• Korean Journal of Applied Biomechanics
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• v.25 no.1
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• pp.77-84
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• 2015

Objective : The purpose of this study was to analyze the effects of lower limb muscle activity on postural stability and ground type in elderly women subjects. Method : Forty two subjects participated in the experiment (high group - age: $74.29{\pm}4.13yr$, height: $152.44{\pm}5.54cm$, weight: $57.43{\pm}6.16kg$, BMI: $24.77{\pm}2.99$, low group - age: $77.67{\pm}5.16yr$, height: $151.40{\pm}3.93cm$, weight: $60.92{\pm}6.40kg$, BMI: $26.59{\pm}2.57$). Wireless EMG with eight channels was used. Ground types were classified as flat and cushion. Results : In the double-support phase, left and right rectus femoris, left biceps femoris, left and right tibialis anterior, and left gastrocnemius did not show a significant difference in postural stability according to ground type. However right biceps femoris and gastrocnemius showed higher muscle activity in the elderly women group with lower postural stability. In the single-support phase, left and right rectus femoris, right biceps femoris, and left and right tibialis anterior did not show a significant difference in postural stability according to ground type. In addition, left biceps femoris had higher muscle activity in the elderly women group with lower postural stability. Left gastrocnemius had higher muscle activity in the elderly women group with higher postural stability and right gastrocnemius had higher muscle activity in the elderly women group on cushion ground. Conclusion : In a dynamic postural stability and cushion ground, biceps femoris and gastrocnemius muscle activity were high. As a result, biceps femoris and gastrocnemius muscle strengthening exercise on cushion ground could be beneficial in the prevention of falling.

• The Journal of Korean Physical Therapy
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• v.24 no.5
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• pp.348-354
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• 2012

Purpose: This study examined the effects of computerized feedback postural training on the balance and electromyography activity of subjects with stroke. Methods: A total of 30 chronic stroke patients were enrolled in this study. Subjects were divided into an experimental group (n=15) and a control group (n=15). Computerized feedback postural training was used in the experimental group. Both groups received intervention for six weeks, 5 times per 30 minutes period. Data analysis was performed using analysis of covariance for determination of statistical significance. Results: Significant difference in static and dynamic balance was observed in the experimental group, compared with the control group (p=0.05), and a significant difference in muscle activity was observed in the gastrocnemius muscle, quadriceps muscle, and elector spinae muscle. However, the hamstring muscle showed no significant difference. Conclusion: Computerized feedback postural training is more effective in improving the ability of balance and muscle activity than neurological physical therapy.

• Physical Therapy Korea
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• v.29 no.3
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• pp.194-199
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• 2022

Background: Older adults use different ankle muscle activation patterns during difficult static balance conditions. It has been suggested that this is related to a decline in proprioception with age, resulting in reduced postural balance. However, the association between proprioception and ankle muscle activity during quiet standing has not been directly assessed. Objects: This study aimed to investigate the effects of age and sensory condition on ankle muscle activity and the association between ankle proprioception and ankle muscle activity. Methods: We recruited 10 young women and 9 older women. Ankle proprioception was evaluated using joint position sense (JPS) and force sense (FS) divided by dorsiflexion and plantarflexion. The electromyographic activity of the tibialis anterior (TA) and gastrocnemius (GCM) muscles was collected during quiet standing. Results: Older women activated GCM muscle more than young during quiet standing and when performing difficult tasks. Older women had more errors in JPS dorsiflexion and FS plantarflexion than did young. The GCM muscle activity is related to JPS dorsiflexion and FS plantarflexion. Conclusion: Lower proprioception of the GCM with age leads to increased muscle activity, resulting in reduced postural balance. There was no difference in TA proprioception or muscle activity among older women with frequent physical activity.

