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In this study, we aimed to determine the difference of motor reaction time and accuracy between the patients with moderate multiple sclerosis (MS) and healthy subjects and to determine whether a specified cognitive-motor training can improve the speed and accuracy of information processing in patients with MS. A total of 205 patients (30% males) and 276 age-/gender-matched healthy subjects (31% males) were included in the study. Furthermore, using a stratified randomization method, patients with MS were randomly assigned to one of two groups: active information processing training (AIPT) (n = 49) or post-control (n = 55). The AIPT group was asked to complete a computerized visual-manual training program and the post-control group asked to complete the same task without an increase in difficulty. Before and after the intervention phase, the simple, choice, and semantic reaction times and accuracies of all participants were evaluated using the VLS measurement battery. Our results demonstrated that the case and control group were significantly different in terms of the simple, choice, and semantic motor reaction times and accuracies. Compared with the pre-intervention phase, the AIPT and control group’s performances in the post-intervention phase were considerably improved in simple, choice, and semantic motor reaction times and choice and semantic motor reaction accuracies. The results also showed that the AIPT group performed significantly better than the post-control group in terms of simple and choice motor reaction times. We showed the positive effects of training on the performance of patients with MS in motor reaction time and accuracy. &nbsp

The aim of this study was to investigate the effect of visual manipulation during walking training on functional balance and selected kinematic parameters of gait in the elderly. 16 accessible older women ranging in age from 65 to 75 were recruited and randomly assigned to a experimental (n: 8) and control (n: 8) groups. Experimental group trained walking while lower visual field was blocked for 12 weeks, 3 training sessions per week. Berg functional balance test was used for measuring subjects’ functional balance and Zebris gait analyzer was used for measuring kinematic gait parameters. We used the paired samples t test to compare the mean test scores before (pre-test) and after (post-test) intervention in each group. Independent t test was also used to evaluate the differences in means between experimental and control groups. A p-value of 0.05 was considered for all statistical methods. Results showed a significant effect of walking training while lower visual field was blocked on stride length, gait velocity, percentage variability of velocity for experimental group (P0.05). Within group analysis showed that there were no significant differences between pretest and post test mean scores of measured gait parameters in control group (P>0.05). Between group analysis showed that there were significant differences between posttest mean scores in two groups in stride length, gait velocity (P

The aim of the present study was to investigate the effect of cognitive loading and sensory manipulations (visual and somatosensory senses) on postural control of wrestlers with different skill levels. Four groups of 10 accessible subjects (25-18 years old) from skilled wrestlers, semi-skilled wrestlers, beginners and control group (non-athlete) were recruited for the study. The subjects performed eight balance tasks on the Biodex Balance System in the manipulated conditions of visual and somatosensory senses and cognitive system, and tasks resulting from the combination of these manipulations. The research design was a combination of two factors in the form of 8 (tasks) × 4 (group) and the statistical method used was intergroup analysis of variance with repeated measures. The results showed that the main effect of conditions, group and also interactive effect were significant (P0.05)., but there was a significant between groups in the four balance tasks of a) somatosensory, b) somatosensory – cognitive, c) somatosensory –visual, d) somatosensory –visual-cognitive in favor of skilled and semi - skilled wrestlers (P

The aim of this study was to investigate the effect of 12 weeks walking training on cobblestone mats on spatio-temporal parameters for the elderly women. Twenty community-dwelling elderly women, aged 65-80, eligible to participate in the study, were randomly allocated to an experimental group (n=10) or a control group (n=10). Experimental group trained walking on artificial cobblestone-mats for 12 weeks, 3 sessions per week. Zebris Gait Analyzing System was used for measuring Balance indices during gait in pre and posttests. Mixed ANOVA test revealed a significant effect of time-group interaction (P0.05).Between group analysis showed that there were significant differences between posttest mean scores in two groups in cadence, stride length, gait velocity and variability of velocity (P

The purpose of this study was to evaluate the relationship between sport participation motivation and the TGfU approach among novice handball players.

