• Physical Therapy Korea
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• v.12 no.3
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• pp.46-55
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• 2005

The purpose of this study was to evaluate the effect of concurrent and reciprocal isometric contraction and angle of ankle joint on fatigue of concentrically contracting contralateral dorsiflexor and plantar flexor. Seventeen able-bodied subjects participated in the study. Concurrent and reciprocal isometric contraction were performed under three different ankle joint angles (dorsiflexion, neutral position, plantar flexion). During concurrent or reciprocal isometric contraction. fatigue of concentrically contracting contralateral tibialis anterior, gastrocnemius, and soleus was investigated and compared. There was no interaction between different ankle joint angles and direction of isometric contraction (p<.05). No significant differences were found among three different ankle joint angles (p<.05). Contralateral muscle fatigability was lower in reciprocal isometric contraction than that in concurrent isometric contraction (p<.05). Therefore, the findings of this study suggest that reciprocal isometric contraction is more beneficial than concurrent isometric contraction inducing less fatigability during contralateral concentric contraction.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.11
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• pp.1628-1633
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• 2017

The purpose of this study was to identify the difference and correlation in elbow joint maximal flexion strength according to measurement methods and characteristics of muscular contraction, and to develop the predictive equation of elbow joint maximal flexion strength for the optimal exercise intensity setting and accurate measurement. Subjects were 30 male university students. Elbow joint maximal flexion strength of isokinetic contraction, isometric contraction at $75^{\circ}$ elbow joint flexion position, isotonic concentric 1RM, manual muscle strength (MMT) were measured with isokinetic dynamometer, dumbbell, and manual muscle tester. Pearson's r, linear regression equation, and multiple regression equation between variables were calculated. As a result, the highest value was isometric contraction. The second highest value was MMT. The third highest value was isokinetic contraction. 1RM was the lowest. Predictive equations of elbow joint maximal flexion strength between isometric and isokinetic contraction, between isometric contraction and 1RM, among isometric contraction, 1RM, and body weight were developed. In conclusion, 1RM and isokinetic elbow joint maximal flexion strength could be seemed to underestimate the practical elbow joint maximal flexion strength. And it is suggested that the developed predictive equations in this study should be useful in criteria- and goal-setting for resistant exercise and sports rehabilitation after elbow joint injury.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.29 no.2
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• pp.69-75
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• 2023

Purpose: This study examined the distance between the coracoid process and the humeral head using an ultrasonography device when shoulder active contraction were applied according to the guided direction in the end range of shoulder mobilization. This study aims to provide essential data on treating shoulder disease patients. Methods: The subjects of this study were 20 adults with healthy shoulder joints. ultrasonography (US) equipment was used to examine shoulder joint mobilization under two conditions: (1) anteroposterior (AP) joint mobilization and (2) superoinferior (SI) joint mobilization. Shoulder active contraction was assessed in the end range. The distance between the coracoid process and the humeral head was measured. A linear probe was used for US; the frequency was set to 7.5MHz, and the US image display method was set to B-mode. The US measurement values were measured in (1) the starting position, (2) the end range position, and (3) the end range position of the shoulder active contraction, and the moving distance was drawn in a straight line through the US image. The distance was determined as the measurement value, and the average values were compared. Reults: The results were as follows: (1) the measured AP Joint mobilization increased by an average of .52cm from the end range of the joint mobilization with shoulder active contraction; (2) the measured SI Joint mobilization increased by an average of .49cm from the end range of the joint. Conclusion: When shoulder mobilization is applied, the distance between the coracoid process and the humeral head increases when muscle contraction occurs through shoulder active contraction in the end range, according to the therapist's guidance. Therefore, shoulder mobilization combined with shoulder active contraction is an effective treatment method for patients with shoulder injuries.

