Citations
To investigate the reliability and validity of a new method for isometric back extensor strength measurement using a portable dynamometer.
A chair equipped with a small portable dynamometer was designed (Power Track II Commander Muscle Tester). A total of 15 men (mean age, 34.8±7.5 years) and 15 women (mean age, 33.1±5.5 years) with no current back problems or previous history of back surgery were recruited. Subjects were asked to push the back of the chair while seated, and their isometric back extensor strength was measured by the portable dynamometer. Test-retest reliability was assessed with intraclass correlation coefficient (ICC). For the validity assessment, isometric back extensor strength of all subjects was measured by a widely used physical performance evaluation instrument, BTE PrimusRS system. The limit of agreement (LoA) from the Bland-Altman plot was evaluated between two methods.
The test-retest reliability was excellent (ICC=0.82; 95% confidence interval, 0.65–0.91). The Bland-Altman plots demonstrated acceptable agreement between the two methods: the lower 95% LoA was −63.1 N and the upper 95% LoA was 61.1 N.
This study shows that isometric back extensor strength measurement using a portable dynamometer has good reliability and validity.
Citations
To investigate the effects of asymptomatic back muscle weakness and spinal deformity on low back pain (LBP).
Sixty healthy subjects without LBP participated in this study. Radiography and an isokinetic/isometric dynamometer were used to respectively measure spinal scoliosis/lordosis and the strength of the trunk flexors/extensors. After 2 years, 48 subjects visited the hospital again and LBP episodes, its severity and the Korean version of the Oswestry Disability Index were assessed. Differences between the group with LBP and the group without LBP were evaluated and the association with LBP incidence and severity was determined.
Sex, age, and trunk strength were significantly different in both group. Sex and age were significantly positive associated with LBP incidence. The isometric trunk flexor and extensor strength, maximum isokinetic trunk flexor and extensor strength were significantly and negatively associated with the LBP severity. The maximum isokinetic trunk extensor and maximum isometric trunk extensor strength was significantly negative associated with the LBP incidence.
LBP incidence is associated with isometric and isokinetic trunk extensor weakness, whereas LBP severity is associated with age, sex, isokinetic trunk extensor and flexor weakness, isometric trunk extensor and flexor weakness.
Citations
To determine the reliability and validity of hand-held dynamometer (HHD) depending on its fixation in measuring isometric knee extensor strength by comparing the results with an isokinetic dynamometer.
Twenty-seven healthy female volunteers participated in this study. The subjects were tested in seated and supine position using three measurement methods: isometric knee extension by isokinetic dynamometer, non-fixed HHD, and fixed HHD. During the measurement, the knee joints of subjects were fixed at a 35° angle from the extended position. The fixed HHD measurement was conducted with the HHD fixed to distal tibia with a Velcro strap; non-fixed HHD was performed with a hand-held method without Velcro fixation. All the measurements were repeated three times and among them, the maximum values of peak torque were used for the analysis.
The data from the fixed HHD method showed higher validity than the non-fixed method compared with the results of the isokinetic dynamometer. Pearson correlation coefficients (r) between fixed HHD and isokinetic dynamometer method were statistically significant (supine-right: r=0.806, p<0.05; seating-right: r=0.473, p<0.05; supine-left: r=0.524, p<0.05), whereas Pearson correlation coefficients between non-fixed dynamometer and isokinetic dynamometer methods were not statistically significant, except for the result of the supine position of the left leg (r=0.384, p<0.05). Both fixed and non-fixed HHD methods showed excellent inter-rater reliability. However, the fixed HHD method showed a higher reliability than the non-fixed HHD method by considering the intraclass correlation coefficient (fixed HHD, 0.952-0.984; non-fixed HHD, 0.940-0.963).
Fixation of HHD during measurement in the supine position increases the reliability and validity in measuring the quadriceps strength.
Citations
To examine the intra-rater, inter-rater, and inter-instrumental reliability of the digitalized pinch muscle strength dynamometer.
Thirty normal subjects were examined for pinch strength, using both the Preston pinch gauge and the digitalized pinch dynamometer. The participants performed all pinch strength tests in the seated position as recommended by the American Society of Hand Therapists (ASHT). Three successive measurements were taken for each hand. The mean of the three trials was used for data analysis. The pinch strength tests performed used a repeated measure design and measurements were taken by each rater.
The relationship between the Preston pinch gauge and the digitalized pinch dynamometer in pinch strength was reliable (the ICC were 0.821 and 0.785 in rater 1 and rater 2 respectively). The relationship between the first session and second session in pinch strength using the digitalized pinch dynamometer was reliable (the ICC were 0.872 and 0.886 in rater A and rater B respectively). The relationship between rater A and rater B in pinch strength using the digitalized pinch dynamometer was reliable (the ICC was 0.754).
The pinch strength measurement using the digitalized pinch dynamometer is reliable within the rater and between raters. Thus, the Preston pinch gauge and the digitalized dynamometer measure grip strength equivalently, and can be used interchangeably.
Citations
To evaluate the relationship between the cross sectional area (CSA) and isokinetic strength of the back muscles in patients with chronic low back pain.
Data of twenty-eight middle-aged patients with chronic back pain were analyzed retrospectively. CSAs of both paraspinal muscles and the disc at the L4-L5 level were measured in MRI axial images and the relative CSAs (rCSA: CSA ratio of muscle and disc) were calculated. The degree of paraspinal muscle atrophy was rated qualitatively. Isokinetic strengths (peak torque, peak torque per body weight) of back flexor and extensor were measured with the isokinetic testing machine. Multiple regression analysis with backward elimination was used to evaluate relations between isokinetic strength and various factors, such as CSA or rCSA and clinical characteristics in all patients. The same analysis was repeated in the female patients.
In analysis with CSA and clinical characteristics, body mass index (BMI) and CSA were significant influencing factors in the peak torque of the back flexor muscles. CSA was a significant influencing factor in the peak torque of total back muscles. In analysis with rCSA and clinical characteristics, BMI was significant in influencing the peak torque of the back flexors. In female patients, rCSA was a significant influencing factor in the peak torque per body weight of the back flexors, and age and BMI were influencing factors in the peak torque of back flexors and total back muscles.
In middle-aged patients with chronic low back pain, CSA and rCSA were influencing factors in the strength of total back muscles and back flexors. Also, gender and BMI were influencing factors.
Citations
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: 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: The purpose of this study was to determine the knee extension force of healthy Korean adults by using a hand-held dynamometer and evaulate the relationship of knee extension force between each decade.
Method: One hundred and twenty healthy subjects (60 males, 60 females) between the ages of 20 and 79 years were tested for knee extension force by using Nicholas Manual Muscle Tester (MMT). Data were analyzed for means, standard deviations, test-retest reliability and correlation with variables by using the SPSSⰒ software package.
Results: The mean value of the knee extension force was 25.9⁑5.8 kg in the males and 16.5⁑4.1 kg in the females. Significant difference between each decade was found in the males but not in the females. The knee extension force of the males was stastically correlated with all of variables, i.e., age, weight and height, but the knee extension force of the females, was correlated only with weight. Intratester correlation coefficients were high for the Nicholas MMT to measure the knee extension force for healthy adults. Also the difference between the dominant and nondominant side for the knee extensor force was not significant, stastically.
Conclusion: This MMT may be useful to quickly and objectively evaluate force in the clinical setting.
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.
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.
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