Search Results (77)

Early identification of neurodevelopmental trajectories is essential for timely intervention in infancy. While joint mobility is often seen as an indicator of motor capacity, its link to early functional performance remains unclear. This study examined whether active shoulder range of motion and the quality of spontaneous movement quality relate to early upper limb function in infants under three months. Thirty-two healthy infants participated in a cross-sectional assessment. Video recordings analyzed with the General Movements Assessment classified movements as Fidgety or Writhing. Fine motor performance was evaluated using five items from the Denver II Screening Test. Active shoulder abduction was measured via two-dimensional frontal-plane analysis with Kinovea^®. Data analysis involved t-tests and Pearson correlations. Results showed that infants with Fidgety movements scored higher on fine motor tests than those with Writhing movements. Shoulder range of motion was slightly higher in infants with Writhing movements, but not significantly. No sex differences were found. Weak, nonsignificant correlations existed between shoulder range of motion and fine motor performance. The findings suggest movement quality, rather than limb mobility, is more connected to early motor function. