle activity between the SWE with adduction force ($28.33{\pm}12.16%$) and the general SWE ($26.54{\pm}13.69%$) (p>.05). Conclusion: Horizontal adduction force while performing SWE is effective at decreasing posterior deltoid activity.

• The Journal of Korean Physical Therapy
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• 제32권2호
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• pp.94-100
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• 2020

Purpose: This study examined the effects of the abdominal hollowing technique applied during plank exercises at different shoulder angles between the ground and the humerus on the abdominal muscle activity Methods: The subjects were 36 male volunteers. They were randomized to perform plank exercises or plank exercises using the hollowing technique at 80˚, 90˚, 100˚, and 110˚ between the ground and the humerus. The abdominis muscles were measured using a surface electromyogram. Independent t-tests examined the changes in the activity of these muscles according to the two exercise methods at each angle. The changes in muscle activity were examined according to the selected angles by one-way analysis of variance. Results: The activity of abdominal muscles was investigated according to the angle between the ground and the humerus during the plank exercise. As a result, the muscle activity increased significantly with decreasing angle in the rectus abdominis, external oblique, and internal oblique·transverse abdominis muscles (p<0.05). In terms of the changes in abdominal muscle activity after hollowing plank exercises at the given angles between the ground and the humerus, an increase in angle resulted in a statistically significant increase in the rectus abdominis muscle activity (p<0.05). The activities of the rectus abdominis, external oblique, and internal oblique/transverse abdominis muscles after hollowing plank exercises showed statistically significant increases (p<0.05) compared to those after plank exercises. Conclusion: The hollowing technique and the increase in the angle between the ground and the humerus may be an effective exercise method for increasing the muscle activity of the abdominis muscles.

• The Journal of Korean Physical Therapy
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• 제36권2호
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• pp.71-77
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• 2024

Purpose: The prolonged use of digital devices has led to the widespread adoption of poor postures, particularly rounded shoulder posture (RSP), associated with shoulder impingement and pain. This study investigates the effects of neuromuscular electrical stimulation (NMES) on RSP in healthy adults. Methods: Thirty adults with RSP were randomly assigned to NMES only, exercise only, or NMES with exercise groups. NMES was applied to the lower trapezius, which was the target muscle in this study, for a total of 2 weeks, 5 times per week, 20 minutes per session. The exercise program included pectoralis minor stretching, wall-slide exercise, dynamic hug exercise with band, and Brugger stretching for upper body with band, which were performed for a total of 2 weeks, 5 times per week, 20 minutes per session. Outcome measures, including the Supine Method (SM) for posture and surface electromyography (EMG) of the lower trapezius for muscle activity, were assessed before the intervention, after 5 sessions, and after 10 sessions. Results: All the groups showed significant changes in the SM and % maximal voluntary isometric contraction (%MVIC) over time (p<0.05). The NMES group had significantly reduced SM at 1 week, while the exercise and combined groups had reduced SM at 2 weeks (p<0.017). All the groups had increased %MVIC at 2 weeks (p<0.017), with no significant differences observed between groups. Conclusion: NMES alone can be as effective as exercise in improving RSP. NMES combined with exercise also showed positive outcomes, thus offering diverse treatment options for this condition.