Purpose: Resistance to fatigue is a key factor in injury prevention that needs to be considered in return-to-sport (RTS) scenarios, especially after severe knee ligament injuries. Fatigue should be induced under game-like conditions. The SpeedCourt (SC) is a movement platform for assessing multidirectional sprint performance, typical of game-sports, due to change-of-direction movements in response to a visual stimulus. Designing adequate fatigue protocols requires the suitable arrangement of several loading variables such as number of intervals, sprint distance or work/relief ratio (W:R). Therefore, this study analysed the acute fatigue effects of different SC protocols on metabolic load, cognitive function and neuromuscular performance. Methods: Eighteen female soccer players (mean ± SD; age: 23.1 ± 4.6 years) of the 1st German Division participated in this randomised, crossover study. Using a random allocation sequence, players completed four volume-equated protocols differing in W:R and sprint distance per interval (P1:12 × 30 m, W:R = 1:2 s; P2:12 × 30 m, W:R = 1:3 s; P3:18 × 20 m, W:R = 1:2 s; P4:18 × 20 m, W:R = 1:3 s). Pre- and post-exercise, metabolic load was measured per blood lactate concentration (BLaC), cognitive function per reaction time (RT), and neuromuscular performance including multiple rebound jumps (MRJ height, primary outcome variable; Reactive Strength Index, RSI) and 5 m sprint times (SP5). Results: Repeated-measures ANOVA revealed significant main time effects (p < .05) with improved performance post-exercise in RT (504 vs. 482 ms, d = 1.95), MRJ height (24.0 vs. 24.8 cm, d = 0.77), RSI (1.39 vs. 1.43, d = 0.52), and SP5 (1.19 vs. 1.17 s, d = 0.56). There was significant main time (p < .001) and time x protocol interaction effects in BLaC (p < .001). P1 induced higher BLaC values (4.52 ± 1.83 mmol/L) compared to P2 (3.79 ± 1.83 mmol/L; d = 0.74) and P4 (3.12 ± 1.83 mmol/L; d = 1.06), whereas P3 (4.23 ± 1.69 mmol/L) elicited higher BLaC values compared to P4 (d = 0.74). Conclusion: All protocols caused an improved cognitive function and neuromuscular performance. The former may be related to enhanced noradrenergic activation or exercise specificity which induced an improved stimulus processing. The latter may be explained by a possible post-activation performance enhancement effect on jump and sprint performance. A shorter relief duration in W:R as opposed to sprint distance per interval produced higher BLaC values. The protocols may serve as reference data for improved RTS decision-making in elite female soccer players. Trial registration: Deutsches Register Klinischer Studien (DRKS), No.: DRKS00033496, Registered 19. Februar 2024, Retrospectively Registered.

Background: The lateral ankle sprain (LAS) is one of the most common injuries in everyday and sports activities. Approximately 20–40 % of patients with LAS develop a chronic ankle instability (CAI). The underlying mechanisms for CAI have not yet been clearly clarified. An inadequate rehabilitation after LAS can be speculated, since the LAS is often handled as a minor injury demanding less treatment. Therefore, the aims of this retrospective study were to determine the CAI rate depending on age and sex and to identify possible determinants for developing CAI. Methods: Between 2015 and 2018 we applied the diagnostic code “sprain of ankle” (ICD S93.4) to identify relevant cases from the database of the BG Klinikum Duisburg, Germany. Patients received a questionnaire containing the Tegner-Score, the Cumberland Ankle Instability Tool (CAIT) and the Foot and Ankle Disability Index. Additionally, there were questions about the modality and beginning of therapy following LAS and the number of recurrent sprains. There was a total of 647 completed datasets. These were divided into a CAI and non-CAI group according to a CAIT cut-off-score with CAI ≤ 24 and non-CAI > 24 points, representing one out of three criteria for having CAI based on international consensus. Results: The overall CAI rate was 17.3 %. We identified a higher CAI rate in females and within the age segment of 41 to 55 years. A later start of therapy (> 4 weeks) after acute LAS significantly increases ankle instability in CAIT (p < .05). There was a significantly higher CAIT score in patients having no recurrent sprain compared to patients having 1–3 recurrent sprains or 4–5 recurrent sprains (p < .001). Conclusions: Females over 41 years show a higher CAI rate which implies to perform specific prevention programs improving ankle function following acute LAS. A delayed start of therapy seems to be an important determinant associated with the development of CAI. Another contributing factor may be a frequent number of recurrent sprains that are also linked to greater levels of subjective ankle instability. Therefore, we would recommend an early start of functional therapy after acute LAS in the future to minimize the development of CAI.