The aim of this study was to investigate the effect of 8 weeks visual and sport skills training on selected visual skills and sport skills among novice table tennis and basketball players. 60 novice male athletes were randomly divided into 6 groups: (1- visual training and basketball layup, 2- visual training and table tennis forehand derive, 3- basketball layup, 4- table tennis forehand derive, 5- visual training and 6- control). Based on their training, Revien and Gabor (1981) visual training and sport skill drills were used. Before and after 8 weeks training, we used 6 visual skill tests and sport training tests. Data analysis done by t test and multiple ANOVA shown that all of the experimental groups had enhancement in their visual skills and sport skills based on their training. Visual and table tennis group had better performance in comparison with visual and basketball group. It seems that the combination of visual and sport skills training is better than exclusive sport and visual training. Also the nature of sport skills and their visual demands can affect the visual training programming.

Background: This research aims to study the effect of neurofeedback training on the working memory and perceptual-motor development of athlete boys. Methods: Thirty athlete boy students of Gorgan province were selected by convenient sampling and participated in the research process. First, a pretest was conducted. All participants had done Wechsler digit span test and Lincoln-Oseretsky perceptual-motor capabilities test. After that, participants were randomly divided into test and control groups. Subjects of the experiment group had 12 one-hour sessions neurofeedback training while the control group subjects received no intervention during this time. Data were analyzed by using multivariate covariance test (MANCOVA) by SPSS 18. Results: The results of data analysis showed that there is a significant relationship between mean direct and reverse digit span numbers and perceptual-motor development of the experiment group before and after treatment (P

The aim of this study was to investigate the relationship of force control and adjustment of dominant hand’s angle to selected psychological traits in athlete and non-athlete students. 120 participants including 99 male and 21 female athlete students (19-29 years old) from different sports and 120 non-athlete students from Tehran university (20 girls, 100 boys) attended in the study. Digital handgrip device and angle joint measurement device were used respectively to assess force reproduction and joint reposition. Profile of Mood States Questionnaire was used to measure mood states and to measure emotional intelligence we used Schutte’s emotional intelligence scale. To evaluate relationship between variables Pearson's correlation coefficient was used. The Z-Fisher was used for investing difference between correlation coefficients. The results showed that there was a significant relationship between POMS’s scores with force control and adjustment of dominant hand’s angle errors in both groups, although the relationship was stronger in nonathletic subjects. The findings indicated that negative mood states can lead to kinesthesis sense errors, but that is less effective in athletes. On the other hand, that there was not significant relationship between EQ’s scores with force control and adjustment of dominant hand’s angle errors in both groups, i.e. kinesthesis sense cannot be affected by cognitive control of emotion and longtime sport participation does not affect on their relationship.

The aim of present study was to investigate the effect of training visual and two different table tennis skills programs on some visual skills in male students. All of the participants completed the optometric screening tests and then were randomly assigned into four groups: 1: visual training &high toss service; 2: visual training & forehand drive; 3: visual training; 4: service & drive training. Before and after eight weeks subjects participated in some standard optometric tests. Mixed ANOVA 4 (group) * 2 (time) indicated that saccadic eye movements in the groups 1 & 2; facility of accommodation in the groups 2 & 3; visual reaction time in the groups 1, 2 & 3 and eye-hand coordination in the group 1 had more improvements after eight weeks (P