• PNF and Movement
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• v.16 no.3
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• pp.433-439
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• 2018

Purpose: Visual information is one of the most important factors for postural balance. The purpose of this study was to investigate the effect of visual deprivation on the lower extremities and trunk muscle activity on an unstable surface during quiet standing. Methods: Fifteen healthy males from a university population participated in this study. Surface electromyography of the rectus abdominis, the erector spinalis, the vastus femoris oblique, the semitendinosis, the tibialis anterior, and the medial gastrocnemius was measured using EMG equipment (Telemyo 2400, Noraxon, USA). The participants were asked to maintain postural balance on an unstable surface (Balance pad, Airex, USA) for 30 seconds with eyes open and with eyes closed during quiet standing. The Wilcoxon test was used to compare the muscle activity of the lower extremities and the trunk between open and closed eyes on an unstable surface. Results: The muscle activity of the trunk and the lower extremities was increased more with eyes closed than with eyes open on the unstable surface during quiet standing. Conclusion: The findings from this study suggest that visual information could alter lower extremity and trunk muscle activity. Therefore, visual deprivation can be used as a method to improve postural balance.

• The Journal of Korean Physical Therapy
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• v.33 no.3
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• pp.148-154
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• 2021

Purpose: This study covered the effect of shoulder stabilization exercise on muscle activity, postural alignment and self-efficacy of the elderly people with round shoulders by visiting village hall in rural area. Methods: 40 elderly people with round shoulders were recruited for this study (experimental group: 20 subjects and control group: 20 subjects). The experimental group was asked to perform shoulder stabilization exercise 60 minutes per one time for 8 weeks and three times in a week and the control group was asked to receive education related to pain management for the initial one time. Before and after the experiment, we measured the subjects' muscle activity of upper trapezius, serratus anterior, infraspinatus, pectoralis major and the lower trapezius, then postural alignment of craniovertebral angle and round shoulder posture. In addition, self-efficacy is measured through the questionnaire. Results: Compared to the control group, the experimental group showed significant differences in the muscle activity of all muscles, posture alignment of the craniovertebral angle. round shoulder posture, and improvement of self-efficacy. Conclusion: We found that shoulder stabilization exercise is effective in muscle activity, postural alignment and self-efficacy of the elderly people through visit-rehabilitation service. This study can be used for improving the physical and mental abilities through active visit-rehabilitation service for areas where have poor medical benefits. It is considered that systematic visit rehabilitation service should have institutional framework ultimately.

• The Journal of Korean Physical Therapy
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• v.15 no.2
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• pp.85-99
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• 2003

Muscle tone is the force with which a muscle resists being lengthened. Muscle tone is often tested clinically by passively extending and flexing a relaxed patient's limbs and feeling the resistance offered by the muscle. Both nonneural and neural mechanism contribute to muscle tone. Muscle tone is the mechanisms that contribute to the generation of tone in individual muscles when a person is in a relaxed state. This background level of activity changes in a certain antigravity posture muscle when we stand upright, thus counteracting the force of gravity. This increased level of activity in antigravity muscles is known as postural tone. The evidence from experiments showing that lesions of the dorsal(sensory) roots of the spinal cord reduced muscle(postural) tone is influenced by inputs from the somatosensory system. Patients with neurological damage have several state of muscle(postural) tone, which display from flaccidity to rigidity. This review article deal with muscle tone and somatosensory system acting on this. The understanding about this contribute to a better therapeutic approach for the rehabilitation of patients to have an abnormal muscle(postural) tone due to neurological damage.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.1
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• pp.21-29
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• 2023

Purpose : Using a smartphone while walking districts attention and increases the risk of losing balance or falling. Ankle instability is caused by decreased muscle strength and decreased neuromuscular ability leading to postural control problems. Dual tasks increases the risk of falls by reducing postural control in adults with ankle instability. This study aimed to investigate the effect of performing a dual task on balance and muscle activity in adults with ankle instability using a smartphone. Methods : Forty-nine individuals with ankle instability participated in this study. A game of finding the wrong picture was performed using a smartphone in the dual task, and only looking at the blank screen of a smartphone was evaluated in the single task. The participants randomly performed single and dual task to evalutate balance and muscle atcitivy. Balance was evaluated using the Biodex balance system (BBS), and muscle activity was evaluated using surface EMG. Muscle activity of the gastrocnemius and tibialis anterior was measured at the same time as balance. Results : The results of this study showed that overall, anteior/posterior, and medial/lateral balance indices all showed significant differences when performing the dual task compared with those during the single task (p<.05). The muscle activity results showed a significant difference compared with that of the gastronemius muscle on the nondominant side during the dual task (p>.05). Conclusion : The results of this study showed that maintaining balance is more difficult when performing the dual task than during the single task, and only the muscle activity of the nondominant gastrocnemius muscle decreased. The dual task causes a decrease in concentration for postural control, which negatively affects postural stability. Individuals with ankle ankle instability should refrain from performing dual tasks, such as using smartphones, to prevent ankle damage.

