To evaluate normal healthy persons without spasticity to observe normal findings of the elbow stretch reflex using a newly developed, portable, hand-driven spasticity-measuring system.
Thirty normal persons without any disease involving the central or peripheral nervous system were enrolled in this study. The portable hand-driven isokinetic system is able to measure the joint angle, angular velocity, electromyographic (EMG) signals, and torque during elbow passive extension-flexion. One set of 10 passive elbow extension and flexion movements was performed for data acquisition at each angular velocity, including 60, 90, 120, 150 and 180 degrees per second (°/sec). Electromyographic data were collected from the biceps brachii and the triceps brachii. Torque data were collected from sensors around the wrist.
We were able to detect EMG activity and torque in all subjects by using the new portable hand-driven isokinetic system. EMG activity and torque increased with incremental increase of angular velocities. The joint angle of maximal EMG activity according to different angular velocities did not show any significant difference (116°-127° in elbow extension and 37°-66° in elbow flexion). The joint angles of maximal torque according to different angular velocities were not significantly different either.
Using the portable hand-driven isokinetic system on the elbows of normal subjects, we were able to obtain expected results. By considering our normal findings of the elbow stretch reflex using this system, we propose that the various aspects of spasticity-related data can be measured successfully.
Citations
Method Sixrteen physically active elderly men and women (age 64.40±3.66) were recruited. The subjects underwent a 12-week knee flexor/extensor isokinetic exercise program of concentric contractions at a velocity of 180 degrees/sec of the both knee twice a week for 12 weeks. Training was carried out on the isokinetic dynamometer. The subjects were evaluated with muscular strength at 90 degrees/sec, endurance at 180 degrees/sec, cardio-pulmonary function, balance, mood and life quality at baseline, 4-week, 8-week and 12-week.
Results Six of 16 people gave up in the middle of the course, 10 people completed a muscle strengthening exercise program. Muscular strength, balance, mood and life quality improved.
Conclusion Isokinetic exercise of the knee joint muscle was carried out and showed the result of multivalent effect in old age. Therefore strengthening exercise in aged persons was thought to be provided for welfare policy of an aging society as well as personal health improvement.
Method: Twenty-one subjects with chronic stroke were participated in this study. All subjects were indoor ambulators. The hemiplegic knee flexors and extensors of the experimental group (n=11) were trained eccentrically using Cybex 770 dynamometer 3 times a week for 6 weeks. Conventional rehabilitation treatment was administrated to the control group at the same duration and frequency as the experimental group. Total peak torque, total work and functional parameters were measured before and after training.
Results: Significantly higher mean percent changes of peak torque and total work were observed in the experimental group compared to the control group at all eccentric angular velocities tested. Functional parameters also showed significant improvements in the gait speed, a timed stair climb up and down, and sit-to-stand time compared to the control group (p＜0.05).
Conclusion: The isokinetic eccentric strengthening training of knee extensors and flexors in patients with chronic hemiplegia were useful in strengthening the affected leg and functional improvement. (J Korean Acad Rehab Med 2003; 27: 824-829)
Method: Using an isokinetic dynamometer we determined the peak torques of knee extensors and knee flexors at angular velocities of 30, 60 and 180 degrees/sec in normal people (120 males, 154 females in the age range 31 to 70 years) and using these peak torque values to calculate functional H/Q ratios and conventional H/Q ratios.
Results: Normative data were presented. As age increased, the magnitudes of the peak torques of most knee flexors and knee extensors decreased, but conventional and functional H/Q ratios were not found to be significantly correlated with age in either sex.
Conclusion: Normative data by decade age in both sexes were obtained. It is hoped that this data will be beneficial for the testing of knee joint function.
Objective: To find useful parameters in biomechanical assessment of spasticity.
Method: Knee extensor muscles of 60 limbs of 47 patients which showed clinical spasticity were stretched by isokinetic dynamometer. Stretch was done with the velocities of 60o/sec, 120o/sec, 180o/sec, 240o/sec. Four parameters [torque onset angle (TOA), peak torque angle (PTA), peak eccentric torque (PET), peak eccentric torque area (PETA)] were measured at each stretch velocity. Then, regression analysis was performed in relationship between each parameter and strech velocity. We analysed the correlation between the slope of each parameter in regression equation and clinical Modified Ashworth Scale (MAS).
