Search Results (138)

Rehabilitation devices such as actuated lower-limb exoskeletons can provide essential mobility assistance for pediatric patients with gait impairments. Enhancing their control systems under conditions of user variability and dynamic disturbances remains a significant challenge, particularly in active-assist modes. This study presents a human-in-the-loop control architecture for a pediatric lower-limb exoskeleton, combining outer-loop admittance control with robust inner-loop trajectory tracking via a non-singular terminal sliding-mode (NSTSM) controller. Designed for active-assist gait rehabilitation in children aged 8–12 years, the exoskeleton dynamically responds to user interaction forces while ensuring finite-time convergence under system uncertainties. To enhance adaptability, we augment the inner-loop control with a twin delayed deep deterministic policy gradient (TD3) reinforcement learning framework. The actor–critic RL agent tunes NSTSM gains in real-time, enabling personalized model-free adaptation to subject-specific gait dynamics and external disturbances. The numerical simulations show improved trajectory tracking, with RMSE reductions of 27.82% (hip) and 5.43% (knee), and IAE improvements of 40.85% and 10.20%, respectively, over the baseline NSTSM controller. The proposed approach also reduced the peak interaction torques across all the joints, suggesting more compliant and comfortable assistance for users. While minor degradation is observed at the ankle joint, the TD3-NSTSM controller demonstrates improved responsiveness and stability, particularly in high-load joints. This research contributes to advancing pediatric gait rehabilitation using RL-enhanced control, offering improved mobility support and adaptive rehabilitation outcomes. Full article

Total Knee Arthroplasty (TKA) is a well-established surgical intervention for the management of end-stage knee osteoarthritis. While the procedure is generally successful, postoperative rehabilitation remains a key determinant of long-term functional outcomes. Traditional rehabilitation protocols, particularly those requiring in-person clinical visits, often encounter limitations in accessibility, patient adherence, and personalization. In response, emerging sensor technologies have introduced innovative solutions to support and enhance recovery following TKA. This review provides a thematically organized synthesis of the current landscape and future directions of sensor-assisted rehabilitation in TKA. It examines four main categories of technologies: wearable sensors (e.g., IMUs, accelerometers, gyroscopes), smart implants, pressure-sensing systems, and mobile health (mHealth) platforms such as ReHub^® and BPMpathway. Evidence from recent randomized controlled trials and systematic reviews demonstrates their effectiveness in tracking mobility, monitoring range of motion (ROM), detecting gait anomalies, and delivering real-time feedback to both patients and clinicians. Despite these advances, several challenges persist, including measurement accuracy in unsupervised environments, the complexity of clinical data integration, and digital literacy gaps among older adults. Nevertheless, the integration of artificial intelligence (AI), predictive analytics, and remote rehabilitation tools is driving a shift toward more adaptive and individualized care models. This paper concludes that sensor-enhanced rehabilitation is no longer a future aspiration but an active transition toward a smarter, more accessible, and patient-centered paradigm in recovery after TKA. Full article