• PNF and Movement
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• v.13 no.1
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• pp.1-7
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• 2015

Purpose: This study aimed to examine the activity of the shoulder flexor and extensor when hold-relax and contraction-relax techniques were applied with shoulder joint flexion. Methods: The subjects of this study were 15 healthy women. With the shoulder joint flexion at $0^{\circ}$ and $90^{\circ}$, hold-relax and contraction-relax techniques were applied for the same submaximal resistance to measure the activities of the deltoid muscle anterior fiber, deltoid muscle posterior fiber, pectoralis major fiber, and latissimus dorsi muscle with surface electromyography. An independent t-test was conducted in order to compare activities of each muscle according to the two techniques. Results: When the hold-relax and contraction-relax techniques were applied with the shoulder joint flexion at $0^{\circ}$, the activities of the shoulder flexor and extensor were not significantly different, but the activity of the flexor was higher when the contraction-relax technique was applied than when the hold-relax technique was applied. When the hold-relax and contraction-relax techniques were applied with the shoulder joint flexed at $90^{\circ}$, the activities of the shoulder flexor and extensor were not significantly different, but the activity of the extensor was relatively higher than when the flexor was at $0^{\circ}$ Conclusion: When the hold-relax and contraction-relax techniques were applied with the shoulder joint flexion at $0^{\circ}$, the activities of the shoulder flexor and extensor were not significantly different, but the activity of the flexor was higher when the contraction-relax technique was applied than when the hold-relax technique was applied. When the hold-relax and contraction-relax techniques were applied with the shoulder joint flexed at $90^{\circ}$, the activities of the shoulder flexor and extensor were not significantly different, but the activity of the extensor was relatively higher than when the flexor was at $0^{\circ}$.

• The Journal of Korean Physical Therapy
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• v.35 no.2
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• pp.43-47
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• 2023

Purpose: This study compared the movement control ability of the ankle joint according to the type of muscle contraction, namely, eccentric or concentric contractions. Methods: Thirty-four healthy adult subjects participated in this study. As a single group, before the experiment, the subjects were trained on achieving the required position of the ankle around the target point by manually controlling the ankle dorsiflexion by 10°. Concentric contraction starts at 0° and continues until the target point of 10° is reached. During an eccentric contraction, the ankle joint starts at 20° ankle dorsiflexion and continues till the target point is reached. Movements using eccentric contraction and concentric contraction were randomly performed 3 times each. Results: The results of comparing the difference in the movement control ability of each type of muscle contraction of ankle dorsiflexion showed that the measurement-remeasurement error was significant in eccentric contraction. Conclusion: In this study, we found a difference in the ability to control movement according to whether the contraction is eccentric or concentric. Therefore, we propose that the ability to control movement is affected by the type of muscle contraction.

• Korean Journal of Applied Biomechanics
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• v.21 no.2
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• pp.189-196
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• 2011

The purpose of this study was to verify the difference in biomechanical variation and pattern of the lower limb between planned and unexpected termination, which is related to the prevention of fatal fall in the elderly. Therefore, selected twenty subjects for each group which composed of females(age: $73.5{\pm}4.63$ year, height: $153.2{\pm}6.46$ cm, body mass: $58.98{\pm}5.82$ kg) and women(age: $23.4{\pm}2.5$ year, height: $164.65{\pm}3.9$ cm, body mass: $58.47{\pm}5.53$ kg) in their twenties. As a result, lower limb's extension moment and power were increased significantly in statistics(p<.05). Also, knee joint power showed instant changes from concentric contraction to eccentric contraction and hip joint power from eccentric contraction to concentric contraction. During unexpected termination there were dramatical increase in eccentric contraction and power(p<.05). In both planned and unexpected termination, ankle joint moment were higher in young group, but the moment of the hip joint were higher in the elderly group(p<.05). In contrast to younger group, there were no changes in knee extension moment in elderly group(p<.05). but showed relatively higher hip joint extension moment and power(p<.05).

• Journal of the Korean Society for Precision Engineering
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• v.28 no.6
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• pp.670-677
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• 2011

This study is to estimate the joint torques without torque sensor using the EMG (Electromyogram) signal of agonist/antagonist muscle with Neural Network Back Propagation Algorithm during the elbow motion. Command Signal can be guessed by EMG signal. But it cannot calculate the joint torque. There are many kinds of field utilizing Back Propagation Learning Method. It is generally used as a virtual sensor estimated physical information in the system functioning through the sensor. In this study applied the algorithm to obtain the virtual senor values estimated joint torque. During various elbow movement (Biceps isometric contraction, Biceps/Triceps Concentric Contraction (isotonic), Biceps/Triceps Concentric Contraction/Eccentric Contraction (isokinetic)), exact joint torque was measured by KINCOM equipment. It is input to the (BP)algorithm with EMG signal simultaneously and have trained in a variety of situations. As a result, Only using the EMG sensor, this study distinguished a variety of elbow motion and verified a virtual torque value which is approximately(about 90%) the same as joint torque measured by KINCOM equipment.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.3
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• pp.1-11
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• 2019

