• Journal of the Korean Applied Science and Technology
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• v.41 no.3
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• pp.813-824
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• 2024

This study was conducted to evaluate the long-term effects of training on the physical development and exercise performance of adolescent weightlifters, aiming to provide effective training and management strategies for improving competitive performance. In order to achieve the objectives of the study, adolescent weightlifters from middle and high schools in Chungcheongnam-do province [male middle school-aged athletes, n=5; female middle school-aged athletes, n=5; male high school-aged athletes, n=12; female high school-aged athletes, n=8] were examined over approximately 10 months of weightlifting-based training to analyse the changes in body composition, physical fitness (muscular strength, muscular endurance, agility, flexibility, dynamic balance, coordination), and isokinetic muscular function (trunk and lower extremity). As a result, it was found that the physical development of middle and high school-aged athletes underwent physical development primarily characterized by an increase in lean body mass. Additionally, back muscle strength and power, which contribute to rapid and efficient force transmission between the upper and lower body, as well as grip strength necessary for controlling the barbell with a stable grip, are significant factors. These aspects were notably enhanced through specialized training and competitive experience for weightlifting performance at the high school level. On the other hand, changes in factors beyond the primary physical attributes contributing to weightlifting performance were limited, suggesting differences in effectiveness likely stemming from the specific composition of training programs or the athletes' experience and skill levels. Collectively, the findings from this study, which evaluates the physical characteristics and exercise abilities of adolescent weightlifters, are expected to contribute to improved competitive performance of weightlifters.

• Physical Therapy Korea
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• v.7 no.2
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• pp.20-34
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• 2000

The purpose of this study was to establish modified physiological cost index (PCI) for predicting energy consumption by heart rate (HR) at isokinetic ergometer exercise testing. The subjects were twenty-eight healthy men in their twenties. All of them performed upper and lower extremity isokinetic ergometer exercise tests which had six loads (400, 500, 600, 700, 800, and 900 kg-m/min) and five loads (400, 500, 600, 700, and 800 kg-m/min) respectively. The exercise sessions were finished when HR was in plateau. HR and oxygen consumption were determined during the final minute. Resting heart rate and oxygen consumption were used for calculating heart rate, oxygen consumption changes and modified PCI. Regression analysis established the relationship between each variable to work load, HR and oxygen consumption. The results were as follows: 1) In the lower extremity ergometer exercise test, oxygen consumption increased continuously as work load increased, but in the upper extremity ergometer test, oxygen consumption only increased until work load was 700 kg-m/min. 2) HR increased as work load increased in both exercise tests, but in the upper extremity ergometer test, HR decreased from the 700 kg-m/min. 3) The modified PCI increased as work load mcreased until the 700 kg-m/min point in the lower extremity ergometer test and until the 500 kg-m/min point in the upper extremity ergometer test when it started to decrease in both tests. 4) In the lower extremity ergometer exercise test, regression analysis established the relation as $dVO_2$ = -.0215HR - .2141 where $dVO_2$ is given in l/min and HR in beat/min ($R^2$ = .2677, p = .000). ln the upper extremity ergometer exercise test. regression analysis established the relation as $dVO_2$ = -.0115HR + .2746 ($R^2$ = .1308, p = .000). The results of this study were similar to previous studies but were different under high work load conditions. So modified PCI should be used with only low intensity work load testing. Subjects for upper extremity ergometer exercise testing should complete a prescribed training course prior to testing, and only low intensity work load should be used for safety considerations.

• International Journal of Highway Engineering
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• v.13 no.3
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• pp.177-184
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• 2011

There are several differences between freeways and general national roads in terms of structures, conditions and limited speeds. Likewise, the characteristics of $CO_2$ emission in these roads differ depending on the road types. For these reasons, it is necessary to compare the two types of roads in terms of $CO_2$ emissions. The study was performed targeting Gyeongbu Expressway and National Highway 1. Firstly, the amount of $CO_2$ emission each car was compared in the whole sections of the both. Secondly, top 10 sections were picked out, and then $CO_2$ emission each section were compared. Lastly, two sections which were with the highest and lowest amount of $CO_2$ emission per car, were compared. As results, it were found that there were less amount of $CO_2$ emission on freeways. because cars are running on uniform velocity at relatively high speed, and that there were more amount of $CO_2$ emission on the national highway. because of frequent intersections and associated congestion. It may be concluded that the amount of $CO_2$ emission at the national highway could be reduced if signal coordination and intersection intervals are improved there.