Results: The slope of TOA and PTA had negative value so that they showed the decreasing trend of their value according to increasing velocity. On the other hand the slope of PET and PETA had positive value which meant that those parameters increased according to increasing velocity. The slope of PET and PETA were correlated statistically. The higher the MAS score was, the larger value of slope of PET, PTEA were noted.
Conclusion: Peak eccentric torque and Peak eccentric torque area are thought to be useful parameters in biomechanical assessment of spasticity. (J Korean Acad Rehab Med 2002; 26: 321-326)
Objective: The purpose of this study was to examine the strength of the knee and pulmonary function comparing collegians and hockey players in college.
Method: KINㆍCOM isokinetic dynamometer and medigraph were used to evaluate strength of the right lower extremity and pulmonary function to 30 male students comprising 15 hockey players and 15 collegians with no significant difference in age, weight, and height between the two groups. All subjects used their right lower limb as dominant limb.
Results: 1) The significant differences between collegians and hockey players were found in the peak torque at 60o/sec,
180o/sec. 2) The siginficant differences between collegians and hockey players were found in forced vital capacity, forced expiratory volume in one second and expiratory reserve volume on the pulmonary function. 3) The significant correlation between isokinetic strength and pulmonary function were found in peak torque.
Conclusion: It is turned out that hockey players in college have much better isokinetic strength and pulmonary function than collegians, so it is suggested this result have to be considered in selecting hockey players and exercise prescription. (J Korean Acad Rehab Med 2002; 26: 228-232)
Objective: The purpose of this study is to evaluate concentric and eccentric trunk muscle strength in patients with chronic low back pain and compare it with healthy controls to determine the role of trunk muscle in chronic low back pain
Method: Subjects were 20 chronic low back pain patients with the duration at least 6 months and 20 normal adults. Concentric and eccentric isokinetic trunk muscle test was performed at specific speeds (30o, 60o, 120o/sec) with Cybex 770 machine in back pain patients and healthy control.
Results: The strength of trunk flexor and extensor muscles of chronic low back pain patients was significantly weaker than that of normal controls. Eccentric peak torque was significantly higher than concentric peak torque in both patients and healthy control. A concentric and eccentric ratio of patients was lower than that of normal controls. The correlation between concentric and eccentric variables was high. Our results show that concentric peak torque has the highest correlation with eccentric peak torque.
Conclusion: Isokinetic evaluations of the trunk muscle offer objective and quantitative data of patients with chronic low back pain and will be clinically useful in muscle power measurement of lumbar muscles.
Objective: To analyze the patterns of isokinetic knee torque curves in normal population and determine the characteristics of those curves.
Method: Two hundred and eightly-six normal subjects were included. The isokinetic knee torque curves were divided into three parts; to the angle of peak torque generation, to the point 10∼20 degrees prior to end of joint motion, and to the end of joint motion. Each part was classified as convex(1), flat(2) and concave(3) type according to the shape. The curves were named such as 1-2-2 in order. Types of the curves, peak torque, angle of knee at peak torque, total acceleration energy, age, and sex of the subjects were compared.
Results: For knee extensors, frequencies of the curve types were 1-2-2(A), 1-2-1(B), 1-3-1(C), and 1-3-2(D). Mean ages of type A and B curves were slightly higher than types of C and D. Mean peak torque was greatest in type D. For knee flexors, the frequencies were 1-2-2(A), 1-2-1(B), and 1-1-2(C). Female predominance were found in type B while type C was found mostly in male. Mean peak torque was greatest in type C.
Conclusion: The most common torque curve type was 1-2-2 for knee extensors and flexors. Torque curve types of knee extensors showed differences in age and torque curve types of knee flexors showed differences in sexual distribution.
Objective: To examine the effects of unilateral leg exercise on the contralateral leg and the cross training effect according to the training intensity.
Method: Nineteen healthy males volunteered to be subjects for this investigation and were divided into a training group (N=13) and a control group (N=6). One leg of each subject in the training group was randomly assigned to a six week, three day/week isokinetic strengthening training program for concentric knee extension-flexion performed at 60 degrees/second (group A, N=6) and 180 degrees/second (group B, N=7). The control group did not train for six weeks. The strength of the knee extensor and flexor was tested before and after the six week period training by Cybex 770 dynamometer.
Results: In both groups A and B, the training resulted in significant increase of knee extensor strength in trained limb compared to control group. However, the strength increment of untrained limb was not significant compared to control group.