Background/Objectives: Patellar instability in adolescents is a significant cause of short- and long-term morbidity and disability. Traditionally, patients with first-time patellar dislocation are managed nonoperatively, although most studies are not focusing on the adolescent athletic population. The primary objective of the current study was to compare patient-reported outcomes and complications in adolescent athletes who underwent surgery either after the first patellar dislocation or after the recurrence of the dislocation with a minimum postoperative follow-up of 48 months (48–75 months). Methods: A total of 39 adolescent athletes who underwent medial patellofemoral ligament (MPFL) reconstruction (Group A, after the first dislocation, and Group B, recurrent patella dislocation) were included in this study. In all the patients, the same MPFL reconstruction technique was applied using a semitendinosus autograft. The graft was fixed on the patella using a transverse tunnel and adjustable loop button fixation and, in the femur, using a tunnel and absorbable screw fixation. The tunnel was drilled obliquely to prevent penetration of the distal femoral physis. The preoperative and postoperative clinical and functional evaluations of the patients were conducted via the visual analog scale (VAS), the Lysholm Knee Scoring System, the Kujala Anterior Knee Pain Scale, and the Pediatric International Knee Documentation Committee (Pedi-IKDC), and the return to sports score was assessed via the Tegner Activity Scale (TAS). Results: At the latest follow-up, both groups demonstrated significant improvement in the Lysholm scores, with Group A achieving a mean of 92.57 ± 6.21 and Group B achieving a mean of 90.53 ± 8.21 (p = 0.062). Postoperatively, Group A achieved a mean Kujala score of 94.21 ± 9.23, whereas Group B reached 92.76 ± 12.39, with no statistically significant difference (p = 0.08). The Pedi-IKDC score improved postoperatively in both groups. In Group A, it increased from 67.98 ± 12.29 to 93.65 ± 4.1, and in Group B, from 56.21 ± 13.6 to 91.67 ± 6.21 (p = 0.067). The preoperative visual analog scale (VAS) score for pain was significantly lower in Group A (3.1 ± 1.13) than in Group B (4.2 ± 3.01, p < 0.01). At the latest follow-up, the VAS scores improved in both groups, with Group A reporting a mean score of 0.47 ± 1.01 and Group B 0.97 ± 1.32 (p = 0.083). The Tegner activity scores were similar between the groups preoperatively, with Group A at 7.72 ± 1.65 and Group B at 7.45 ± 2.09 (p = 0.076). Postoperatively, Group A had a mean score of 7.28 ± 2.15, whereas Group B had a mean score of 6.79 ± 3.70 (p = 0.065). The mean time to return to sports was significantly shorter in Group A (5.1 ± 1.3 months) than in Group B (7.6 ± 2.1 months) (p < 0.01). Overall, 84.61% of the patients returned to their previous activity level. Specifically, 95.2% (20/21) of patients in Group A achieved this outcome, whereas 72.22% (13/18) achieved it in Group B. Patient satisfaction was generally high, with 76% (16/21) of patients in Group A reporting being satisfied or very satisfied, compared with 77% (14/18) in Group B. Conclusions: MPFL reconstruction is a safe and effective procedure for both acute and recurrent patellar dislocation in adolescent athletes. While patients who underwent acute reconstruction returned to sport more quickly and showed higher absolute postoperative scores, the greatest overall improvement from preoperative to final follow-up was observed in those treated for recurrent instability. Both surgical approaches demonstrated high satisfaction rates and minimal complications, supporting MPFL reconstruction as a reliable option in both acute and recurrent cases. Full article

Background and Objectives: This study aims to investigate the relationship between isokinetic knee strength and competition performance in elite male ski mountaineering sprint athletes and to identify strength parameters that predict performance and contribute to injury prevention. Materials and Methods: Thirteen male athletes participating in the Ski Mountaineering Turkey Cup final stage were included. Isokinetic knee flexion (FLX) and extension (EXT) strength of dominant (DM) and non-dominant (NDM) legs were measured at angular velocities of 60°/s and 180°/s using the DIERS-Myolin Isometric Muscle Strength Analysis System. Competition performance was evaluated using the ISMF scoring system. Data were analyzed using SPSS 26.0 with Pearson correlation and multiple regression analyses after normality, linearity, and homoscedasticity checks. Results: Strong positive correlations were found between hamstring strength at high angular velocities (180°/s) and performance (DM FLX: r = 0.809; NDM FLX: r = 0.880). Extension strength showed moderate correlations at low velocities (60°/s) (DM EXT: r = 0.677; NDM EXT: r = 0.699). Regression analysis revealed that DM FLX at 180°/s and DM EXT at 60°/s explained 49% of performance variance (Adj. R² = 0.498). For NDM legs, only 180°/s FLX was a significant predictor (β = 1.468). Conclusions: High-velocity hamstring strength plays a critical role in ski mountaineering sprint performance, particularly during sudden directional changes and dynamic balance. Quadriceps strength at low velocities contributes to prolonged climbing phases. Moreover, identifying and addressing bilateral strength asymmetries may support injury prevention strategies in elite ski mountaineering athletes. These findings provide scientific support for designing training programs targeting explosive hamstring strength, bilateral symmetry, and injury risk reduction, essential for optimizing performance in the 2026 Winter Olympics sprint discipline. Full article

