• Physical Therapy Korea
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• v.16 no.1
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• pp.1-9
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• 2009

An abdominal drawing-in maneuver (ADIM) with a pressure biofeedback unit can be used to prevent excessive lumbar lordosis during bridging exercise. Therefore, in this research, the effects of an ADIM on lumbar lordosis and lower extremity muscle activity during bridging exercise were investigated in thirty healthy adults. Surface electromyography (EMG) and VICON system were used to collect kinematic data and muscle activity, respectively. A paired t-test was used to determine a statistical significance. The results showed as follows: (1) When performing bridging exercise with an ADIM, the height of the anterior superior iliac spine and greater trochanter decreased significantly (p<.05). (2) When performing bridging exercise with an ADIM, the trunk extension angle and pelvic angle increased significantly (p<.05). (3) When performing bridging exercise with an ADIM, the EMG signal amplitude increased significantly in the rectus abdominis, internal oblique abdominis, external oblique abdominis, medial hamstring, and lateral hamstring (p<.05). (4) When performing bridging exercise with an ADIM, the EMG signal amplitude decreased significantly in the erector spinae (p<.05). From the result of this research, an ADIM trained with pressure biofeedback unit during bridging exercise is effective to prevent excessive contraction of erector spinae, to limit excessive motion of pelvis from sagittal plane and to increase muscle activity of abdominal muscles and hamstring muscle.

• Korean Journal of Applied Biomechanics
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• v.32 no.1
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• pp.31-36
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• 2022

Objective: The purpose of this study was to investigate muscle activation according to the four strap lengths in the TRX plank exercise to provide scientific and accurate data on effective training methods. Method: Twenty healthy men who had at least 6 months of weight training experience and could fully adjusted plank exercise, were participate in this study (age: 25.2 ± 3.7 yrs., height: 174.2 ± 3.9 cm., weight: 71.2 ± 9 kg). To pursue the study purpose, surface electrodes were attached to trunk muscles (pectoralis major, rectus abdominis, external oblique, internal oblique, erector spinae, latissimus dorsi) and lower extramity muscles (gluteus maximus, rectus femoris, gastrocnemius), and the muscle activity was measured using 11-channel electromyography equipment. In order to verify the muscle activation according to the four strap lengths during TRX plank exercise, an one-way ANOVA with repeated measure was used with statistical significance level set at as α=.05. Results: First, there were statistically significant differences in pectoralis major, rectus abdominis, external oblique, internal oblique, and erector spinae among TRX strap lengths. Second, there were statistically significant differences in gluteus maximus, rectus femoris, and gastrocnemius among TRX strap lengths. Third, even though no statistically significant difference found in latissimus dorsi, but increased muscle activation tendency was showed as the length of the strap increased. Conclusion: From the results of this study, it may be possible that TRX exercise prevent injuries and improve lower extremity muscle as well as trunk muscles by setting appropriate length of strap.

• Physical Therapy Korea
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• v.29 no.1
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• pp.79-86
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• 2022

Background: Bird dog exercise (BDE) is one of the lumbar stabilization exercises that rehabilitate low back pain by co-contraction of the local and global muscles. Previous studies have reported the effect of various type of BDEs (for example, practicing the exercises on various surfaces and changing the limb movement) for muscle co-contraction. Objects: This study aimed to investigate the effect of knee joint flexion position of the raised lower limb on abdominal and back muscle activity during BDE in patients with chronic low back pain (CLBP). Methods: Thirteen males participated in this study (age: 32.54 ± 4.48 years, height: 177.38 ± 7.17 cm). Surface electromyographic (SEMG) data of the internal abdominal oblique (IO), external abdominal oblique (EO), lumbar multifidus (MF), and thoracic part of the iliocostalis lumborum (ICLT) were collected in two knee joint flexion positions (90° flexion versus 0° flexion) during BDE. The SEMG data were expressed as a percentage of root mean square mean values obtained in the maximal voluntary isometric contraction. Results: Greater muscle activity of the IO (p = 0.001), MF (p = 0.009), and ICLT (p = 0.021) of the raised lower limb side and the EO (p = 0.001) and MF (p = 0.009) of the contralateral side were demonstrated in the knee joint flexion position compared to the knee joint extension position. Greater local/global activity ratios of the abdominal muscle (i.e., IO and EO) of the raised lower limb (p = 0.002) and the back muscle (i.e., MF and ICLT) of the contralateral side (p = 0.028) were also noted in the knee joint flexion position. Conclusion: BDE with a knee joint flexion position might be recommended as an alternative lumbar stabilization exercise to enhance muscle activity in both the raised lower limb and the contralateral sides of the trunk for individuals with CLBP.

