Mira Ambrus

The high rate of reinjury after anterior cruciate ligament reconstruction (ACLR), persistent sex-related disparity, and increased susceptibility during transitional stages in female football players highlight the need for more specific strategies to identify biomechanical parameters associated with valgus collapse. This study aimed to compare three-dimensional knee kinematic and synchronized electromyography (EMG) muscle activity of the medial and lateral thigh muscle complexes during a change of direction (COD) task, between ACLR and healthy controls players. A cross-sectional case–control study was conducted with 26 under-23 semiprofessional female football players (22.89 ± 2.68 years), divided into ACLR (n = 13) and control (n = 13) groups. The maximum and minimum peaks and range of knee angular velocity across three planes, along with the average and peak electromyography (EMG) muscle activity of the Biceps Femoris (BF), Semitendinosus (ST), Vastus Medialis (VM), and Vastus Lateralis (VL), were recorded during the preparation and load phases. Between-group differences were assessed using independent t-tests or Mann–Whitney U tests. Statistical significance after Holm–Bonferroni correction was established at p-Holm < 0.05. ACLR players demonstrated significant increased knee valgus angular velocity, alongside 4% reduced average ST muscle activity and 27% diminished peak BF muscle activity during the load phase, compared to controls. These findings indicate altered knee kinematic and muscle activity patterns during COD in ACLR players, suggesting persistent long-term functional adaptations in female football players after ACLR.

Introduction: Anterior cruciate ligament (ACL) injuries are among the most severe and frequent injuries in alpine skiing, often occurring in non-contact situations during high-demand turns. Various instrumental techniques were used to assess susceptibility to anterior cruciate ligament (ACL) injuries in alpine ski racers and recreational skiers. This cross-sectional exploratory study aimed to identify key factors contributing to ACL injury susceptibility, comparing lab-based and on-snow tests. Materials and Methods: We examined nine elite ski racers and nine recreational skiers with strong athletic backgrounds. Skiing technique was analyzed using an instrumented insole system (CARV) to measure body position, pressure symmetry, and edge angle. Dynamic Q-angle symmetry during single-leg squats were assessed with an optical system (DynaKnee), while balance, strength, and agility were evaluated through ACL-specific lab tests (CoRehab). Group comparisons were performed using the nonparametric Mann–Whitney U test. Results: No significant differences were found between groups in ACL-specific lab tests, including balance, agility, and jump performance. However, ski racers exhibited 34.9% higher asymmetry in the Q-angle symmetry index during the one-leg squat. In contrast, ski technique differences were significant: ski racers achieved 16.3% higher Edge Similarity, 48% better Pressure Symmetry, and 5.8% better Fore-Aft Balance compared to recreational skiers. Conclusions: Despite similar general athletic abilities, elite skiers showed higher Q-angle asymmetry, which has been previously associated with ACL injury risk. However, their advanced skiing technique may partially mitigate the functional consequences of this asymmetry during on-snow tests. This suggests that refined skiing skills may influence functional performance in racing conditions, while pronounced one-sided dominance could indicate potential injury risk.

Background: Pelvic instability is often associated with angular deviations of lower limb and often causes valgus shift of the knee joint under load. In addition, non-contact ACL tears during sport activity are often caused by muscle weakness around the pelvis. Therefore, reinforcing the pelvic stabilizing muscles may counterbalance dynamic knee valgus (DKV). The aim of this research is to increase the activity of the pelvic stabilizing muscles through a specific exercise program and to investigate its effect of DKV after six-week pelvic stabilization training. Methods: Twenty-two subjects (male/female: 15/7) participated in the study. They performed pelvic stabilization program for six-weeks. Before and after the training, DKV was determined on both sides by performing ten single leg squats using a Kinect camera, the Gluteus maximus, medius and vastus medialis muscles activity and strength were measured by EMG system and wireless dynamometer. Results: DKV decreased from 3.15% to 1.03% for the left knee and from 3.89% to 1.26% for the right knee, the magnitude of change was significant ( p < 0.001). Maximal Isometric Force increased significantly in all tested muscles, including the gluteus maximus, gluteus medius, and biceps femoris (all p < 0.05 or p < 0.001). This functional improvement was supported by neuromuscular changes, with EMG amplitudes increasing considerably in all assessed muscles (gluteus maximus, gluteus medius, and vastus medialis obliquus), with all six sides showing significant change (all p < 0.001). Conclusions: Strengthening the pelvic stabilization muscles induced a substantial improvement in knee valgus, and thus reduced the risk of developing cruciate ligament injuries. This study provides a direct link between an easy diagnosed predisposing factor a common sports injury, and offers a simple countermeasure in the form of specific exercises, that may be included against ACL injuries.

