• 대한정형도수물리치료학회지
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• 제20권1호
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• pp.15-20
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• 2014

Background: The purpose of this study was to investigate the effect of differing insole height on the electromyographic (EMG) activity and muscle fatique in tibialis anterior and gastrocnemius a lot of repeat college students from the desk during a sit to stand activity. Methods: For the 20 subjects (males), let them wear insole in order. Using EMG equipment measured the difference in muscle activity and muscle fatigue degree. All subjects measured for 3 seconds in standing up from the chair. It's measured total 3 times. Results: The summary of results stated above is as follows: It's sitting to standing activity when there were no significant differences between the muscles. But sitting activity in muscle fatigue-calf muscle during standing activity correlated only. Conclusion: The results of this study, the height of an adult male lead in adequate to maintain a healthy foot function and health elements of effective and aesthetic elements based on a significance in that it presents.

• 한국응급구조학회지
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• 제26권2호
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• pp.61-71
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• 2022

Purpose: This experimental study compared the chest compression quality, muscle activity, and subjective fatigue of paramedic students who did or did not wear a mask. Methods: The subjects of this study were 13 paramedic students at college D located in B city. Frequency percentages, mean standard deviations, and paired sample t-tests were conducted using the SPSS/WIN 23.0 program. Results: This study revealed that chest compression depths (t=-2.151, p=.053) and compression rates (t=-2.714, p=.019) were higher in mask-wearers, while muscle activity and subjective fatigue (t=2.382, p=.035) of the erector spinae (t=7.082, p=.001), rectus abdominis (t=4.776, p=.001), and pectoralis major muscles (t=3.193, p=.008) were lower in mask-wearers. Conclusion: The results of this study can be used as a basis to increase the resuscitation rates of cardiac arrest patients and provision of high-quality chest compressors to rescuers when infectious diseases recur in the future.

• 대한인간공학회지
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• 제34권4호
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• pp.313-326
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• 2015

Objective: The objective of this research is to quantitatively analyze muscle activities of arm and shoulder, according to direction in various types of one-handed manual material handling, based on surface electromyography. Background: Workers in industrial sites frequently carry out one-handed manual material handling using arm and shoulder muscles. Therefore, chronic load and accumulated fatigue occur to arm and shoulder muscles, which becomes a main cause of upper arm and shoulder musculoskeletal disorders. The shoulder muscles have widely range of motion, and complex interactions take place among various muscles including rotator cuff muscles. In this regard, research on interactions among should muscles, according to such various dynamic motions, is required. Method: Ten male subjects in their 20s participated in this research. This research considered upward, downward, leftward, rightward, forward and backward directions and fourteen muscles around arm and shoulder (biceps brachii and trapezius, etc.) as independent variables. The mean muscle activity was set as the dependent variable. This research extracted $4^{th}{\sim}7^{th}$ repetition signals according to ten times of repetitive muscle contraction, and analyzed the muscle activity concerned using the envelope detection technique. Results: The mean muscle activity of upward direction was analyzed highly statistically significant. The reason is that the effect of gravity works to arm and shoulder muscles. Also, it is conjectured that deformation of coracoacromial ligament was caused, and its contact pressure increased, due mainly to the shoulder flexion, and therefore load was analyzed high. Muscle activity was analyzed significantly low, according to concentric ballistic motion used in the concentric contraction phase by storing elastic energy in the eccentric contraction phase with a motion to bring the weight to the front of subject's body as to downward, leftward and backward directions. Because, elbow joint's flexion-extension motions mainly occurred, biceps brachii was analyzed high muscle activity as the prime mover. Conclusion: The information on the quantitative load of muscles can be applied to ergonomic work design for one-handed manual material handling to minimize muscle load. Application: This research has effectively identified muscle activity according to dynamic contraction by applying an envelope detection technique. The results can be used for ergonomic work design to minimize muscle load during the one-handed manual material handling, according to each direction. The research results are expected to be used for musculoskeletal disorder prevention and physiotherapy in the rehabilitation medical field, based on the muscle load of arm and shoulder in various directions.

• The Journal of Korean Physical Therapy
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• 제21권4호
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• pp.57-63
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• 2009

Purpose: To better understand falls in elderly women, we measured differences in muscle activities of 4 lower extremity muscles (tibialis anterior, soleus, rectus femoris, biceps femoris) based on angle plantar-flexion in elderly women. Methods: Subjects were 15 healthy elderly women. No subjects had musculoskeletal or nervous disorders. EMGs were used to check muscle activity of lower extremity muscles. For statistic analysis, data were expressed as a percentage of maximal voluntary isometric contraction (%MVIC). We measured %MVIC for 5 sec under 4 conditions and did not use data for the first and last second. Muscle activities of the muscles of the lower extremities were measured based on the degree of plantar-flexion of the ankle joint. The 4 conditions corresponded to different degrees of: 0, 10, 20 and 30 degrees. This was done using a 50 cm board for measuring the degrees. Results: The tibialis anterior, soleus, and bicpes femoris showed increasing muscle activity associated with increasing degree of plantar-flexion of the ankle joint. All muscles showed a significant increase in muscle activities in association with increasing degrees. Rectus femoris showed a significant increase in muscle activity for 0 degrees and for the other degrees, but there were no further changes when plantar flexion of the ankle joint was over 10 degrees. Conclusion: Activities of the muscles of the lower extremities except rectus femoris were higher with increasing degree of plantar flexion. High muscle activity may result in muscle fatigue. Thus, increasing degree of plantar flexion may be risk factors of falls in elderly women.

• 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.

