• Physical Therapy Korea
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• v.17 no.1
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• pp.1-8
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• 2010

The purpose of this study was to compare EMG activity for pectoralis major muscle during shoulder movement with various abduction angle and rotation position in supine position. Fifteen healthy subjects were recruited for this study. All subjects performed shoulder horizontal adduction holding a 2 kg dumbbell in shoulder abduction $40^{\circ}C$, $70^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$, $160^{\circ}C$ with shoulder neutral, internal rotation (IR), and external rotation (ER). Surface EMG activity was recorded from pectoralis major clavicle part and pectoralis major sternum part for 5 seconds and EMG activity was normalized to the value of maximal voluntary isometric contraction (%MVIC). Dependent variables were examined with 3 (Neutral, IR, ER) ${\times}$ 5 ($40^{\circ}C$, $70^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$, $160^{\circ}C$) analysis of variance with repeated measures. The EMG activity of pectoralis major muscle was significantly different between shoulder abduction angles and between shoulder rotation positions (p<.05). The highest value of EMG activity of pectoralis major clavicle part among shoulder abduction angles was in $70^{\circ}C$ and, $90^{\circ}C$ in that order. The highest value of EMG activity of pectoralis major sternum part among shoulder abduction angles was in $130^{\circ}C$ and, $90^{\circ}C$ in that order. According to the rotation degree, shoulder ER showed the highest value and IR showed the lowest value in both muscle parts. These results suggest that shoulder abduction $70^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$ will be effective during manual muscle testing (MMT) and strengthening exercise for pectoralis major muscle. It is also supposed that shoulder ER is the efficient posture for strengthening of pectoralis major muscle.

• Physical Therapy Korea
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• v.17 no.1
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• pp.77-85
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• 2010

This study was conducted to find the effects of scapular taping on muscle activities of the scapular rotators and upper trapezius pain in subjects with upper trapezius pain. Fifteen male subjects were recruited from Yonsei University for this study. Muscle activity of upper trapezius, lower trapezius, and serratus anterior was measured using surface electromyography. Visual analog scale was used for measuring upper trapezius pain. The subjects were asked to maintain $90^{\circ}$ shoulder flexion position with holding a 1 kg dumbbell in standing position. Scapular taping was applied over the muscle belly of the upper trapezius and attached parallel with the lower trapezius muscle fibers. For normalization, % maximal voluntary isometric contraction (%MVIC) was conducted. Paired t-test was applied to compare the muscle activities of scapular rotator and upper trapezius pain before and after applying the scapular taping. The muscle activity of the upper trapezius muscle and serratus anterior decreased significantly after tape application (p<.05). However, no significant difference was observed in lower trapezius muscle. The level of pain in the upper trapezius muscle significantly decreased after tape application (p<.05). The results of this study suggest that scapular taping can be used an additional therapy for reducing muscle activity of upper trapezius, serratus anterior and upper trapezius pain during shoulder flexion in patient with upper trapezius pain.

• The Journal of Korean Physical Therapy
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• v.28 no.2
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• pp.106-111
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• 2016

Purpose: The aim of this study is to determine the effect of glenohumeral (GH) rotation position in modified knee push-up plus exercise (MKPUP) by examining the surface electromyography (EMG) amplitude in serratus anterior (SA), pectoralis major (PM), and upper trapezius (UTz) and the activity ratio of each muscle. Methods: A total of 22 healthy subjects volunteered for the study. Each subject performed the MKPUP at $0^{\circ}$, $45^{\circ}$, and $90^{\circ}$ of GH joint internal rotation. EMG of the SA and PM, UTz was compared between GH rotation positions and each muscle activity ratio. EMG was used to measure the muscle activity in terms of ratios to maximal voluntary isometric contraction (MVIC). Results: The difference in EMG activity during the exercise in three GH joint internal rotation positions was observed with the SA and the PM. The greater the GH joint internal rotation angle was, the lower the activity of the PM. In contrast, the SA showed higher activity. However, the activity of UT was similar under all conditions. The ratio of the SA and the PM was considerably greater at $90^{\circ}$ GH joint internal rotation than at $0^{\circ}$ and $45^{\circ}$. Conclusion: When excessive activation of the PM or imbalanced activation between the PM and the SA occurs, the MKPUP exercise is most effective at $90^{\circ}$ of GH joint internal rotation. Use of this position would be a beneficial strategy for selective strengthening of the SA and minimizing PM activation.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.1
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• pp.63-73
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• 2015