• Physical Therapy Korea
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• v.5 no.3
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• pp.63-71
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• 1998

Trunk holding test (Sorensen test) appear to have more value than strength test in prediction the occurrence of low back pain. Electromyographic activity of trunk extensor muscles during these test may provide clues to the etiology of neuromuscular-based low back pain. This study investigated the difference in back muscle endurance between healthy adult men and women using surface electromyographic (EMG) power spectral analysis. Thirty hea1thy subjects (15 men and 15 women) performed an unsupported trunk holding test for 60 seconds. Recording surface electrodes were placed over the erector spinae medially and laterally at vertebral levels of $L_1$ and $L_5$. Slope of total frequency was evaluated using the MP100WSW Fast Fourier Transform spectrum analysis program. The slopes of all indices of back muscle fatigue, except right $L_5$, were significantly steeper in men than in women (p<0.05). Our results indicated that the trunk holding test using EMG power spectral analysis of erector spinae muscles is useful for the evaluation of fatigue rate of these muscles. Our results also showed a higher muscle endurance in healthy adult women than in men.

• Journal of International Academy of Physical Therapy Research
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• v.10 no.3
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• pp.1818-1822
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• 2019

Background: Ipsilateral pelvic elevation has been reported as a common compensatory movement during side-lying hip abduction. It has been reported that pelvic elevation inhibits sufficient contraction of gluteus medius. However, few studies have identified the effects of controlled pelvic elevation on the trunk and hip muscles. Objective: To examine the effects of controlled pelvic elevation using visual biofeedback on the muscle activity of the trunk and hip muscles. Design: Crossover study. Methods: Twelve healthy males performed side-lying hip abduction exercises with and without visual biofeedback for pelvic elevation. Electromyography (EMG) activities of the gluteus medius, quadratus lumborum, and multifidus were analyzed using a wireless EMG system while the ipsilateral pelvic elevation angle was measured using a motion sensor during side-lying hip abduction exercises. Results: EMG activities of the gluteus medius (p = .002), quadratus lumborum (p = .022), and multifidus (p = .020) were significantly increased and ipsilateral pelvic elevation was significantly decreased (p = .001) during side-lying hip abduction with visual biofeedback compared to without visual biofeedback. Conclusions: The results of this study suggest that the application of biofeedback for pelvic motion could improve the trunk and hip muscle activation pattern and decrease compensatory pelvic motion during side-lying hip abduction exercise.

• Journal of the Ergonomics Society of Korea
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• v.30 no.3
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• pp.395-401
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• 2011

Objective: This study examined the effects of working chair that was developed for farmers who work in grapevine's cluster thinning. Background: Agricultural work involves some of the nation's highest occupational risk exposures. Fruit cultivation has been recognized as one of the most hazardous crops in which to work. Grapevine cluster thinning task involve activities related to the main risk factors associated with upper limb work-related musculoskeletal disorders. Method: An experiment was designed to test the working chair. Six healthy male($25.8{\pm}4.9years$) were selected as the subjects for this study. Electromyography(EMG) was used to monitor the muscles activity, and Electro-goniometer was used to measure the ranges of motions of the elbow, trunk and knee. Subjective test was also carried out to examine discomfort body parts and their pain intensity. A grapevine's working space was built for the experiment and working chair was installed on it. In order to examine the muscle activity and range of motion, subjects used to the working chair for 30 minutes for each experimental condition. Another test without working chair was also performed for comparison. %MVC was used to quantify the level of muscle activity. Results: Decreases of muscle activity was found in all leg muscles and significant decrease of muscle activity was found in left Gastrocnemius. The range of motion of the trunk and knee also decreased when working chair used. Discomfort in lower back, thigh and shank region were reduced significantly. However, in upper limbs muscle activity tended to increase in working chair compared with conventional task. Conclusion: Improvement for cushion in seat back and pan required to reduce discomfort in buttocks. Application: Overall findings verified that the working chair might help to prevent upper limb and lower back MSDs based on the current study. These results can be practically used for work improvement for the grapevine growers to prevent MSDs.

