• Journal of Korean Physical Therapy Science
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• v.19 no.2
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• pp.1-7
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• 2012

Purpose : The purpose of this study was to investigate the effect of different heel height on the electromyographic (EMG) activity in Rectus abdominis (RA) and Erector spinae (ES) during gait activity. Methods : A repeated measures design was used. 33 healthy females carried out a standardized gait activity under 3 conditions; with heel wedges of 1, 7, and 12cm in height. EMG activity was recorded from RA and ES during the activity. Data was analysed using the repeated one-way ANOVA. Results : First, as the shoe-heel height was getting higher, change of muscle activation indicated the statistically significant difference in rectus abdominis(p<0.05). Second, as the shoe-heel height was getting higher, change of muscle activation indicated the statistically significant difference in erector spinae(p<0.05). Conclusion : We found that as heel height increased, there was an increase in EMG activity in both RA and ES. This indicated that no RA : ES imbalance was elicited. This study provides information that will inform future research on how heel height affects muscle activity around the trunk.

• Journal of International Academy of Physical Therapy Research
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• v.8 no.1
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• pp.1077-1083
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• 2017

The purpose of this study was to investigate the effects of stable and unstable bridging exercises on the EMG activity of abdominal muscles. Twenty healthy women participated in this study and the muscle activities of left-right rectus abdominis (RA), external oblique (EO), and internal oblique (IO) muscles were recorded during 4 bridging exercises (unilateral/ bilateral, stable/unstable). The activity of the right EO muscle was the highest during unilateral exercise in unstable condition, and left EO muscle also produced the same result. The activity of the right IO muscle was the highest during unilateral exercise in an unstable condition, and left IO muscle also produced the same result. The activity of the right RA muscle was the highest during unilateral exercise in a stable condition, and left RA muscle produced the same result. Unstable/unilateral (USUL) represented the highest activity among the 4 exercises. EO/IO muscles represented the highest activity during the USUL exercise, and RA did so during the stable/unilateral exercise. These results suggest that specific posture (USUL) can be administered targeting a specific side of abdominal muscles.

• Physical Therapy Korea
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• v.23 no.1
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• pp.65-71
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• 2016

Background: The unilateral prone arm lift (UPAL) is commonly used to exercise the lower trapezius muscle. However, overactivation of the upper trapezius can induce pain during UPAL exercises in subjects with upper trapezius tenderness. Objects: The purpose of this study was to investigate the effects of position of ipsilateral neck rotation (INR) on the inhibition of upper trapezius muscle activity and the facilitation of the lower trapezius muscle when performing UPAL exercises. Methods: In total, 19 subjects with upper trapezius tenderness were recruited for the study. Electromyographic (EMG) activity was measured in the upper, middle, and lower trapezius muscles during UPAL with and without INR position. Wilcoxon signed-rank test was used to compare EMG activity in the trapezius muscles and the muscle ratios. Results: EMG activity in the upper trapezius muscles was decreased significantly in the INR condition compared to without the position with INR during UPAL exercises (p<.05). EMG activity in the middle and lower trapezius was not significantly different between the with and without INR conditions (p>.05). However, the ratio of lower to upper trapezius activation showed a significant increase in the INR condition compared to the without INR condition (p<.05), indicating greater lower trapezius activation relative to the upper trapezius in the INR position than in the without INR position. Conclusions: The EMG results obtained in this study suggest that the position with INR reduced overactivation in the upper trapezius and improved muscle imbalance during lower trapezius exercises in individuals with upper trapezius tenderness.

• Physical Therapy Korea
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• v.19 no.1
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• pp.37-45
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• 2012

The purpose of this study was to assess the influence of patellar height on quadriceps muscles' electromyography (EMG) activity during a squat exercise in adults with patella baja. For the study, we recruited 15 volunteers who had patella baja on the right side. We measured the EMG activity of the right rectus femoris, vastus medialis oblique, and vastus lateralis muscles during squat exercises under two conditions, specifically with and without an infra-patellar strap. The infra-patellar strap was applied below the tested patella to elevate the patella to a normal height. A paired t-test was used to compare the effects of patella height on EMG activity of the quadriceps muscles. The EMG activity of the rectus femoris (RF), vastus medialis oblique (VMO), and vastus lateralis (VL) muscles were significantly decreased during the squat exercise with the infra-patellar strap compared to the same exercise without the infra-patellar strap (p<.05), while the VMO/VL ratio was not different significantly between two conditions (p>.05). The findings of this study suggest that an infra-patellar strap may benefit people with patellar baja, as changes in patellar height could improve the efficiency of the quadriceps muscles.

