• Safety and Health at Work
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• v.9 no.4
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• pp.468-472
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• 2018

Background: Firefighters are required to use self-contained breathing apparatus (SCBA), which impairs ventilatory mechanics. We hypothesized that firefighters have elevated arterial $CO_2$ when using SCBA. Methods: Firefighters and controls performed a maximal exercise test on a cycle ergometer and two graded exercise tests (GXTs) at 25%, 50%, and 70% of their maximal aerobic power, once with a SCBA facemask and once with protective clothing and full SCBA. Results: Respiratory rate increased more in controls than firefighters. Heart rate increased as a function of oxygen consumption ($V_{O_2}$) more in controls than firefighters. End-tidal $CO_2$ ($ETCO_2$) during the GXTs was not affected by work rate in either group for either condition but was higher in firefighters at all work rates in both GXTs. SCBA increased $ETCO_2$ in controls but not firefighters. Conclusions: The present study showed that when compared to controls, firefighters' hypoventilate during a maximal test and GXT. The hypoventilation resulted in increased $ETCO_2$, and presumably increased arterial $CO_2$, during exertion. It is proposed that firefighters have altered $CO_2$ sensitivity due to voluntary hypoventilation during training and work. Confirmation of low $CO_2$ sensitivity and the consequence of this on performance and long-term health remain to be determined.

• The Korean Journal of Food & Health Convergence
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• v.8 no.1
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• pp.21-30
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• 2022

This study proposed a multiple regression equation for predicting VO2max of elderly men and women using functional performance variables required to conduct daily activities. The subjects of this study were 58 elderly men (72.4±5.9 yrs) and 117 elderly women (73.4±4.5 yrs) aged 65-90 who belong to the senior welfare center. The maximal graded exercise test using a cycle ergometer and functional performance representing muscle strength, endurance, static and dynamic flexibility, mobility, and agility were measured. For statistical processing, multiple regression analysis was performed, and the statistical significance level was α = .05. As a result, the VO2max estimation formula for the elderly was 0.419 (standing up and sitting down a chair) + 0.199 (leg endurance against wall) + 5.383, and R2=0.406. In addition, the VO2max estimation formula for elderly women is - 0.737 (standing up from a supine position) - 0.144 (waking around two cones in a figure 8) - 0.135 (%body fat) + 0.042 (one leg balance with eyes open) + 29.395, R2=0.367 was calculated. The conclusion is that if the maximal graded exercise test is not available, it is considered that VO2max of the elderly can be predicted properly by using the estimation formula calculated based on the functional performance variable.

• Journal of Digital Convergence
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• v.16 no.5
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• pp.463-468
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• 2018

The purpose of the study was to investigate the gender differences of anaerobic capabilities between anaerobic capacity(AC) from Wingate test and anaerobic work capacity(AWC) from critical power test in untrained male and female adults. Both tests were carried out to 12 male and 13 female subjects on a Monark cycle ergometer. The results of this study demonstrated that men were higher than women in AC for the Wingate test, but no gender difference(J/kg) in AWC for the Critical Power test. There was a significant relationship between AC(J/kg) and AWC(J/kg) in women(r=0.61, p<0.05), but no significant relationship in men(r=-0.32, p>0.05). ANCOVA analyses using $VO_{2max}$ and body weight as covariates had significant influence on the AWC gender difference. The study provides preliminary data on gender differences of anaerobic capabilities.

• Science of Emotion and Sensibility
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• v.7 no.4
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• pp.19-24
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• 2004

The purpose of this study is to evaluate the possibility of identifying joint damping property through commercially available isokinetic ergometer (BIODEX). The proposed method is to estimate the damping torque of the knee joint from the difference between the external joint torque for maintaining isokinetic movement and the gravity torque of the lower leg. The damping torque was estimated at various joint angular velocities, from which the damping property would be derived. Measurement setup was composed of the BIODEX system with an external force sensor and Labview system. Matlab was used in the analysis of the damping property. The experimental result showed that the small variation in angular velocity due to acceleration and deceleration of the crank arm resulted in greater change of inertial torque than the damping torque. Therefore, the estimation of damping property from the isokinetic movement is difficult.

