فصلنامه پژوهش های فیزیولوژی و مدیریت در ورزش
سال ششم شماره 4 (زمستان 1393)

How and when muscles are activated influences knee's ability to absorb and disperse forces and thereby preventing ACL injuries. The aim of this study was to investigate the effect of six weeks of perturbation training on timing of quadriceps and hamstring activation in active subjects with neuromuscular dominance quadriceps deficit. For this purpose, 53 active students (26 subjects in control group and 27 subjects in experimental group) with neuromuscular dominance quadriceps deficit were selected. Hurd et al. modified perturbation training were applied for experimental group for six weeks (18 sessions). EMG data of quadriceps and hamstring (during single limb drop-landing task) were assessed in pretest and after six weeks of training. For statistical data analysis, the analysis of variance with repeated measures, paired and independent sample t tests, one-way analysis of variance (ANOVA) and Tukey post hoc tests were used (significance level of 0.95% and α≤0.05) with SPSS version 18.0. Perturbation training used in this study significantly decreased the timing of rectus femoris and vastus lateralis whereas it increased the timing of vastus medialis,medial and lateral hamstring [there were sex differences]. Earlier hamstring activation is considered as a positive adaptation after perturbation training. Finally, because the neuromuscular dominance quadriceps deficit is considered as one of the most important mechanisms of ACL non-contact injuries in athletes and the effect of perturbation training in eliminating this problem was indicated in this study, so coaches are recommended to use perturbation trainings in order to eliminate this defect.

This research was designed to examine the cycling barriers of Iranian women. The method used in this research was descriptive-analytical and the statistical population included all Iranian women over 14 years old. 7200 subjects were selected by cluster sampling method as the statistical sample and the questionnaires were distributed by cluster method among them and collected. A researcher-made questionnaire which had been designed based on a comprehensive review of literature was used to collect data. The reliability and validity of this questionnaire was investigated by common methods. Descriptive and inferential statistics (exploratory factor analysis and Friedman test) were used to analyze the data. The results of exploratory factor analysis showed that three factors explained 55.528% of the variance of all items: facility-cultural, safety-security and personal barriers. The results also showed that the facility – cultural barriers were the most important barriers to women`s cycling. In addition, all items for each barrier were ranked accordingly.

The consumption of legal sports supplements in recent years has become one of the most important parts of an athlete's preparation for competitions. The aim of this study was to compare the short-term effect of creatine, beta-alanine, creatine-beta-alanine combination and the amount of their consumption on the torque of knee extensor muscles in angular velocities of 60 and 180 degree/second. The peak torque, time to reach peak torque and torque development of knee extensor muscles of dominant leg in 40 young athletes were measured by the isokinetic machine in angular velocities of 60 and 180 degree/second before and after the supplement consumption. Creatine was consumed in five consecutive days and beta-alanine supplement was consumed as capsules by the experimental group three times daily along with their major meals. Analysis of covariance was used for data analysis. No significant changes in peak torque, time to peak torque and torque development of knee extensor muscles after short-term consumption of creatine, beta-alanine and creatine-betaalanine combination in speeds of 60 and 180 degree/second. Short- term consumption (5 days) of creatine, beta-alanine and creatine-beta-alanine combination did not improve peak torque, time to peak torque and torque development of knee extensor muscles in velocities of 60 and 180 degree/second.

The aim of the present study was to compare employee's psychological empowerment and its relationship with organizational justice perception in sport and youth offices of Khorasan Razavi province. The statistical population consisted of employees of sport and youth offices of Khorasan Razavi province (N=237). The statistical sample consisted of 153 subjects. Two standard questionnaires of psychological empowerment (Spreitzer, 1995) and organizational justice (Niehoff and Moorman, 1993) were used to collect data. For data analysis, K-S test, Pearson and Spearman correlation coefficients, independent samples t test and Mann- Whitney U test were used. The results indicated that the mean score of employee's empowerment was good and psychological empowerment was significantly higher in those employees who were educated in physical education. There was also a significant and direct relationship between empowerment and its components with the organizational justice perception. According to the findings, it is suggested that sport organizations managers should pay a greater attention to organizational justice in their organizations in order to elevate employee's empowerment level.

The aim of this study was to investigate the effect of long-term garlic supplementation with two doses of 500 and 1000 mg on protein damage after an exhaustive exercise in non-athlete students. 26 male non-athletes (mean age 21±1.23 yr, weight 69.38±8.28 kg and height 178.9±6.11 cm) were divided randomly into three groups: the placebo group (n=8) and two garlic supplementation groups (n1=9 and n2=9) with two dosages of 500 and 1000 mg/day. The first and second blood samples were collected at the baseline and after the exhaustive exercise and the third and fourth samples were taken after 8 weeks of supplementation in the baseline and after the exhaustive exercise. The data were analyzed by ANOVA with repeated measures and one-way ANOVA (α=0.05). The results showed that a session of exhaustive exercise significantly increased protein damage. In addition, long-term garlic supplementation with 500 and 1000 mg/day decreased protein damage in the baseline and after the exhaustive exercise. Also, 1000 mg of garlic consumption decreased protein damage more than 500 mg supplementation in the baseline and after the exhaustive exercise. Therefore, athletes are recommended to consume long-term garlic supplementation in order to prevent oxidative stress caused by intensive exercises.

