• Physical Therapy Korea
• /
• v.23 no.2
• /
• pp.75-83
• /
• 2016

Background: Several studies have discussed diverse exercise methods considered to be useful for the selective contraction of the vastus medialis oblique (VMO) muscle for the treatment of patellofemoral pain syndrome. Some studies have reported that exercise methods, including hip adduction, in closed kinetic chain exercises are more effective in terms of the muscle activation of the VMO and the timing of the muscle's initial contraction. We focused on isometric contraction during a closed kinetic chain exercise with hip adduction. Objects: The purpose of this study was to examine muscle activation in the VMO and the vastus lateralis (VL) and the onset time difference between their initial contractions via closed kinetic chain isometric quadriceps femoris exercises including hip adduction. Methods: In total, 36 healthy subjects adopted two hip positions during isometric contraction of the quadriceps femoris in a closed kinetic chain exercise (hip neutral and hip adduction position). Statistical analyses were conducted using a paired t-test (${\alpha}=.05$). Results: Isometric contraction of the quadriceps femoris in a closed kinetic chain exercise caused a greater increase in VMO muscle activity in the hip adduction position [$52.68{\pm}22.21$ percentage of maximal voluntary isometric contraction (%MVIC)]than the hip neutral position ($43.43{\pm}19.85%MVIC$). The onset time difference (VL-VMO) decreased more in the hip adduction position ($-82.14{\pm}34.2ms$) than the hip neutral position ($73.94{\pm}2.94ms$). Conclusion: We recommend this exercise as a clinically useful therapeutic method for patients with patellofemoral pain syndrome due to weakening of the VMO muscle and lateral inclination of the patella.

• Physical Therapy Korea
• /
• v.11 no.3
• /
• pp.51-58
• /
• 2004

The purpose of this study was to compare the postural muscle activity during wearing a lead apron with and without applying waist belt at working posture. Ten healthy male subjects were recruited for this study. Electromyography using a surface EMG recorded the activity of the splenius capitis, trapezius, and erector spinae. EMG activity was recorded at quiet standing, 45 degrees of neck flexion, 45 degrees of neck flexion with 15 degrees of trunk flexion. The testing order was selected randomly. The subjects were asked to maintain the each posture for 3 minutes. The mean root mean square (RMS) of EMG activity was calculated. EMG activity was normalized using the maximum voluntary isometric contraction (MVIC) elicited using a manual muscle testing technique. Two-factor repeated measures analysis of variance (ANOVA) was used to compare the average RMS value of EMG activity for each condition. The EMG activity of trapezius muscle was significantly decreased with applying waist belt (p<.05). The muscle activity of splenius capitis and erector spinae showed significant difference according to postures (p<.05). These results suggest that applying waist belt during wearing a lead apron will be useful to prevent shoulder pain.

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

• PNF and Movement
• /
• v.14 no.2
• /
• pp.131-137
• /
• 2016

Purpose: The purpose of this study was to compare muscle activities in the frontal plane and scapular plane of the middle fiber and lower fiber of the trapezius muscle at different shoulder abduction angles. Methods: Twenty male and female students in their 20s participated in this study. Each subject maintained shoulder abduction at $75^{\circ}$, $90^{\circ}$, $125^{\circ}$, and $160^{\circ}$ in a standing position and repeated motions three times each in the frontal plane and the scapular plane. While maintaining the motions for 10 seconds in each posture, surface electromyography (EMG) was used to measure muscle activity of the middle fiber and lower fiber of the trapezius muscle. The collected EMG data were normalized using maximal voluntary isometric contraction (MVIC). Differences in muscle activity of the middle fiber and lower fiber of the trapezius muscles according to the angles at each plane were statistically processed using repeated measured analysis of variance, and an independent t-test was used to examine the differences between the two planes at each angle. Results: Muscle activity of the middle and lower trapezius during shoulder abduction in the frontal plane and scapular plane significantly increased as the angles increased (p<.05). However, muscle activity of the middle trapezius was significantly lower in the scapular plane than in the frontal plane for all shoulder abduction angles (p<.05). Conclusion: The results of this study suggest that during shoulder abduction, angles should be different according to the goals, and for training during an acute phase or early phase for functional recovery, it is more efficient to perform the training in the scapular plane than in the frontal plane.

• The Journal of Korean Physical Therapy
• /
• v.36 no.2
• /
• pp.71-77
• /
• 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.

