Joint position sense (JPS) is the awareness of joint location in space, indicating accuracy and precision of the movement. Therefore, the aim of the present study is to determine the reliability of active and passive JPS assessment regarding the knee joint. This was carried out using the Luna EMG rehabilitation robot. Further analysis assessed whether the examination of only the dominant site is justified and if there are differences between sites. The study comprised 24 healthy male participants aged 24.13 ± 2.82 years, performing sports at a recreational level. Using the Luna EMG rehabilitation robot, JPS tests were performed for the right and left knees during flexion and extension in active and passive mode, in two separate sessions with a 1-week interval. Both knee flexion and extension in active and passive modes demonstrated high reliability (ICC = 0.866–0.982; SEM = 0.63–0.31). The mean JPS angle error did not differ significantly between the right and left lower limbs (p < 0.05); however, no between-limb correlation was noted (r = 0.21–0.34; p > 0.05). The Bland–Altman plots showed that the between-limb bias was minimal, with relatively wide limits of agreement. Therefore, it was concluded that the Luna EMG rehabilitation robot is a reliable tool for active and passive knee JPS assessment. In our study, JPS angle error did not differ significantly between left and right sides; however, the slight asymmetry was observed (visible in broad level of agreement exceeding 5° in Bland–Altman plots), what may suggest that in healthy subjects, e.g., active athletes, proprioception should always be assessed on both sides.

The Athletic Shoulder (ASH) test was introduced as a tool for quantifying the ability to produce and transfer force across the shoulder girdle. Whether using the portable isometric-based strength training device Active5™ is a reliable alternative to a gold standard force plate for ASH testing purposes remains unknown; therefore, the present study determined the reliability and validity of Active5™ usage in the ASH test compared to force plates. Fifty-one healthy participants performed the ASH test using Active5™ and K-Force plates in three separate sessions. The maximal force was measured bilaterally in a prone position at three shoulder abduction angles, precisely at 180°, 135°, and 90°. The first rater carried out the first and third sessions, spaced at a one-week interval. A second rater performed the second session. The reliability was assessed using the intraclass correlation coefficient (ICC). The linear Pearson’s correlation coefficient (r) calculation was used to determine the relationship between ASH test results using the two devices. The ICC = 0.77–0.99 result indicated good to excellent reliability for Active5™ usage. A high to a very high correlation between the two devices at 180° and 90° was noted (r = 0.75–0.95). This data supports the isometric-based strength training device Active5™ as a reliable and valid tool for ASH test performance.

This study aimed to develop and evaluate the reliability of a surface electromyography-based (sEMG) index to quantify knee muscle coactivation in healthy recreational athletes during the Lower Quarter Y-Balance Test (YBT-LQ). A prospective observational repeated measures design was used to assess both intra- and inter-rater reliability. Forty males completed three trials, with two raters independently conducting assessments. sEMG signals from the vastus medialis, vastus lateralis, biceps femoris, and semitendinosus muscles were collected to calculate four coactivation indices (CoAIs) for different muscle pairs. The reliability evaluation of these CoAIs was based on intraclass correlation coefficients. The results revealed that the reliability of the CoAIs varied depending on the muscle pair, direction, and limb examined. The highest intra- and inter-rater reliability was noted for the left lower limb in the posterolateral direction. The lowest reliability was found for the right lower limb in the anterior direction. Statistical analyses indicated significant differences in specific CoAIs across different YBT-LQ directions. These findings highlight the potential of sEMG-based CoAIs for assessing knee muscle activity during the YBT-LQ in healthy male recreational athletes. However, choosing CoAIs is critical for reliable clinical and research assessments of knee stability and neuromuscular control.

Introduction: The number of revision anterior cruciate ligament reconstruction (RACLR) procedures is increasing in proportion to the increase in the number of anterior cruciate ligament reconstruction (ACLR) procedures. Although approximately 50–75% of these procedures can be performed in a single-stage procedure, not all of them can. The choice of graft may influence the results of RACLR. The most commonly mentioned graft materials for RACLR are allografts and autografts. Background/Objectives: The aim of the study was to evaluate the results of single-stage RACLR using a semitendinosus (ST) autograft or allograft and to follow-up and compare the results of both groups after 2 years. Methods: The retrospective cohort study was carried out between 2008 and 2021, during which time 2327 ACLRs were performed. Graft rupture occurred in 198 (8.5%) patients, and 98 (4.2%) patients underwent RACLR. RACLR was performed as a single-stage procedure using a semitendinosus autograft or allograft in 56 patients. The KT-2000, Lachman and axis shift, range of motion, Tegner, Lysholm, KSS, KOOS, and IKDC tests were used to assess outcomes. Results: There were no differences between the groups in terms of age, time of revision after procedure, parameters for the graft (screw diameter, endobutton length, femoral tunnel length) or for the procedure and revision, BMI, or in the time needed for returning to dynamics and training. The groups did not differ in quality of life in any measurements, stiffness, pain function, or sport. Analysis showed higher Lysholm results on the day of treatment in the autograft group than in the allograft group (p = 0.11). The allograft group had higher KSS scores on the day of treatment (p = 0.11) and after 60 months or at the moment of breakup than the autograft group (p = 0.025). Conclusions: Single-stage revision anterior cruciate ligament reconstruction with an autograft and ST provides good knee stability. The results of single-stage revision anterior cruciate ligament treatment using an ST autograft or an ST allograft are similar.

Background: A comprehensive rehabilitation program is recommended following anterior cruciate ligament reconstruction (ACLR) to restore function, strength and lower limb stability. Despite advancements in surgical techniques, high reinjury rates highlight the need to refine rehabilitation strategies. This study investigates performance across various physically demanding tasks and compares outcomes between the injured and uninjured leg, using a modified Back in Action (BIA) test battery. It is hypothesized that due to test learning effects patients exhibit faster improvement in coordinatively demanding tasks compared to strength-related tasks. Methods: Thirty-two patients (aged 18–40) following primary unilateral ACLR participated in a prospective cross-sectional study within the context of a larger trial. Participants completed a modified BIA test battery, including stability, countermovement jump (CMJ), drop landing, speedy jumps, and quick-feet test (QFT). Each test was conducted in three sets, with three immediate repetitions. Self-reported outcomes were also collected. Results: Patients showed significant within-session improvements in coordinative tasks, with 32% in the injured and 26% in the uninjured limb during the speedy jumps [p < 0.05]. No significant learning effects were observed in strength-related tasks (drop landing, stability test, CMJ). Patients with lower baseline performance exhibited greater improvement than patients with higher performance level from baseline. Furthermore, a correlation between self-assessed abilities and actual performance was identified. Conclusions: This study showed that improvement of coordinative tasks after Return to Sport (RTS) testing of ACLR patients are rather affected by test learning effects. In contrast, this phenomenon is not seen in strength-related tasks. Rehabilitation programs should integrate both types of exercises while considering individual baseline abilities. Tailoring rehabilitation to individual needs, establishing sport-specific rehabilitation programs and incorporating self-assessment tools can enhance patient-centered care and reduce reinjury risks.