The purpose of this study was to analyze the content of papers in scientific journals of motor behavior and sport psychology in Iran from 2009 to 2017. The present study was an applied research and content analysis method. In this study, a total of 814 papers have been reviewed in six different journals.For this purpose, content analysis was done quantitatively and in terms of subject matter dispersion. After referring to archived published journals and the entry of some raw data in the coding sheet, descriptive statistics were calculated using SPSS software and frequency distribution tables were created. The results showed that the Journal of Motor Behavior with the highest number 28% and the Journal of Sport Management Research and Motor Behavior 5.7% had the lowest number of papers. It was observed Sports Psychology Studies Journal had the shortest review processes3.50±2.227 months). The authors of the papers were mostly men 70.9% in PhD degree 11.8% with assistant professor position 20.5%, and motor behavior field 71.4%. We also found that most of the papers have been published in sport psychology domain and motor learning domain was in the second position. Less attention has been paid in paper publications to the motor and control development domains. Meanwhile, topic of emotion 13.3% was the most respected by researchers to study. In the reviewed papers, most of subjects were non-athlete and in terms of skill level they were beginner and only 7.2% were elite. Most of papers were about "health". The major statistical samples of the papers were human, young and healthy subjects, and only 12.5% of the subjects had disabilities. The results showed that English language references were used more than Persian sources in the papers. The highest self-citations of the journal were in the Journal of Motor Learning and development -Sport (124 self-citations) and the most self-citation of the author was related to the Journal of Motor Behavior (146 self-citations). Most researches were practical and used semi-experimental research method. It was also found that Tehran University (477 cases) has the largest share of papers among participating academic institutions. little attention has been paid to community of the elderly and the disables, as well as the imbalance of studies conducted in various areas of motor behavior, the identification of research priorities based on the need-assessment in various journals and informing researchers can be a step towards the elimination of scientific and research deficiencies. The lack of qualitative research, the lack of interdisciplinary studies, the low share of associate and full professors in paper publication, the low tendency for research work on motor control and development domains and low focus on children and the elderly as a research sample are some important weaknesses and limitations in reviewed papers.

The purpose of present investigation was to assess the effect of three warm up programs on simple and choice reaction time. 32 nonathlete girl students (19-23 yr) of Tehran university were selected and randomly assigned to four groups: static, dynamic stretch, compound (slow runing, stretch and dynamic movement). All groups performed a simple and choice reaction time test with SW8 instrument before and after of performing warm up protocols. The results of analysis showed that there is no significant difference between prestest and posttest scores means in SRTof groups. But there is a significant difference between pretest and posttest scores means in CRT of dynamic stretch and compound groups ( p < 0/05) and there is no significant difference between pretest and posttest scores means in CRT of static stretch group. In addition, there is a significant difference (p < 0/05) between all groups in CRT (post test) The results of present study showed that warm up may improve CRT,meanwhile compound wann up program is more effective than two other, but totally warms up does not affect on SRT.

Background & Objective: Fundamental motor skills are basic skills necessary for movement competence and considered the basic building blocks for more complex motor skill development. However, autistic children have significant delays in fundamental motor skills. Additionally, motor impairments in autistic children can have a negative impact on other developmental aspects of them like social communication and social interaction skills in this population. With regard to the marked differences in developmental aspects between children with autism spectrum disorder and normal children, it is recommended to develop interventions or games requiring whole body exercises for children with autism spectrum disorder to improve their gross motor growth. Rainbow parachute is one of the most popular active play toy used recently in kindergartens and playhouses to carry out various types of active play programs. It seems that this toy has the indices needed to design the motor games of children with autism spectrum disorder. It seems that this toy instrument has the indices needed to develop active games for children with autism spectrum disorder. The present study aimed to determine the effect of selected Rainbow parachute games on motor development of autistic children. The parachute is a multicolored, nylon sheet used by arranging children on the outside. That is commonly used in kindergarten and elementary school physical education classes. The aim of this study was to survey the effect of selected rainbow parachute games on motor development of autism spectrum disorder children. Methods: This study was quasi–experiment. 20 autistic children (4 to 6 years old) from two rehabilitation centers of Tehran city (capital city of Iran), based on their pre–test scores randomly were selected and divided into two groups, control (n=10) and experimental (n=10). Test of gross motor development–2 Ulrich (TGMD–2) was used to assess the motor development. TGMD–2 is one of the reliable tools for evaluating development of gross motor skills; that was provided by Ulrich (1985) in the United States of America for the first time and reported its stability and justifiability for 3–10 years old American children. The test reliability was 96% and the stability was 87%. The test included six displacement skills (running, trotting, hopping, skipping, jumping, sliding) and six object control skills (striking a stationary ball, stationary dribble, catch, kick, overhand throw and underhand roll). Running pretest, the experimental group played selected parachute games for 8 weeks (2 sessions per week each 45 min.). Each session started at 10 a.m. and was divided into 3 sections: (a) warm–up activities: 10 min.; (b) selected parachute games: 25–min; (c) cool down activities: 10 min. The main focus of the program was on developing fundamental motor skills but developing physical fitness by modifying the intensity, duration and complexity of the activities was also considered. The program was developed based on rough–and–tumble play, running around, and other physical play that provides whole–body exercise and helps the child develop gross motor skills. During games, all experimental children had the experience of interacting with other each other and objects in their surroundings. One head coach managed sessions and three qualified trained assistants. At the end of the play program, pretests were re–performed in both experimental and control groups. Data were analyzed using analysis of covariance, Shapiro–Wilk test and Levin tests by statistical package of SPSS (version 17) at a significance level of 0.05. Results: The results showed that selected parachute games significantly affected running (p=0.011), skipping (p=0.042), hopping (p=0.033) and jumping (p=0.026) skills from the displacement scale and striking (p=0.033), throwing (p=0.032) and rolling (p=0.044) from object control scale. In addition, results showed that the intervention did not have significant effect on remained subscales of displacement and object control scales. Conclusion: The results revealed that the selected rainbow parachute games, which have been developed according to fundamental motor skills, could improve some subscales of displacement and object control scales in children with autism spectrum disorder. Therefore, it seems that engaging in physical activity programs by rainbow parachute games resulted in greater sensory integrity and more environmental information, which may increase brain activity and improve bilateral coordination in children with autism spectrum disorder. Exercise may improve motor skill in individuals with autism by strengthening whole muscle, enhancing motivation through improvement in self–esteem, and using cognitive techniques to sharpen the child ability in a new task. We encourage mentors to use rainbow parachute games to improve motor development of children with autism spectrum disorder.