Background/Objectives: Prolonged sitting is linked to musculoskeletal discomfort, yet optimal sitting posture remains poorly defined, and the consistency with which individuals reproduce specific sitting strategies is unclear. This study examined postural variability across three sitting strategies—comfortable, habitual, and correct—using three common chair types: a stool, computer chair, and ergonomic chair. Methods: Thirty healthy young adults (fifteen men, fifteen women) participated. Global sagittal joint angles—head inclination (HI), trunk angle (TA), and knee angle (KA)—were measured using a motion analysis system across five repetitions per condition. Results: The chair type significantly influenced HI and TA (p < 0.001), with ergonomic chairs encouraging more upright trunk postures. The sitting strategy significantly affected TA and KA (p < 0.01), with comfortable sitting associated with more extended angles. Women exhibited greater TA (114.8° vs. 109.0°, p < 0.001) and lower within-subject variability. Substantial postural variability was observed across all conditions, with mean ranges exceeding minimum detectable change thresholds for HI (10.3°), TA (6.9°), and KA (11.3°). Notably, correct sitting reduced KA variability compared to other strategies (p < 0.01). Conclusions: These findings highlight the individualized and variable nature of sitting posture, even under controlled instructions. The results question the reliability of memory-based seat adjustments and emphasize the need for dynamic, user-centered ergonomic design and personalized clinical guidance to support musculoskeletal health. Full article

Background/Objectives: Alkaptonuria (AKU) is a rare genetic disorder characterized by elevated levels of circulating homogentisic acid (HGA), which accumulates in connective tissues. The musculoskeletal system is particularly susceptible to HGA deposition, often resulting in severe ochronotic osteoarthropathy, especially in the hips, shoulders, knees, and spine. However, little is known about the effects of AKU on skeletal muscle tissue. The study aimed to evaluate changes in lower limb muscles associated with AKU. Methods: This case report describes the treatment of ochronotic osteoarthropathy in the knee of a 73-year-old male patient. Muscle properties were assessed using the MyotonPRO device. The rectus femoris, vastus medialis, and patellar tendon were examined both preoperatively and three months postoperatively. Results: Following total knee arthroplasty (TKA) of the right knee, the patient demonstrated significant improvement in functional outcomes. The MyotonPRO assessment revealed measurable differences in muscle properties between the operated and non-operated limbs. Postoperative measurements indicated improvements in muscle tone, elasticity, and viscoelastic parameters in the treated limb. Conclusions: This case report supports the effectiveness of TKA as a treatment for ochronotic osteoarthropathy. Furthermore, it is the first study to use the MyotonPRO to assess muscle and tendon properties in a patient with AKU. These findings highlight the need for further research into the muscular effects of this rare metabolic disorder. Full article

Background: Total Hip Replacement (THR) is a standard treatment for advanced hip osteoarthritis; yet, its effects on gait recovery remain understudied. This study examines gait pattern changes in women undergoing monitored rehabilitation after unilateral THR, using Statistical Parametric Mapping (SPM) to detect significant motion differences over time. Methods: This longitudinal study included 32 women who underwent primary cementless THR. Gait was assessed preoperatively and postoperatively at 6 weeks, 3 months, 6 months, and 12 months using a motion analysis system. Repeated measures ANOVA and post hoc SPM{t} analyses were conducted to evaluate significant gait changes across time points. Results: Significant improvements (p < 0.05) were observed in spatio-temporal parameters. Velocity increased from 0.42 ± 0.10 m/s (Ex1) to 0.72 ± 0.06 m/s (Ex5), stride length from 0.85 ± 0.12 m to 1.15 ± 0.07 m, and step length (involved leg) from 0.32 ± 0.08 m to 0.48 ± 0.05 m. Cycle time decreased from 1.50 ± 0.20 s to 1.22 ± 0.10 s, indicating improved gait efficiency. Post hoc SPM{t} analysis revealed significant kinematic changes in hip flexion-extension, knee flexion, and pelvic tilt, particularly between Ex2 and Ex3. Statistically significant improvements (p < 0.001) were observed in key spatio-temporal parameters. Conclusions: Gait parameters improved significantly within the first year post-THR, with the most pronounced changes occurring between the early and mid-term recovery phases. These findings support the need for targeted rehabilitation strategies in the first six months post-surgery. SPM analysis provides a robust method for detecting subtle gait adaptations, contributing to the refinement of post-THR rehabilitation strategies. 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: Among older adults, there is a high incidence of history of fall (HoF), fear of falling (FoF), and falls on stair descent during gait transitions. Purpose: We aim to evaluate the association between HoF and FoF on spatiotemporal and lower-limb kinematic parameters in older adults during stair descents and gait transitions. Methods: Sixty older adults (>60 years) were evaluated through an optoelectrical motion capture system during stair descents and gait transitions, using the mean value of the task velocity and time; single- and double-support time; peak downward center of mass (CoM) velocity; hip, knee, and ankle positions of ipsi and the contralateral limb; and foot clearance and foot placement, assessed through multivariate analysis of variance. Results: FOF exhibited longer time to complete (p = 0.009) and double-support (p = 0.047) and single-support (p = 0.009) times and a reduced peak downward CoM velocity (p = 0.043). In the gait transition cycle, HOF exhibited reduced ipsi ankle angles at toe-off (p = 0.015), and FOF presented reduced ipsi ankle angles at heel-strike (p = 0.041) and toe-off (p = 0.026) and reduced contralateral ankle angles at toe-off (p = 0.022). Conclusion: Older adults with HoF and FoF exhibit biomechanical changes during stair descents and gait transitions, in line with the use of more conservative strategies to avoid falling. Full article