Background/Objectives: Anterior cruciate ligament (ACL) injuries continue to present significant clinical and rehabilitative challenges. Despite advances in surgical techniques and rehabilitation protocols, persistent reinjury rates and increased pressure for early return to sport require a critical reassessment of current practices. This narrative review provides a comprehensive overview of the evolution, current standards, and future directions of ACL surgery and rehabilitation. Content: The literature search was conducted primarily in PubMed/MEDLINE and Web of Science using ACLRelated keywords, with emphasis on systematic reviews, randomized controlled trials, registry data, and consensus guidelines published within the past two decades. The evolution of ACL treatment is shaped by the transition from open to arthroscopic and anatomic reconstructions, as well as the refinement of fixation and augmentation techniques. In parallel, rehabilitation concepts shifted from rigid, time-based schedules to criteria-driven, individualized approaches. Key aspects include early mobilization, prehabilitation, and the integration of innovative tools such as anti-gravity treadmill and blood flow restriction training. Evidence on bracing suggests no routine benefit, while structured prevention programs have proven effective. Return-to-play strategies now emphasize objective functional criteria and psychological readiness. Conclusions: ACL therapy has evolved toward personalized, function-oriented rehabilitation. Future developments—including markerless motion analysis, AI-supported rehabilitation, and digital health applications promise for further individualization of care and optimization of long-term outcomes.

Background: The lateral ankle sprain (LAS) is the most common injury in the field of everyday and sports-related activities. There is a high rate of patients with LAS who will develop chronic ankle instability (CAI). A possible explanation for this high rate is an insufficient rehabilitation and/or a premature return to intense exercise and workloads. Currently, there are general rehabilitation guidelines for LAS but there is a lack of standardized evidenced-based rehabilitation concepts for LAS, which effectively reduce the high CAI rate. The primary aim of the study is to investigate the effectiveness of a 6-week sensorimotor training intervention (SMART-Treatment, SMART) in contrast to standard therapy (Normal Treatment, NORMT) after an acute LAS on perceived ankle joint function. Methods: This study will be a prospective, single-center, interventional randomized controlled trial with an active control group. Patients (14–41 years) with an acute LAS and a MRI confirmed lesion or rupture of at least one ankle ligament will be included. Exclusion criteria are acute concomitant injuries of the ankle, pre-injuries of the ankle, serious lower-extremity injuries of the last 6 months, lower-extremity surgery, and neurological diseases. The primary outcome measure will be the Cumberland Ankle Instability Tool (CAIT). Secondary outcomes include the Foot and Ankle Ability Measurement (FAAM), isokinetic and isometric strength diagnostics, joint repositioning sense, range of motion, measurements of postural control, gait and run analysis, and jump analysis. This protocol will follow the SPIRIT guidance. Discussion: Current management of LAS rehabilitation lacks since there is a high rate of patients developing a CAI. It has been shown that exercise therapy improves ankle function in acute LAS as well as in patients with CAI. It is further recommended to address specific impairment domains in ankle rehabilitation. However, empirical data for such a holistic treatment algorithm is missing. Therefore, this study has the potential to improve the healthcare for LAS patients and might be used for a future standardized evidence-based rehabilitation concept. Trial registration: “Prospectively registered” ISRCTN – ISRCTN13640422 17/11/2021; DRKS (German Clinical Trials Register) – DRKS00026049.

Background/Objectives: Anterior cruciate ligament (ACL) injuries continue to present significant clinical and rehabilitative challenges. Despite advances in surgical techniques and rehabilitation protocols, persistent reinjury rates and increased pressure for early return to sport require a critical reassessment of current practices. This narrative review provides a comprehensive overview of the evolution, current standards, and future directions of ACL treatment and rehabilitation. Additionally, we present original data evaluating the effectiveness of brace-free rehabilitation following ACL reconstruction (ACL-R). Methods: The review synthesizes developments in surgical techniques and rehabilitation strategies, including blood flow restriction training, anti-gravity treadmill use, and return-to-play criteria. Complementary to the literature, we report results from a controlled, longitudinal study (n = 137) comparing isokinetic strength and functional outcomes between brace-based and brace-free early rehabilitation after ACL-R using hamstring grafts. Results: The literature reflects a shift from time-based to criteria-driven rehabilitation, emphasizing individualization and functional readiness. Our original data revealed no significant differences in quadriceps and hamstring torque production between groups at 16, 26, and 52 weeks postoperatively. Statistical parametric mapping confirmed the non-inferiority of brace-free rehabilitation in terms of isokinetic performance. Conclusions: ACL therapy has evolved toward personalized, function-oriented rehabilitation. Our findings suggest that postoperative bracing may be unnecessary in many cases, supporting a more progressive approach. Future developments may include markerless motion analysis, AI-supported rehabilitation, and digital health tools to further individualize care.