In this paper, we study efficient and robust computational methods for solving the security-constrained alternating current optimal power flow (SC-ACOPF) problem, a two-stage nonlinear optimization problem with disjunctive constraints, that is central to the operation of electric power grids. The first-stage problem in SC-ACOPF determines the operation of the power grid in normal condition, while the second-stage problem responds to various contingencies of losing generators, transmission lines, and transformers. The two stages are coupled through disjunctive constraints, which model generators' active and reactive power output changes responding to system-wide active power imbalance and voltage deviations after contingencies. Real-world SC-ACOPF problems may involve power grids with more than 30k buses and 22k contingencies and need to be solved within 10-45 minutes to get a base case solution with high feasibility and reasonably good generation cost. We develop a comprehensive algorithmic framework to solve SC-ACOPF that meets the challenge of speed, solution quality, and computation robustness. In particular, we develop a smoothing technique to approximate disjunctive constraints into a smooth structure which can be handled by interior-point solvers; we design a distributed optimization algorithm to efficiently generate first-stage solutions; we propose a screening procedure to prioritize contingencies; and finally, we develop a reliable and parallel architecture that integrates all algorithmic components. Extensive tests on industry-scale systems demonstrate the superior performance of the proposed algorithms.

The purpose of this study was to examine the effect of I goal setting on choice reaction time (CRT). 50 male athlete students (19-23 yr.) from physical education Faculty of Tehran university were selected. 10 subjects were selected by simple random sampling method from 50 subjects as a base group (who did not participate in the main study). Then base group were tested on a CRT test and their scores mean recorded as base record. Other 40 subjects were tested on a choice reaction time test too and assigned to 4 conditions (personal, easy and difficult goal group and control group) by random assignment method. The difficult and easy goal was set far and close to base record and personal goal was set by subjects themselves. After 4 practice sessions groups were tested CRT test. Data analysis indicate significant difference between pre and post test means of groups (p

Purpose: The present study was carried out to investigate the effect of participating in a course of recreational sport activity on the self-efficacy and resilience of the physical education teachers. Methodology: This study was conducted with a quasi-experimental design. The statistical population of the present study included all the female physical education teachers in Tehran Province (Iran) who were not involved in the recreational sports activities. According to the empirical research, 40 individuals in the control and experimental groups (20 individuals per each study group) were selected as the sample of the study. Baek Habitual Physical Activity Questionnaire (BHPAQ), Self-Efficacy Questionnaire (developed by Neff et al., (2013)), and Resilience Questionnaire (developed by Lutens et al., (2007)) were used for data collection. Analysis of Covariance (ANCOVA) was used for data analysis. Results: The results showed that participating in a course of recreational sport activity had a significant effect on the self-efficacy and resilience of the physical education teachers p < 0/05. Conclusion: It can be concluded that paying attention to recreational sports activities and promoting these activities in teachers' extracurricular programs can increase the self-efficacy and resilience of the physical education teachers.