PURPOSE: This study compared the changes in the range of motion (ROM ) on the knee joint according to three different isometric contraction intensities when applying Evjenth - Hamberg stretching (EHS) to the hamstring muscles of healthy subjects. METHODS: Forty eight healthy subjects aged between 20 and 39 years were allocated randomly to four groups; performing EHS at 10% maximum voluntary isometric contraction (MVIC) group, EHS at 50% MVIC group, EHS at 100% MVIC group, and control group (CG) pre-, and post-intervention. The flexibility of the hamstring muscles was evaluated using a digital goniometer for measuring the knee joint ROM motion. A Chattanooga stabilizer was used to adjust the MVIC intensity by 10%, 50%, and 100%, respectively. RESULTS: These results show that the pre- and post-intervention knee joint ROM were significantly different in all four groups (p<.05). The post-intervention knee joint ROM showed a significant difference between the 100% MVIC group and non-MVIC group (p<.05). The knee joint ROM difference between the pre- and post-interventions was similar in the 10% MVIC and 50% MVIC groups but significant differences were observed among the other groups (p<.05). CONCLUSION: EHS of the hamstring muscles was effective in improving the knee joint ROM with an isometric contraction intensity of 10%, 50%, or 100% MVIC, and of these, 100% MVIC was most effective.

• Journal of the Korean Society of Clothing and Textiles
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• v.17 no.4
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• pp.608-621
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• 1993

The Purposes of this study were 1)to find the body surface total line and segment line significantly(${\alpha}$=0.05) changed by the leg movement including all movement direction of hip joint, knee joint and ankle joint for the more functional clothing. 2)to classify them into 3 types-expansion type, contraction type, expansion & contraction type, and 3)to identify the characteristics of the body surface length changes. 10 Crosswise and 5 lengthwise body surface total lines and 48 crosswise & 39 lengthwise body surface segment lines of 26 female college students aged from 18 to 24 years were measured directly on the body surface and were analyzed by ANOVA & Multiple Comparison Test (Tukey). The results were as following : Body surface total lines significantly changed were all the body surface total lines except abdoman girth, 1/2thigh girth of lower leg and ankle girth, and these were classified into 3 types : Center front leg line belonged to expansion & contraction type, whereas lateral leg line, legscye girth, and total crotch length belonged to contraction type. The rest belonged to expansion type. Knee girth showed maximum expansion, whereas center front leg line showed maximum contraction. Body surface total lines have shown large expansion crosswise whereas lengthwise they have mainly shown contraction. At least more than one component segment line of each body surface total lines except abdoman girth and ankle girth have shown significant change. Top segment of inner leg line showed maximum expansion. whereas just below top segment of center front leg line showed maximum contraction. Crosswise all the body surface segment lines have shown expansion except inner back segments of thigh girth and 1/2thigh girth of upper leg which have shown contraction. Lengthwise they have shown both expansion and contraction according to the location of front or back, and below or upper 1/2thigh girth line except the component segment lines of lateral leg line, which has shown contraction only.(cf. figure 2. figure 3. and table 2-2).

• The Korean Journal of Physiology
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• v.17 no.1
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• pp.37-43
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• 1983

Electromyographic analysis was made in the forearm to clarify the prime mover of the wrist joint in flexion and extension. Loads of 5 and 10 pounds were given to the hand during isometric and isotonic contraction. The results of this study were summarized as follows: 1) M. flexor carpi ulnaris and m. extensor carpi radialis acted as the prime mover during flexion and extension, respectively, of the wrist joint. 2) The flexor and the extensor of the forearm showed synergistic activities under isotonic contraction, but under isometric contraction the flexor only acted. 3) Muscular activity during the isotonic contraction slightly increased compared with the isometric contraction. 4) EMGs and integrated EMGs were somewhat enhanced as the load increased, but there was no significant difference between 5 and 10 pounds load.