• Physical Therapy Korea
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• v.18 no.1
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• pp.9-17
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• 2011

The purpose of this study was to assess visual biofeedback's influence on trunk muscles' (EMG) activity and endurance holding time for correct position during whole-body tilt exercise. For the study, we recruited 14 volunteers who showed no symptom of lumbar disease during medical tests. We measured the EMG activity of their rectus abdominis, external abdominal oblique, internal abdominal oblique and erector spinae muscles, and their endurance holding time for correct position during $40^{\circ}$ anterior and posterior whole-body tilt under two conditions: whole-body tilt with and without visual biofeedback. Resistance with gravitational force on the trunk during whole-body tilt was applied by using a device that had a monitor on which the subjects could check their alignment and that sounded an alarm if a subject's alignment collapsed. The study showed an increase in the EMG activity of external abdominal oblique, internal abdominal oblique/rectus abdominis ratio and endurance holding time for correct position during both $40^{\circ}$ anterior and posterior whole-body tilt with visual biofeedback compared with without visual biofeedback (p<.05). We suggest that the whole-body tilt exercise with visual biofeedback could be a beneficial strategy for selectively strengthening the internal abdominal oblique muscle and minimizing the rectus abdominis muscle's activity while maintaining correct alignment during whole-body tilt exercise.

• 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.

• The Journal of Korean Physical Therapy
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• v.28 no.3
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• pp.195-200
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• 2016

Purpose: This study was designed to evaluate the effects of the different condition of leg support surface on the upper extremity and core muscle activity during the push-up exercise. Methods: Fifteen healthy subjects that were practicable push-ups were recruited in this study. Subjects were instructed the push-up exercise in the different condition of the leg support surface. Each condition of support surface was set to the high and lower, and the unstable and stable condition. Muscle activation was measured by using the surface electromyography (EMG), and recorded from the triceps brachii, serratus anterior, latissimus dorsi, rectus abdominis, abdominal external oblique, and erector spinea muscle. Results: In the results of experiments, there was no significant difference of muscle activation in upper extremity between the high unstable and high stable support surface. By contrast, muscle activation of the rectus abdominis and abdominal external oblique was significantly higher in the low unstable support surface, compared with those of the low stable support surface. It is well known that the core muscle was important to stabilization of trunk stability. Conclusion: This result demonstrates that the low and unstable support surface for the lower extremity was suited for training of core muscle for trunk stabilization during the push-up exercise.

• PNF and Movement
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• v.11 no.1
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• pp.55-62
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• 2013

Purpose : This study was assessed muscle activity and onset time in trunk and upper extremity on functional reaching. Methods : The participant was 18 female(young 10, old 8). As functional reaching, we collection data by using EMG(MP150) on transverse abdominis, external oblique, erector spinae, deltoid middle and serratus anterior. Results : 1) In functional reaching, transverse abdominis, external oblique, erector spinae and deltoid middle muscle activity was augmented on old female(p>.05). Serratus anterior was augmented on young female(p>.05). 2) In functional reaching, transverse abdominis and erector spinae muscle onset time is significantly faster old female than young female(p<.05). External oblique and serratus anterior muscle onset time is faster old female than young female(p>.05). 3) As increase of age muscle activity of external oblique was more increased that we found .511 a coefficient correlation and onset time more faster on transverse abdominis and erector spinae were each -.492 and -.554 coefficient correlation. Conclusion : The muscle activity and onset time was difference in functional reaching according to ageing and task context. It is necessary concentration and attention to old female than young female. Therefore, these results suggest that importance of anticipatory postural control and selective strategy of postural control.