Search

The study focuses on the design and manufacture of an Eccentric Smith Machine, incorporating specialized mechanical components for enhanced athletic benefits, minimizing injuries, and promoting hypertrophy. The Eccentric Smith Machine comprises three main parts: A stable Smith machine adapted for electrical motor shocks, an electrical component with a panel and motor, and a transmission system using four pulleys and two cables. The mechanical design facilitates acute and smooth bar movement, ensuring safety and ease of use for athletes of varying heights and strengths. The Eccentric Smith Machine demonstrates resilience to electrical motor power, simplicity in usage, and safety advantages. Its adaptability makes it accessible to athletes with diverse physical characteristics, providing a tool for effective and safe resistance training. The designed device has the potential to enhance physical fitness, particularly muscle hypertrophy. It stands as a viable option for athletes, offering a reduced risk of injuries during workouts. The Eccentric Smith Machine presents itself as an alternative for those recovering from minor injuries, contributing to overall workout safety. [ABSTRACT FROM AUTHOR]

Background: Artificial neural network helps humans in a wide range of activities, such as sports. Objective: This paper aims to investigate the effect of artificial intelligence on decision-making related to human gait and sports biomechanics, using computerbased software, and to investigate the impact of artificial intelligence on individuals' biomechanics during gait and sports performance. Material and Methods: This review was conducted in compliance with the PRISMA guidelines. Abstracts and citations were identified through a search based on Science Direct, Google Scholar, PubMed, Elsevier, Springer Link, Web of Science, and Scopus search engines from 1995 up to 2023 to obtain relevant literature about the impact of artificial intelligence on biomechanics. A total of 1000 articles were found related to biomechanical characteristics of gait and sport and 26 articles were directly pertinent to the subject. Results: The extent of the application of artificial intelligence in sports biomechanics in various fields. In addition, various variables in the fields of kinematics, kinetics, and the field of time can be investigated based on artificial intelligence. Conventional computational techniques are limited by the inability to process data in its raw form. Artificial Intelligence (AI) and Machine Learning (ML) techniques can handle complex and high-dimensional data. Conclusion: The utilization of specialized systems and neural networks in gait analysis has shown great potential in sports performance analysis. Integrating AI into this field would be a significant advancement in sport biomechanics. Coaches and athletes can develop more precise training regimens with specialized performance prediction models. [ABSTRACT FROM AUTHOR]

The aim of this research was to investigate the effect of acute fatigue on the plantar pressure distribution in professional young male volleyball players. A total of 38 young male volleyball players (aged 16-20 years) volunteered for this study and were randomly divided into two groups: the experimental group (n=20) who performed the functional fatigue protocol, and the control group (n=18) who did not perform the fatigue protocol. The fatigue protocol in this study was of a functional and volleyball-specific nature, consisting of six repetitive cycles of movements until fatigue was reached. Plantar pressure distribution was measured using a foot scanner before and after the application of functional fatigue during walking task. One-way ANOVA was used to investigate between-group differences, and repeated measures ANOVA was used to examine the fatigue effect within each group. The data were analyzed using SPSS software (version 21) at a significance level of p = 0.05. The results showed that after fatigue, between-group differences of plantar pressure distribution increased in both feet. Significant differences between the two groups were observed in the force values of the left small toe, first, second, and third metatarsals, midfoot, and heel medial of the right foot (p < 0.05). The results indicated that fatigue leads to an increase in maximum distributed force. These factors can potentially increase the risk of injury in individuals. [ABSTRACT FROM AUTHOR]