Vestibular sensory system is one of the main sensory systems contributing motor movements especially balance control which lead to appropriate body position in different situations. The aim of this study was to design, construct and test reliability of a vestibular measurement system. After constructing of the device, 20 male non-athlete students participated voluntarily in the study. An examiner measured vestibular sense system function in 20 subjects for 10 times to evaluate the intra-experimenter reliability. For evaluating inter experimenter reliability 4 examiners were taught how to measure with the device and they measured 4 times. To evaluate the stability of device reliability, at different interval times the examiner measured 8 subjects at two days alternatively during morning and evening. All tests were performed in both sagittal (moving forward and backward) and frontal (moving laterally) planes. Correlation coefficient was used to measure to measure inter and intra experimenter reliabilities. The results showed that intra experimenter correlation coefficient for sagittal plane was 0.95 and for frontal plane was 0.93. Inter experimenter correlation coefficient score for sagittal plane was 0.89 and for frontal plane 0.85. Reliability of time consistency of the device between morning and evening measurements for sagittal and frontal planes were 0.85 and 0.89 respectively. The results indicated that high correlation coefficient values in inter and intra experimenter reliability in sagittal and frontal planes. So the device can be used for measuring vestibular sense system function in these planes.

The aim of this study was to determine the effect of weight transfer training on static and dynamic balance of older women. 20 accessible subjects that met our criteria divided randomly into two experimental and control groups. The experimental group trained for 6 weeks, 3 times a week and each session 60 minutes a day. Biodex balance system used for training and testing procedures. Data analysis used by repeated measure ANOVA showed significant main effects and interaction for dynamic balance parameters including overall dynamic balance, anterioposterior dynamic balance and mediolateral dynamic balance) .Intrasubject analysis using t test indicated weight transfer balance training, compared to static balance, improved significantly dynamic balance parameters. The dynamic balance improvement following weight transfer training mat resulted from its effectiveness on sensory and motor systems involved in the dynamic balance of older women.

Introduction and purpose: Balancing is recognized as one of the most important challenges in the aging period. The purpose of the present study was to determine the effect of dual and single task training on the balance traits of male elderly people. Materials and methods: Twenty elderly subjects who were available and qualified were selected and randomly divided into two groups of 10, including a walking practice group in dual homework conditions and a single practice group. The dual task team performed a specific cognitive task for each individual while walking, and the other group was practicing routine walking. In the pre-test and post-test phases, the selected kinematic parameters of the selected step were measured using the ZBIS analyzer, which included: step width, step length, dual retention percentage, track, velocity, and velocity changeability. The groups performed exercises for 8 weeks, 3 sessions each 60 minutes a week. Findings: The results of statistical analysis of repeated measuers ANOVA (2 × 2) with intra-group time (before and after training) and the inter-group type of exercise showed a significant intra-group effect. Also a significant different was found between groups in mentioned parameters More analysis revealed the intra-group effect for dual task group for step length parameters, dual stance time, tracks, speed, and velocity variability (P≤0.05). This effect was not seen on the step width (P> 0.05). Also a significant different was found between groups in mentioned parameters Conclusion: Walking exercises in dual cognitive situations can improve some of the parameters of the step-up in relation to the balance of male elderly.

