• 대한인간공학회지
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• 제28권3호
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• pp.81-85
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• 2009

Work related musculoskeletal disorders(WMSDs) was a leading cause of sick leave and injuries in the industries of our country. Posture was an important consideration in the design of work method and workplaces, because it affected the ability of workers to use various equipments and influenced how long they could perform their job without feeling discomfort, fatigue, and musculoskeletal disorders. Imbalanced lower limb postures such as a squatting posture were awkward working postures common to the shipbuilding shops, farms, automobiles assembly lines in our country. Different awkward working postures were known to be associated with specific musculoskeletal disorders. Eight postures in lower limb postures divided into balanced and imbalanced postures were evaluated by electromyographic(EMG) activity for lower limb muscles. Twelve male subjects participated in this study. This paper was to analyze the effects of lower limb muscles workload according to lower limb postures(knee angle) and working time. The ANOVA results showed that most EMG root mean square(RMS) values were statistically significant effect according to lower limb postures(knee angle) and working time. Therefore, the results of this study will provide the basis to evaluate workload of lower limb postures correctly adopted by workers in various jobs and the ergonomic reference to prevent WMSDs.

• 대한물리의학회지
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• 제4권1호
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• pp.43-48
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• 2009

Purpose : The purpose of this study is to determine the effects of high heeled shoes on the static balance and EMG activity of lower extremity muscles. Methods Twenty subjects were composed of control group(wearing low-heeled shoes) and experimental group(wearing high-heeled shoes). Two groups participated in bearfoot standing and measured static balance and EMG activity of lower extremity muscles. Balance Performance Monitor(BPM) was used to measure the static balance and FlexComp $Infiniti^{TM}$ was used to measure the EMG activity of lower extremity muscles. Results In static balance, sway area and path of experimental group was significantly larger than control group(p<0.05). And sway velocity of experimental group was significantly faster than control group(p<0.05). They means static balance of experimental group was significantly lower than control group(p<0.05). In EMG activity, L5 paraspinalis and biceps femoris of experimental group was significantly more increased than that of control group(p<0.05). Conclusion : The long-time experience in wearing high heeled shoes may have caused change in static balance and EMG activity of lower extremity muscles.

• 대한통합의학회지
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• 제10권3호
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• pp.131-140
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• 2022

Purpose : Although many studies have explored the effect of seating side angles on the spinal curve and surrounding muscles during seating, only a few studies have investigated the effect of different seating face angles on different lower limb and deep trunk muscles. Therefore, this study investigated the effects of seating surface angles (0 degrees, 10 degree anterior, and 10 degree rear) on lower extremity and deep trunk muscles in healthy adults. Methods : Thirty people were asked to sit once on each seating surface three times during the day, and their muscle thicknesses were measured by ultrasound while sitting. The method of sitting was the same when sitting on the three seating surfaces. Results : From the comparison results of the muscle thicknesses according to the seating surface angles, a significant difference existed in the muscle thicknesses of the vastus medialis, vastus medialis oblique, vastus intermedius, soleus and gastrocnemius (p<.05). However, no significant difference was found in the transversus abdominis, internal obliques, rectus femoris and vastus lateralis (p>.05). Conclusion : Our findings revealed that the lower back load decreases, the leg load increases, and the legs specific muscles are affected as the body tilts forward when sitting on the seating surface inclined forward. Therefore, it is possible to suggest a forwardly inclined seating surface that reduces lower back loads and utilizes the posture-maintaining muscles of the legs when sitting in a person with a poor sitting posture or lower back pain at ordinary times.

• 대한물리의학회지
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• 제10권1호
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• pp.1-7
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• 2015

PURPOSE: The aim of this study was to investigate the effects of distal movement on shoulder muscle activation during diagonal pattern of exercises. METHODS: Seventeen healthy male participants volunteered to participate. Five muscles of shoulder were investigated during standing performance of diagonal shoulder exercises with and without visual trace. Two patterns of the diagonal exercises were used as diagonal 1 flexion and extension (D1F-E), and diagonal 2 flexion and extension (D2F-E). Two way repeated measures analysis of variance was used, which the factor was the presence of distal movement and exercise variations. RESULTS: The average muscle activity values of the lower trapezius and anterior deltoid are higher with the D2F-E, compared to the D1F-E (p<.05). The distal movement effect was observed within included all muscles except the lower trapezius, which the values are significantly greater in exercise with distal movement (P<.05). All significant increase of the muscles during the exercise with distal movement condition showed over 0.9 for the observed power in present study. CONCLUSION: Present result suggested that the diagonal pattern of exercise with distal movement has additional advantages of activating the scapulothoracic muscle as well as glenohumeral muscles. In addition, the D2F-E exercise pattern is effective for activating lower trapezius and anterior deltoid muscles.

• 대한물리치료과학회지
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• 제25권2호
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• pp.55-61
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• 2018

Purpose: This study is to compare muscle activation of leg muscles with forward and backward gait and treadmill speed. Method: The experimenter is a healthy ten male and female. They practice walking on the treadmill for 2 minutes and then walk 2km/h and 4km/h in front and back for 3 minutes. Muscle activities were recorded from the lower limb muscles (rectus femoris [RF], biceps femoris [BF], gastrucnemius [GCM]). Results: According to the study, lower extremity muscles have higher backward gait than forward gait. Conclusion: Muscle activity at the speed indicated that the muscular activity of the lower limbs was 4.0km/h, which is higher than 2.0km/h.