Purpose: The current research aims to examine the effect of taping on the feedforward activity of the lower limb muscles in elite volleyball players with and without chronic ankle instability while performing single-leg jump-landing. Methods: The electromyographic activities of the lateral gastrocnemius, tibialis anterior, peroneus longus, rectus femoris, gluteus medius, and vastus lateralis of the non-dominant leg were registered before and after taping in 26 volleyball players while performing the spike skill with single-leg landing. These volleyball players entered the research by purposive sampling. The root mean square (RMS) was employed to compute muscle activity before and after taping. The multivariate analysis of variance (MANOVA) test at P=0.05 was utilized to analyze the data. Results: The results of the multivariate analysis of variance (MANOVA) test demonstrated that the groups did not have a significant factor in any of the variables in the feedforward phase, except for the maximum root mean square (RMS) of the peroneus longus muscle (P=0.01). Conclusion: The results showed that taping cannot improve the feedforward activity of the selected muscles during single-leg landing in people with chronic ankle instability. Therefore, it is recommended to use other methods and exercises to improve the muscle feedforward activity in these individuals during the rehabilitation phases. [ABSTRACT FROM AUTHOR]

Objective Identifying the factors affecting the reduction of ankle sprain complications, rapid recovery, and prevention of re-injury after an ankle sprain are essential. Therefore, the present meta-analysis investigates which training modalities have a better effect on the balance and motor function of people with chronic ankle instability. Materials & Methods The relevant articles were identified by searching 8 international databases of MEDLINE/ PubMed, Embase/Scopus, LILACS, CINAHL, Central (Cochrane Central Register of Controlled Trials), Web of Science, PEDro, and Google Scholar. This work was also done in Persian databases Magiran, Irandoc, Iranmedex, MedLib, and SID, equivalent to English keywords searched from 8 databases. After collecting the search results, first, the title and then the abstracts of the articles were read. If the articles met the inclusion and exclusion criteria, their results would be used in the review study, otherwise discarded. The search period comprised from the beginning to December 2021. In addition, a manual search and full review of article sources was performed. The exclusion criteria were articles whose statistical population was people other than people with chronic ankle instability, published articles other than English and Persian, and articles that examined the effect of exercise programs on factors other than balance and motor function had paid. Hedges' effect size (ratio of the mean difference between the two groups to the mixed weight standard deviation) was used for meta-analysis. Heterogeneity between studies was assessed using the I2 index. If the heterogeneity is above 50%, the random effects model method is used, and if it is below 50%, the fixed-effects model method is used. The bias of published studies was assessed using Egger's test. Comprehensive meta-analysis v.2.0 software was used to analyze the data. Results After reviewing the full text of the found articles, 21 articles using 24 training protocols were selected. The final articles were divided into two categories for analysis: articles comparing neuromuscular exercises with other exercises and articles comparing new and combined balance exercises with other exercises with traditional balance exercises. By a superficial qualitative review of articles with the PEDro tool, the average scores that articles received from this scale were higher than 7, which shows that the articles used for the meta-analysis of this study are of high quality and the results of these studies are reliable. Conclusion The results of studies showed that neuromuscular training has a better effect on static and dynamic balance in people with chronic ankle instability than other training protocols. However, there was no significant difference between the two types of training groups in motor performance. The results of studies also showed that balance-combination exercises, as well as new methods of balance exercises compared to traditional balance exercises, have a more significant effect on static balance and motor function of people with chronic ankle instability. However, no significant difference between the two types of training groups was observed in the dynamic balance. Also, the effect of new combined-balance exercises on dynamic balance was better than traditional balance exercises. It seems that the usefulness of balance-combination exercises and performing balance exercises with new methods is more useful than other training protocols on balance and postural control of people with chronic ankle instability. [ABSTRACT FROM AUTHOR]

Purpose: Due to the paucity of information regarding the lower limb biomechanics in running at slow speed, as well as the concentration of most previous studies on a single movement plane, this study aimed to investigate lower limb joint kinetics with increasing running speed. Methods: Twenty-eight runners were asked to stay on the treadmill at a bent velocity which was incrementally increased to 2.5 m/s, 3.5 m/s, and 4.5 m/s speeds. The three-dimensional joint moment and sagittal mechanical muscle power of the lower limb were calculated during the stance phase of running. Repeated measures analysis of variance (ANOVA) with Bonferroni post hoc test was used to examine the variables during running at various speeds. Results: The results showed that at the hip joint in the frontal plane, an adduction moment developed in the middle of the stance phase, and the highest peak adduction moment was obvious at the highest speed condition (4.5 m/s). Also, the time elapsed to peak in the highest speed condition was less than the others. In the transverse plane, although the 3.5 m/s-speed condition experienced the maximum external rotation peak moment, the 4.5 m/s-condition speed reached the internal status earlier than the two other speeds. In the sagittal plane, the highest speed condition showed the highest extension and flexion moments. Conclusion: Increasing running speed in runners leads to more kinetic output and mechanical power gradient. [ABSTRACT FROM AUTHOR]

