Papers by Nader Farahpour
Pizhūhish-i tavānbakhshī dar parastārī, Jun 1, 2020
Introduction: After reconstructing the anterior cruciate ligament, to prevent re-injury of the li... more Introduction: After reconstructing the anterior cruciate ligament, to prevent re-injury of the ligament, evaluation of neuromuscular function is of clinical importance in coordinating the onset time and time to peak of lower limb's muscles activity. Aim: Therefore, the purpose of this study was to compare the timing of muscle activity in the stance phase of running between athletes with reconstructed anterior cruciate ligament and healthy subjects. Methods: This study was a semi-experimental and applied type. Ten athletes with reconstructed anterior cruciate ligament who at least one year had passed since their surgery, as experimental group and ten healthy subjects as the control group of Hamedan city were volunteered to participate in the study. The control group, in terms of age, height, and weight, were homological with the experimental group. The surface electromyography system was used to quantify the onset time and time to peak of the lower limb's muscle activity. Multivariate MANOVA, with a significance level of P < 0.05, was used for statistical analysis. Results: In the experimental group, the onset of the activity in tibialis anterior, medial gastrocnemius, vastus medialis, vastus lateralis, gluteus medius (P = 0.001), as well as the time to peak in tibialis anterior, vastus lateralis, vastus medialis, gluteus medius, semitendinosus (P = 0.001) and biceps femoris (P = 0.045), were delayed. Conclusions: During the stance phase of running, the experimental group displayed a delay in the activation onset and a longer time to peak in the lower limb's muscles. It is not clear if these changes are due to a neuromuscular adaptation or proprioception related damage. A more comprehensive study is recommended to clarify this aspect. It is recommended to assess the possible link between these delays with the reoccurrence of anterior cruciate ligament rupture.
Three sensory systems of visual, atrial and somatosensory have roles in maintaining upright stand... more Three sensory systems of visual, atrial and somatosensory have roles in maintaining upright standing posture and balance control in gait [1, 2]. If it is presumed that to maintain the posture, we need all information about the sensory systems, the lack of information of one of the sensory systems affects the balance of the body during standing and gait [1]. The visual system collects the information of the surroundings of the individual, such as distance and plays a significant role in taking and maintaining balance and stability and planning the course of the movement [3, 4]. People with visual impairment, specifically in congenitally blind individuals, have never received visual stimuli. In spite of the lack of vision from the beginning, they have learned motor activity and motor skills, such as orientation and motor activities in everyday life. However, their motor patterns may differ from ordinary people [5]. In blind people, the lack of vision input data affects gait patterns [6]. In blind people, walking speed and step lengths are shorter and retention time is longer than the normal [3], and a greater base of support and toes outward [6] prudent posture maintenance state are among the walking features of these people [7]. McGuan indicated that step length, walking speed, stance time, and angle of the joints in the lower extremities of blind children are different from children with full-sight [8]. Majlesi and Farahpour
DOAJ (DOAJ: Directory of Open Access Journals), Mar 1, 2017
Medical Engineering & Physics, Sep 1, 2009
Body segment moments of inertia (MOI) are estimated from data obtained from cadavers or living in... more Body segment moments of inertia (MOI) are estimated from data obtained from cadavers or living individuals. Though these methods can be valid for the general population, they usually are limited when applied to special populations (e.g., obese). The effect of two geometric methods, photogrammetry and two new methods, namely, inverse dynamics and angular momentum on the estimations of MOI in individuals of different body mass index (BMI) were compared to gain insight into their relative accuracy. The de Leva (1996) method was chosen as a criterion to determine how these methods behaved. MOI methods were not different in individuals with a normal BMI. On the average, MOI values obtained with inverse dynamics and angular momentum were respectively 13.2% lower for lean participants and 17.9% higher for obese subjects than those obtained from the de Leva method. The average Pearson coefficients of correlation between the MOI values, estimated by the de Leva method, and the other methods was 0.76 (+/-0.31). Since the proposed methods made no assumption on the mass distribution and segments&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; geometry, they appeared to be more sensitive to body morphology changes to estimate whole body MOI values in lean and obese subjects.
IEEE Transactions on Biomedical Engineering, May 1, 2011
Classical models to estimate the head and trunk (HT) moments of inertia (I) are limited to popula... more Classical models to estimate the head and trunk (HT) moments of inertia (I) are limited to populations from which the anthropometric measures were obtained. The purposes of this study were to determine if the angular momentum technique can be used to estimate subject-specific HT&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s I values and test its validity and sensitivity. Twenty-three adults who participated in this study were divided into three morphological groups according to their body mass index (BMI). Using the proposed technique, the HT&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s I values were estimated for the whole sample and compared to three well-known methods to test its validity. The sensitivity of the proposed method was verified while applied to individuals with different BMI (i.e., lean, normal, and obese). The angular momentum technique gave I values within the range of those of the three methods for the entire sample. Statistical differences were identified between the lean and obese groups in relative radii of gyration for the anteroposterior and mediolateral axes ( P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). Since the proposed technique makes no assumption on the mass distribution and segments&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; geometry, it appeared to be more sensitive to body morphology changes in estimating the HT&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s I values in lean and obese subjects compared to the classical methods.
Medical Engineering & Physics, Jun 1, 2014
Studies in Medical Sciences, Oct 10, 2020
Clinical Biomechanics, 2019
Frequency coherence analysis of postural balance in able-bodied and in non-treated adolescent idi... more Frequency coherence analysis of postural balance in able-bodied and in non-treated adolescent idiopathic scoliotic girls.
Journal of Research in Rehabilitation Sciences, Feb 6, 2010
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Journal of Mazandaran University of Medical Sciences, Oct 15, 2013
Background and purpose: Decreasing of motion is one of the characteristics of aging that caused t... more Background and purpose: Decreasing of motion is one of the characteristics of aging that caused the decrease of quality of life and generative problems of others. The objective of this study was to compare the effect of an exercise program on kinematic analysis of gait of elderly men and women who are residents in a sanatorium. Material & methods: From the sanatorium elderly residents, 15 men and 15 women between 65 to 80 years old were studied. Berg questionnaire was used to evaluate falling risk, cadence (the number of steps in one minute) and a digital camera (Sony DCR-HC54) was used to measure kinematic variables of gait (speed and joints angles (ankle, knee and hip)). All measurements were repeated after a 24-session physical training program including walking, strength training, balance and endurance training. Independent and paired sample t-test were used for the statistical analysis (P<0.05). Results: The falling risk was reduced about 20% in elderly women and 12% in elderly men (P=0.000) and cadence was improved about 20% and 10% in elderly women and men, respectively (P=0.01). Walking speed was increased about 19% (P=0.000) in elderly men and 45% (P=0.002) in elderly women after exercise. The exercise program has improved the joint angles (ankle and knee) approximately 2 degrees that was not significant (P=0.01) but it has improved the hip angle approximately 3 degrees (P=0.01). Conclusion: Exercise (walking with weight) will improve their gait performance and reduce the risk of fall more specially in women. The exercise program in this research is performed in elderly sanatorium simplicity that it can improve walking speed. We suggest that in future studies, the effect of exercise programs investigate on kinetic variables of gait of old people.
Journal of Foot and Ankle Research, Apr 1, 2014
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Papers by Nader Farahpour