درخت حوزه‌های تخصصی

Background: Perturbation training which is in the context of volleyball routine practice is a type of neuromuscular exercises that is useful in overhead sports; leads to contraction responses through unpredictable perturbation. Aim : The present study aims to investigate the effects of perturbation training on volleyball players strength proprioception and performance. Materials and Methods: Twenty-four volunteer male volleyball players (age: 24.42±2.15 years; height: 181.46±3.00m; Weight: 73.87±3.77kg; BMI: 22.43±0.80) were recruited and randomly assigned into perturbation and control groups, Before the intervention, a set of isokinetic dynamometry was carried out to measure shoulder proprioception as well as rotator cuff muscles strength, what is more, the upper extremity performance was evaluated using Y-Balance Test. For a course of 6 weeks, players of the perturbation group implemented perturbation trainings, 3 times weekly while the control group performed its routine training. The dynamometry was repeated at the end of training period to compare trainings outcome. The Repeated Measures ANOVA statistic was used to find differences between groups. Results: A significant difference in shoulder proprioception, as well as the YBT-UQ test, was observed between the groups; Also, the ANOVA showed a significant difference ( P <0.05) in functional strength ratio followed by 6 weeks of perturbation training. Conclusion: Perturbation trainings might have benefit to volleyball players conditioning by improvement rotator cuff strength, shoulder proprioception and upper extremity performance. Given this adopting kind of training as a part of regular basic training for volleyball players is highly recommended.

Background: The SARS-CoV-2 virus is viewed as one of the defining crises of the current era, with various adverse ramifications for sports performance. Aim: The objective of the present study was to investigate the effect of aerobic exercise and caffeine supplementation on the cognitive performance and balance of college student-athletes recovered from COVID-19. Materials and Methods: Forty male student-athletes aged between 18 to 25 years from the Imam Khomeini International University of Qazvin were randomly assigned to four groups: 1. exercise + caffeine supplementation, 2. aerobic exercise + placebo, 3. aerobic exercise, and 4. control, in a pre-test post-test design. The Shapiro-Wilk test was used to check the normality of data distribution and covariance analysis was used for inter-group comparison. Results : The ANCOVA analysis showed significant differences in cognitive performance and balance among the four groups ( P <0.05). Pairwise comparisons using the Bonferroni post-hoc test showed statistically significant differences in cognitive performance and balance between the aerobic exercise + caffeine group versus the aerobic exercise + placebo group (P<0.05) and the aerobic exercise versus the control group ( P <0.05). Also, there was significant differences in mean cognitive performance and balance indices between AE+CAF versus CONT ( P <0.005) and AE+CAF versus AE ( P <0.005). Conclusion: The results of this study show that aerobic exercise with caffeine supplementation can improve cognitive performance and balance of student-athletes recovered from COVID-19.

Background: Transcranial alternating current stimulation (tACS) is a non-invasive method that offers a potential solution to reduce the effects of aging on brain function. Aim: The aim of this study was to investigate the effect of offline tACS over the supplementary motor area on bimanual coordination in elderly people. Materials and Methods: Thirty-one women aged of 60-75 years were selected as convenience. They were assigned to 2 conditions: tACS and Sham, in random order, with one-week interval between conditions. After pre-test, each participant completed four trials of 5 min using Purdue pegboard task. Concurrently, participants received beta tACS with a current intensity of 1 mA. Immediate retention test, transfer test, and delayed retention tests after 48 hours and 1 week were conducted. A 2(condition) x 4(test) ANOVA with repeated measures was performed on gain scores. Results: The main effects of condition and test were significant ( P <0.0001). The Bonferroni tests revealed the significant improvement of bimanual coordination in the tACS condition compared to the sham condition in all retention and transfer tests ( P <0.05). Conclusion: The findings highlights the potential use of offline beta tACS over the SMA as a modulatory factor for enhancing bimanual coordination in the elderly women.

Background : Work-related musculoskeletal disorder is the most important occupational disease that threatens the health of employees. Aim: The aim of this study was to investigate the relationship between workers' posture and musculoskeletal disorders. Materials and Methods: Eighty-two male and female workers working in a home appliance factory participated in this cross-sectional study. Musculoskeletal disorders were investigated using Nordic questionnaires. Posture evaluation was performed to measure the angles of forward head, rounded shoulders, and thoracic kyphosis using photogrammetry. Craniovertebral, shoulder, and thoracic kyphosis angles were photographed during the work and then measured using ImageJ software. Data analysis was done using SPSS 26 and Spearman's correlation test at a significance level of 0.05. Results : A significant relationship between the craniovertebral angle and musculoskeletal disorders in the last twelve months was observed in the cervical region ( P <0.001). Also, a significant relationship was observed between the kyphosis angle and musculoskeletal disorders in the last twelve months in the upper back and lower back ( P <0.001). Conclusion : The results showed that the workers’ posture during work is correlated with the prevalence of musculoskeletal disorders. Therefore, it is suggested to pay attention to ergonomic principles during work to maintain and improve the physical health of workers.