This study examines the impact of support leg kinematics on kicking performance and its direct relationship with ball velocity and spin. Seventy-eight players performed maximal instep kicks each with their preferred and non-preferred leg, which were recorded with a three-dimensional motion capture system. Linear mixed models were used to analyze the effects of discrete data of lower limb on ball velocity and spin. Professional male players exhibited significantly smaller hip internal-external rotation range of motion (ROM) and angular velocity compared to other groups (p < 0.05). In professional players, the preferred leg kicks showed greater knee flexion-extension ROM, flexion angular velocity, and extension angular velocity than the non-preferred leg kicks (p < 0.01). Regression analysis revealed that hip and knee extension angular velocities, as well as knee flexion-extension ROM, positively influenced kicking performance, while hip adduction-abduction ROM had a negative impact. These findings emphasize the critical role of the support leg in modulating ball velocity, ball spin, and stability during instep kicking. Training should prioritize hip and knee extension strength for power generation and frontal plane stability for postural control. This study offers novel insights into support leg kinematics across competitive levels, with implications for coaching and performance enhancement. Future research should explore phase-specific support leg dynamics during kicking. Full article

This study investigated whether prior eccentric exercise of knee extensors could attenuate muscle damage in ipsilateral elbow flexors, supporting the presence of an ipsilateral repeated bout effect (IL-RBE) across heterogeneous muscle groups. Sixteen young women were randomized into an intervention group (NL/NU) and a control group (C/NU). The NL/NU group performed eccentric knee extensor exercise 14 days before elbow flexor eccentric loading. Compared to the C/NU group, the NL/NU group exhibited an earlier return to baseline in muscle stiffness (D3: NL/NU = 1.14 ± 0.05 vs. Pre = 0.96 ± 0.03 m/s), joint release angle at 30° (D3: NL/NU = 22.79 ± 1.02 vs. Pre = 24.46 ± 0.87°), and joint release angle at 45° (D2: NL/NU = 37.75 ± 1.38 vs. Pre = 38.83 ± 0.87°), indicating a faster recovery trend in these specific neuromuscular and morphological measures. These results suggest that prior remote eccentric loading induces systemic and neuromuscular adaptations, facilitating improved functional recovery. The findings expand IL-RBE applicability to heterologous muscles within the same limb and support its integration into training and rehabilitation protocols. Full article

Knee osteoarthritis (OA) is a common degenerative joint disease affecting global health. Its increasing prevalence, particularly among aging populations, remains a leading cause of disability. Besides conventional pharmacological and surgical treatments, dietary interventions are promising strategies to alleviate OA symptoms and progression. Unfortunately, scientific evidence does not support many commonly used, misleading ideas about nutrition in knee OA. Recent data highlight the detrimental effects of high-carbohydrate and high-fat diets, particularly those rich in refined sugars and saturated fats, which exacerbate systemic inflammation and contribute to cartilage degradation. Conversely, diets rich in omega-3 fatty acids, polyphenols, and dietary fiber have shown anti-inflammatory and chondroprotective properties. A Mediterranean diet rich in these nutrients effectively prevents the development of OA and its comorbidities, including obesity and cardiovascular disease. The role of supplements, such as glucosamine, chondroitin, and vitamin D, is questioned due to the lack of evidence supporting their efficacy in treating knee OA. Despite dietary recommendations published annually, there is still a need to debunk many myths that are not confirmed by current evidence. The significant research gaps require more extensive, controlled studies to establish evidence-based dietary recommendations (particularly carbohydrates, dietary fiber, and antioxidant intake). This comprehensive review provides insight into the various indications for the impact of nutrition on knee OA, focusing on key nutrients such as carbohydrates, fats, proteins, antioxidants, and selected micronutrients, providing the clinician with ready-to-implement nutritional modifications. Such an analysis may help clinicians and patients incorporate dietary strategies into treating knee OA, emphasizing the need for personalized, sustainable approaches. Full article