Conclusion: There was no significant cross training effect following unilateral leg strength exercise.
Objective: The purpose of this investigation was to document the isokinetic performance deficiencies of the invertor and evertor muscles of chronically sprained ankles.
Method: Eversion/Inversion testing was performed by a Cybex 6000 isokinetic dynamometer at the speeds of 60o/sec and 120o/sec on 17 subjects who had unilateral chronic ankle sprain. Values were compared between the involved and uninvolved sides.
Results: The inversion peak torque deficits between the involved and uninvolved extremities were significantly greater than eversion deficits at 60o/sec and 120o/sec. Evertor/Invertor peak torque ratios of involved sides at 60o/sec were significantly greater than uninvolved sides.
Conclusion: We conclude that chronic ankle sprains associate an ankle invertor weakness rather than an evertor weakness. Ankle invertor weakness might be resulted from a disuse atrophy and painful ankle inversion. Further prospective study is needed to determine the relationship between the invertor weakness and the chronic ankle sprain.
Objective: We designed this study to evaluate muscle tone by using a biomechanical method and to provide data for the future studies about muscle tone.
Method: We evaluated 29 subjects without known neuromuscalar diseases using the biomechanical method. Both plantar flexors of each subject were passively stretched by isokinetic dynamometer from 30oplantar flexion position to 10odorsiflexion position. Peak eccentric torque (PET) and torque threshold angle (TTA) were calculated at angular velocity of 10o/sec, 90o/sec and 300o/sec. Regression lines from torque/position curve at 10o/sec and 300o/sec were considered an intrinsic stiffness index (ISI) and total stiffness index (TSI). Stretch reflex threshold speed (SRTS) was defined as the minimum speed of plantar flexion movement in which EMG reflex activity in plantar flexor muscles is induced.
Results: The mean of TTA was higher in 10o/sec than in 300o/sec. The means of ISI and TSI were 0.11⁑0.08, and 0.18⁑0.04. The mean of SRTS was 125.2⁑48.3o. No statistical difference in each parameter was found according to the side or gender.
Conclusion: ISI, TSI, PET, TTA and SRTS using a biomechanical method are thought to be useful parameters for the quantitative assessment of muscle tone change of ankle plantar flexors.
Objective: To determine whether muscle fatigue affects knee joint proprioception.
Method: Thirty healthy subjects (18 male and 12 female) with an average age of 22.1 years were selected for this study. Angular errors were measured to test propriocetive function in the knee joint. In a sitting position, the subject's dominant leg was passively positioned to the 45o knee flexion stimulus point for 2∼4 second, while the subject concentrated on this position, the leg was passively returned to the 90o flexion position, afterward the subject was asked to duplicate the stimulus point actively. The difference, in degrees between the stimulus point and the reproduced point is an angular error. All subjects were blindfolded and underwent proprioception measurement before and after the muscle fatigue. Isokinetic exercises performed at 180 degree/sec on the Cybex Orthotron II(Cybex, a division of Lumex, Inc. USA) were used to induce the muscle fatigue. All subjects performed an isokinetic exercise with their dominant leg. Exercise was continued until 50% of the initial peak torque was reached. When the subjects were fatigued to less than 50% of the initial peak torque, the isokinetic exercises were discontinued. Then we immediately retested the proprioception using the same method.
Results: The mean and standard deviation of the angular error increased from 2.79⁑1.17o to 6.40⁑3.42o after muscle fatigue.
Conclusion: The proprioception significantly decreased after the muscle fatigue(p＜0.001). This result suggests that the muscle fatigue must be considered when an injured professional athlete a patient with fatigable disease is set in a rehabilitation program. Further studies are required to determine the physiological mechanisms of the role of muscle fatigue for the decreasing proprioception.
Objective: To investigate the torque curves and heart rate responses to isometric, eccentric and concentric isokinetic exercises with a maximal voluntary contraction of the right knee and elbow joints in 30 healthy men(26.6⁑2.2 years).
Method: Subjected performed the eccentric and concentric isokinetic exercises with 10 repetitions at 60o/sec, while performing the isometric exercises at a joint angle of 60 degrees for the same period of time with Cybex 6000. Peak torque, angle of peak torque, and total work were measured and the flexor-to-extensor ratios of peak torque were calculated.