• The Journal of Korean Physical Therapy
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• v.10 no.1
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• pp.81-98
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• 1998

Isokinetic evaluation of trunk flexors and trunk extensors was performed at $60^{\circ}/sec\;and\;120^{\circ}/sec$ of angular velocity by using cybex 6000TEF Unit on 31 healthy male white workers and 15 post-operative HILD patients with no significant difference in mean age and mean body weight between two groups, and compared each other. The purpose of this study is to obtain the isokinetic normative strength values and endurance latins for Dunk extensors and trunk flexors, and is to provide a guideline for rehabilitation program of post-operative HILD patients. The collected data were analyzed by ANOVA, Duncan's Nyktuoke Range Test, and Pearson correlation coefficiency in PC-SAS program, The results obtained were as follow ; 1. Post-operative subjects has lower isokinetic values than normal subjects in peak torque, peak torque $\%$ by body weight, total work, total work $\%$ by body weight, average power, average power $\%$ by body weight, TAAE of trunk flexors and trunk extensors, and there are significant differences with statistic value in trunk extensors at $60^{\circ}/sec$ and in trunk flexors and trunk extensors at $120^{\circ}/sec$ between two groups(p<0.05). 2. Pest-ooperative subjects has lower values for angle of peak torque than normal subjects in trunk extensors, and there are significant differences with statistic value at $60^{\circ}/sec$ and $120^{\circ}/sec$ between two groups. 3. Post-operative subjects has higher values for endurance ratios than normal subjects in trunk extensors and flexors, but there are no significant differences with statistic value between two groups. 4. Post-operative subjects has higher values than normal subjects in peak torque ratios, total work ratios, average power ratios of trunk flexors to trunk extensors, and there are significant differences with statistic value between two groups(p<0.01). 5. There is significant positive-correlation with statistic valve between peak torque and height and body weight in normal subjects(p<0.05), but Thjere is significant negative-correlation between peak torque of trunk extensor at $120^{\circ}/sec$ and age (p<0.05). 6. There is significant positive-correlation with statistic value between peak torque of trunk flexors and body weight in post-operative subjects (p<0.05), but There is significant negative-correlation between peak torque of trunk extensor add age (p<0.05). In conclusion, post-operative subjects have greater weakness in trunk musculature than normal subjects, especially there is more significant weakness in trunk extensors than in trunk flexors

• Journal of Korean Foot and Ankle Society
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• v.19 no.4
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• pp.142-150
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• 2015

Purpose: Restoration of ankle stability through the strengthening exercise of peroneus muscles is considered an important factor for achievement of successful outcomes, in the rehabilitation program following ankle ligament injuries. However, there were few definitive data on normal muscle strength, including eversion power by peroneus muscles. This study was conducted to evaluate the muscle strength of ankle joint measured using an isokinetic dynamometer in normal Koreans. Materials and Methods: Sixty adults (120 ankles) were recruited and divided into three groups (20 in their twenties, 20 in thirties, and 20 in forties). Each group consisted of 10 males and 10 females. The selection criteria were no history of ankle injury and no evidence of instability. The peak torque, total work, and deficit ratio were measured using the Biodex$^{TM}$ (Biodex Medical Systems). Differences in muscle strength by age, gender and dominant versus non-dominant side were analyzed. Results: The peak torque of dorsiflexion was average 31.5 Nm at $30^{\circ}/s$ of angular velocity and 18.8 Nm at $90^{\circ}/s$; average 69.3 Nm ($30^{\circ}/s$) and 42.4 Nm ($90^{\circ}/s$) on plantarflexion; average 19.6 Nm ($30^{\circ}/s$) and 10.8 Nm ($90^{\circ}/s$) on inversion; average 12.9 Nm ($30^{\circ}/s$) and 8.0 Nm ($90^{\circ}/s$) on eversion. The deficit ratio of strength in women was average 61.1% of men on dorsiflexion; average 66.2% on plantarflexion; average 48.5% on inversion; average 55.4% on eversion. The deficit ratio in non-dominant foot was average 88.6% of dominant foot on dorsiflexion; average 90.1% on plantarflexion; average 85.1% on inversion; average 85.6% on eversion. Conclusion: The muscle strength of the ankle joint showed a tendency to weaken with age. There were significant differences in muscle strength by gender and dominancy. Further studies for comparison of patients with ankle instability, a comparison between before and after surgery for instability, the correlation between clinical outcomes and the recovery in muscle strength will be needed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3902-3909
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• 2009

