Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 2 4 2017 3 1 The Effect of a Period Stretching Training on Functional Dynamic Balance Performance and Range of Motion Patients with Knee Osteoarthritis 5 18 FA Edris Bavardi Moghadam Department of Sports Injury and Corrective Exercises, Faculty of Physical Education and Sport Sciences, Kharazmi University of Tehran, Tehran, Iran. Seyed Sadradin Shojaedin Objective: This study was done to investigate the effect of a period of stretch training on functional dynamic balance performance and range of motion in patients with knee osteoarthritis. Methods: the population from which the sample of the study was selected included active older men with knee osteoarthritis in West Azerbaijan. 20 active man who were paid to exercise at least twice a week, were randomly divided into two groups of 10 patients. Subjects for 8 weeks, three times a week. To measure the functional dynamic balance three tests were used, and goniometer was used to measure the range of motion of the knee. To analyze the data, independent samples t-test was used for evaluating the between groups performance, and Paired samples t tests was used to check the within the group’s performance. Cohen's d-test was used to estimate the effect size. Results: Results of the study showed that there were significant differences within groups,  in Get Up and Go test (s) (p = 0.001), knee Range of motion, 30- Second Chair stand (the number) and Agility 8 foot time up and go for the elderly (s) (p = 0.0001). In between groups comparison also there were meaningful differences in Get Up and Go test (s) (p = 0.049), knee Range of motion, 30- Second Chair stand (the number) and Agility 8 foot time up and go for the elderly (s) (p = 0.0001). Conclusion: Stretch training can significantly improve functional dynamic balance and range of motion in active older men with knee osteoarthritis.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 2 4 2017 3 1 A Kinematic Analysis of Upper Extremity Joint when Punching by Three Different Methods in Athletes of Different Skill Levels 19 27 FA Morteza Madadi Shad Department of Sport Biomechanics, Faculty of physical education and sport science, Bu Ali Sina University, Hamedan, Iran. Nader Farahpour Department of Sport Biomechanics, Faculty of physical education and sport science, Bu Ali Sina University, Hamedan, Iran and Department of physical education and sport science, Islamic Azad University, Hamedan branch, Hamedan, Iran. Objective: The aim of this study was to comare the Kinematics Analysis of attackting arm of Boxors when they perform punching using three techniques: shadow boxing, punch against punching bag and punch against guard of opponent. The influence of technical skill level was also investigated by comparing two groups: elite Boxors and Amateurs. Methods: The study was carried out on 10 elite Boxors and 10 Amateurs with healthy shoulder and elbow joint in dominant arm. Each participant was asked to perfom six shadow punching (punch to virtual opponent), six punches against punching bag and six punch against guard of opponent as hard as possible, while Kinematics variable of punching arm and forearm was recorded by using four vicon cameras at 200 HZ. A repeated measures ANOVA was performed to test the effect of three techniques and the effect of group was tested through a multivariate ANOVA with significant level set at p ≤ 0/05. Results: The effect of technique was found to be significant (p=0.000). The punch against guard of opponent and shadow boxing produced maximum and minimum of angular velocity in both attackting arm and forearm, respectively. The effect of group was also significant (p=0.000).  Indicating that elite Boxors presented higher arm and forearm angular velocity during punch. Conclusion: It seems that when there is not a real target for punching, such as in shadow boxing condition, Amateurs were confused dealing with this circumstance and had minor arm forearm angular velocity and Imuls in attacking arm. The results obtained suggest the presence of a skill-dependent activation strategy in the execution of the three punch technique. As, a reciprocal effect exist between the factors of different skill level and punching technique.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 2 4 2017 3 1 An Investigation of Knee Injury Prevalence and its Mechanism among Premier League Soccer Referees in Iran 29 39 FA Hamid Mahdavi Mohtasham Shahnaz Shahrbanian Department of Sport Injuries & Corrective Exercise, Faculty of Physical Education and Sport Sciences, Bu-Ali Sina University, Hamedan, Iran Objective: The aim of the current study was to investigate the knee injury mechanism and its prevalence among the Premier League soccer referees in Iran. Methods: In This cross sectional study a sample of 59 Premier League soccer referees in Iran )age  36.30±4.1 years, height 179±5.8 cm and weight 74.55±6.3 kg( were selected. The information of knee injuries such as injury history, injury mechanism, and effects of knee symptoms on the ability to perform daily activities and recreational activities was obtained through Knee Outcome Survey (KOS). Using the Pearson correlation coefficient, this study examined the relationships between different variables including KOS subscales as well as the current level of self-reported knee joint function and proprioception. Results: The results indicated that 81% of soccer referees experienced knee injury. Meniscus injury accounted for the highest percentage of knee injuries (40%).  In addition, knee injuries of non-dominant leg were more prevalent than those of the dominant leg. Also, the referees were mostly injured during training sessions. The value of KOS was 85±13 for activities of daily living subscale and 90±9 for sports-recreational subscale. Conclusion: The results of this study highlight the importance of including special training in warm-up programs such as interval training, proprioception exercises, strength training (e.g. Nordic hamstring), flexibility training, and muscular endurance training which have been designed to prevent knee injuries. The results help to design and set-up an injury prevention program for the Referees Committee of the Iranian Football Federation.