Purpose: The improvement of cognitive and motor components and sports performance evaluation process is important in game-based approaches. This study aimed to standardize the game performance evaluation tools (G-PET) in football schools in Iran. Method: However, 48 experienced and novice players of soccer schools in children, adolescents, and young adult age categories (all groups included 8 experienced and 8 novice players) played 3×3 football game with the keeper was in a small field with dimensions of 25×35 m. Using digital camera and in the height of 5 meters above the playground, the games were captured and coded using G-PET. Consulting with 6 specialists and physical education instructors to delete and modify some behavioral descriptions, the content validity Index (CVI) of this tool in offensive behavior of on and off the ball players was 0.99. For assessing the intra-observer reliability, one of the game videos was randomly selected and two observers’ perceptions were evaluated at an interval of 2 weeks. Findings: There was positive correlation among the results of tactical appropriate behaviors including ball possession, attacking the opponent's goal, and scoring. The coding of two observers for the video was compared to evaluate the interobserver reliability. The one-way ANOVA results showed that there is no significant difference between the two observers in terms of tactical and technical variables. Describing accurately the offensive behaviors in football, the G-PET tool helps coaches and instructors to evaluate the offensive behavior of on and off the ball football learners according to tactical situation at that moment

The aim of this study was to investigate the effect of 12 weeks walking training on cobblestone mats on spatio-temporal parameters for the elderly women. Twenty community-dwelling elderly women, aged 65-80, eligible to participate in the study, were randomly allocated to an experimental group (n=10) or a control group (n=10). Experimental group trained walking on artificial cobblestone-mats for 12 weeks, 3 sessions per week. Zebris Gait Analyzing System was used for measuring Balance indices during gait in pre and posttests. Mixed ANOVA test revealed a significant effect of time-group interaction (P0.05).Between group analysis showed that there were significant differences between posttest mean scores in two groups in cadence, stride length, gait velocity and variability of velocity (P

Objective: Motor skill learning is one of the main problems of children with developmental coordination disorder (DCD). Since the prevalence of this disorder among children is considerable, thus this study carried out for determine the frequency of feedback about knowledge of result (KR) on throwing skill’s motor learning in children with DCD. Methods: This study was semi-experimental study with pretest-posttest design. The study populations were DCD children 7 to 9 years’ old boys and girls who lived in district 1 & 2 of Tehran that among these population, 30 children were participated after make sure to study inclusion criteria by Convenience Sampling. Data were collected with DCDQ'7 diagnostic questionnaire and Chiviacowsky accuracy of Children throwing. Data were analyzed by paired sample t-test, ANOVA and LSD post hoc test. Results: Feedback based on KR 100% and 50% were effective on motor learning in DCD children (p= 0.001). But the relative feedbacks with 50% frequency of KR lead to better than 100% on motor learning in throwing skill (p< 0.001). Conclusion: The present study confirms the guidance hypothesis feedback and suggests that 50% KR frequent feedback lead to enhanced learning in children with developmental coordination disorder.

The present study aimed to determine the effect of selected Rainbow parachute games on motor and social development of children. 20 pre-school children (5-6 years old) from Aran and Bidgol City (Isfahan, Iran) were randomly selected and divided into two 10-person experimental and control groups. Test of gross motor development (Ulrich Test) and Vineland social maturity questionnaire were used to assess the motor and social development, respectively. Running pretest, the experimental group played selected parachute games for 8 weeks (3 sessions per week). The Rainbow parachute which is a round and colored play tools is made of light weight nylon fabric. At the end of the play sessions, pretests were re-performed in both experimental and control groups. Data were analyzed using analysis of covariance, Shapiro-Wilk test and Levin tests by statistical package of SPSS (version 17) at a significance level of 0.05. The results showed that selected parachute games significantly affected running, galloping and leaping skills from the locomotor subscale of the test of gross motor development as well as social skills (P>0.05). However, the results showed non-significant effect on hopping, sliding, and horizontal jump from locomotor subscale and object control skills (P

