Search Results (357)

Genu valgum (GV) is a common lower limb deformity that may increase the risk of anterior cruciate ligament (ACL) injury. This study used OpenSim musculoskeletal modeling and kinematic analysis to investigate the mechanical responses of the ACL under fatigue in females with GV. Eight females with GV and eight healthy controls completed a running-induced fatigue protocol. Lower limb kinematic and kinetic data were collected and used to simulate stress and strain in the anteromedial ACL (A–ACL) and posterolateral ACL (P–ACL) bundles, as well as peak joint angles and knee joint stiffness. The results showed a significant interaction effect between group and fatigue condition on A–ACL stress. In the GV group, A–ACL stress was significantly higher than in the healthy group both before and after fatigue (p < 0.001) and further increased following fatigue (p < 0.001). In the pre-fatigued state, A–ACL strain was significantly higher during the late stance phase in the GV group (p = 0.036), while P–ACL strain significantly decreased post-fatigue (p = 0.005). Additionally, post-fatigue peak hip extension and knee flexion angles, as well as pre-fatigue knee abduction angles, showed significant differences between groups. Fatigue also led to substantial changes in knee flexion, adduction, abduction, and hip/knee external rotation angles within the GV group. Notably, knee joint stiffness in this group was significantly lower than in controls and decreased further post-fatigue. These findings suggest that the structural characteristics of GV, combined with exercise-induced fatigue, exacerbate A–ACL loading and compromise knee joint stability, indicating a higher risk of ACL injury in fatigued females with GV. Full article

Quadricep weakness is frequently observed in patients following anterior cruciate ligament (ACL) injury or in those with knee osteoarthritis, often contributing to functional impairments and persistent symptoms. While high-intensity resistance training has been shown to effectively improve muscle strength, its application may be limited in certain populations due to pain or the risk of surgical complications. In recent years, blood flow restriction (BFR) training has emerged as a promising alternative. Growing evidence indicates that low-load BFR exercise can significantly improve muscle strength, induce hypertrophy, and enhance knee function, with outcomes comparable to those of high-intensity resistance training. When implemented using appropriate protocols, BFR training appears to be a safe and efficacious rehabilitation strategy for individuals with knee pathology. Full article

Background: The incidence of anterior cruciate ligament ruptures in football has experienced a marked increase in recent years, affecting both professional and amateur players. This injury is characterised by being highly disabling, causing the player to withdraw from the field of play for prolonged periods and there is no clear consensus on how to carry out the different phases of rehabilitation, which poses a major challenge for health professionals. Case presentation: This study followed a semi-professional player who suffered an anterior cruciate ligament tear following two forced valgus actions without direct contact in the same match. Outcome and follow-up: The patient underwent surgery using an autologous hamstring graft. He followed a progressive rehabilitation programme consisting of one preoperative phase and six phases after the operation. After a 12-month follow-up, with exercises aimed at perfecting step-by-step basic and specific physical skills, the player showed a complete functional recovery, achieving the desired parameters. Conclusions: This case highlights the importance of structured rehabilitation adapted to the specific needs of the football player through an approach with coherent progressions, which considers the muscle chains that determine the movements performed on the football pitch. Full article

Background and Objectives: Anterior cruciate ligament (ACL) injury rates remain high and have a significant impact on female football players. This study aims to evaluate knee kinematics and lower limb muscle activity in players at risk of ACL injury compared to healthy players through three side-cutting tests. It also investigates how the amplitude of a change in direction influences stabilization parameters. Materials and Methods: A cross-sectional case–control study was conducted with 16 second division female futsal players (23.93 ± 5.16 years), divided into injured (n = 8) and healthy groups (n = 8). Injured players had a history of non-contact knee injury involving valgus collapse, without undergoing surgical intervention. Three change of direction tests, namely the Change of Direction and Acceleration Test (CODAT), Go Back (GOB) test, and Turn (TURN) test, were used for evaluation. The peak and range of knee joint angles and angular velocities across three planes, along with the average rectified and peak envelope EMG signals of the Biceps Femoris (BF), Semitendinosus (ST), Vastus Medialis (VM), and Lateral Gastrocnemius (LG), were recorded during the preparation and load phases. Group differences were analyzed using two-factor mixed-model ANOVA with pairwise comparisons. Statistical significance was set at p < 0.05. Results: Injured players demonstrated lower external tibial rotation angular velocity and a greater range of motion in tibial external rotation compared to healthy players. Additionally, the injured group showed significantly higher average rectified muscle activity in VM and LG both increased by 4% during the load phase. The CODAT and TURN tests elicited higher BF and VM muscle activity, compared to the GOB test. The TURN test also showed greater extension angular velocity in the sagittal plane. Conclusions: The results revealed differences in knee kinematics and muscle activity between players at risk of ACL injury and healthy players, influenced by the amplitude of directional changes. Players altered transverse plane mechanics and increased VM and LG activation during LOAD may reflect a dysfunctional motor pattern, while the greater sagittal plane angular velocity and VM and BF activation from the CODAT and the TURN test highlight their higher potential to replicate ACL injury mechanisms compared to the GOB test. Full article