The purpose of this study was to examine EMG activities and VMO/VL ratio of the vastus medialis oblique, and vastus lateralis during step up exercise according to ankle and knee positions in soccer players with patellofemoral pain syndrome. Methods: Subject(patellofemoral pain syndrome, PFPS: n=8 and without PFPS, non PFPS; NPFPS: n=8) perfomed step up exercise at each knee and ankle position(knee flexion $30^{\circ}$, $60^{\circ}$, and $90^{\circ}$, ankle internal rotation $30^{\circ}$, neutral, and external rotation $30^{\circ}$) while EMG activity was collected. The EMG signals were expressed by the % maximal voluntary isometric Contraction(%MVIC) values. Statistical analysis consisted of two way repeated measures analysis of variance with post hoc analysis. Results: Main results were as follows: 1) EMG of VMO, and VL was tend to be lower in PFPS compared to NPFPS. 2) EMG of VMO and VL with knee flexrion $60^{\circ}$ was significantly higher the results with knee flexion $30^{\circ}$, and $90^{\circ}$. VMO and VL with ankle external rotation $30^{\circ}$ was significantly higher the results with internal rotation $30^{\circ}$ and neutral position. Conclusion: Considering the EMG activity was reduced due to the to the PFPS and that performing step up with knee flexion $60^{\circ}$ with ankle external rotation $30^{\circ}$ position may provide the most effective condition for patients with patellofemoral pain syndrome.

• PNF and Movement
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• v.15 no.2
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• pp.167-176
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• 2017

Purpose: This study investigated the effect of core and abdominal muscle-strengthening exercises on muscle activity in the lower extremity on unexpected perturbation. Methods: Twenty subjects were randomly divided into the core exercise group (n=10) or the abdominal muscles strengthening group (n=10). The two groups performed their exercises during three sessions a week for a total of four weeks. The muscle activity in the lower muscles (rectus femoris, biceps femoris, tibialis anterior, gastrocnemius) was assessed using surface electromyography (EMG) and normalized maximal voluntary isometric contraction (MVIC) before and after the exercises. Results: An increase in the tibialis anterior activity after the core and abdominal muscles strengthening exercises was found after four weeks. A significant difference in the pre- and post-exercise was found. The gastrocnemius muscle activity increased in the core exercise group more than the abdominal muscles strengthening group. However, the difference was not significant. Conclusion: The results of this study suggest that the core and abdominal muscles strengthening exercises increased the tibialis anterior muscle activity. It is expected to help make more balance ability that affect who has abdominal muscles weakness.

• Physical Therapy Korea
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• v.11 no.1
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• pp.19-25
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• 2004

The purpose of this study was to investigate the effects of backrests of varying degrees ($90^{\circ}$, $100^{\circ}$, $110^{\circ}$) on three abdominal muscles (upper rectus abdominis, external oblique, internal oblique) and back extensor activation during lower extremity exercise. The three different conditions during bilateral knee extention exercise were: (1) leaning on a chair with a $90^{\circ}$ backrest, (2) leaning on a chair with a $100^{\circ}$ backrest, (3) leaning on a chair with a $110^{\circ}$ backrest. Fifteen healthy muscle subjects (mean age=24.2 years [SD=2.96], mean height=175.6 cm [SD=7.46], mean weight=69.1 kg [SD=7.36]) with no history of neuromusculoskeletal disease voluntarily participated in this study. Electromyography was used to collect muscle activation, and the muscle activation was expressed as a percentage of maximal voluntary isometric contraction (%MVIC). Repeated one-way analysis of variance (ANOVA) was used to determine the statistical significance. The results were as follows: (1) upper rectus abdominis, external oblique, internal oblique activation measured significantly lower. (2) measured significantly lower when lower degree.

• Journal of Korean Physical Therapy Science
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• v.13 no.3
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• pp.15-25
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• 2006

The purpose of this study was to investigate effects of different chair type (with backrest chair and without backrest chair) and pelvic position (anterior pelvic tilting and posterior pelvic tilting) on three abdominal muscles (upper rectus abdominis, external oblique, internal oblique) and back extensor activation during lower extremity exercise. The four different conditions during bilateral knee extension exercise were: (1) leaning on backrest chair with anterior pelvic tilting, (2) leaning on backrest chair with posterior pelvic tilting, (3) anterior pelvic tilting without backrest chair, and (4) posterior pelvic tilting without backrest chair. Fifteen healthy male subjects with no history of neuromusculoskeletal disease voluntarily participated in this study. Electromyography (EMG) was used to collect muscle activation data, and muscle activation data was expressed as a percentage of maximal voluntary isometric contraction (%MVIC). One-way repeated analysis of variance (ANOVA) was used to determine the statistical significance, and Bonferroni comparison was used as a post hoc test. The results of this study were the following: (1) Erector spinae activation was significantly lower in posterior pelvic tilting without backrest compared with that in leaning on backrest chair with anterior pelvic tilting. (2) Upper rectus abdominis activation was significantly lower than erector spinae in all four different chair type and pelvic tilting conditions.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.2
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• pp.215-223
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• 2011

