Sport Sciences and Health Research

Background: Observational learning is an effective pedagogical approach that can be used as a method to improve motor skill acquisition and also a useful instrument to promote psychological variables such as self-efficacy by emphasizing the motivational aspect. Although, little research is known about the model type and the observation conditions which will optimize learning. Aim: This study aimed to clarify the effect of using a combination of ideal model-observation and self-observation on self-efficacy and learning the forehand service of table tennis. Materials and Methods: Forty females were assigned to one of four experimental groups. All groups received the same instructions concerning how to perform the task, filled out a self-efficacy questionnaire, and then performed 10 pre-test trials. The acquisition phase included six sessions. The retention test was done 72 hours after the last acquisition session. Mixed ANOVA with repeated measures and Bonferroni post hoc tests were conducted, and one-way ANOVA was used to determine group significant differences. Results: The results indicated that observing the combination of skilled and learning models led to the highest self-efficacy for learning, compare with other experimental models. Also, significant learning of the task was shown in the acquisition phase in which the performance of all three experimental groups was clearly superior to the control group. Although in this phase there was no significant difference between the performances of two groups of combined skilled-learning and skilled. The results of the delayed retention test indicated that the performance scores of the combined skilled-learning group were significantly higher than the other three groups. Also, in this phase, the difference between the combined skilled self-observation and control or skilled groups was not significant. Conclusion: Demonstrating a skilled model is the most popular type of observational learning among the instructors and physical education teachers, it is suggested that adding a learning model to that leads to better performance and enhancing the self-efficacy.

Background: Expression of mucosal levels would affect the function of internal organs of the body and the digestive system, such as by creating a blockage for the progression of cancerous tumors and the failure of the target tissue, especially the large intestine. Aim : The purpose of this sudy was to investigate the effect of 8 weeks of quercetin supplementation and intermittent exercise on protein levels of intestinal Muc5Ac, Muc4 and polyphosphate in rats with colon cancer. Material and Methods: Tewenty-four rats were randomly assigned into four groups including quercetin (n=6), exercise (n=6), quercetin + exercise (n=6) and control group (n=6). Colon cancer induction was provided with the use of 1,2-dimethylhydrazine for 8 weeks and daily quercetin supplementation of 50 mg/kg body weight of mice by Gavagene method. Exercise protocol was performed 5 sessions per week with intensity of 60-70%, maximum speed of 23 m/min with 2-min rest in 8 weeks. ANOVA was used to analyze data. The level of significance was set at P <0.05. Results: It was suggested that there was a significant difference in protein levels of intestinal Muc5Ac, Muc4 and polyphosphate in all groups ( P <0.05). Furthermore, it was also indicated that Muc5Ac levels was significantly higher in the quercetin+ exercise group other than pther groups ( P <0.05). Conclusions: It was concluded that intermittent exercise and quercetin supplementation would increase the levels of Muc5Ac and Muc4 proteins in the large intestine of mice with colon cancer.  

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: Karate consists of two somewhat different disciplines, kata, and kumite; each one may have a different effect on foot structure and dynamics in the longterm.   Aim : As pedobarography is indicative of foot function, the present study aimed to compare pedobarographic profile during gait between young females participating in international kata and kumite competitions and non-karate-ka females. Materials and Methods: Displacement and velocity of the center of pressure, and peak pressure in ten regions of the foot of 10 kata-ka, 12 kumite-ka, and 16 non-karate-ka were measured with a pressure platform during barefoot walking. Results: Peak pressure in the lateral-heel and lateral-toes of kata-ka and kumite-ka was significantly lower than non-karate-ka ( P <0.05). Furthermore, peak pressure in the kata-ka midfoot was lower than non-karate-ka ( P =0.01 in medial-foot, P =0.01 in lateral-midfoot). In the anteroposterior direction, center of pressure velocity and displacement were significantly different among the three groups ( P <0.05). Conclusion: It can be concluded that the practice of repeated intensive karate exercises has a demonstrable effect on foot progression, dynamic loading velocity, and plantar load distribution during gait. Moreover, practicing kata probably has a greater impact on the measured parameters.

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.