Anterior cruciate ligament (ACL) injury (ACLI) is a prevalent sports injury. Genetic factors play a crucial role in determining the risk of ACLI. This systematic review aimed to identify the association between the COL5A1 rs13946 polymorphism and susceptibility to ACLI. Methods: Searches were performed in PubMed Central, Web of Science, EBSCOhost, Scopus, and CNKI. The Newcastle–Ottawa Scale (NOS) was used to assess potential bias, and data from the included studies were analyzed using RevMan 5.4. The odds ratio (OR) and 95% confidence intervals (95% CI) were calculated to determine the strength of the association between COL5A1 rs13946 and the risk of anterior cruciate ligament injury. A p value < 0.05 was considered statistically significant. Seven studies met the inclusion criteria for screening the association between COL5A1 rs13946 and ACL injury and were included in this meta-analysis. The meta-analysis revealed no significant heterogeneity across five genetic models. Statistically significant findings were observed in the recessive (OR = 1.29, 95% CI [1.06, 1.58], p = 0.01) and allele models (OR = 0.85, 95% CI [0.73, 1.00], p = 0.04). The TT genotype or T allele of rs13946 showed a distinct susceptibility to ACLI under the recessive model, particularly in Caucasians. This study supports the association between COL5A1 rs13946 and the risk of ACLI, particularly in Caucasians. More specifically, the C/- genotype of rs13946 provides protection against ACLI in Caucasians. Further research with larger sample sizes and well-balanced gender-specific cohorts is necessary to validate this association and strengthen our findings. Full article

Youth sport participation provides undeniable physical, emotional, and social benefits. However, the current landscape of pediatric athletics has shifted toward early sports specialization (ESS), year-round training, and heightened competitive pressures. This has led to an increased prevalence of overuse-related traumatic injuries in adolescent patients, as well as increased risk of worsening mental health due to burnout, depression, suicide, and general psychological distress. There are numerous innovations and solutions aimed at addressing the increased risk of injury associated with current sporting trends, such as neuromuscular training programs, delayed specialization, promotion of free play, and pediatric specific surgical techniques mindful of future growth, such as those seen for anterior cruciate ligament reconstruction (ACL-R). However, the social factors associated with an injury remain problematic and are not adequately addressed; these include social isolation, depression, anxiety, and academic decline. Sport psychology is a promising solution to address many risk factors associated with poor performance, address the challenges associated with injury, and increase return-to-play in adolescent sports medicine. Integrating sport psychology into pediatric sports medicine offers the ability to directly address the emotional and cognitive demands of injury and recovery. Emphasizing mental health support and redefining success in youth sports—prioritizing enjoyment, personal growth, and long-term health over scholarships and professional aspirations—are key steps in preserving the overall benefits of pediatric sport participation. Yet sport psychology remains often underutilized and has been slow to gain traction, particularly in youth sports. This editorial serves to highlight the current state of mental health advocacy in pediatric sports medicine and how sport psychology can help young athletes manage the mental stress of high-performance athletics and mitigate the detrimental effect of injury and delayed return to sport. Full article

