(1) Dynamic knee valgus is a predisposing factor for anterior cruciate ligament rupture and osteoarthritis. The single-leg squat (SLS) test is a widely used movement pattern test in clinical practice that helps to assess the risk of lower-limb injury. We aimed to quantify the SLS test using a marker-less optical system. (2) Kinect validity and accuracy during SLS were established by marker-based OptiTrack and MVN Xsens motion capture systems. Then, 22 individuals with moderate knee symptoms during sports activities (Tegner > 4, Lysholm > 60) performed SLS, and this was recorded and analyzed with a Kinect Azure camera and the Dynaknee software. (3) An optical sensor coupled to an artificial-intelligence-based joint recognition algorithm gave a comparable result to traditional marker-based motion capture devices. The dynamic valgus sign quantified by the Q-angle at the lowest point of the squat is highly dependent on squat depth, which severely limits its comparability among subjects. In contrast, the medio-lateral shift of the knee midpoint at a fixed squat depth, expressed in the percentage of lower limb length, is more suitable to quantify dynamic valgus and compare values among individual patients. (4) The current study identified a new and reliable way of evaluating dynamic valgus of the knee joint by measuring the medial shift of the knee-over-foot at a standardized squat depth. Using a marker-less optical system widens the possibilities of evaluating lower limb functional instabilities for medical professionals.

Article: Dynamic valgus knee revealed with single leg jump tests in soccer players - The Journal of Sports Medicine and Physical Fitness 2023 March;63(3):461-70 - Minerva Medica - Journals

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.

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.

Összefoglalás. A fizikai képességek magas színvonala nélkülözhetetlen a hon- és rendvédelmi szervek személyi állományának tagjai számára. A hadrafoghatóság, bevethetőség alapvető feltétele a fizikai, mozgásszervi egészség és edzettség megléte. Az állomány felmérésére jelenleg alkalmazott fizikai tesztelési eljárások a sérülések megelőzésére, a teljesítmény optimalizálására kevésbé alkalmasak, pedig a hosszú távon fenntartható magas szintű teljesítmény a szervezeti hatékonyság és a produktivitás kulcseleme. A hon- és rendvédelmi területen dolgozó szakemberek kiképzési, oktatási költsége jelentős anyagi ráfordítás mellett valósítható meg, így a sérüléseik megelőzése, fizikai alkalmasságuk fenntartása igen fontos feladat. Külföldi példák alapján a biomechanikailag helytelen mozgások kiszűrése hozzájárul a sérülések megelőzéséhez. Summary. High level of physical fitness is an essential requirement towards the members of armed forces, firefighters, law enforcement services and other government services. Physical condition assessment is routinely used to determine operational readiness of these units, however, these routine tests are not suited for injury prevention. A musculoskeletal disorder, or injury can negatively influence the success of the mission and cause a long-term disability and inefficient productivity. Therefore, specific tests are required to measure musculoskeletal properties which play a significant role in the mechanisms of injury in order to screen potential injury and apply preventive measures. Several countries apply movement analysis tests and functional movement screening for their armed forces. These tests can efficiently predict the possibility of musculoskeletal injuries, thus keep soldiers in service. In most cases at the operational level specific positions mandate special physical requirements from the subjects. Task-specific testing methods provide a comprehensive report about the subjects’ current physical state. Our research team have previously developed a user-friendly, simple and cost -effective movement analysis system that can monitors and records the subjects’ movements with artificial intelligence-based Kinect Azure camera without any markers, which enables state of the art measurement, documentation and can avoid subjective evaluation or conformation bias. This method is able to provide a biomechanical report about the subject during key movement patterns such as walking, running, jumping, or squatting. The system can detect the incorrect and the well-executed technics. A corrective treatment plan is also provided if sub-optimal movement patterns are recognized. During musculoskeletal rehabilitation there is a need for objective testing and retesting in order to provide optimal quantity and quality of training loads to avoid further injury. Repeated testing provides feedback about successful rehabilitation process.