The analysis of human movement is crucial in biomechanical research and clinical practice. Quantitative movement analysis evaluates sports performance by tracking joint angles, segmental velocities, and body positions. There are high-accuracy motion-tracking systems like Vicon Motion Systems (Oxford, UK) or OptiTrack (Corvallis, OR, USA), but they are expensive, require expertise, and lack portability. This study assessed a low-cost virtual reality-based motion-tracking system with a customized eMotion data acquisition and analysis application to describe joint movements during squatting. The system, which utilizes commonly available virtual reality accessories, successfully collected kinematic data and continuous tracker trajectories. The results showed high repeatability comparable to advanced optoelectronic motion-capture systems. The eMotion system protocols exhibited low variability for most rotations, with inter-trial values ranging from 0.65° to 2.20° except for hip and knee flexion, which reached 3.09° and 4.01°. The motion-tracking technology that is part of VR headsets has great potential in supporting training and rehabilitation by enabling quantitative assessment of any activity in both the real and virtual worlds. The use of low-cost solutions can increase the potential for human motion measurements in clinical practice and biomechanical research. Full article

MAI Motion is a motion capture system designed to assess lower-limb biomechanics during functional movements like the sit-to-stand (STS) test. Determining how many repetitions are needed to obtain reliable measurements is critical for balancing data quality and participant burden. This study evaluates whether three repetitions (3x) of STS provide reliable data compared to five repetitions (5x). Three-dimensional videos of participants (n = 20) performing 5x STS movements were captured using MAI Motion. Primary measurements were the mean values of each joint angle and the coefficient of variation (CV). Statistical comparisons (including one way ANOVA followed by paired t-tests or non-parametric equivalents) determined whether differences in mean (DiM) values or CV existed between 3x and 5x. The analysis revealed minimal DiM angles between 3x and 5x. Variability, assessed via CV, showed no clinically meaningful differences. Although ankle angle, knee and hip abduction had higher CV values than the other metrics, 3x and 5x performed similarly. Participants reported that 3x required less effort than 5x, underscoring its potential for clinical application. These findings demonstrate that the MAI Motion system captures comparable biomechanical data to the 5x STS protocol when using a 3x approach. This supports the adoption of 3x as a practical alternative, reducing participant burden. Full article

Hand osteoarthritis (OA) is a prevalent and disabling condition, yet its pathogenesis remains less studied than OA in large weight-bearing joints. Emerging genetic, epigenetic, and microbiome research suggests that hand OA might be biologically distinct, involving joint-specific pathways not shared by knee or hip OA. This review integrates genome-wide association studies specific to hand OA, highlighting key molecular contributors such as inflammatory cytokines. These genetic insights, together with emerging data on epigenetic alterations and gut microbial dysbiosis, point to broader systemic and regulatory influences on hand OA onset and progression. We also assess pharmacologic interventions tested in randomized controlled trials that have attempted to target these pathways. While agents such as TNF and IL-6 inhibitors, hydroxychloroquine, and corticosteroids have shown limited success, emerging evidence supports the potential of methotrexate in synovitis-positive general hand OA, platelet-rich plasma in thumb carpometacarpal (CMC) OA, and prolotherapy in interphalangeal (IP) OA. These findings illustrate the persistent gap between mechanistic understanding and therapeutic success. Future work must prioritize multifactorial strategies for addressing pain and translational frameworks that link molecular mechanisms to treatment response. In summary, this review offers an update on hand OA and identifies key opportunities for more targeted and effective therapy. Full article