• Physical Therapy Rehabilitation Science
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• 제7권2호
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• pp.83-87
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• 2018

Objective: The purpose of this study was to investigate the relationship between heart rate (HR), self-awareness of exercise intensity (rating of perceived exertion, RPE), and 5-meter walk test (5MWT) of persons affected by stroke during backward walking according to the preferred stride frequency (PSF), PSF+3 and PSF+6 conditions. Design: Cross-sectional study. Methods: A total of 11 persons with stroke (9 males, 2 females) participated voluntarily. All patients underwent backward walking under the PSF, PSF+3, and PSF+6 conditions in underwater and ground environments, and each condition was performed for 5 minutes. The HR, RPE, and walking speeds were measured during walking, and the measured values from underwater and ground environments were compared. Results: The HR and RPE in the ground environment were significantly increased (p<0.05), and although the 5MWT showed an increase in speed, it was not significant. The HR and RPE in the underwater environment were also significantly increased (p<0.05), however, although the 5MWT results was increased, it was not significant. The HR and RPE were significantly increased in the PSF+6 condition (p<0.05). Conclusions: The results of this study showed that backward gait training underwater can provide an appropriate exercise intensity for stroke survivors and suggests that exercises performed in an underwater environment is more effective compared to the ground environment.

• 운동영양학회지
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• 제23권1호
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• pp.1-6
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• 2019

[Purpose] To date, there have been no studies on the response of wrist tremor to increased muscle activity during exercise. This study aimed to evaluate the wrist tremor response with increasing muscle activity during bench press exercise. [Methods] Triceps muscle activity and wrist tremor response were measured by electromyography and an accelerometer, respectively, during bench press exercise in 11 healthy men without weight-training experience. Subjects performed bench press at 30% repetition maximum (RM), and the rating of perceived exertion (RPE) and lactate concentration were measured before and after exercise. One week later, an equivalent number of bench presses at 30% RM was performed without weight load as a control trial (CT). [Results] RPEs and lactate concentrations significantly increased after resistance exercise (30% RM) from 7.4 to 14.3 and 1.7 to 4.9, respectively (P<.01), but no such difference was observed in the CT. Muscle activity linearly increased during the 30% RM exercise, and wrist tremors were shown to linearly decrease. A strong negative correlation was observed between the two variables (r=-0.88, P<.001). [Conclusion] We found that wrist tremors during resistance exercise, as measured using an accelerometer, can be used to predict muscle activity.

• 대한인간공학회지
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• 제31권2호
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• pp.281-289
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• 2012

Objective: The purpose of this study is to evaluate the potential risk of shoulder muscle at particular working postures in sitting. Background: The cause of shoulder pain needs to be specifically studied in relation with particular shoulder postures to prevent shoulder MSDs in workplace. Method: In this study MVC, fatigue and subjective workload were investigated depending on the change of shoulder posture. An experiment was designed to evaluate the six shoulder muscles at nine shoulder postures including the combination of 30(adduction), 0, 30(abduction) degrees and 60, 90, and 120 degrees of shoulder flexion. Surface electrodes were attached to the middle trapezius, inferior middle trapezius, anterior deltoid, posterior deltoid, serratus anterior and teres major. Thirteen subjects participated in the experiment. Dependent variables were RPE (rating of perceived exertion), MVC(maximum voluntary contraction) and MPF(mean power frequency) shift by EMG (electromyography). Results: The middle trapezius and inferior middle trapezius were not significantly fatigued at all postures. The decline of MPF slope was less than 10% at all postures. The anterior deltoid was significantly fatigued all postures. The decline of MPF slope was more than 10% at all postures. The posterior deltoid was significantly fatigued 30 degrees of adduction and 90 degrees of flexion. And, neutral and 30 degrees of abduction postures were fatigued more than 90 degrees of flexion. The serratus anterior was significantly fatigued except for 30 degrees of adduction and 60 degrees of flexion posture. The teres major was significantly fatigued except for neutral and 60 degrees of flexion, 30 degrees of abduction and 60 degrees of flexion posture. Conclusion: It was found that a certain muscle was fatigued fast at particular posture compared to other muscles, which would mean that a certain shoulder muscle at particular posture could be easily exposed to the risk of musculoskeletal disorders than other muscles. Application: It is expected that the result can be applied to design workplace using shoulder muscles.