The knee is one of the most frequently injured joints, involving various structures. To prevent reinjury after rehabilitation, braces are commonly used. However, most studies on knee supports focus on subjects with anterior cruciate ligament (ACL) injuries and do not account for muscle fatigue, which typically occurs during prolonged intense training and can significantly increase the risk of injury. Hence, this study investigates the acute effects of wearing a knee brace on biomechanics in subjects with a history of various unilateral knee injuries or pain under muscle fatigue. In total, 50 subjects completed an intense fatigue protocol and then performed counter-movement jumps and running tests on a force plate while tracking kinematics with a marker-based 3D motion analysis system. Additionally, subjects filled out a visual analog scale (VAS) to assess knee pain and stability. Tests were conducted on the injured leg with and without a knee brace (Sports Knee Support, Bauerfeind AG, Zeulenroda-Triebes, Germany) and on the healthy leg. Results indicated that wearing the knee brace stabilized knee movement in the frontal plane, with a significant reduction in maximal medio-lateral knee acceleration and knee abduction moment during running and jumping. The brace also normalized loading on the injured leg. We observed higher maximal knee flexion moments, which were associated with increased vertical ground reaction forces, segment velocities, and knee flexion angles. Subjects reported less pain and greater stability while wearing the knee brace. Therefore, we confirm that wearing a knee brace on the injured leg improves joint biomechanics by enhancing stability and kinematics and reducing pain during running and jumping, even with muscle fatigue. Consequently, wearing a knee brace after a knee joint injury may reduce the risk of reinjury. Full article

Background: Anterior cruciate ligament (ACL) injury is more prevalent in young athletes and women. A deficit of knee flexor strength and a H/Q strength ratio below 0.6 in athletes are risk factors. Therefore, the main objective of this study is to determine if there are differences in the strength of the knee musculature, joint work, and H/Q ratio between professional and junior elite basketball players and sexes, since there are differences in the incidence of ACL injuries between these groups. Methods: Forty-three professional (27 male and 16 female) and 42 junior elite (28 male and 14 female) basketball players were evaluated. Dynamometric knee flexion and extension measurements were performed on both lower limbs at three angular velocities: 30°/s, 120°/s, and 180°/s. Concentric knee flexion and extension strength variables were measured in Newtons, the strength ratio between flexors and extensors in H/Q ratio, and muscle work (product of force times displacement) in Joules. Comparisons of the measured variables were made between categories and sexes. Results: Significant differences (p < 0.05) were found between categories (professional and junior) in all measured strength parameters as well as in joint work. No differences were found between categories in the H/Q ratios. Significant differences (p < 0.05) were found between sexes in most measured strengths and joint work. However, no differences were found in most of the H/Q ratios. Female basketball players have lower values of strength and muscle work than male players, however, in the H/Q ratio data there are no differences between the two groups. The same occurs between junior and professional athletes. Conclusions: The authors conclude that flexor and extensor strength values should be analyzed in isolation and not in terms of the H/Q ratio. Full article

Background: Previous studies have tested the association between the COL5A1 rs12722 polymorphism and the risk of anterior cruciate ligament (ACL) injury. Overall, their results are contradictory because most studies used relatively small samples and data from ACL ruptures during sport activities have been mixed with ruptures suffered in non-sporting contexts. Objective: To examine the association between the COL5A1 rs12722 polymorphism and the prevalence of ACL rupture in a homogeneous sample of professional male football players. Methods: A total of 268 professional male football players participated in this study. The COL5A1 rs12722 genotype (CC, CT and TT) was obtained from each player using genomic DNA samples obtained from a buccal swab and measured with PCR RFLP. Players with history of ACL rupture during their professional career were identified by the medical staff of each team. Only ACL injuries obtained during football exposure were considered for this investigation. In this process, we identified 49 ACL ruptures pertaining to 43 players suffered between 2013 and 2024. The situational pattern (i.e., attacking or defending, type of football action, moment of the season, match/training exposure, etc.) was also obtained for each injury. A sub-analysis of non-contact ACL ruptures was conducted, as these injuries are more likely to be influenced by genetic factors. Results: The distribution of genotypes was similar in players with history of ACL rupture (n = 43; CC/CT/TT, 24.4/48.9/26.7%) and with no history of ACL rupture (n = 225; 25.3/49.8/24.9%; p = 0.973). Overall, the prevalence of players with history of ACL injury was 16.2% for the whole group of CC players (11 out of 68 players), 16.4% for whole group of CT (22 out of 135 players) and 15.2% for the group of TT players (10 out of 66 players; p = 0.973). However, the COL5A1 rs12722 genotype affected the dominance of the injured leg (p = 0.012), the type of action that originated the injury (p = 0.047), and the distribution of non-contact ACL injuries depending on the time of the match (p = 0.020). Specifically, CC players suffered ruptures predominantly in the dominant leg, when landing or reaching (offensive actions) and in the last 15 min of the match (all p < 0.050). On the contrary, TT players had ACL ruptures predominantly in their non-dominant leg, when pressing the opponent (defensive actions) and in the first 15 min of the match (all p < 0.050). Conclusion: There was no association between any of the COL5A1 rs12722 genotypes and the overall prevalence of ACL rupture in professional football players. However, the COL5A1 rs12722 polymorphism appeared to influence specific characteristics of the injury, such as the type of action leading to the rupture and the timing within the match, suggesting a potential genetic contribution to injury susceptibility. Full article

