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Mohamad Parnianpour

Bio: Mohamad Parnianpour is an academic researcher from Sharif University of Technology. The author has contributed to research in topics: Trunk & Isometric exercise. The author has an hindex of 50, co-authored 274 publications receiving 7835 citations. Previous affiliations of Mohamad Parnianpour include New York University & Hong Kong Polytechnic University.


Papers
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Journal ArticleDOI
15 Jun 2006-Spine
TL;DR: The Persian versions of the ODI, RDQ, and QDS are reliable and valid instruments to measure functional status in Persian-speaking patients with LBP and can be recommended in a clinical setting and future outcome studies in Iran.
Abstract: STUDY DESIGN. Cross-cultural translation and psychometric testing were performed. OBJECTIVES. To cross-culturally translate the Oswestry Disability Index (ODI), Roland-Morris Disability Questionnaire (RDQ), and Quebec Back Pain Disability Scale (QDS) into Persian, and then investigate the psychometric properties of the Persian versions produced. SUMMARY OF BACKGROUND DATA. To the authors' knowledge, there is no validated instrument to measure functional status in Persian-speaking patients with low back pain (LBP) in Iran. To our knowledge, the widely used back-specific measures, the ODI, RDQ, and QDS, have not been translated and validated for Persian-speaking patients with LBP. METHODS. The translation and cross-cultural adaptation of the original questionnaires were performed in accordance with published guidelines. A total of 100 patients with chronic LBP were asked to complete a questionnaire booklet (the Persian versions of the ODI, RDQ, QDS, Short Form Health Survey (SF-36), and visual analog scale measure of pain). There were 31 randomly select patients with chronic LBP asked to complete the second questionnaire booklet 24 hours later. RESULTS. The Cronbach-I± for the ODI, RDQ, and QDS was 0.75, 0.83, and 0.92, respectively. The ODI, RDQ, and QDS showed excellent test-retest reliability (intraclass correlation coefficient = 0.91, 0.86, and 0.86, respectively) (P < 0.01). The correlation among the ODI, RDQ, QDS and physical functioning scales of the SF-36 was -0.66, -0.62, and -0.69, respectively (P < 0.001). The correlation among the ODI, RDQ, and QDS and visual analog scale was 0.54, 0.36, and 0.46, respectively (P < 0.001). CONCLUSIONS. The Persian versions of the ODI, RDQ, and QDS are reliable and valid instruments to measure functional status in Persian-speaking patients with LBP.They are simple and fast scales, and the use of them can be recommended in a clinical setting and future outcome studies in Iran. ©2006, Lippincott Williams & Wilkins, Inc.

356 citations

Journal ArticleDOI
01 Sep 1988-Spine
TL;DR: The effects of isodynamic fatiguing of flexion and extension trunk movements on the movement patterns and the motor output of the trunk were investigated and significantly less motor control and greater range of motion in the coronal and transverse planes were displayed.
Abstract: Previous studies have shown that reduction of precise motor control accompanies local muscular fatigue. The effects of isodynamic fatiguing of flexion and extension trunk movements on the movement patterns and the motor output of the trunk were investigated. Twenty male subjects with no history of low-back pain for the past 6 months volunteered for the study. A triaxial dynamometer was used that simultaneously provided measurement of torque, angular position and velocity of each axis. Resistances were set independently for each axis by an interfaced computer. The subjects performed trunk flexion and extension movement against a sagittal plane resistance equal to 70% of their maximum isometric extension strength in the upright position. The minimum resistances in the coronal and transverse planes were set up at 7 Newton meters. The subjects were asked to perform trunk movement as quickly and as accurately as possible while exerting the maximum efforts until exhaustion. Analysis of variance, the MANOVA procedure with a repeated measure design, was performed among the selected parameters of the first, middle and last three repetition cycles. The selected parameters are the trunk motor output and movement patterns; the total angular excursion, range of motion, maximum and average torque and angular velocity of the trunk. All the selected parameters were significantly reduced in the sagittal plane. Subjects displayed significantly less motor control and greater range of motion in the coronal and transverse planes in performing the primary task of flexion and extension. The reduction in the functional capacity of the primary muscles performing the required task is compensated by secondary muscle groups and the spinal structure is loaded in a more injury prone pattern, as identified by finite element models. In addition it is suggested that the fatigued muscles would be less able to compensate any perturbation in the load or position of the trunk. The repetitive loading results in a weakening of the viscoelastic passive elements of the spineless structure. The loss of ability to protect these weakened passive elements makes the spine susceptible to industrial and recreational injuries.