• Physical Therapy Korea
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• v.15 no.2
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• pp.30-37
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• 2008

Anticipatory postural adjustments are pre-planned by the central nervous system (CNS) before the activation of agonist muscles in the limbs, and minimize postural sway. Most previous studies on this topic have focused on upper-limb movement, and little research has been conducted on lower-limb movement. The purpose of this study was to investigate the recruitment order of left and right trunk muscles during limb movement. Fifteen healthy subjects (10 male, 5 female) were enrolled. Electro-myographic signals were recorded on the muscles of: (1) deltoid, lumbar erector spinae, latissimus dorsi and internal oblique during shoulder flexion, (2) rectus femoris, rectus abdominis, external oblique and internal oblique during hip flexion. During right upper limb flexion, the onset of left erector spinae muscle and left internal oblique muscle activity preceded the onset of right deltoid by 8.09 ms and 19.83 ms, respectively. But these differences were not significant (p>.05). A similar sequence of activation occurred with lower limb flexion. The onset of left internal oblique muscle activity preceded the onset of right rectus femoris muscle by 28.29 ms (p<.05). The onset of right internal oblique muscle activity preceded the onset of left rectus femoris muscles by 23.24 ms (p<.05). The internal oblique muscle was the first activated during limb movement. Our study established the recruitment order of trunk muscles during limb movement, and explained the postural control strategy of the trunk muscles in healthy people. We expect that this study will be used to evaluate patients with an asymmetric recruitment order of muscle activation due to impaired CNS.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.3
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• pp.29-41
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• 2020

PURPOSE: The aim of this study was to provide evidence for the treatment of Forward Head and Rounded Shoulder Posture (FHRSP) using posture correction exercises by comparing muscle activity and onset time around the neck and shoulder area during an arm elevation task. METHODS: The subjects were divided into FHRSP (21 persons) and non-FHRSP (19 persons) groups to measure muscle activity and onset time of muscle contraction. Wireless surface electromyography was used to assess the muscle activity and onset time of the right and left sternocleidomastoid (SCM), splenius capitis, anterior deltoid, middle deltoid, serratus anterior, upper trapezius, pectoralis major, and infraspinatus during an arm elevation task. After the pre-measurement, the participants performed the postural correction exercises, and then the post-measurement was conducted. RESULTS: After the posture correction exercises, there were significant differences in the muscle activity and onset time of all muscles in the FHRSP group. The results of the comparison of the muscle onset time during an arm elevation task demonstrated that after the postural correction exercises, the muscle onset time was significantly reduced in the right and left SCM and left splenius capitis, but there were no significant changes in the onset time of other muscles. CONCLUSION: The results of this study help us understand the change in muscle activities and muscle contraction onset time in a person with FHRSP when lifting the arm and suggest the relevant basis to apply the posture correction exercise in clinical settings.

• Physical Therapy Korea
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• v.21 no.3
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• pp.38-44
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• 2014

The aim of this study was to investigate the effects of different postural correction in the electromyographic (EMG) activity of the trunk and hip muscles during bridging exercises. Twenty-four healthy subjects volunteered for this study. The muscle activity was recorded with surface electrodes over the erector spinae, multifidus, gluteus maximus (GM), and hamstring (Ham) muscles; it was measured by using surface EMG equipment under the following 3 experimental conditions: manual postural correction, verbal correction, and no correction. The maximal voluntary isometric contraction (MVIC) was determined for each muscle group in order to represent each exercise as a percentage of MVIC and allow for standardized comparison between subjects. A one-way analysis of variance was used to determine significant differences in the EMG activities of each muscle between the 3 experimental groups. During bridging exercises, the manual postural correction on normalized EMG activity of the GM muscle during manual guiding was significantly higher than during verbal guiding and without guiding (p<.05). Furthermore, the GM/Ham ratio was significantly higher during manual guiding than during verbal guiding and without guiding (p<.05). These findings suggest that the activities of the hip and trunk muscles may be favorably modified with manual guiding during bridging exercises.