Background: Trunk control defect is one of the neuromuscular defects that can cause sports-related injuries in athletes. Aim: This research investigated whether neuromuscular training affects several kinetic parameters in male athletes who had trouble controlling their trunks during a change-of-direction movement. Materials and Methods: The present study used a pre-test-post-test design and was conducted semi-experimentally. Purposefully chosen male athletes (n= 29) with trunk control defects were randomly divided into two groups: control (n= 14) and experiment (n= 15). A Kistler force plate was used to quantify kinetic variables. The exercises were performed for 6 weeks, 3 sessions per week (30 min each session). To analyze the data, dependent t-test and analysis of covariance and SPSS software version 21 were used at the significance level of P <0.05. Results: The findings indicated a significant decrease in the time to peak anterior-posterior force ( P =0.010), time to peak mediolateral force ( P =0.001), time to peak vertical force ( P =0.003), and rate of loading ( P =0.001) of the experimental group. The differences in all control group variables were insignificant, P >0.05. Conclusion: Performing neuromuscular training is likely to improve the direction change mechanism and prevent injury in athletes with trunk control defects.

Background: High-velocity low-intensity actions result in reduced hemodynamic responses. Additionally, eccentric actions are associated with reduced hemodynamic and metabolic responses. Aim: This study aimed to investigate acute hemodynamic, hematological, and electrocardiographic responses to high-velocity low-intensity concentric resistance exercise (HVLICRE) and low-velocity high-intensity eccentric resistance exercise (LVHIERE) in healthy young adults. Materials and Methods: In this study, 16 healthy young men were divided into two groups (HVLICRE: 40% 1RM, LVHIERE: 80% 1RM). The exercise protocol consisted of five sets of 10 repetitions, with 90 sec of rest between the sets and a two-second interval between actions. For data analysis, repeated measures ANOVA, one-way ANOVA, and Bonferroni's post hoc test were performed at a significance level of P ≤0.05. Results: LVHIERE led to greater RPE ( P ≤0.05), compared to HVLICRE. Also, LVHIERE was associated with a significant increase in the activity of the sympathetic nervous system and a significant decrease in the parasympathetic nervous system as compared to HVLICRE ( P ≤0.05). Conclusion: HVLICRE and LVHIERE produced similar effects on blood glucose, serum lactate, hematocrit, systolic and diastolic blood pressure and heart rate. LVHIERE can be investigated as part of the strategy of rehabilitation programs in future studies.

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 : Cold sprays (CS) are widely used in sport competitions as an effective, simple, and high available treatment. Aim: The aim of present study was to investigate immediate and longtime effects of CS application onto the knee joint anterior-medial area of dominant leg on timing and activation pattern of selected muscles during one-leg landing. Materials and Methods: Thirty (15 control and 15 experimental) able-bodied male participated in this study. Electromyography activity of vastus medialis, rectus femoris, vastus lateralis, biceps femoris, semiendineus and medial gastrocnemius were recorded during one-leg landing tests (with dominant leg) for each of three conditions including before CS application (pre-test), immediately after (post-test 1), and 20 min later (post-test 2). To determine the effect of group and time on each dependent variable, three independent 2×2 multivariate repeated measures analyses of variance were performed (α < 0.05). Results : The results showed following trends rather than significant differences: the muscles in the experimental group had lower activity level and later onset immediately after CS application compared to before application, and they had higher activity level and sooner onset after 20 min from removing CScompared to immediate application. No significant interaction was found for normalized peak activation and time to peak activation ( P > 0.05). However, decrease in skin temperature after cold spray application was observed. Conclusion : These results show short-time cold application, which is so practical after many injuries for returning athletes to sport environment, may not predispose individuals to risk of re-injury or failed landing mechanism.

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.

Background: Physical activity affects the health of the body's organs through several processes. Apoptosis is one of the important cellular processes that play a role in maintaining the balance between cell death and tissue growth. Aim: The aim of the present study was to examine the previous findings regarding the effect of physical activity and exercise on apoptosis in order to obtain a relatively comprehensive knowledge of this effect by summarizing and analyzing the data. Materials and Methods: To collect the information of the articles, a search was made from PubMed, MEDLINE, SID, IranMedex, IranDoc, Magiran and Medlib databases. More than 80 scientific articles from 2000 to 2023 were reviewed. The keywords used were: physical activity, aerobic exercise, endurance exercise, apoptosis and cell suicide. After the review, finally 26 articles were selected. Then, the selected items were fully studied and finalized, and the items that were more complete than the others were selected as references. Conclusion: Physical activity and exercise, especially aerobic exercise, as a safe, cheap and accessible method, can reduce apoptosis through several mechanisms. The breadth of studies in this field, and the overlapping of many data, allows us to confidently introduce exercise and aerobic activity as one of the best methods of regulating body homeostasis and reducing apoptosis.