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 2 4 2017 3 1 Assessment of the Symmetry of the Ground Reaction Forces in Patient with ACL Rupture during Vertical Jump 41 50 FA Keyvan Sharifmoradi Department of physical education and sport sciences, faculty of humanities, University of Kashan, Kashan, Iran Arash Raji Objectives: The aim of this study was to assess the symmetry of ground reaction forces in patient with ACL rupture during vertical jump. Methods: Six men with ACLD (anterior cruciate ligament disease) participated in this study. Ground reaction forces components were assessed during Sargent jump by Kistler force plate. Data were analyzed running dependent Samples T-test and Repeated Measure in at p≤0.05. Result: Peak anterior posterior ground reaction forces were significantly greater in sound limb compared to the affected limb during landing phase (P=0.04). During landing, vertical (p=0.00) and anterior posterior (p=0.01) impulse in sound limb were significantly greater than those of affected limb. There were no significant differences between loading and unloading rates between both side in take-off and landing phases (p<0.05). Conclusion: The pattern of vertical jump ground reaction forces changes in landing phase after ACL rupture. Also, there is no difference in the impact between injured and uninjured leg in take-off phase, but there is a meaningful difference between two sides in landing phase. It is proposed that people with ACL rupture avoid repeated jumping performance because the increased impact on sound leg can put the sound leg in risk of injury. Thereafter the possibility of ACL rupture of sound leg will decrease.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 2 4 2017 3 1 The Relationship between Anthropometric Characteristics and Crawl and Breaststroke Performance in Adolescent Girl Swimmers 51 59 FA Shirin Yazdani Department of Motor Behavior, Faculty of Physical Education and Sport Sciences, University of Tabriz, Tabriz, Iran. Nader Farahpour Department of Sport Biomechanics, Faculty of Physical Education and Sport Sciences, Bu Ali Sina University, Hamedan, Iran. Nafiseh Akbari Department of Physical Education and Sport Sciences, Faculty of Humanities, Islamic Azad university, Boroujerd branch, Boroujerd, Iran Objective: The aim of this study was to investigate the relationship between anthropometric characteristics and crawl and breaststroke performance in adolescent girl swimmers with an emphasis on ratio of length and width of limbs to the height of subjects. Methods: Twenty adolescent female swimmers voluntarily participated in this study. Anthropometric variables, including height , length of thigh, leg, foot, arm, forearm and hand , arm span, widths of pelvic, shoulders, knees, wrists and ankles were measured using a tape measure and caliper. Then the ratio of length and width of limbs to the height of subjects was calculated. Pearson correlation test at a significance level of 0.05 was used for statistical analysis. Results: Significant relationship were found between crawl record and subjects’ height, thigh, arm and forearm lengths, arm span, shoulder width, the ratios of arm, palm and foot length to the height and ratio of arm span to height (p<0.05). Also, the relationship between breaststroke record and subjects’ height, arm and thigh lengths, arm span, shoulder and palm widths, the ratios of forearm and thigh lengths to the height, ratio of shoulder girdle width to height and ratio of shoulder girdle to pelvic width were all found to be significant (p<0.05). Conclusion: In addition to the effect of anthropometric characteristics such as height, arm, forearm, thigh lengths, arm span, palm and shoulder girdle widths on the performance of adolescent girl swimmers, the ratios of limb lengths and widths to the height and ratio of shoulder girdle to pelvic width were positively related with swimming record. Thus, it is recommended that to achieve better results in swimming talent, coaches consider the ratio of limbs to the height.

Islamic Azad University, Hamedan Branch Journal of Sport Biomechanics 2476-4906 2 4 2017 3 1 The Effect of Foot Pronation on Postural Control of Body and Electrical Activity of Selected Ankle Muscles during V-Cut Motion 61 69 FA Zahed Mantashloo Department of Sports Biomechanics, Faculty of Physical Education and Sports Sciences, Kharazmi University, Tehran, Iran. Heydar Sadeghi Mehdi Khaleghi Tazji Objective: Due to the disruption of the body's natural posture because of the loss of medial arch of the foot in people with foot pronation, which may change postural control of body and electrical activity of muscles during the v-cut movement, the aim of this study was to study the effect of foot pronation deformity on postural control of body and electrical activity of the ankle muscles during v-cut motion.  Methods: In this semi-experimental study, from male students of Physical Education and Sports Sciences in Kharazmi University, 15 people with pronated foot deformity and 15 normal people participated as subjects in this study. Force plate was used to measure postural control of the body. Surface electromyography signals were recorded in v-cut test using Electromyography synchronized with the force plate was run. To analyze data MATLAB software was used and to compare two groups MANOVA was performed. Results: Statistical results indicated that there was a statistically significant difference in medial- lateral direction of differences in the center of mass and center of pressure between the foot pronation (pronated) and in the normal groups during v-cut movement. However, there was not any statistically significant difference in the anterior-posterior direction between the two groups in the center of mass and center of pressure (p>.0.05). In variable of electrical muscular activity (rms activity/mvc activity) during v-cut movement in medial Gastrocnemius and Soleus muscles, a statistically significant difference was not observed between normal and pronated foot groups (p>0.05), but there was statistically significant difference in anterior Tibialis and Peroneus Longus muscles between the two group (p <0.05). conclusion: Based on the obtained results it seems that foot pronation can be regarded as a factor affecting the biomechanics of v-cut by changing postural control of body in medial-lateral direction and electrical activity of anterior Tibialis and anterior Peroneus Longus muscles during v-cut movement.