Core stability is essential for proper load balance in the spine and pelvis. The so-called core is the group of trunk muscles that surround the spine and abdominal viscera. Core stability and its motor control have been shown to be imperative to initiate functional limb movements in athletes. The aim of this research was to study the relationship between core stability and time of speed swimming in female trained swimmers. 23 swimmers (mean age 10.91±1.59 yr, weight 40.26±9.21 kg and height 145.30±11.83 cm) who were undergoing training at least three years and were provincial members of swimming team were selected by purposive sampling method. Core stability was measured by McGill protocol that included right and left side bridges, trunk flexion and back extension tests. Swimming was assessed using the records of 50m and 100m front crawl, breaststroke and butterfly stroke and 50m backstroke. The data were analyzed by Pearson correlation test. The results showed a significant and negative relationship only between trunk flexion and record of 50m backstroke (r = -0.42, P=0.02). The results of the present study showed that as different factors influence athletic performance and swimmer's achievements, core stability may not be a proper variable for swimmers to achieve success.

The aim of this study was to compare the behaviors related to watching sport events on television between male and female students in the city of Kermanshah. Data were analyzed by SPSS software using descriptive and inferential statistics (independent t test, Pearson correlation coefficient). Using Cronbach's alpha, the internal reliability of these variables was calculated as affinity 0.87, intentionality 0.99 and attentiveness 0.79. These results supported their acceptable reliability. The statistical population consisted of the students of state and private universities of Kermanshah city. Based on Morgan table, 401 male and female students (209 girls, 192 boys) were randomly selected as the sample of the study. Results revealed a significant difference in the attentiveness and affinity towards the sport events on television between girls and boys, that is to say the means of both variables in boys were more than the girls. However, there were no significant difference in the means of intentionality between the groups, that is to say both groups had the same amount of intentionality to watch sport events on television. Among the TV sport events, football event was the first priority to watch for both groups.

The aim of this research was to study the effect of 8 weeks of beta-alanine supplementation and pyramid resistance training on changes of resting levels of carnosine and IL-8 in nonathlete men. 40 young men with age range of 20-25 years old were randomly divided into four groups of supplementation (n=10), supplementation and training (n=10), placebo (n=10) and training and placebo (n=10). Resistance training was performed for eight weeks, three sessions per week with intensity of 70-90% of 1RM. To examine the changes, dependent t test was used and to compare the groups, one-way ANOVA was applied. Bonferroni post hoc test was supposed to be used in case of significance (P≤0.05). Results showed a significant increase in carnosine (P=0.01) while IL-8 increase was not significant (P=0.46). Hypertrophy indexes significantly increased (P=0.04). It can be concluded that pyramid resistance training along with beta-alanine supplementation significantly increased carnosine and muscle hypertrophy in non-athlete men.

The aim of this study was to analyze those selected factors affecting football games and therefore the performance of Spain national football team in three events of Euro 2008 and 2012 and 2010 World Cup was studied. Research method was descriptive-analytical and data were observationally collected by a VCD set, 32-inch TV set and recording sheets. Statistical population and sample of the study were the same (N=n) including 19 games of Spain team in the final rounds of these three events. Data analysis was performed by descriptive statistical indexes and inferential statistics tests. The results showed a significant difference between Spain team winnings and ball possession of lower and higher than 50%. A significant difference was observed between the number of goals scored with 0-4 passes and 5 or more continuous passes. Also, a significant difference was observed between the number of goals scored with 0-8 seconds of ball possession and more than 8 seconds. A significant difference was observed between the number of goals scored and taking over the ball in different thirds of the ground and also a significant difference was observed between the number of goals scored according to each six 15 minutes of the games (P≤0.05). In general, some actions such as increasing ball possession to more than 50%, increasing the number of passes to more than 4 continuous passes during the attacks, increasing the time of ball possession to more than 8 seconds in each attack, defensive pressing in the middle of the ground and increasing attacks in the final 15 minutes can result in positive outcomes for teams.

Today organizations seek to employ individuals who can perform better in groups and on the other hand they possess the ability to communicate and adjust to people from varied cultures. Therefore, they need to know about other cultures and to interact with people from different cultural backgrounds. Consequently, they need cultural intelligence. The aim of this study was to investigate the relationship of cultural intelligence and communication skills with effectiveness of experts of physical education and health deputy of the general office of education in Tehran. Statistical population of this study included all male and female experts working in physical education and health deputy of the general office of education in Tehran and all of them participated as the sample in this study (n=100). The method used in this study was descriptive and correlation. For data collection, three questionnaires were used including Ang et al. Cultural Intelligence (2007), Barton Jey Communication Skills (1991) and Hsu Effectiveness (2002). Data were analyzed by descriptive and inferential statistics including Pearson correlation coefficient and multiple regression analysis (P≤0.05). The results showed s a positive and significant relationship between cultural intelligence and its subscales (metacognition, cognition, motivation, behavior) and communication skills and its subscales (verbal, listening, feedback) in male and female physical education experts. Cultural intelligence was a better predictor of effectiveness of male and female physical education experts than communication skills. From cultural intelligence subscales, metacognition and also from communication skills subscales, verbal and listening factors were the best predictors of the effectiveness of male and female physical education experts.