• 한국응급구조학회지
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• 제25권3호
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• pp.81-92
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• 2021

Purpose: The aim of the study is to measure the quality of cardiopulmonary resuscitation (CPR) and the fatigue of rescuers wearing PPE (Level D) during a CPR session and to ultimately provide suggestions of safety standards for rescuers. Methods: 36 subjects were enrolled in the study. The subjects were divided randomly into three groups of two-members, three-members, and four-members. Each group performed CPR for 30 minutes. Blood lactate concentration, heart rate, rating of perceived exertion, chest compression depth and rate were measured before experiment and after each cycle. Results: There was a difference in the blood lactate concentration during CPR cycle by member of shifts (p=.014). The blood lactate concentration increased during CPR (p=.000). Subjective fatigue was a significant difference of chest compression in cycles 3, 4, and 5 for the member of shifts during CPR (p=.049, p=.009, p=.015). Depth and rate of chest compression were not different for the member of shifts during CPR. Conclusion: It is necessary to establish standards for the member of shifts during CPR, to reduce the fatigue of rescuers.

• 대한인간공학회지
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• 제24권2호
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• pp.65-70
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• 2005

Evaluation of repetitiveness for upper extremity intensive tasks is essential to determine the level of risk for upper extremity musculoskeletal disorders at the workplace. However, experimental data available to establish the acceptable levels of repetitiveness for various postures and forces is lacking. The present study examined the maximum acceptable frequencies(MAFs; motions/min.) of shoulder, elbow, wrist, and index finger motions at different forces(1kgf and 4kgf for shoulder, elbow, and wrist; 0.25kgf and 1 kgf for index finger) in sitting. Seventeen right-handed males in 20s without having any history musculoskeletal disorders participated in the MAF experiment. The participants determined their MAFs for the upper extremity motions by using the self-adjustment method and their work pulse(increase in heart rate; beats/min.) and rating of perceived exertion(RPE) were measured when working at MAF. The MAFs of elbow, wrist, and index finger motions for each force level were about 2, 3, and 6 times the corresponding MAF(9 at the high force and 24 at the low force) of shoulder motion and the MAFs at the low force increased about 2 times those at the high force. The work pulses of elbow, wrist, and index finger motions for each force level were 70%, 50%, and 30% of the corresponding work pulse(17 at the high force and 12 at the low force) of shoulder motion and the work pulses at the low force were about 70 % of those at the high force. Lastly, the RPEs of the upper extremity regions were about level 3(moderate) or below.

• Journal of Korean Biological Nursing Science
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• 제4권2호
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• pp.5-18
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• 2002

Purpose: Women have been often underdiagnosed and undertreated when they have as high mortality as men of ischemic heart disease, such as angina. One of the reasons of women's under treatment is associated with either vague, non-traditional symptoms or longer delay in seeking professional help when they experience ischemic heart disease. This study was conducted to investigate the characteristics of women's anginal pain induced by the treadmill test and to explore the potential relationship(s) between anginal pain and other psycho-physiologic factors. Methods: Of 22 female patients referred to treadmill test, 7 with positive finding participated in this study. Anginal pain in the past was analyzed by Rose questionnaire, whereas anginal pain induced by the treadmill test was identified by McGill pain scale, visual analogue scale and present pain index. Results: Women expressed more heaviness than sharp pain, and complained splitting more often than subjects in previous study that included both men and women. Pain intensity by VAS $3.64{\pm}3.94$, Pain rating index was $5.14{\pm}7.29$, present pain index was $1.57{\pm}1.81$, duration of pain was $5.14{\pm}4.8$ min. Exercise intensity was $6.0{\pm}4.63$ METs, exercise duration was $364.29{\pm}141.39$ sec, ST change was -2.0mm and rate of perceived exertion was $16.29{\pm}2.06$. The relationships between pain intensity and pain duration, ST segment changes were significant. Correlation among pain measures was significant. Conclusion: Generalization of these pilot findings may be inappropriate, and therefore, further larger study is needed.

• Journal of Korean Biological Nursing Science
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• 제13권3호
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• pp.276-282
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• 2011

Purpose: The aim of the present study was to investigate the effects of a aquatic exercise program on body mass index, body fat percentage and skeletal muscle mass, physical fitness using SFT (senior fitness test) and depression in elderly women. Methods: This study included 59 elderly women. Aquatics exercise program was performed three times per week for 12 weeks using rating of perceived exertion and body mass index, body fat percentage, skeletal muscle mass, physical fitness and depression were measured before and after exercise program. Statistical analysis was performed using t-test. Results: Body mass index (p=.002) and body fat percentage (p=.021) were significantly decreased after aquatic exercise program. Chair stand (p=.009), 2 minute step test (p<.001), back scratch (p<.001), and chair sit and reach (p<.001) were significantly increased after the aquatic exercise program. But, there was no significant differences in the depression. Conclusion: It is suggested the aquatic exercise program may play a significant role in improving body fat and physical fitness in the elderly women. However, as well as aquatic exercise program, sustained encouragement are required to improve physical and psychological traits.