• Physical Therapy Korea
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• v.13 no.1
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• pp.54-60
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• 2006

This study aimed to compare movement patterns of shoulder joints between the right and left symmetry in stroke patients and control subjects. This study proposes use of the voluntary response index (VRI) calculated from quantitative analysis of surface electromyographic (sEMG) and motion data recorded during voluntary movement as a feeding task. The VRI is comprised of two numeric values, one derived from the total muscle activity recorded for the voluntary motor task (magnitude), and the other from the sEMG distribution across the recorded muscles with the similarity index (SI). Five stroke patients and five age-matched healthy controls were recruited. Feeding motion was performed using the provided spoon five times with rests taken on a chair in between tasks. EMG data were digitized and analyzed on the basis of the root mean square (RMS) envelope of activity. The average amplitude of responses was calculated. Responsiveness and clinically meaningful levels of discrimination between stroke patients and control for EMG magnitude and SI were determined. The similarity index of the results from two successive examinations of both sides apart for stroke patients and control subjects were .86 and .95 in motion analysis and .84 and .99 in electromyographic analysis. The SI of sEMG data and motion data was significantly correlated in stroke patients. The data suggest that SI is a sensitive program for comparing and analyzing the symmetry of muscle activity and motion in both sides. This analysis method has a clinical value in grading muscular activity and movement impairment after brain injury.

• Physical Therapy Korea
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• v.15 no.2
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• pp.54-63
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• 2008

The purpose of this study was to examine the effect of the hip internal rotation on knee extensor and hip abductor electromyographic (EMG) activity during stair up and stair down mobility. Eighteen healthy subjects were recruited. All subjects performed stair up and down movements on a step of 30cm height while maintaining the hip in neutral (condition 1) and hip in internal rotation (condition 2). Surface EMG activity was recorded from five muscles (gluteus maximus, vastus lateralis (VL), vastus medialis oblique (VMO), posterior gluteus medius (Gmed), and tensor fascia latae (TFU)) and hip internal rotation angle was measured using a three dimensional motion analysis system The time period for stair up and down was normalized using the MatLab 6.5 program, and EMG activity was normalized to the value of maximal voluntary isometric contraction (%MVIC). The EMG activities according to the hip rotation (neutral or internal rotation) during the entire time period of stair up and down in each phase were compared using a paired t-test. During the entire period of stair up, the EMG activities of VL and TFL in condition 2 were significantly greater than in condition 1 (p<.05). During the entire period of stair down, the EMG activities of VL and TFL in condition 2 were significantly greater than in condition 1 (p<.05). However, the EMG activities of the other muscles were not significantly different between the conditions (p>.05). These results suggest that the stair up and down maintaining hip internal rotation was could be a contributing factor on patellar lateral tracking.

• Journal of Korean Physical Therapy Science
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• v.19 no.4
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• pp.41-46
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• 2012

Background : The purpose of this study was to investigate the electromyographic(EMG) amplitude of the gluteus medius muscle bilaterally at various hip angles and motions(flexion, extension and abduction). Methods : Thirty young with a mean(SD) age of 21.03(1.69) years performed hip motions(flexion, extension and abduction) while the surface EMG activity of the gluteus medius muscles was recorded bilaterally. Subjects were instructed to use the right lower limb during moving 3 different direction. Differences in EMG amplitudes in according with movement direction and angle were assessed by use of paired t-test analyses of variance for the right and left lower extremities. The alpha level was set at .05. Results : Gluteus medius muscle EMG activities in the both side were significantly greater for abduction at angles of 30 degrees than those for other motions at other angles. Conclusion : Hip abduction at angles of 30 degrees on the standing position may be effective in activating the gluteus medius muscle.

