درخت حوزه‌های تخصصی

Background : Excessive repetitions of the landing and jumping task are a key risk factor for lower extremity injury (specially ACL) in female volleyball players. Aim: this study investigates the effect of Sports-Metrics Volleyball Training (SMVT) on landing technique in female volleyball players. Materials and Methods : The participants of this study were 25 female young volleyball players and randomly divided into training (TG, n=13) and control groups (CG, n=12). The TG performed SMVT for 18 sessions, and the CG performed their regular training. Landing error scoring system (LESS) test were used for assessing landing errors. SPSS (version 25) was used to analyze the statistical data ( P <0.05). Results : The results of the data analysis showed a significant improvement ( P =0.01) in LESS in TG (from 8.62 to 5.54), but no significant changes in CG the LESS ( P =0.62, from 8.00 to 8.23). Eighteen sessions SMVT reduced the landing error by 35.73% in the TG. Conclusion : Base on previous research the SMVT reduces lower extremity injuries and the results of this study showed that SMVT significant improvement the landing technique. Therefore, performing SMVT is recommended for female volleyball players because it is effective in both preventing injuries and improving landing technique.

Aim and background: The aim of this study was to investigate Kinematics and kinetics Symmetry of Lower Limbs during running at a constant speed. Methods: 28 Elite runner (age: 34.75±6.63years) participated in this study. Running at constant speed was conducted by each subject at 2/5 m.s-1 on treadmill while kinematic and kinetic data were captured at 150 Hz and 300 Hz, respectively. The peak of joint moments and flexion angles in sagittal plane were calculated. The normality and homogeneity of variances assumptions of the dependent variables was tested using Bartlett and Leven’s test. Independent t tests were conducted to examine the symmetry of hip, knee and ankle moments between dominant and non-dominant joints during stance phase of running (p<0.05). Results: results of the present study showed no significant difference exists between dominant and non-dominant lower joints regarding the peak moments of Hip, Knee and ankle in sagittal plane during stance phase (p>0.05) as well as between peak flexion angles during running. Conclusion: Symmetry exists in lower joints sagittal moments and flexion angle during running at the constant speed. According to the results dominant and non- dominant lower joints play propulsive and absorbent roles cooperatively.

The athlete's skills and psychological state often influence success in sports performance. The current study aims to explain the performance in paintball competitions based on cognitive resilience and cognitive regulation of emotion. The study participants included all paintball players participating in national paintball competitions (the year 2022), including 17 teams of 7 players, a total of 116 people. In order to investigate the psychological components affecting the athletes' performance, Conner-Davidson Resilience Scale (CD-RISC) and Cognitive Emotion Regulation Questionnaire (CERQ) were used. After completing these questionnaires, IBM SPSS Statistics version 26 was used to analyze the data. Pearson's correlation coefficient and stepwise regression were used to analyze the data. The results showed a significant relationship between resilience scores, the overall score of cognitive emotion regulation, and the scores of 9 emotion regulation strategies with the players' performance in the paintball competition (P≤0.05). Players who achieved better results in tournaments, scored higher on the resilience factor. Also, players who achieved better results in matches had higher scores on emotion regulation strategies like self-blame, positive refocusing, refocus on planning, positive reappraisal, and putting into perspective, and lower scores on the acceptance, rumination, catastrophizing and other-blame strategies. This study showed that cognitive resilience and emotion regulation could be used as predictors of success and winning positions in paintball competitions.

Background : There are conflicting findings regarding the effect of various training modalities on the cardiovascular disease mechanisms induced by undesirable modifications in extracellular matrix (ECM) factors such as MMP-9 and TIMP-1. Aim: This study was conducted to investigate the effect of different training protocols on the MMP-9 and TIMP-1 gene expression in the myocardium of Wistar male rats. Materials and Methods: Forty-eight adult Wistar male rats (aged: 8 weeks) were randomly allocated into two control (Con8w/base, n=8; and Con16w/end control, n=8) and four training groups (MICT, n=8; PICT, n=8; HIIT, n=8; and MIST, n=8). The training protocols consisted of 8 weeks (5 days/week) of Moderate-Intensity, Continuous Training (MICT: 37 min running with 65% vVO 2 max), Moderate-Intensity, Swimming Training (MIST: 30 min free-swimming), Progressive-Intensity, Continuous Training (PICT: 28 min running with a progressive increase in the incline of the treadmill by 2% per week), and High-Intensity Interval Training (HIIT: four running bouts 4 min with 90 to 100% vVO 2 max + 3 min with 50-65% vVO 2 max). Myocardial samples were isolated 24 hours after the last training session. Gene expression was determined using the real-time PCR method. All data (M±SD) were analyzed by one-way ANOVA and Tukey's post-hoc tests at α ≤0.05. Results : There were significant differences between MMP-9 and TIMP-1 expression in the animals myocardium after different exercise training protocols ( P <0.01). The lowest and highest MMP-9/TIMP-1 ratios were in the HIIT and MICT protocols, respectively. Conclusion: According to our findings, the HIIT protocol may play a more influential role in enhancing myocardial ECM-remodeling and fibrosis indicators during lifespan than the other exercise protocols.

The present study brings forward a model of workplace health with an approach to staff’s physical activity improvement. this study was an applied and descriptive research that has been conducted with a mixed approach for data collection (qualitative and quantitative). The methodology is performed qualitatively on the basis of grounded theory of Glaser approach. The research participants in qualitative included 18 subjects selected through judgmental sampling method with snowball approach. In addition, the sample in quantitative section, 384 subjects were studied through convinience sampling based on  Krejcie and Morgan table. The analysis in the quantitative section is second-order confirmatory factor analysis. According to the results, components of workplace health comprising the physical environment with sub-components of preparing infrastructure along with strenuous company; the psycho-social environment with sub-components of education, culturalization, encouragement along with support; the health resources with the sub-components of evaluation, supervision and alignment of plans; and participation of the company which comprises management and planning.

Background: The coaching styles are a powerful force that can affect the health of athletes and their view of sports. Aim : The purpose of this study was to investigate the relationship between Coaches' Behavioral Style (CBS) and Exercise Pleasure (EP) and Athletes' Moral Health (AMH). Materials and Methods: This research is descriptive-correlational. The statistical population of this study included all athletes in Neyriz city. Three questionnaires were used for data collection: CBS questionnaire of Chelladurai and Saleh (1980), EP questionnaire of Scanlan et al. (1993), and AMH questionnaire of Vallerand et al. (1996). Descriptive statistics and the Spearman correlation coefficient were used for data analysis. Results: The results showed that although some of the components of AMH and CBS, such as negativism, were inverse, overall, there was a positive and significant relationship between CBS and AMH. Also, there was a positive and significant relationship between AMH and EP. Conclusion: According to the results, CBS can affect AMH and EP. Therefore, sports coaches should choose their behavior style according to athletes' needs, however, based on their willingness in supportive and participatory styles