Background: Given the persistent sex-based disparities in anterior cruciate ligament (ACL) injury prevalence and the heightened susceptibility observed during critical stages of development in female academy-level players, it is necessary to enhance the effectiveness of prevention programs, particularly during change of direction (COD). Objectives: This study aims to evaluate whether a multicomponent periodized program modifies three-dimensional knee angular velocity and hamstrings and quadriceps muscle activity during a COD task in under-16 female football players. A secondary objective was to determine whether adaptations differed based on lower limb dominance. Methods: A non-randomized, multicenter controlled trial with a pre–post design was conducted involving 35 players (age: 15.50 ± 1.22), allocated to either an intervention (n = 17) or control (n = 18) group. The intervention group undertook a 12-week multicomponent periodized program within their usual training program whilst the control group undertook their usual training program. The peak and range of thigh and shank angular velocity across three planes, along with the average rectified and peak envelope EMG signals of the Biceps Femoris (BF), Semitendinosus (ST), Vastus Medialis (VM) and Vastus Lateralis (VL), were recorded during the preparation and load phases, using the Change of Direction and Acceleration Test. Three-factor mixed model ANOVAs and non-parametric tests were applied, with statistical significance set at p < 0.05. Results: Post-intervention analysis revealed significant improvements in sagittal and coronal planes shank angular velocities and thigh coronal and transverse plane angular velocities. Muscle activity patterns also improved, particularly in the ST and VM, suggesting enhanced medial stabilization and neuromuscular control. Functional improvements were most evident in the dominant limb. Conclusions: The 12-week multicomponent periodized program effectively modified three-dimensional knee kinematics and muscle activity during a COD task in under-16 female football players.

This study aimed to investigate the effect of the FIFA 11+ program on knee instability and motor performance in male youth soccer players. Thirty male youth soccer players were divided into two groups: the experimental group (FIFA+) performed the FIFA 11+ program for 10 weeks, while the control group followed their usual warm-up routine. Dynamic knee valgus (DKV) and squat depth were assessed using a Microsoft Azure Kinect camera and dynaknee software. Maximal isometric muscle force was measured with a dynamometer. The Y Balance test was used to evaluate dynamic balance, while a countermovement jump test assessed lower limb power. The knee range of motion was measured with a goniometer, and the t-test was used to evaluate agility. After the intervention, the FIFA+ group showed a significant decrease in DKV and squat depth (p < 0.05), while the control group showed no significant changes (p > 0.05). Both groups improved in motor performance, with slight progress noted in the FIFA+ group. However, neither group demonstrated significant improvement in dynamic balance (p > 0.05). While the FIFA 11+ program may not substantially enhance overall motor performance or match the effectiveness of other training regimens, it shows potential for addressing biomechanical deficiencies and reducing the risk of injuries, particularly those related to dynamic knee valgus.

Knee injuries are very common in soccer players. High loads on the knee during landing or changes of direction can lead to a valgus shift of the knee, known as Dynamic Knee Valgus (DKV). Many studies have shown that a large shift in DKV is a predisposing factor for knee injuries and disease, such as anterior cruciate ligament injury (ACL), patellofemoral pain syndrome or osteoarthritis. Functional training could be a great tool to reduce DKV. Thus, in this pilot study, nine male youth soccer players (mean age: 16.4 ± 0.2 years) took part in six weeks of functional training program. DKV was measured in pre- and post-measurements during single leg squats using Kinect Azure camera with DynaKnee software. In addition, maximal voluntary muscle contraction (MVC) was measured using a dynamometer and muscle activation amplitude (MAA) was measured using electromyography. Data were analysed using a non-parametric Wilcoxon signed rank test to assess differences in DKV, MAA and MVC at a 5% significance level. Data showed a small improvement of DKV in the dominant leg. MVC increased slightly in all variables. The MAA of the involved muscles in the single-leg squat did not show a higher value, but rather a decreasing trend. However, none of the analyses showed significant changes. The small number of participants and the short duration of the training might have been a limiting factor. Further studies should repeat the procedure with a larger group of participants and a longer training period.

