Background: This study examined the relationships between impulse and kinetic variables during jumping and landing in elite young male volleyball players. Methodology: Eighteen players were recruited and asked to jump on a force plate, which allowed for the direct extraction of jump and landing kinetic data. The data was then analysed using stepwise regression to explore the relationship between landing impulse and various kinetic variables. Results: Our findings revealed a significant positive relationship between the peak rate of force development concentric (PRFD _CON) and impulse at landing (β = 0.537, p = 0.02). In a secondary analysis, we found that PRFD _CON (β = 0.497, p = 0.01) and time to peak power concentric (TPPC) (β = 0.424, p = 0.04) were also positively correlated with landing impulse. Importantly, PRFD _CON and TPPC were the variables that had the most muscular predictive power for impulse at landing. Conclusion: These findings offer crucial insights into the biomechanics of jumping and landing in elite young male volleyball players, informing the development of more effective training programs. Our study identifies PRFD _CON and TPPC as critical factors for improving landing impulse, emphasizing the need to consider multiple kinetic variables when designing training programs for explosive skills. These insights can help optimize performance and reduce the risk of injury in elite young male volleyball players.

The purpose of the current study is to evaluate the effect of 4 weeks of home-based balance training (HBBT) on the performance of individuals with functional ankle instability (FAI) in daily activities and sports. Thirty college students diagnosed with FAI and with a mean weight of 79.8 ± 3.4 kg, height of 182.5 ± 5.1 cm, age of 23.5 ± 1.2 years, and instability score of 20 ± 2.3 were selected to participate in this study and were randomly divided by computer-generated methods into two groups: the HBBT group and the control group (CG), each consisting of 15 subjects. The HBBT group performed the program at home for 4 weeks, while the CG was non-exercise. Before and after the 4 weeks of exercise program, a form containing the foot and ankle ability measure for daily activities and sports was completed by the individuals. For data analysis, intra- and inter-group comparisons were performed using paired and independent sample t-tests, respectively, at a significance level of p ≤ 0.05. The results showed that 4 weeks of progressive HBBT were sufficient to significantly improve the measurement of the ability of ankle and foot function in individuals with FAI, even with a total volume of only 60 min per week. Accordingly, it is suggested that individuals with FAI can benefit from short-term HBBT programs, which are simple yet powerful enough to promote improvements in daily activities.

Background: The main aim of this study was to evaluate the relationships between training workload (WL) parameters with variations in the change of direction (COD) in under-16 soccer players. Methods: Twenty-seven under-16 elite soccer players were daily monitored for their WL across 15 weeks during the competitive soccer season. Additionally, players were assessed two times for anthropometric measures (weight, height, sitting height and leg length), COD performance (modified 505 test) and maturity offset measured using the peak height velocity (PHV). Results: A correlational analysis was performed to determine the relationship between the variation in COD performance and accumulated WL parameters. Moreover, a regression analysis was executed to explain the variations in the percentage of COD performance considering the accumulated WL parameters and PHV of the season (r = 0.93; p ≤ 0.01) and training monotony during the early-season (r = 0.53; p ≤ 0.05). There were associations between the acute workload during the start of the season and the COD during the end of the season (r = 0.47; p ≤ 0.05). The multiple linear regression analysis showed that 55% of the variation in COD performance between the early and end of season could be explained by the acute or chronic WL, training monotony or strain and the PHV. Conclusions: This information might be useful for practitioners and coaches aiming to improve the COD performance in youth soccer players during an entire competitive season.

Background and Objective: Individuals with a history of anterior cruciate ligament (ACL) injury are at a higher risk of re-injury compared to healthy individuals. ACL-injured patients exhibit weaker longitudinal arches and increased foot pronation compared to healthy individuals. This study aimed to determine the effect of short-term use of anti-pronation insoles on ...

Background and Aims Ankle injuries are one of the most common musculoskeletal injuries in atheletes. Proper landing after jumping leads to the preparation for the next skill as well as prevention of various ankle injuries. This study aims to compare the electrical activity of selected ankle muscles in athletes duirng landing from different heights. Methods This is a comparative study. Participants were 15 athletes (Mean age= 18.23 ± 2.3 years, mean height= 183.190 ± 6.3 cm, mean weight= 64.72 ±14.12 kg) with 3-5 years of experience in championship competitions. The landing skill was assessed from different heights (50%, 75%, 100% of maximum jump height). Electrical activity of selected ankle joint muscles (Gastrocnemius and Soleus) was recorded using an eight-channel BIOMED electromyography device with 96.34% validity and 91.29% reliability. Mean and standard deviation were used to describe the data, Shapiro-Wilk test was used to evaluate the normality of data distribution, and repeated measures analysis of variance was used to compare the collected data between groups followed by Bonferroni post hoc test. The significance level was set at 0.05. Results There was no significant difference in co-contraction of medial/lateral gastrocnemius and soleus muscles after jumping from three different heights. The peak contraction amplitude of the lateral gastrocnemius muscle was significantly different between the heights 50-75% (P= 0.006) and 50-100% (P= 0.002). The peak contraction amplitude of the medial gastrocnemius muscle was also significantly different between the heights 50-75% (P= 0.002) and 50-100% (P= 0.007). The peak contraction amplitude of soleus muscles was significantly different between the heights 75-100% (P=0.013) and 50-100% (P= 0.17). Conclusion There is an increase in the contractile activity of selected ankle muscles in the anterior-posterior plane caused by the increase in jump height and subsequent landing due to the optimal use of appropriate strategies to control the eccentric muscle contraction and the extensor torque of the ankle joint by increasing the electrical muscle activity during the ground contact, resulted in the prevention of injury to the ankle joint. Coaches and athletes can use these results to adopt training methods to strengthen these ankle muscles by considering the optimal implementation of landing skills with an injury prevention approach.

Background & Aims: The impact of the weight of backpacks with different weights on the foot, which is the link between the human body and the ground, has received less attention from researchers. Therefore, the aim of this study was to compare ground reaction force distribution between dominant and non-dominant ...