• Journal of the Korean Society of Clothing and Textiles
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• v.11 no.3 s.25
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• pp.41-55
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• 1987

The purpose of this study is to investigate the effects of napping of knitted fabric on wear sensation and physiological responses. Experimental garments were four types of warm-ups made of either $100\%$ PET or $65/35\%$ P /C and either napped or unnapped respectively. Two healthy young female adults were chosen as subjects for the experiment. Experimental room conditions were as follows: Temp., $22\pm0.5^{\circ}C$ R.H., $54\pm3\%$ and Air Velocity, 0.25m/ sec or 2. 86m/sec. The subjects exercised on bicycle ergometer and rested alternatively for totally 45-min. The results are summarized as follows. 1) With napped Warm-up, chest, back, mean skin temp. and microclimates, i.e., temp., relative humidity and water vapor pressure inside the clothing, were higher than with unnapped warm-up. And there was no difference in pulse rate between napped and unnapped warm-ups. 2) Wear sensations of thermal, humidity, tactile and comfort were 'more hot' and 'more uncomfortable' in 0.25m/sec air velocity. but in 2.86m/sec condition the tactile sensation was 'better' and 'more comfortable' with napped warm-ups. According to Pearson's Correlation, among various kinds of wear sensations, tactile is most related with comfort. From these results, it can be concluded that napped fabric decreases the rate of heat trans? mission and moisture diffusion through the clothing. Therefore skin and body temp. and temp., R.H., Vapor Pressure inside the clothing are increased.

• Journal of Biomedical Engineering Research
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• v.3 no.1
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• pp.23-30
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• 1982

The regimen of physical activity of the patient with coronary artery disease requires that he should not overshoot the prescribed heart rate based on his age, health and fuctional status of the heart during his exercise. The step input of work load, however, involves a great danger of overshooting. The purpose of this study was to desigil a system that makes it passible for a subject to check the overshooting. This system shows on tile H.R-meter, the amplified and filtered heart-rate signal of the subject received by the photosensor on his earlobe, puts it in the lead coinpensational circuit where it is conpared with the reference input signal(=the presfribed heart rate). The output of the lead compensational circuit works the aull meter. By means of this null meter, the subject knows whether he is overshooting the prescribed heart rate or not. He can continue the natl meter needle at the'Zero'position through the control of the speed of pedaling of the bicycle ergometer, An experimental test, made on eight men and four women in healthy condition, showed that 91. 7% of them vlaintained the stable heart rate and that the overshooting of the desired heart rate did not exceed $\pm$2BPM. According to the result of this experiment, since the heart rate feedback controller makes it possible for the subject to take the prescribed exercise based not on the work load but on the heart rate which incidentally is inexpensive, it can be made use of as the instrument for the regimen of pflysical activity by the patient with coronary artery disease.

• Journal of the Korea Safety Management & Science
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• v.12 no.1
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• pp.51-57
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• 2010

Cycling that transform human energy into mechanical energy is one of the man-machine systems out of sports fields. Benchmarking means "improving ourselves by learning from others', therefore benchmarking toward dominant cyclist is necessary on field. The goals of this study were to provide important factors on multi-disciplines (kinematics, physiology, power, psychology) for a tailored-training program that is suitable to individual characteristics. Two cyclists participated in this study and gave consent to the experimental procedure. One was dominant cyclist (years: 21 yrs, height: 177 cm, mass: 70 kg), and the other was non-dominant cyclist (years: 21, height: 176, mass: 70). Kinematic data were recorded using six infrared cameras (240Hz) and QTM (software). Physiological data (VO2max, AT) were acquired according to graded exercising test with cycle ergometer and power with Wingate test used by Bar-Or et. al (1977) and to evaluate muscle function with Cybex. Psychological data were collected with competitive state anxiety inventory (CSAI-2) that was devised by Martens et. al (1990) and athletes' self-management questionnaire (ASMQ) of Huh (2003). It appears that the dominant's CV of ankle joint angle was higher than non-dominant's CV and dominant's pedaling pattern was consistent in biomechanics domain, which the dominant's values for all factors ware higher than non-dominant's values in physical, and physiological domain, and their values between cognitive anxiety and somatic anxiety were contrary to each other in psychology. Further research on multi-disciplines may lead to the development of tailored-optimal training programs applicable with key factors to enhance athletic performance by means of research including athlete, coach and parents.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.8 no.3
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• pp.293-301
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• 2001