Background: Anterior cruciate ligament (ACL) rupture is one of the most common injuries in playing rugby. The aim of this study was to assess the effect of a custom-designed training program on changes in dynamic knee valgus angle (DKV) and Reactive Strength Index (RSI), which are the main risk factors, in a group of female Rugby-7 players. Methods: A total of 16 professional Rugby-7 players completed an 8-week KAT program intervention, which was incorporated twice a week throughout this time. In both the pre- and post-tests, dynamic knee valgus was assessed during the drop jump (DJ) test using the frontal plane projection angle (FPPA) method. The jumps were analyzed using Dartfish 2024 software. Results: The post-tests revealed an increase in RSI values (p = 0.0496; SD = 1.25 ± 0.44 vs. 1.40 ± 0.35) and a reduction in valgus of the left knee joint (p = 0.01; SD = 9.08 ± 11.86 vs.0.00 ± 7.42). The correlation between RSI and the valgus angle produced inconclusive results (rs = −0.69; p < 0.01; rs = −0.35; p = 0.25; rs = −0.38; p = 0.2; rs = −0.2; p = 0.51). Cohen’s d = −0.37964. Conclusions: The training program proved effective in improving RSI scores and reducing the valgus angle of the left lower limb, which functioned as the supporting leg. These findings potential KAT implementation as a warm-up routine in professional women’s rugby clubs. Full article

Objectives: Osteoarthritis (OA) is a prevalent chronic degenerative joint disorder marked by cartilage degradation, subchondral bone remodeling, and synovial inflammation. Despite its widespread occurrence, effective pharmacological interventions to halt or reverse OA progression remain elusive. Thus, an in-depth understanding of its pathogenesis is imperative for developing novel therapeutic strategies. Methods: Sixty-four male Sprague-Dawley rats (8 weeks old, weighing 180–220 g) were randomly assigned to two groups: the anterior cruciate ligament transection (ACLT) group and the sham-operated group. Primary osteoblasts were isolated from the subchondral bone at 0, 4, 8, and 12 weeks after ACLT. Nuclear magnetic resonance (NMR)-based metabolomics was used to elucidate metabolic changes and the underlying mechanisms in osteoblasts. Results: A total of 26 metabolites were identified from the NMR spectra of osteoblasts. Distinct metabolic profiles were observed in the ACLT group at 0, 4, 8, and 12 weeks after surgery. In particular, several differential metabolites were identified, including glucose, lactate, NADP⁺, phosphocreatine, and alanine, as well as eight perturbed pathways, such as alanine, aspartate, and glutamate metabolism, phenylalanine metabolism, and taurine metabolism. Conclusions: Key energy-related metabolites, including glucose, lactate, creatine phosphate, and creatine, were identified as key markers of osteoblast dysfunction in OA, underscoring the profound metabolic perturbations induced by ACL injury. These disturbances in energy homeostasis are strongly implicated in the progression of OA. In addition, branched-chain amino acids emerged as potential biomarkers, further highlighting the metabolic dysregulation associated with the disease. Taken together, the metabolic changes observed in rat osteoblasts following ACL injury reveal a complex interplay between energy and amino acid metabolism, providing critical insights into the pathogenesis of post-traumatic OA and highlighting potential therapeutic targets. Full article