Heart rates were recorded simultaneously at rest and immediately after the exercise, and the time required to return to the resting heart rate level was also recorded for each exercise session.
Results: Peak torque and total work for the eccentric exercise were significantly higher than those for the concentric exercise(p＜0.01) of the knee and elbow joints. Eccentric peak torques for flexors and extensors of the knee joint occurred at a significantly longer muscle length than the concentric peak torques(p＜0.01).
Flexor-to-extensor ratios of a peak torque of the knee joint between the eccentric and concentric isokinetic exercises did not show a significant difference.
Torques at a joint angle of 60 degrees were highest in the eccentric isokinetic exercise, followed in the order by isometric, and then concentric isokinetic exercises of the knee joint(p＜0.01), and concentric torque at a joint angle of 60 degrees was significantly lower than those of the eccentric and isometric exercises of the elbow joint.
The increase in heart rate and the time of returning to the resting heart rate level were independent of the size of the contracting muscle mass and the types of exercise. The increment ratio for the heart rate was 70.4⁑23.6%.
Conclusion: In conclusion, the response of heart rate to the exercise is not influenced by the contracting muscle mass or the types of exercise in a short duration of maximal voluntary contraction, implying that special precautionary measures are not required for the isometric, eccentric and concentric isokinetic exercises.
Objectives: The biomechanical assessment of spasticity has been developed recently, but not standardized yet for the test procedures and parameters of measurement. This study was designed for the development of standardized method of the biomechanical assessment of spasticity using the isokinetic dynamometer.
Method: The plantar flexor muscles of both ankles were stretched from 40o plantar flexion to 20o dorsiflexion using the isokinetic dynamometer at the angular velocities of 15o, 30o, 60o, 90o, 120o, 180o, and 300o per second. Three parameters, peak eccentric torque(PET), torque threshold angle(TTA), and angle at peak torque(PTA) were analysed.
Results: PET increased and TTA decreased significantly in the involved side. The side to side difference of PET and TTA increased in the patient group with more spasticity. The side to side difference of PET increased, but the side to side difference of TTA decreased with the increase in the angular velocity.
Conclusions: The isokinetic dynamometer is useful in the assessment of the spasticity of ankle plantar flexor of hemiplegic patients. PET and TTA are useful parameters. The faster angular velocities seemed to be more appropriate for the analysis of torque values and the slower angular velocities seemed to be more appropriate for the analysis of thresholds.
Muscle functions are limited in patients with osteoarthritis of knees. In patients with osteoarthritis, isokinetic testing of knee musculature reveals decreased peak torque and increased walking time(50-ft). The purpose of this study was to demonstrate deficiency in muscular performance of knee, and the relationship between walking time and isokinetic parameters of muscular strength, endurance and pain of knee in patients with osteoarthritis of knees. The subjects were divided into a control group and the study group. The control group consisted of 40 persons without a knee pain, and the study group consisted of 30 patients with osteoarthritis of knees. The peak torque of patients in the study group was decreased by 16∼21%, compared to that the control group. There was a negative relationship between the walking time and the endurance of knee extensors(r=0.7195). These findings suggest that exercises to increase the strength and endurance of extensors and flexors of knees should be emphasized in the rehabilitation program for the osteoarthritis of knees.
The understandings of the characteristics of eccentric exercise are very important because all sports and daily activities under the gravity force should be well coupled between concentric contraction and eccentric contraction as accelerator and decelerator respectively. We tested 40 knee flexors and extensors of 20 normal young persons at different anglular velocities of 60o/sec and 120o/sec using Cybex 6000(A division of Lumax, New York) isokinetic dynamometer in order to know the characteristics of eccentric isokinetic contraction parameters by comparing with concentric isokinetic parameters.
Compared to the concentric isokinetic contraction, eccentric isokinetic the peak torque and average power values of knee extensor and flexor muscles showed negative values which means that eccentric contractions were coupled with concentric contractions as decelerator and energy absorptioner. The peak torque values of eccentric contraction were 38∼61%, 44∼79% higher in flexor and extensor, respectively than those of concentric contraction and not so decreased as the peak torque of concentric contraction decreased in high angular velocity. The average power values of knee flexor and extensor muscles were definitely low in eccentric contracton than those of concentric contraction but were increased simultaneously with high angular velocity contraction. Further studies about the velocity dependency, muscle soreness, methodology to measure real eccentric activities and other parameters of eccentric contraction are needed imminently.
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