• Investigative Magnetic Resonance Imaging
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• 제26권2호
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• pp.117-124
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• 2022

Purpose: In this study, we provide a way to assess even a slight effect of exercise on trunk-muscle activity. Materials and Methods: Seven healthy male participants (mean age, 24.7 ± 3.2 years; height, 171.2 ± 9.8 cm; and weight, 63.8 ± 11.9 kg) performed 15 sets of an exercise with 20 repetitions of 90° hip and right-knee flexion while lying supine. The exercise intensity was measured using the 10-point Rating of Perceived Exertion Scale after the first and 15th sets of exercises. Although cross-sectional areas and functional T2 mapping using ultrafast imaging (fast-acquired muscle functional magnetic resonance imaging, fast-mfMRI) have been proposed for imaging to evaluate exercise-induced muscle activity in real time, no previous studies have reported on the evaluation of trunk-muscle activity using functional T2 mapping. As a method for assessing trunk-muscle activity, we compared functional T2 mapping using ultrafast imaging (fast-mfMRI) with cross-sectional areas. Results: Although the muscle cross-sectional areas were increased by the exercise, there was no significant difference at rest. On the other hand, for all sets, the changes in T2 were significant compared with those at rest (P < 0.01). These results demonstrate that T2, calculated from fast-mfMRI images can be used to detect even a small amount of muscle activity induced by acute exercise, which was impossible to do with cross-sectional areas. Conclusion: Fast-mfMRI, which can also display functional information with detailed forms, enabled non-invasive real-time imaging for identifying and evaluating the degree of deep trunk-muscle activity induced by exercise.

• Journal of Nutrition and Health
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• 제38권2호
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• pp.117-124
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• 2005

We investigated the effects of prolonged exposure in hot environmental condition and ingestion of fluid on various physiological variables including plasma glucose, lactate, the rating of perceived exertion (RPE), and heart rate as well as golf putting performance. Six male professional golfers were voluntarily participated in three different putting trials which were separated by seven days of time interval period. Three different putting trials were conducted at either 20℃ or 32℃, or 32℃ + Fluid ingestion. Performing 32℃ + Fluid ingestion trial, all subject ingested sport drink as much as their body mass was decreased. For each experiment, all subjects were undertaken total 48 putting, which separated by four x 12 putting in four different time points (i.e., Rest, 1 hr, 2 hr, and 3 hr). Plasma glucose concentration was significantly decreased with hot ambient condition but it was almost fully recovered by fluid ingestion. Plasma lactate concentration was significantly higher when subjects were exposed in hot environmental condition, and it did not change with fluid ingestion. There was a no different in putting performance and psychological fatigue level (performed by GRID test) at any environmental conditions. The RPE, commonly used for evaluating of physical fatigue level, was significantly dropped by fluid ingestion which indicates lower physical fatigue level. In addition to this, heart rate (HR) was also significantly decreased after fluid ingestion. Based on these results, it was concluded that the ingestion of fluid during prolonged exposure in hot ambient condition decrease the degree of physical fatigue levels and heart rate, which will possibly improve the golf performance when exposed in extreme weather condition in summer. (Korean J Nutrition 38(2): 117～124, 2005)

• 재활복지공학회논문지
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• 제6권1호
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• pp.51-58
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• 2012

본 연구에서는 근전도 신호를 기반으로 하여 환자의 재활 운동 시 발생하는 근 피로도의 변화에 따른 능동형 운동 부하 제어 시스템을 개발하였다. 본 능동형 부하 제어 시스템에 적합한 근 파라미터를 선정하기 위해 건강한 남성 12명을 대상으로 사전 실험을 수행하여 근전도 신호를 획득하였다. 또한 선정된 근 파라미터를 이용한 능동형 운동 부하 제어 시스템을 평가하기 위하여 근 골격계 질환이 없는 건강한 남성 10명을 대상으로 실험을 수행하였다. IEMG(Integrated electromyogram) 변화에 따른 운동 부하 변화를 관찰하여 개발된 능동형 부하 제어 시스템의 유용성 및 정확성을 확인하였으며, 개인의 주관적 피로도를 나타내는 운동자각도(rating of perceived exertion)를 활용하여 근 피로도와의 상관관계를 분석하였다. 따라서 본 연구에서 제안한 능동형 운동 부하 제어 시스템은 재활 운동 수행 시 환자 개개인에 적합한 초기 부하 및 운동량 조절에 유용할 것으로 사료된다.