• Textile Coloration and Finishing
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• v.23 no.1
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• pp.60-68
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• 2011

The effect of compression wear for sport performance and muscle function was investigated based on the physiological test and electromyograph(EMG). The EMG test was used to study muscle activity after fitting the compression wear during exercise. It showed slight difference between men and women testee groups in the results of anaerobic, aerobic, fatigue, and EMG test due to muscle content in the body. In addition, the exercise performance was increased to some extent even the muscle activity was decreased. It is estimated that the compression effect to muscle by the compression wear decreased the muscle vibration and improved blood circulation which helped the entire sport performance. However, it is necessary to study the effect of compression wear in long-term wearing in the future study.

• Korean Journal of Applied Biomechanics
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• v.16 no.2
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• pp.55-63
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• 2006

The purpose of this study was to investigate the effects of vibration exercise using surface electromyography. Seven male collegiate wrestlers were participated in this study. Each subject stood on the platform and the vibration was induced for 1min. WEMG8 EMG system was used to record muscle activity from Vastus lateralis, Biceps Femoris, Tibialis Anterior, and Gastrocnemius. The EMG data were sampled for 30 sec. during non-vibration and vibration half squat position, respectively. The raw data were band pass filtered to remove noise and full wave rectified Paired sample t-test were performed to see the differences of maximum and average EMG between non-vibration and vibration trials. The results indicated that vibration produced much more muscle contraction than that of non-vibration trial for all selected muscles even though the significant difference was found only from Biceps Femoris. This phenomenon was due to the individual differences so care must be taken to evaluate vibration intensity and position before personal training.

• Physical Therapy Korea
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• v.20 no.1
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• pp.1-9
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• 2013

The purpose of this study was to determine the effect of the pelvic compression belt (PCB) on the electromyography (EMG) activities of trunk muscles during sit-to-stand (SitTS), and stand-to-sit (StandTS) tasks. Twenty healthy subjects (7 men and 13 women) were recruited for this study. The subjects performed SitTS, and StandTS tasks, with and without a PCB. Surface EMG was used to record activity of the internal oblique (IO), external oblique (EO), rectus abdominis (RA), erector spinae (ES), and multifidus (MF) of the dominant limb. EMG activity significantly decreased in the RA (without the PCB, $8.34{\pm}6.04$ %maximal voluntary isometric contraction [%MVIC]; with the PCB, $7.64{\pm}5.11$ %MVIC), EO (without the PCB, $14.83{\pm}11.82$ %MVIC; with the PCB, $11.98{\pm}7.60$ %MVIC), MF (without the PCB, $21.74{\pm}7.76$ %MVIC; with the PCB, $18.50{\pm}8.04$ %MVIC), and ES (without the PCB, $18.39{\pm}7.16$ %MVIC; with the PCB, $16.63{\pm}6.31$ %MVIC) during the SitTS task and in the IO (without the PCB, $20.58{\pm}15.60$ %MVIC; with the PCB, $17.27{\pm}12.32$ %MVIlC), RA (without the PCB, $8.04{\pm}5.68$ %MVIC; with the PCB, $7.40{\pm}4.71$ %MVIC), EO (without the PCB, $13.29{\pm}8.80$ %MVIC; with the PCB, $11.24{\pm}6.14$ %MVIC), MF (without the PCB, $18.59{\pm}7.64$ %MVIC; with the PCB, $15.86{\pm}6.48$ %MVIC), and ES (without the PCB, $17.14{\pm}6.44$ %MVIC; with the PCB, $15.46{\pm}5.62$ %MVIC) during the StandTS task when a PCB was used (p<.05). In men the EMG activity of the MF significantly decreased during the SitTS task when a PCB was used (p<.05): in women, the EMG activity of the RA, EO, MF, and ES during the SitTS task and that of the EO, MF, and ES during the SitTS task significantly decreased when a PCB was used (p<.05). In addition, the rates of change in the EMG activity of each muscle differed significantly during the SitTS and StandTS tasks before and after the use of the PCB. However, the EMG activity did not significantly differ between the male and female subjects. These findings suggest that the PCB may contribute to the modification of activation patterns of the trunk muscles during SitTS, and StandTS tasks.