• 한국안전학회지
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• 제28권1호
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• pp.81-87
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• 2013

Crane operators usually work with their necks bent forward in a seating position for a long period. They have complained of their musculoskeletal stress at their necks. The objective of this study was to find the level of stress at the neck when crane operators bend their neck forward during their work. Experiments were conducted in the laboratory where subjects bent their necks forward for 1 minute and took a rest for 0.5 minute and repeated this performance for 60 minutes. Subjective evaluation using Borg's CR-10 scale and electromyography (EMG) were used to check the level of the stress at the neck. Subjects reported that the level of pain at the end of 60 min. experiment was close to the extreme pain(level 8.95). The EMG level(amplitude) increased 80% on the average and the center frequency of EMG shifted to the lower frequency level which indicated fatigue of neck muscles. Thus, it was found that there is quite much neck stress for crane operators when they maintain their neck posture of bending forward for a long time during their work. This information will be a basis in searching for an intervention measure for the crane operators' neck stress.

• 한국정밀공학회지
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• 제29권7호
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• pp.805-810
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• 2012

Determining of the exercise intensity is very important in terms of induction of low fatigue during exercise. Little information is available on the contraction level of the trunk muscles during whole body tilts with and without axial rotation. This study was to investigate the difference muscle activation level according to axial rotation. Twenty subjects were participated. The muscle activities of the five trunk muscles were bilaterally measured at eight axial rotation angles with 12 tilt angles along $15^{\circ}$ intervals. The results showed that tilt with $45^{\circ}$ axial rotation was more balanced in the same tilt angle and was maintained approximately level of 40% MVC at over $60^{\circ}$ tilt angle with respect to co-contraction of abdominal and back muscle. Lumbar stabilization exercise using whole body tilts would be more effective with axial rotation than without axial rotation in terms of muscle co-contraction.

• Physical Therapy Rehabilitation Science
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• 제7권3호
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• pp.127-133
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• 2018

Objective: The purpose of this study was to investigate the effects of foam roller (FR) stretching, kinesiotaping (KT), and dynamic stretching (DS) on gait parameters after inducing muscle fatigue in the ankle joint. Design: Cross-sectional study. Methods: The subjects were thirty healthy young adults between the ages of 20 and 31 years at Baekseok University who voluntarily participated in this study. The participants were randomly assigned to either the FR group, KT group, or the DS group after inducing muscle fatigue of the ankle joint. Fatigue induction of the ankle joint muscles was performed by alternating a heel up and down exercise with the standing posture on the ground. The speed was maintained at 40 beats/minute using a metronome. Subsequently, the respective intervention was applied to each group. Gait parameters were measured before and after ankle muscle fatigue induction, and after intervention using the GAITRite system. One-way ANOVA was used to compare gait parameters among groups, while repeated measures ANOVA was used to compare gait parameters within each intervention group. Results: The FR group increased significantly in velocity, step length, and stride length except for cadence after intervention compared to after ankle muscle fatigue induction (p<0.01). Furthermore, the KT group showed significant increases in velocity, cadence, step length, and stride length after intervention, especially in cadence group (p<0.05). All intervention groups showed significant increases in stride length after intervention, especially the DS group (p<0.05). Conclusions: Therefore, we suggest that KT, FR, and DS can be an effective intervention on gait parameters when the ankle joint is unstable and injured.

• 대한의용생체공학회:의공학회지
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• 제32권4호
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• pp.312-318
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• 2011

The purpose of study was to evaluate effects for repetitive use of thumb according to two different input types (button and touch) of mobile phones. A total of eight young and healthy subjects (6 males and 2 females: $24.63{\pm}8.04$ years) volunteered, and force measurement on thumb using film type pressure sensor was carried out for an hour. Before the experiment De Quervain's syndrome test were performed to check the left and right muscles related with thumb motion and after measuring the pressing force fatigue feeling survey achieved. For a statistical analysis, 1-to-5 ranking scale was used to score the fatigue feeling. From the result of pressure measurement, forces acting on thumb in button type were 3.36 times (the right thumb) and 3.16 times (the left thumb) for the touch type. And the result of survey, fatigue by using the button type of mobile phone was largely triggered than by using touch type. The abductor pollicis brevis and the flexor pollicis brevis were found as common part of fatigue for repetitively using thumb during texting messages. In the further study, some quantitative fatigue comparisons for various input motions are required to analyze repetitive strain injury syndrome.

• 한국전문물리치료학회지
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• 제15권1호
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• pp.1-11
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• 2008

The purpose of this study was to assess the influence of two shoe size conditions on foot pressure, ground reaction force (GRF), and lower extremity muscle fatigue. Seven healthy men participated. They randomly performed walking and running in two different conditions: proper shoe size and 10 mm greater than proper shoe size. Peak foot pressure, and vertical, anterior and mediolateral force components were recorded with the Parotec system and Kisler force platform. To assess fatigue, the participants performed treadmill running for twenty-five minutes twice, each time wearing a different shoe size. Surface electromyography was used to confirm localized muscle fatigue using power spectral analysis of four muscles (tibialis anterior, gastrocnemius medialis, rectus femoris, and biceps femoris). The results were as follows: 1) In walking conditions, there was a significantly higher peak pressure in the 10 mm greater than proper shoe size insole sensor 1, 2, 14, and 18 (p<.05). 2) In running conditions, there was a significantly higher peak pressure in the 10 mm greater than proper shoe size insole sensor 5, 14, and 15 (p<.05). 3) In walking conditions, there was a significantly higher first maximal vertical GRF in the 10 mm greater than proper shoe size (p<.05). 4) In running conditions, no GRF components were significantly different between each shoe size condition (p>.05). 5) Muscle fatigue indexes of the tibialis anterior and rectus femoris were significantly increased in the 10 mm greater than proper shoe size condition. These results indicate that wearing shoes that are too large could further exacerbate the problems of increased foot pressure, vertical GRF, and muscle fatigue.