مطالب

Background: Plyometric training is defined as a quick, powerful movement involving a system of reactive exercises and an eccentric contraction, followed immediately by an explosive concentric contraction. Aim : This study aimed to determine the effect of plyometric and aerobic training on peak power and performance in female elite rowers. Materials and Methods: Sixteen female elite rowers with a minimum of 1 year’s competitive rowing experience were recruited to perform six weeks of plyometric or cycling endurance training for 30 min before practice on the water three days per week. Rowing performance was assessed through a 500-m rowing time trial (TT), while peak rowing power (PR) was evaluated by over three maximal trials of 15 s on the rowing ergometer. The recorded value for peak power was the highest wattage observed during the 15-s period. All statistics were performed using commercially available software (SPSS v. 23, Armonk, NY). Pre-planned t-test comparisons were used to determine significance at baseline in changes within both groups. Results: The results showed 500-m TT performance significantly improved for the plyometric group ( P < 0.05) but not for the endurance group ( P > 0.05). Moreover, PR was considerably higher in the plyometric group in post-test than endurance training. Conclusion: These results suggest that plyometric can improve rowing performance in female elite rowers, and rowing coaches should continue using this form of training. Coaches can perform plyometrics in conjunction with other strength training methods or as a warm-up before beginning rowing-specific training.

Background: There are relationships between exercise effect on mental health, especially negative emotions such as anxiety and stress. Aim : The aim study was the effect of participation in public sports activities based on the theory of planned behavior on the public health. Methods: This study is a descriptive correlation study with confirmatory factor analysis approach. Data was collected from 288 public sports participants of Tehran Municipality. Three standard questionnaires, including Goldberg General Health (1979) with 28 questions were used for collecting data. Results: Construct Variance extracted was 0.4, composite reliability 0.9 and Cronbach’s Coefficient Alpha 0.7. As a result, the convergence validity and reliability of the model were acceptable. Divergent validity, convergent validity and discriminant validity of the model were confirmed by first order and second order confirmatory factor analyses. The positive validity of all subscriptions for latent variables indicated the appropriate quality of the measurement model. In this model, it was found that regular physical activity combined with planned behavior had a direct effect of 53% (correlation 0.729) on general health. Conclusion: According to the structural equation model, it was found that regular physical activity combined with planned behavior has a direct effect of 58% on general health.