The game analysis is known as a useful tool for understanding the level of technicaltactical performance of volleyball. As one of the main characteristics of volleyball is defined as the intense relationship between its skills and concluded performance, the present study aimed to perform a comprehensive analysis of the serve reception zone, set zone and attack quality of the top-level volleyball players. The analysis process included reviewing the videos of the games by an experienced scout man who was an expert analyst and specialist in the knowledge of volleyball skills. Initially, during each game video checking, data were collected, and irrelevant/invalid outputs were deleted. Data were exported to the Data Volley special volleyball analysis software. Bivariate associations were assessed for pairs of variables with Pearson's chi-squared tests. Statistical significance was set at p<0.05. Moreover, the effect size was calculated in terms of Crammer's V, with values of <0.1, 0.1 - 0.3 and > 0.5 for small, medium, and large effects respectively. The results showed that there were significant relationships between reception zone with setting zone, setting zone with attack quality as well as reception zone with attack quality. Coaches may consider the relationship between critical skills of volleyball to promote their team performance. [ABSTRACT FROM AUTHOR]

Purpose: Various kinematics and kinetics methods have been proposed for the assessment of jumping ability as a critical skill in professional volleyball players, but little is known about the accuracy and differences between these methods. Therefore, the objective of the current study was to answer the question "Is there any difference between the results of various kinetic methods in the assessment of block jump height in volleyball players or not?" Methods: Twenty-one healthy male junior volleyball players of the Iran national team performed the block jump task on a force platform. Three common formulas mostly used in literature based on kinetics output of force platform were selected for the comparison of resultant jump height. Descriptive analysis, Shapiro-Wilk test, and ANOVA were used for statistical calculations (P<0.05). Results: The results showed no significant difference between the means of block jump heights measured based on different kinetic methods in volleyball players. Conclusion: Formula calculation methods are very valid for measuring the jump height of the block jump and lead to very similar results for estimating jump height and are also replaceable with each other. [ABSTRACT FROM AUTHOR]

Purpose: Frequent and powerful jumps and landings in volleyball exert significant stresses on lower extremities which can be determinant of injury prevalence. This study aimed to investigate the possible correlation between Maximum Jump (MJ) performance and force-time variables of volleyball block landing. Methods: Thirty elite junior volleyball players (Mean±SD of age: 18.140±1.125 y, sports background: 4.390±0.957 y, and height: 197.100±3.161 cm) performed three block jumps, and best of trials was considered for further analysis. The study data were collected by the KISTLER force platform (1000 Hz). Force-time, velocity-time, and displacement-time were obtained using the Excel program. The Kolmogorov-Smirnov and Pearson correlation coefficient were used for assessing data normality and possible correlations between variables using SPSS v. 21 (P<0.05). Results: Peak vertical impact forces were reported in a range of 1.8-3.5 BW (F1, F2) during 27 to 83 ms of peak times (T1, T2). Significant positive correlations were obtained between temporal variables of time of peaks (T1, T2), the time elapsed between peaks (TP), and end of landing time (Tf). A significant negative correlation was found between F2 and T2 and a significant positive correlation between MJ performance with peak vertical forces (F1, F2). Conclusion: According to the findings, T1 has little impact on shock absorption. Coaches and volleyball players should consider the importance of soft landing through increasing T2, which decreases F2, not only for performance improvement but also for reducing injuries. [ABSTRACT FROM AUTHOR]