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

• Journal of the Korean Applied Science and Technology
• /
• v.36 no.3
• /
• pp.1028-1040
• /
• 2019

The current study was performed to investigate the magnitude of exercise-induced muscle damage (EIMD) after downhill running (DR) of different intensities and to examine the availability of muscle echo intensity as biomarkers to detect regional damage within quadriceps muscle group (QG) following DR. Healthy college-age men (n=11) were experienced twice DR sessions [$50%HR_{max}$ DR, LDR; $70%HR_{max}$ DR, HDR] separated by a 2-week wash-out period with the random order. After DR, severity of EIMD according to exercise intensity were determined by serum creatine kinase (CK) activity, muscle tenderness, and neuromuscular function indicators such as a maximal voluntary isometric contraction (MVIC) and range of motion (ROM). Transvaginal B-mode imaging had been employed to evaluate regional muscle echo intensity within QG [rectus femoris, RF; vastus lateralis, VL; vastus medialis, VM; vastus intermedius, VI]. After both DR sessions, changes in serum CK activity and muscle tenderness have tended to more increase in HDR compared to those of LDR. There was a significant interaction effect between exercise intensity during DR and the time course of serum CK activity(p<.05). However, there were no statistical differences between sessions in muscle tenderness. The time course of changes in the neuromuscular functions after DR were similar to those of regional muscle echo intensity regardless exercise intensity. Although neuromuscular function showed to decline in HDR more than those of LDR after DR, no statistical differences between sessions. In contrast, there were significant interaction effects between sessions and time course of changes in RF and VL muscle echo intensity(p<.01), but not shown in those of VI and VM. These results indicated that each muscles within the QG show different response profiles for EIMD during DR, exercise intensity influences on these responses as well. In particular, current findings suggested that muscle echo intensity derived from ultrasound imaging is capable of detecting regional muscle damage in QG following DR.

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

• Physical Therapy Rehabilitation Science
• /
• v.13 no.1
• /
• pp.78-85
• /
• 2024

Objective: This Study aimed to examine the changes in muscle activity of trunk muscles by performing three squat exercises on normal adults. Design: cross-sectional study Methods: Thirty-two adult subjects participated in this study. General squat, overhead squat, and overhead squat combined with abdominal stabilization were randomly performed for 5 seconds, 3 times, to calculate the average muscle activation. Muscle activation was normalized using electrodes on the rectus abdominis, external oblique, internal oblique, and erector spinae muscles to measure maximum voluntary isometric contraction (MVIC) for 5 seconds, repeated 3 times each. Results: There was a significant difference in the mean and maximal muscle activity of the bilateral erector spinae (ES) when comparing the squat to the overhead squat (p<0.05). There was a significant difference (p<0.05) in the mean and maximal muscle activity of the bilateral external oblique (EO) when comparing the overhead squat to the overhead squat combined with the abdominal stabilization technique. When comparing the squat to the overhead squat with abdominal stabilization, there was a significant difference in the mean and maximum muscle activity of the bilateral RA, EO, and left Internal oblique (IO) (p<0.05), and there was a significant difference in the maximum muscle activity of the bilateral erector spinae (ES) (p<0.05). Post hoc tests showed significant differences between squatting methods for the RA, EO, IO, and ES (p<0.017). Conclusion: The results of this study showed that squats combined with abdominal stabilization were more effective at activating core muscles than squats or overhead squats alone.

• Journal of International Academy of Physical Therapy Research
• /
• v.4 no.1
• /
• pp.523-531
• /
• 2013

Most patients with chronic low back pain experience functional disability of trunk muscle, and limitations in physical activity. While there are many types of exercise programs available, in recent years sling exercise has been emerging as the exercise program for spinal stabilization. It has been supported by a great amount of research with positive findings on its effectiveness. This research studies the effects of bridging exercise, conducted on a sling, on pain level and trunk muscle activation in supine, sidelying, and prone positions during a 4 weeks period. 10 healthy people(normal group, n=10) and 28 patients with low back pain participated in this study. 28 patients were divided into two groups; one group participated in exercise with the sling(experimental group, n=14) and the other group exercised without the sling(control group, n=14). They were asked to use the Numerical Rating Scale(NRS) to answer to the level of their pain they felt (no pain: 0 point, severe pain: 10 points). During sling bridging exercises, the muscle activity level in each muscle measured in each position was standardized as three seconds of EMG signals during five seconds MVIC. In conclusion, the experimental group with four weeks of sling bridging exercise experienced a statistically significant reduction in the pain level(p<.05) and increase in the muscle activities of erector spinae when in supine position, internal oblique when in sidelying position, and rectus abdominis in prone position(p<.05). Regular sling bridging exercise reduces the low back pain and enhances other trunk muscle activation, thereby positively affect spinal stabilization.