• The Journal of Korean Physical Therapy
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• v.14 no.4
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• pp.260-265
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• 2002

There are many methods for muscle strengthening. Muscle strengthening with eccentric contraction work is the best way by researcher's report. Also, eccentric contraction need proper resistance for muscle strengthening. Combination of isotonic in PNF is a muscle strengthening method with manual resistance. It makes concentric contraction $\rightarrow$ eccentric contraction $\rightarrow$ concentric contraction with continually and without muscle relaxation. Combination isotonic technique use with PNF pattern. Therefore, it will make development and increasing of active control motion, coordination, actual range of motion, strengthen and functional training in eccentric control of movement. Concentric contraction have the 3rd lever system and eccentric contraction have the 2nd lever system with combination of isotonic. Serial concentric contraction $\rightarrow$ eccentric contraction $\rightarrow$ concentric contraction make strong SEC and PEC. It will be increase elasticity of SEC, PEC and contractile components either.

• The Journal of Korean Physical Therapy
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• v.24 no.4
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• pp.262-267
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• 2012

Purpose: This study was designed to analyze the differences in cerebral cortex activity of the elderly after extracting the movement related cortical potentials (MRCPs) from electroencephalogram (EEG) during a concentric and eccentric contraction of the elbow joint flexors, and entering them into the brain-mapping program to make the images. Methods: Right-dominant normal elderly people were divided into an eccentric contraction group and a concentric contraction group. Then, their MRCPs were measured using EEG and sEMG, during an eccentric and concentric contraction. Then, they were converted into images using the brain-mapping program. Results: Eccentric contraction group's $C_3$ and Cz showed statistically higher mean values of MRCP positive potential than the concentric contraction group. Conclusion: Researching a cerebral cortex activity, using MRCP, would provide basic data for clinical neuro-physiological researches on aging or neural plasticity of patients with a central nervous system injury.

• 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.

• The Journal of Korean Physical Therapy
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• v.10 no.2
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• pp.57-69
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• 1998

The role of eccentric muscle activities in functional everyday activities and sport is important and equally significant to concentric conditions. Eccentric and concentric exercise and evaluation are, therefore, very important. The purposes of this study were to measure eccentric md concentric peak torgue, percentage of peak torque, average power and percentage of average power of trunk flexors and extensors by using the Cybex NORM isokinetic dynamometer, and to standardize the value obtained. Thirty four young volunteers were tested, 17 females and 17 males, who had no history of back pain or abnormality. Each subjects were tested on three repetitions for isokinetic concentric and eccentric contraction at 5 velocities. The results were as follows; 1) Peak torque percent body weight of eccentric contraction were significantly greater than concentric contraction at each angular velocity and in trunk flexors and extensors(p<0.01). 2) Peak torque percent body weight of concentric contraction were significantly decreased as the angular velocity increased both male and female(p<0.01). 3) Peak torque percent body weight of eccentric contraction were not significantly changed as the angular velocity increased both male and female(p<0.05), 4) Peak torque percent body weight of male were significantly greater than female at each angular velocity and in concentric and eccentric contraction of trunk flexors and extensors(p<0.01)

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1575-1579
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• 2008

The purpose of this study was to investigate how maximum-effort eccentric exercise over different contraction ranges affects the characteristics of torque-angle relationship of human ankle plantarflexor in-vivo. Subjects were randomly assigned in two groups. One group (n=6) performed 120 maximum-effort eccentric ankle dorsiflexion contractions at short muscle length (ankle range of motion from -5 to 15 deg) and the other group (n=6) at long (ankle range of motion from 10 to 30 deg) muscle length. Eccentric exercise decreased the maximum isometric ankle plantarflexion torque ${\sim}40%$. It was found that the optimum ankle joint angle changed from 7.5 deg to 11.1 deg and 10.1 deg, shifted toward the longer muscle length, regardless of the exercise range. The results of this study suggest that eccentric exercise alters the characteristics of torqueangle relationship of the muscle but there is no differential effect of the eccentric contraction range.

• Physical Therapy Korea
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• v.12 no.3
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• pp.94-100
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• 2005

Eccentric muscle contraction is more effective than concentric and iosmetric muscle contraction in increasing muscle strength. Also, eccentric or concentric-eccentric training has greater effective in neural activation and muscle hypertrophy than concentric training. In some study, eccentric exercises have been shown to reduce pain and improve function on Achilles tendinopathy. The purpose of this study was to evaluate the effect of eccentric isokinetic exercise in a patient with dislocation of the tarsometatarsal joint by traffic accident. After eccentric isokinetic training, peak torque, average work, and average power were increased. Also, the patient was fully weightbearing with a pain free normal gait thus making good recovery.