The purpose of this study was to investigate the spontaneous therapy, TENS(transcutaneous electrical nerve stimulation) and ice therapy after induction of DOMS(delayed onset muscle soreness) through application of eccentrically exercise in ralation to biceps brachii muscle of opposite-dominance. And to explain this, we analyzed VAS(visual analogue scales), peak torque, RMS(roots mean square) when exercising elbow joint. The subjects were 30 adults without any physical defect. Subjects were divided into three groups that spontaneous therapy, TENS therapy and ice therapy after DOMS induction, choosen movement could get the maximal peak torque in angular velocity of $60^{\circ}$/sec, and mearsured peak torque, RMS and VAS. 1. The VAS was significantly decreased after 3 days application of TENS than other groups(p<.05). 2. The peak torque was significantly increased after 3 days application of TENS than other groups(p<.05). 3. The RMS was significantly increased after 3 days application of TENS than other groups(p<.05). This study showed that TENS therapy application were effective treatment strategy on DOMS than spontaneous therapy and ice therapy. Therefore, it could be considered as a treatment method in the patients with DOMS.

• Journal of Korean Physical Therapy Science
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• v.8 no.2
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• pp.967-976
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• 2001

The purpose of the present study was to the investigate the effect of aging in men and women on muscle strength of knee extensor and flexors by using the cybex 6000 isokinetic dynamometer. A total of 100 volunteers participated in this study and were divided into five groups according to their chronological age as follows: 20s, 30s, 40s, 50s, 60s, 10 men and 10 women in each decade respectively. Isokinetic ($60^{\circ}{\cdot}s-l$) knee extensor and flexor peak torque, peak torque to body weight ratio, opposing muscles(flexor/extensor) peak torque ratio, deficit of peak torque between dominant and non-dominant were measured. The results obtained were as follows: 1) In men, While the aged increased. the peak torque of the knee flexor and extensor statistically sig nificant decreased in the dominant and non-dominant side. 2) In women, Statistically significant difference of knee extensor peak torque was found as the aged increased in the dominant and non-dominant side, but significant difference of knee flexor peak torque did not that. 3) In men, No significant difference in the peak torque of knee flexor to body weight ratio was found as the aged increased in the non-dominant side, but statistically significant difference in the peak torque of knee flexor to body weight weight ratio was found as the aged increased in the dominant side. 4) In women. No significant difference in the peak torque of knee flexor to body weight ratio was found as the aged increased in the dominant side, but statistically significant difference in the peak torque of knee flexor to body weight ratio was found as the aged increased in the non-dominant side. 5) In men and women, While the aged increased, statistically significant difference was found the dominant and non-dominant side in the peak torque of knee extensor to body weight ratio. 6) Peak torque of hamstring to quadriceps ratio of dominant and non-dominant side in men and women were not significantly different as the age increases. 7) Mean deficit of peak torque between dominant and non-dominant side in men and women were not significantly different as the age increases. From these results we conclude a proper exercise program is need before 50s decade to preserve in muscle strength of knee flexors and extensors.

• Current Research on Agriculture and Life Sciences
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• v.31 no.2
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• pp.131-138
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• 2013

The precision aerial application of small farms, such as paddy, upland and orchard fields using agricultural unmanned helicopters became a new paradigm. The objective of this study was to evaluate the performance of a GPS module and algorithm, controlling drift of agricultural helicopter by the crosswind and maintaining the position for emergency landing. Purpose of the drift control, of which an algorithm works while hovering is related with the emergency sequence that coping with abnormal conditions of rotorcraft system. However, the inertial attitude control cannot detect a drifting motion of fuselage moving at the constant velocity, thus the crosswind takes the helicopter away from the landing position. Performance of the drift control module, based on the GPS that a hovering position did not deviate within 5m in diameter, were tested and evaluated. Initially, the reaction against a disturbing gust wind was sensitive, soon the helicopter maintained its locking position and azimuth within 5m in diameter. It was, however, difficult for the helicopter to recognize the swaying and nodding, the some deviation was expected due to the discrepancy characteristics of the GPS signal. The performance of the drift control proved the effectiveness of the module to maintain the position against an unintended drift during the emergency landing or hovering.

