Journal of Advanced Sport Technology
Volume:7 Issue: 4, Autumn 2023

This research aimed to investigate the most important characteristics of elite volleyball players to identify sports talents. 150 elite and 150 non-elite volleyball players were selected by random sampling and accessible to perform the tests. The measured variables included anthropometric indices, physiological abilities, psychological characteristics, and skill abilities. Independent t-test and the Mann-Whitney statistical test were used to compare the variables of the two groups. Principal component analysis was used to determine the main variables. The significance level of 0.05 was considered. The result showed the variables of height, arm span index, brachial index, leg cororal index, aerobic power, anaerobic power, vigor, hand grip strength, Sargent's jump, spike jump, overhead serve, forearm, and overhead pass in elite volleyball players were significantly higher than in non-elite players. Variables of weight, body mass index, sitting height index, waist-to-hip circumference index, tension, and anger were significantly higher in non-elite players than in elite players. By using principal component analysis, the most important variables in the research to identify elite volleyball players were obtained, respectively: height, overhead serve and forearm pass, vigor, sitting height index, brachial index, spike jump, and anaerobic power. In the current research, the differences between the elite and non-elite groups, along with the most important variables from the anthropometric, physiological, psychological, and skill areas of the elite volleyball players, were obtained, and the main variables for the identification of sports talent were determined.

Freestyle wrestling requires precise and coordinated movement execution, with the Double-Leg Attack technique playing a crucial role in gaining an advantage. Understanding the underlying mechanisms and effects of specialized wrestling training is essential for optimizing performance. Muscle synergy or modular movement control involves coordinated patterns of muscle activation and the organization of muscles into functional units or modules. Exploring these concepts in freestyle wrestling can provide insights into optimizing movement coordination and performance outcomes by studying the synergistic interaction of different muscles. This study  investigates the effect of consistent and specialized Freestyle wrestling training on upper limb muscle synergy during the Double-Leg Attack maneuver, specifically comparing elite and sub-elite wrestlers. Thirty-eight junior Iranian male freestyle wrestlers were categorized based on their skill level. Elite group (n = 19) who participated in national or international-level competitions and achieved notable success and sub-elite group (n = 19) actively engaged in training but have not yet reached the same competitive level. We recorded EMG activity from five unilateral upper limb muscles and employed a non-negative matrix factorization (NMF) algorithm to extract the muscle synergy composition and temporal activation patterns during the Double-Leg Attack maneuver. In both the elite and sub-elite groups, three distinct muscle synergies (Syn1, Syn2, and Syn3) were identified and extracted. Notably, both groups showed impressive coherence within their respective groups in terms of spatial structures and temporal activation patterns of muscle synergies during the Double-Leg Attack technique. However, it was observed that elite wrestlers exhibited significantly higher values in temporal activation patterns compared to their sub-elite counterparts (P=0.000). The findings of this study highlight the importance of consistent and specialized Freestyle wrestling training in optimizing muscle synergy during the Double-Leg Attack technique. Significant differences observed in the temporal activation patterns suggest that elite wrestlers possess a higher level of temporal precision and coordination, which may contribute to their competitive advantage. These findings provide valuable insights for wrestlers and coaches to guide training strategies focused on enhancing muscle synergy and temporal coordination for improved performance in Freestyle wrestling.

Running is one of the most popular physical activities in the world and is usually done on different surfaces. Different levels of running are associated with overuse injuries. Therefore, this study aimed to evaluate the effect of eight weeks of training on artificial grass, natural grass, and synthetic surface on ankle joint co-contraction during running in individuals with over-pronation. This study was designed as a double-blinded randomized controlled trial. Sixty participants aged 18–30 years with diagnosed excessive pronation of foot were randomly allocated into three intervention groups (natural grass, artificial grass, and synthetic surface) and a control group. Electromyography data during pre and posttest was collected using surface electromyography system. Results did not demonstrated and statistically significant between group differences in in directed and general ankle joint co-contraction (P>0.05). The results of the present study showed that the ankle joint co-contraction during training on three types of artificial grass, natural grass, and synthetic surfaces was not statistically different in individuals with over-pronation.

The purpose of this research was to design and manufacture various sports equipment, including cardiovascular system strengthening devices, which holds great significance in the public health. Special mechanical parts were used for the design and manufacture of the stand rollick device. This device consists of two general parts with different fragments: A. The front part and B. The rear part including two rollers, metal structure, front wheel stopper, movable arms and its movable forks, stopper belt, machine wings and fixed shaft were used. The base of the stand rollick has the ability to be adjusted for all types of mobile bicycles, due to the fact that the chassis of this device is sliding and can be easily enlarged and reduced. Due to the lightness and simplicity of the designed stand rollick, it can be easily adjusted in any place and any mobile bicycle can be placed on it. According to the results of the study, it can be concluded that the designed and manufactured device can improve physical fitness, especially the cardiovascular system, at any time and in any place especially in the cold and rainy weather, where outdoor exercise training is difficult for all people in all age groups. This device can be a good alternative to moving bicycles in critical times such as an outbreak of a viral disease.

Ankle sprain is one of the common injuries among athletes and the general public. It seems that limiting the range of motion of ankle inversion can have positive effects on reducing the recurrence rate of ankle sprains. Therefore, the aim of this research is to use medical insoles to prevent excessive ankle movements. 10 soccer players with ankle sprains participated in this research. Kinematic data were collected using a motion recording system including four Vicon cameras and light-reflecting markers with a sampling rate of 100 Hz in two conditions running with and without insoles. Then the peak range of motion of inversion/eversion, dorsiflexion/plantarflexion, abduction/adduction in the ankle and flexion movements, internal/external rotation, abduction/adduction in the knee and flexion/extension movements, internal/external rotation and abduction/adduction in the hip joint in two conditions, with and without medical insoles was evaluated. Repeated measurement analysis of variance was used for intragroup comparison with a significance level (P˂0.05) for statistical analysis. The results of this research showed that medical insoles reduce ankle dorsiflexion (p=0.036, d=1.14), inversion (p=0.003, d=1.44) and abduction (p=0.007: d=1.6). Also, the use of insoles decreased the internal rotation of the knee (p=0.04, d=0.61). Therefore, the use of insoles reduces the kinematic risk factors of ankle sprain and helps the stability of the ankle joint during running. As a result, the use of medical insoles can be suggested as a suitable therapeutic intervention to prevent ankle sprains.

This study investigated the potential link between lower extremity alignment and Anterior Cruciate Ligament (ACL) injuries in elite male wrestlers. It was hypothesized that lower extremity alignment could predict ACL injury risk. Sixty male wrestlers, divided into injured (n=30) and non-injured (n=30) groups. Lower extremity alignment indices, including pelvic inclination, hip anteversion, quadriceps angle, knee hyperextension, tibial torsion, plantar arch index, and rear foot angle, were measured. Multiple logistic regression analysis was employed to identify predictor factors for ACL injuries. The results revealed that only the plantar arch index was a statistically significant predictor for non-contact ACL injuries in elite male wrestling athletes (P<0.05). Consequently, the findings suggest that focusing on distal variables of the knee may be crucial when designing ACL injury prevention programs.