Purpose: The purpose of this study was to determine the effect of leg muscle activation by applying proprioceptive neuromuscular facilitation (PNF) arm patterns to unilateral upper extremities under the condition of both open and closed kinetic chains in a seated position. Methods: Twenty-two healthy subjects participated in this study. Four PNF patterns were applied to each subject's unilateral upper extremity. EMG data were collected from the vastus medialis, biceps femoris, tibialis anterior and gastrocnemius. The measured EMG data were digitized and processed to root mean square (RMS) and expressed as percentage maximal voluntary isometric contraction (%MVIC). The data were analyzed using two-way analysis of variance (ANOVA) with repeated measures to determine the statistical significance. Results: The results of this study were summarized as follows: Firstly, in comparison to muscle activation of the biceps femoris, there was a significant increase in the D2 flexion pattern when it was compared with D2 extension pattern and when it was compared with D1 flexion pattern (p<.05). Secondly, there was a significant increase in the muscle activation of the vastus medialis and tibialis anterior with a closed kinetic chain rather than an open kinetic chain (p<.05). Conclusion: In conclusion, in order to increase muscle activation of the biceps femoris, the D2 flexion pattern can be applied, regardless of kinetic chain. In addition, in order to increase muscle activation of the vastus medialis and tibialis anterior, four arm patterns can be applied with a closed kinetic chain.

• The Journal of Korean Physical Therapy
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• v.25 no.3
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• pp.149-154
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• 2013

Purpose: Spinal instability due to weakness of abdominal muscles is one of the major causes that induces low back pain (LBP). The purpose of this study was to investigate any differences in abdominal muscle activity during curl up, roll out, and jack knife exercises using a swiss-ball or sling. Methods: Twenty healthy subjects were randomly assigned into either a swiss-ball exercise group (SBEG) or a sling exercise group (SEG). Subjects performed curl up, roll out and jack knife exercises using the swiss ball or sling. Activity of abdominal muscles (rectus abdominis and external oblique muscle) was assessed using surface EMG and normalized maximal voluntary isometric contraction (MVIC). The significance of differences between the sling exercise group and the swiss-ball exercise group was evaluated by the independent t-test. Results: These Results indicated that activities of rectus abdominis on right and left of the SEG during the curl up exercise were significantly greater than the SBEG. During the roll out exercise, activity of the abdominal muscle was not significantly different between the SEG and SBEG. In addition, during the jack knife exercise, activities of the right rectus abdominis and left external oblique muscle in the SEG were significantly greater than the SBEG. Conclusion: In conclusion, activity of the abdominal muscles was maximized when curl up and jack knife exercise were performed using the sling rather than the swiss-ball. Therefore, if increased activation of the abdominal muscle is the goal of an exercise program, curl up and jack knife exercises may be useful.

• The Journal of Korean Physical Therapy
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• v.32 no.4
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• pp.210-216
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• 2020

Purpose: This study examined the effects of curl-up using XCO^® on trunk muscle activation in healthy adults. Methods: This study design was a single-blind randomized controlled trial. Twelve participants were enrolled in this study. The subjects were instructed to perform curl-up exercise in STCU (straight curl-up), LTCU (left twist curl-up), RTCU (right twist curl-up), TWCU (twist curl-up), and PPCU (power push curl-up). Electromyography was used to assess the percent maximal voluntary isometric contraction (%MVIC) of the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and erector spinae (ES) muscles. The data were analyzed using two-way ANOVA with a repeated measure. The statistical significance level was set to α=0.05 Results: The IO showed significant differences in the main effect of the group and the interactions between the group and exercise (p<0.05). In particular, the IO represented the interactions between group and exercise in the RTCU and PPCU (p<0.05). The RA, EO, and ES did not show significant interactions between the group and exercise (p>0.05). The RA, IO, and EO showed significant differences in the main effect of the group (p<0.05). The EO showed a significant difference in the main effect of exercise (p<0.05). Conclusion: These findings suggest that XCO^® can be used to increase the muscle activation of the internal oblique, which is the lumbar stabilizing muscle, when XCO^® is combined in the curl-up exercise with rotation. In the future, research on the intensity, frequency, and duration of XCO^® exercise will be needed according to the individual characteristics and preferences.