290 citations

Journal ArticleDOI
TL;DR: Measurements of endurance, kinematics, postural stability, and coordination, in addition to strength, are necessary to fully document the patients' functional capabilities to guide physical therapists in their rehabilitation of low back pain patients.
Abstract: Because of the inability of strength tests to accurately discriminate between low back pain patients and healthy subjects, a multifactorial evaluation of low back pain patients is warranted. It is postulated that measurements of endurance, kinematics, postural stability, and coordination, in addition to strength, are necessary to fully document the patients' functional capabilities. This research study was conducted in order to understand the effects of fatigue on the above factors. Twelve healthy male subjects performed a repetitive lifting test in which a submaximal load was lifted at a maximal rate. Knee, hip, and trunk motion was measured using videography and electrogoniometry, postural stability was measured using a forceplate, and coordination parameters were determined using phase-plane analysis. Fatigue was documented by a 31% reduction in lifting power. At the end of the endurance test, there was less knee and hip range of motion and greater spine peak flexion, while the coordination measures demonstrated that there was greater hip and lumbar spine extension earlier in the lifting phase. The postural stability declined as the test endured. Utilization of these measures may guide physical therapists in their rehabilitation of low back pain patients.

195 citations

Journal ArticleDOI
01 Dec 1995-Spine
TL;DR: Higher-order trunk motion characteristics hold great promise as a quantitative indicator of the trunk's musculoskeletal status and may be used as a measure of the extent of a disorder and as a measures of rehabilitative progress.
Abstract: Study DesignThis study observed the trunk angular motion features of healthy subjects and those experiencing chronic low back disorders as they flexed and extanded their trunks in five symmetric and asymmetric planes of motion. Trunk angular positon, velocity, and acceleration were evaluated during

164 citations


Cited by
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Journal Article
TL;DR: This book by a teacher of statistics (as well as a consultant for "experimenters") is a comprehensive study of the philosophical background for the statistical design of experiment.
Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

13,333 citations

Journal ArticleDOI
TL;DR: Evidence for "central" fatigue and the neural mechanisms underlying it are reviewed, together with its terminology and the methods used to reveal it.
Abstract: Muscle fatigue is an exercise-induced reduction in maximal voluntary muscle force. It may arise not only because of peripheral changes at the level of the muscle, but also because the central nervous system fails to drive the motoneurons adequately. Evidence for “central” fatigue and the neural mechanisms underlying it are reviewed, together with its terminology and the methods used to reveal it. Much data suggest that voluntary activation of human motoneurons and muscle fibers is suboptimal and thus maximal voluntary force is commonly less than true maximal force. Hence, maximal voluntary strength can often be below true maximal muscle force. The technique of twitch interpolation has helped to reveal the changes in drive to motoneurons during fatigue. Voluntary activation usually diminishes during maximal voluntary isometric tasks, that is central fatigue develops, and motor unit firing rates decline. Transcranial magnetic stimulation over the motor cortex during fatiguing exercise has revealed focal cha...

3,200 citations

01 Mar 1995
TL;DR: This thesis applies neural network feature selection techniques to multivariate time series data to improve prediction of a target time series and results indicate that the Stochastics and RSI indicators result in better prediction results than the moving averages.
Abstract: : This thesis applies neural network feature selection techniques to multivariate time series data to improve prediction of a target time series. Two approaches to feature selection are used. First, a subset enumeration method is used to determine which financial indicators are most useful for aiding in prediction of the S&P 500 futures daily price. The candidate indicators evaluated include RSI, Stochastics and several moving averages. Results indicate that the Stochastics and RSI indicators result in better prediction results than the moving averages. The second approach to feature selection is calculation of individual saliency metrics. A new decision boundary-based individual saliency metric, and a classifier independent saliency metric are developed and tested. Ruck's saliency metric, the decision boundary based saliency metric, and the classifier independent saliency metric are compared for a data set consisting of the RSI and Stochastics indicators as well as delayed closing price values. The decision based metric and the Ruck metric results are similar, but the classifier independent metric agrees with neither of the other metrics. The nine most salient features, determined by the decision boundary based metric, are used to train a neural network and the results are presented and compared to other published results. (AN)

1,545 citations

Book
01 Aug 2011
TL;DR: This chapter discusses the development of a measurement instrument, field testing - item reduction and data structure, and systematic reviews of measurement properties Index.
Abstract: 1. Introduction 2. Concepts, theories and models, and types of measurements 3. The development of a measurement instrument 4. Field testing - item reduction and data structure 5. Reliability 6. Validity 7. Responsiveness 8. Interpretation 9. Systematic reviews of measurement properties Index.

1,262 citations