• Journal of Biomedical Engineering Research
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• v.18 no.4
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• pp.413-420
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• 1997

In this paper, we analyzed the contraction patterns of active elbow muscles during isometric, concentric and eccentric contraction. The analysis parameters consist of frequency domain parameters (mean frequency, median frequency, peak frequency, peak power, skewness, kurtosis) and time domain paraseters (zero crossing, positive maxima, integrated EMG). The results of this study were as follows; The BR/BB of isometric contraction appeared to be Venter as the elbow joint was more extended. The BR /BB during concentric and eccentric contraction tended to increase with more extension of the elbow joint angle, but there was no significant difference between concentric and eccentric contraction. Further, the EMG power spectrum due to the type of contraction were different betwen eccentric and concentric contraction. According to the results, it was found that the activation pattern in elbow flexor muscles was different during three different muscle contraction pattern. Therefore, elbow flexor muscles should not be considered a single functioning unit. Especially, at the time domain analysis, IEMG is a dominant parameter for analysis of activation patterns, and the skewness kurtosis can be useful parameters in functional recognition for prosthesis control purpose.

• PNF and Movement
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• v.17 no.3
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• pp.487-497
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• 2019

Purpose: This tutorial review investigated the effect of prior fatigue and passive stretches on eccentric contraction-induced muscle injuries, as well as the underlying mechanisms of eccentric contraction-related injuries. Methods: Contraction-induced muscle damage is the most common disabling problem in sports and routines. The mechanisms underlying the pathology and prevention of muscle damage lessened by prior fatigue or stretches are critical in assessing musculoskeletal injuries. Even though there are treatments to reduce eccentric contraction-induced muscle injuries, fatigue negatively influences them. Therefore, we reviewed previous studies on eccentric contraction-induced muscle injuries with prior treatments using the MEDLINE and PubMed databases. Results: Prior passive stretching had a preventative and therapeutic effect, but prior lengthening contractions did not. On the other hand, prior isometric contractions involving relatively small forces may not provide a sufficient stimulus to induce protection. As a result, high force isometric contractions may be necessary. The studies supported the positive effects of prior fatigue, concluding that it was a factor in determining the amount of damage caused by eccentric exercise. This was due to a reduction in force and increased temperature. Studies that did not support the positive effects of prior fatigue concluded that a shift in optimal length to a longer length and reduced energy absorption during lengthening are evidence that fatigue is not related to muscle injuries induced by lengthening. Conclusion: The variability of the experiment models, conditions, muscles, and treatment methods make it necessary to interpret the conditions of previous studies carefully and draw conclusions without making direct comparisons. Thus, additional studies should be carefully conducted to investigate the positive effect of fatigue on lengthening.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.6 no.1
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• pp.59-65
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• 2012

In this study, muscle fatigue of biceps and triceps during isometric exercise depending on concentric contraction and eccentric contraction was evaluated using EMG. 12 healthy male volunteers was performed concentric exercise and eccentric exercise by maximum flection and extension of elbow joint. Integrated EMG (IEMG) in time domain and mean power frequency (MNF) in frequency domain were calculated. MNF of the biceps and triceps was decreased, whereas IEMG was increased during concentric contraction and eccentric contraction. But muscle fatigue index appeared higher at region of stretched muscle length. in this result, muscle fatigue occurs at both biceps and triceps muscle during concentric and eccentric exercise, and muscle fatigue was affected by muscle contraction and extension.

• Physical Therapy Rehabilitation Science
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• v.5 no.1
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• pp.40-46
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• 2016

Objective: The purpose of this study was to examine the effect on multifidus and external oblique abdominis muscle activation during hip contraction of three types (concentric, isometric, eccentric) in standing position. Design: Cross-sectional study. Methods: Twenty healthy adult men volunteered to participate in this study. Muscle activation was recorded from gluteus maximus, both multifidus, and both external oblique abdominis by surface electromyography (EMG) while holding position in the type of gluteus maximus contraction. EMG values were normalized by maximum muscle contractions (% maximum voluntary isometric contraction). All subjects performed hip extension with three contraction methods. The type of gluteus maximus contraction using Thera-band was composed of concentric contraction (type 1), isometric contraction (type 2), and eccentric contraction (type 3). To measure muscle activation on the gluteus maximus contraction type, each position were maintained for 5 seconds with data collection taken place during middle three seconds. Muscle activation was measured in each position three times. Results: For the results of this study, there was no significant difference within three contraction patterns of the gluteus maximus (concentric, isometric, and eccentric) each both multifidus, both external oblique abdominis, and gluteus maximus. And there was no significant difference among both multifidus, both external oblique abdominis, and gluteus maximus each hip extension contraction type. Conclusions: These findings suggest that specific contraction types of the gluteus maximus does not lead to a more effective activation of the multifidus, external oblique abdominis, and gluteus maximus.