• Journal of Korean Physical Therapy Science
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• v.7 no.1
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• pp.377-396
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• 2000

After warming-up exercise for 20 minutes, Isokinetic measurement of trunk strength for flexor and extensor was done by using Cybex 6000 TEF Unit on 91 healthy male white workers from 22years old to 49 years old, and compared each other. 20 repetitions of trunk extension-flexion were done at $120^{\circ}$/sec angular velocity. After resting for 1 minutes, Four repetitions at two different angular velocities($60^{\circ}$/sec, $120^{\circ}$/sec) were done with 30 seconds of resting interval between each angular velocity. The purpose of this study is to obtain the isokinetic normative strength values for trunk extensors and flexors, and is to know the correlation between age, height, weight of subjects and data from isokinetic trunk strength measurement, and is to provide a guideline for exercise program of male white collar workers The collected data were analyzed by ANOVA, Duncan's Multiple Range Test, and Pearson correlation coefficiency in PC-SAS program. The results obtained were as follow; 1. There is significant positive-correlation with the statistic value between weight and peak torque of trunk muscles at two different angular velocities($60^{\circ}$/sec, $120^{\circ}$/sec)(p<01), between height and peak torque of trunk muscles at two different angular velocities($60^{\circ}$/sec, $120^{\circ}$/sec) except peak torque of trunk flexor at $60^{\circ}$/sec(p<01). 2. There is nagitive-correlation between age and peak torque of trunk muscles at two different angular velocities($60^{\circ}$/sec, $120^{\circ}$/sec), there is significant differences with statistic value between age and peak torque of trunk extensor at $120^{\circ}$/sec(p<.01). 3. Mean peak torque and mean peak torque % by body weight of trunk extensor is 1.1 times higher values than trunk flexor at $60^{\circ}$/sec. 4. There is the increase in peak torque angle of trunk flexor with increasing of age, and the decrease in peak torque angle of trunk flexor with increasing of age at two different angular velocities($60^{\circ}$/sec, $120^{\circ}$/sec). there is significant differences with statistic value in peak torque angle of trunk flexor at $120^{\circ}$/sec(p<.01). 5. There is significant decrease in endurance ratio of trunk extensor with increasing of age at $120^{\circ}$/sec(p<.01). In conclusion, peak torque of trunk extensor is 1.1 times higher values than trunk flexor in healthy male white collar workers.

• Journal of Korean Physical Therapy Science
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• v.7 no.2
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• pp.711-725
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• 2000

The purpose of this study was to determine the effects of knee flexor isokinetic training on the mean peak torque of knee muscles and hamstrings-to-quadriceps ratio(H/Q ratio) in hemiplegia able to walk independently for more than 10 meters, to analyze the effect of torque increasing on functional aspects; fatigability and ambulation times, also. Forty-one adult subjects with hemiplegia secondary to a stroke partipated in this study. All participants were in/out patients at the College of Medicine, Pocheon CHA University, Pundang CHA General Hospital. The patients were allocated to two groups: one group exclusively for isokinetic maximal voluntary knee flexor training at $150^{\circ}$/sec(n=20) and the other exclusively for isokinetic maximal voluntary knee flexor training from $30^{\circ}$/sec to $150^{\circ}$/sec (n=21) gradually. The allocation was performed according to patient age, sex, affected side to minimize imbalance between the two training groups. Training was carried out from February 14th, 2000 to April 15th, 2000. Analysis of the data was done by means of t-test, x2-test, paired t-test, ANOVA, and multiple regression analysis. The results of this study were as follows: 1. There were no significant differences between the two groups in mean peak torque of knee muscles and relative decreases in knee extensor mean peak torque with increased knee flexor velocities before training (P<.05). 2.There was no significant differences between the two groups in the H/Q ratio, and no relative increases with increased knee flexor velocities before training. 3. there were significant changes in mean peak torque in group A after training(P<.05), but no significant differences as the velocity increased 4.there were significant changes in mean peak torque in group B after training(P<.05), but no significant differences as the velocity increased 5.there were no significant differences between the two groups, and no significant differences in mean peak torque increase rate between the groups with increased knee flexor velocities after training 6.H/Q ratio increased with increased knee flexor velocities between the two groups, but not statistically And there was no significant differences between the groups with increased knee flexor velocities 7.After training, Ambulation time and its decreasing rate decreased significantly in group B (P<.05) 8Before and after training, there was no significant differences between the groups in the fatiguability 9. In the multiple regression analysis, mean peak torque increase rate of the knee extensor and flexor were higher in group B than A(P<.05), and significantly higher with increased knee flexor velocities (P<.05) Also, training method influenced on Ambulation times decreases significantly(P<.05). Results indicated that knee flexor isokinetic training was effective to knee extensor and flexor mean peak torque increase in the hemiplegia able to walk independently for more than 10 meters. Therefore, we were able to conclude that gradual training from low to high velocity was more effective in the increase of mean peak torque of knee joint and decrease of Ambulation times than training only at high velocity.