This study investigates electromyography activation and force development differences in key lower limb muscles between female football players with previous anterior cruciate ligament injuries compared with healthy players. Twenty-two semi-professional players were divided into ACL-injured (n = 11) and non-injured groups (n = 11). Participants underwent maximal voluntary isometric contractions while electromyography activation, peak and average, and peak torque of force were measured. Results indicated significant differences in electromyography activation patterns between anterior cruciate ligament players and non-injured players, particularly in biceps femoris and gluteus maximus muscles. These differences were also evident when comparing between limbs within anterior cruciate ligament players. Interestingly, both groups exhibited similar peak torque of force during maximal contractions, suggesting a compensatory neuromuscular strategy that supports a return to sport based on kinetic and kinematic factors. However, these findings underscore persistent muscle integration imbalances potentially contributing to the high rate of anterior cruciate ligament reinjury. In conclusion, this study highlights the importance of evaluating electromyography activation alongside force development in understanding neuromuscular adaptations post anterior cruciate ligament injury. These insights emphasize the need for comprehensive rehabilitation strategies that address muscle imbalance to mitigate the risk of recurrent anterior cruciate ligament injuries in female football players.

Introduction: Professional athletes are endangered by COVID-19 and belong to the high-risk population due to their lifestyle. To obtain information on the behavior of COVID-19 in professional athletes, serological, cytokine, and virus neutralization capacities were analyzed. Materials and methods: Hungarian national teams participated in international sports events during the early phases of the COVID-19 epidemic in 2020. Altogether, 29 professional athletes volunteered to donate plasma. Their serological status was evaluated by IgA, IgM, and IgG ELISAs and the highest virus neutralization titer in an in vitro live tissue assay. Plasma cytokine patterns were analyzed with a Bioplex multiplex ELISA system. Results: Surprisingly, only one athlete (3%) had anti-SARS-CoV-2 IgG, while IgA was more common (31%). Neither plasma showed direct virus neutralization in a titer over 1:10; hence, they were not suitable for reconvalescent treatment. The ‘cytokine storm’ markers IL-6 and IL-8 were at baseline levels. In contrast, either the TNF-alpha-related cytokines or the IFN-gamma-associated cytokines were elevated. There was a strong negative correlation between the TNF-alpha- or IFN-gamma-related cytokines. Conclusions: Professional athletes are susceptible to the SARS-CoV-2 infection without developing long-term immunity through neutralizing immunoglobulins. Elevated secretory and cellular immunity markers indicate that these systems are probably responsible for virus elimination in this subpopulation.

Introduction and Aim: The pandemic Covid-19 imposes several difficulties to organize multi-day international sports events. This is - in part - due to the close physical contact among the athletes, known to promote the spread of virus, even in individual sports, such as wrestling. Thus, at the Wrestling Qualifier it was of utmost importance to introduce screening for the disease and exclude infected participants (and then isolate them). The medical team and the COVID Marshals worked together on developing a screening protocol and aimed to test the efficacy during this competition. Material and Methods: The event was attended by 281 competitors from 37 countries. The criteria to enter Hungary were a negative polymerase chain reaction (PCR) test, epidemiological and symptomatic negativity within 72 hours. We also performed Antigen rapid tests (ART, chromatographic immunoassay) and retesting if necessary. Upon departure a negative PCR test or a certificate issued after the end of the quarantine period was required. Results: In total, 1,287 PCR tests and 1,250 rapid tests were performed. At arrival, there were 21 PCR positive (1.4%) individuals, and they were quarantined. At the departure 6 PCR tests were positive (0.47%). One of the ARTs performed at the accreditation was positive. Conclusion: The medical staff has developed a successful protocol to screen for Covid-19 and isolate participants as indicated by the very low positivity for Covid-19 at departure. Thus such protocol can be used for organizing multi-day international sports events.