• 대한물리의학회지
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• 제10권2호
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• pp.9-16
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• 2015

PURPOSE: The objective of this study was to identify the effects of shoulder abduction strength and EMG activities of the selected scapular and shoulder muscles during isometric shoulder abduction. METHODS: Thirty-four healthy young females were recruited for this study. Surface EMG equipment with inline force sensor was used to determine the shoulder abductor strength and the activity of the serratus anterior (SA), upper trapezius (UT), lower trapezius (LT), and middle deltoid (MD) during three shoe heel height conditions: (1) barefoot, (2) 3-cm shoe heel height, and (3) 7-cm shoe heel height. RESULTS: Isometric shoulder strength showed statistically significant difference among the conditions (p<0.05), and post-hoc test showed lower strength during the 7-cm condition ($49.98{\pm}17.56kg$) than during the barefoot ($44.97{\pm}20.15kg$) and 3-cm conditions ($36.59{\pm}17.07kg$). Furthermore, EMG activities of the SA, UT, and MD appeared to be statistically significantly different among the conditions, with lower values in the 7-cm condition compared to the barefoot condition (p<0.05). EMG ratios (MD/UT and SA/UT) were lower during the 7-cm condition than during the barefoot condition (p<0.05). CONCLUSION: These findings suggest that isometric shoulder abduction strength and EMG activities of scapular and shoulder muscles may be adversely changed with increasing shoe heel height.

• International Journal of Internet, Broadcasting and Communication
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• 제16권2호
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• pp.169-178
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• 2024

This study aimed to investigate the effects of water depth and speed on the activation of lower muscles during squat exercises, utilizing electromyography(EMG). It involved ten male participants in there. Participants performed 30 squats over a minute at a speed of 60bpm and maximum speed squats until exhaustion within a minute. The Integrated electromyography(iEMG) readings for the rectus femoris showed statistically significant differences due to water depth and speed, with a significant interaction effect between depth and speed during squat exercises. The iEMG readings for the biceps femoris also showed statistically significant differences, with a significant interaction effect between depth and speed during squat exercises. The iEMG readings for the gastrocnemius showed statistically significant differences according to water depth and speed. However, the interaction effect of water depth and speed during squat exercises did not show a statistically significant difference. In contrast, the iEMG readings for the tibialis anterior demonstrated statistically significant differences, with a statistically significant interaction effect during squats. These findings suggest that water depth and speed positively influence the activation patterns of lower muscles. Therefore, appropriately tailored aquatic exercises based on water depth for individuals with musculoskeletal discomfort, including the elderly or those with physical impairments, can effectively reduce physical strain and enhance balance, as well as physical and perceptual aspects. It is concluded that such exercises could provide a safer and more effective method of exercise compared to ground-based alternatives.

• 국제물리치료학회지
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• 제11권2호
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• pp.2065-2070
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• 2020

Background: Weakness of the abdominal and mid thoracic muscles the lead to thoracic kyphosis of stroke patients. The trunk muscles activity of stroke patients is significantly related to upper extremity. Objectives: To investigate the effect of seated exercise of thoracic and abdominal muscles on upper extremity function and trunk muscles activity in stroke patients. Design: One-group pretest-posttest design. Methods: A total of 27 stroke patients were recruited. All stroke patient were given seated abdominal exercise (posterior pelvic tilt exercises) and thoracic exercise (postural-correction exercise). All exercises were conducted for 30 minutes, three times a week for four weeks. The manual function test (MFT) and electromyography (EMG) were measured, and EMG electrodes were attached to thoracic paraspinal muscles and lower rectus abdominal muscles. EMG signal is expressed as %RVC (reference voluntary contraction). Results: Experimental group showed significant increases in abdominal muscles, paraspinal muscles activity and MFT total score, items of arm motion (forward elevation of the upper extremity, lateral elevation of the upper extremity, touch the occiput with the palm) in MFT after four weeks. Conclusion: These results suggest that, in stroke patients, seated exercise of thoracic and abdominal muscles contribute to improve trunk muscles activity and upper extremity function in stroke patients.

• 대한통합의학회지
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• 제3권2호
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• pp.47-54
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• 2015

Purpose: This study was to investigate the effects of lumbar stabilization exercise and lower extremity strengthening program on pain, lower extremity muscle in patients with chronic low back pain. Method: The subject were randomly divided two groups. 15 people who were conducted lower extremity exercises and lumbar stabilization exercises called the combined exercise group and other(15 people) who were only conducted lower extremity exercise group. The assessment tools were the pain level and the led muscle power. Exercise was conducted for eight weeks. Result: Pain of the combined exercise group showed significant differences in the change in pain level(p<.05). The leg muscle power showed significant differences within group which hip flexor, extensor muscles and abductor muscles. there were significant differences within combined exercise group (p<.05). But the knee joint in each group showed a significant difference within group (p<.05). Conclusion: This study suggest that the lumbar stabilization exercises and lower extremity exercises showed more efficient results in the pain levels and leg muscles power than only the lower extremity exercise for patients with lumbar instability.

• PNF and Movement
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• 제15권2호
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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.