Background/Objectives: This retrospective study aimed to evaluate whether PRP infiltrations improve quadriceps muscle strength recovery following anterior cruciate ligament reconstruction (ACLR), while minimizing the recovery time required to resume daily activities and sports. Numerous studies have explored the use of platelet-rich plasma (PRP) in treating ACL injuries. PRP therapy has demonstrated high efficacy in accelerating ligament healing in animal models. However, clinical trials involving human participants have reported inconsistent results regarding the effects of PRP on ACL reconstruction outcomes. Methods: Between 2020 and 2024, a total of 68 subjects who underwent ACLR were included in the study. Participants were divided into two groups, namely a treatment group that followed a standard rehabilitation protocol and received PRP infiltrations, and a control group that followed the same protocol without PRP treatment. Muscle strength was assessed using the isometric max strength balance (IMSB) test and the concentric max strength balance (CMSB) test, both performed using the Kineo Intelligent Load device (Globus Kineo 7000, Italian Excellence, Rome, Italy). Results: The results of IMSB test showed a significant difference between treatment groups according to a two-way ANOVA test (F(1, 198) = 7.345; p = 0.0073). The PRP-treated group showed significantly higher quadriceps muscle strength at 6 months (34.9 ± 9.6 vs. 30.0 ± 8.2 kg). The CMSB test also showed a significant difference at 6 months (F(1, 198) = 5.976; p = 0.00154), with the PRP-treated group having significantly higher concentric muscle strength (35.5 ± 9.5 vs. 30.7 ± 8.5 kg). Conclusions: These findings suggest that post-ligamentoplasty PRP infiltrations may have beneficial effects on muscle strength recovery. However, further prospective studies with larger sample sizes are necessary to confirm these results. Full article

This study aimed to analyze the biomechanical differences in knees that underwent reconstruction using four-strand hamstring or bone–patellar tendon–bone autografts during the side-hop test. This case–control study included 46 participants: 18 controls, and 28 individuals who underwent reconstruction with hamstring (n = 15) or patellar (n = 13) tendons. The Theia Markerless system and Visual3D provided information on knee kinematics, namely time of contact with the ground, maximum varus and valgus angles, and flexion during maximum valgus and varus. Additionally, we assessed the activity levels of the participants pre- and post-surgery using the Tegner Activity Scale. Data analysis was conducted using ANOVA and Tukey’s post hoc test. Significant differences were observed in terms of contact time with the ground between the control and autograft groups (p = 0.025, g = −1.13; p = 0.014, g = −1.09), but not between the autograft groups. Other variables did not demonstrate statistically significant differences; however, there was a slight tendency to greater valgus in patellar autografts and greater varus with hamstring tendons. The absence of significant differences between the groups may indicate that both autografts allow knee kinematics restoration by engaging neuromuscular and proprioceptive mechanisms that compensate for anatomical alterations. Full article

Background/Objectives: The number of systematic reviews evaluating the incidence of anterior cruciate ligament (ACL) injuries in sports is increasing. To synthesize pooled incidence and prevalence rates of sport-related ACL injuries based on published systematic reviews with meta-analyses. Methods: An overview of systematic reviews with meta-analysis was conducted. The CINAHL, Embase, PubMed, and SPORTDiscus databases were searched from inception to 17 October 2023. AMSTAR 2 was used to assess the methodological quality of reviews. The degree of overlap between reviews was calculated when possible. Results: Seven systematic reviews including 51 meta-analyses of interest were included. The prevalence of ACL injuries was not meta-analyzed. Meta-analyses mainly showed that ACL injuries may have a high incidence in American football, basketball, European football/soccer, and volleyball, among other sports. In addition, ACL injuries may have a higher incidence in females than males in some sports. For example, the pooled incidence rates of ACL injuries in basketball ranged from 0.091 (95%CI, 0.074–0.111) to 0.110 (95%CI, 0.094–0.128) among female athletes, whereas this incidence ranged from 0.024 (95%CI, 0.016–0.034) to 0.027 (95%CI, 0.019–0.035) among male athletes. Conclusions: Sport-related ACL injuries may have a high incidence in sports such as American football, basketball, European football/soccer, or volleyball and show differences between sexes. Therefore, a sex-specific prevention of these injuries may be needed. Full article