This thesis presents an innovative methodology of describing propagation path of hydraulically induced fractures in the presence of pore pressure anomalies. Pore pressure anomalies can occur in different geological settings such as mud volcanoes, magmatic dykes, hydrothermal vents or fluid in faults. Also, many different physical processes may cause local non-uniform pore pressure distribution. The effect of non-uniform pore pressure (pressure anomaly) on propagation behaviour of single and multiple fractures is investigated by using a fully coupled poroelastic numerical model. A new technique, named mean rotation angle (MRA) is used to study the impact of evolved shear stresses on mixed-mode fracturing. MRA is a measure of potential deviation angle evaluated based on the average of normal and shear stresses at nodes located within a specified area near the fracture tip. The tempo-spatial variation of evolved shear stress which represents alteration of original orientation of principal stresses is correlated to the curvature characteristics of the pressure source. It is shown that minimum shear stress variation is consistently correlated to the minimum principal curvature of the pore pressure in semi-3D superficies. From the results of this thesis it is concluded that presence of induced or in-place pore pressure anomalies in a medium can change the stress state such that the dominant direction of propagation deviates from the straight course. In the case of single fracture, a closely spaced circular zone of anomalous pore pressure is considered. Non-uniform variation of pore pressure results in alteration of original stress state at the fracture tip and prompts fracture deviation. Finally, the concept of pore pressure induced stress reorientation is evaluated in the case of closely spaced multiple transverse fractures. Three distinct flow patterns and three associated shear stress patterns have been identified during simultaneous pressurization of a pair of parallel fractures. These patterns are clearly exhibited three distinct trends of the calculated mean rotation angle representing different fracture deviation tendency. The results show the significance of considering the spatial distribution pattern of pore pressure in evaluation of local stress reorientation. These implications can lead to development of next generation of hydraulic fracturing techniques which could control the propagation path of hydraulic fractures by inducing desirable local stress conditions.

The aim of the present study was to investigate the effect of cognitive loading and sensory manipulations (visual and somatosensory senses) on postural control of wrestlers with different skill levels. Four groups of 10 accessible subjects (25-18 years old) from skilled wrestlers, semi-skilled wrestlers, beginners and control group (non-athlete) were recruited for the study. The subjects performed eight balance tasks on the Biodex Balance System in the manipulated conditions of visual and somatosensory senses and cognitive system, and tasks resulting from the combination of these manipulations. The research design was a combination of two factors in the form of 8 (tasks) × 4 (group) and the statistical method used was intergroup analysis of variance with repeated measures. The results showed that the main effect of conditions, group and also interactive effect were significant (P0.05)., but there was a significant between groups in the four balance tasks of a) somatosensory, b) somatosensory – cognitive, c) somatosensory –visual, d) somatosensory –visual-cognitive in favor of skilled and semi - skilled wrestlers (P

The purpose of this study was to examine the effect of I goal setting on choice reaction time (CRT). 50 male athlete students (19-23 yr.) from physical education Faculty of Tehran university were selected. 10 subjects were selected by simple random sampling method from 50 subjects as a base group (who did not participate in the main study). Then base group were tested on a CRT test and their scores mean recorded as base record. Other 40 subjects were tested on a choice reaction time test too and assigned to 4 conditions (personal, easy and difficult goal group and control group) by random assignment method. The difficult and easy goal was set far and close to base record and personal goal was set by subjects themselves. After 4 practice sessions groups were tested CRT test. Data analysis indicate significant difference between pre and post test means of groups (p

The aim of this study was to investigate the effect of visual manipulation during walking training on functional balance and selected kinematic parameters of gait in the elderly. 16 accessible older women ranging in age from 65 to 75 were recruited and randomly assigned to a experimental (n: 8) and control (n: 8) groups. Experimental group trained walking while lower visual field was blocked for 12 weeks, 3 training sessions per week. Berg functional balance test was used for measuring subjects’ functional balance and Zebris gait analyzer was used for measuring kinematic gait parameters. We used the paired samples t test to compare the mean test scores before (pre-test) and after (post-test) intervention in each group. Independent t test was also used to evaluate the differences in means between experimental and control groups. A p-value of 0.05 was considered for all statistical methods. Results showed a significant effect of walking training while lower visual field was blocked on stride length, gait velocity, percentage variability of velocity for experimental group (P0.05). Within group analysis showed that there were no significant differences between pretest and post test mean scores of measured gait parameters in control group (P>0.05). Between group analysis showed that there were significant differences between posttest mean scores in two groups in stride length, gait velocity (P