Purpose: The purpose of this study was to investigate the effect of exercise therapy and relaxation therapy on the level of ACTH and cortisol in workers and to determine, from this information, the effectiveness of applied exercise therapy and relaxation therapy as a nursing intervention method for workers experiencing stress. Method: The subjects were divided into an exercise therapy group. a relaxation therapy group, and a control group. The research design was a nonequivalent control group pretest-posttest design (exercise therapy : n=12. relaxation therapy: n=12, control group, the group without exercise or relaxation therapy: n= 12). The subjects in the exercise therapy group were given a particular intensity for each kp over 30 min, bicycle ergometer which uses the LX PE training system before and after four weeks of training. The subjects did 60-70% exercise intensity exercise therapy for eight weeks The relaxation therapy subjects were trained using a modified Jacobson's relaxation technique for eight weeks. The exercise and relaxation therapy groups were trained at the following intensity for eight weeks (3 times/week, 30 min/day). Changes in the levels of ACTH and cortisol were identified. Two-way ANOVA and multiple range test (SNK: Student Newman Keul) were used to examine the effects of exercise therapy and relaxation therapy at four and eight weeks. Result: 1. Changes in the level of ACTH in the relaxation therapy group were statistically significant at .05 level, and were better than that of the exercise therapy group after eight weeks. But there was no significant difference between the exercise therapy group and the control group. 2. Change in the level of cortisol in the relaxation therapy group were statistically significant at .05 level as compared to the exercise therapy group and the control group after four weeks, but not after eight weeks. Also, the relaxation therapy was statistically significant at .05 level after four weeks compared to before treatment, but there was a tendency toward increased cortisol after eight weeks. Conclusion: Relaxation therapy was found to be more effective in stress treatment than exercise therapy and as such is a desirable nursing intervention method for stress hormone reduction in workers.

• Journal of Biomedical Engineering Research
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• v.34 no.2
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• pp.63-68
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• 2013

Activeness of exercise is critical for stroke rehabilitation so that application of stimulation in response to patient's intention would be effective in FES cycling. The purpose of this study was to investigate the relationship between muscle reaction force (MRF) and electromyogram (EMG) during cycling exercise, for the future usage of MRF as patients' intention signal. Seven young men ($24{\pm}1.63$ yrs) participated in this study. Cycling speed was set to 20 RPM and 60 RPM. MRF and EMG were measured in the vastus lateralis muscle of right leg. Active cycling was performed at the maximal load (16 Nm) of an ergometer. Angle dependent artifact in MRF was measured from passive cycling and was subtracted from the MRF of active cycling. The delay of MRF with respect to EMG envelope and their correlation coefficients were derived from the best of cross correlation. MRF was significantly correlated with EMG amplitude in all subjects (p<0.01). Their mean correlations were 0.84 and 0.91 for 20 RPM and 60 RPM, respectively. Mean delay in MRF was 59.14 ms and 53.14 ms for 20 RPM and 60 RPM, respectively. The result suggests that MRF can be used to assess patient's intention for exercise as a substitute to EMG. The method may be applied to FES cycling to encourage patient's effort which is critical for stroke rehabilitation.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.2
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• pp.183-192
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• 2006

Predicting energy expenditure (EE) is important to prevent work-related musculoskeletal disorders (WMSDs). The problem to predict EE is that the standard of EE is based on western data. The authors checked average EE by job categories to provide basic data for suggesting proper work intensity for Korean workers. This study was conducted from 2003 to 2005. Study subjects were recruited from 4 car parts assembly plant, 2 car assembly plant, 2 Heavy machine manufacturing plant and 2 shipyards. Total study subjects were 515 male workers. To estimate VO2max, sub-maximal test was conducted to measure VO275%max by bicycle ergometer (Combi Co, Aerobike 75XL II). Heartbeats were recorded with heartbeat recorder (Polar Electro Co, Finland, S810) during work. EE of work was calculated by recorded heartbeat and individual regression equation which was derived from sub-maximal test. Subjects were classified into 4 industry and 8 work posture, 23 job task categories. Mean EEs (S.D.) according to industry classification (kcal/min) were 4.9 (0.7), 4.8 (0.7), 4.9 (0.7), 5.0 (0.9), and 4.0 (0.5) for Car Part manufacture, Car Assembly, Ship Building, Heavy Machinery Manufacture, and Hospital Office, respectively. The results suggest that Korean male workers of exceeding to the NIOSH criteria will be needed to plan for job rescheduling to maintain $worker^{\circ}$Øs health. Further study to establish Korean work intensity standard would be needed.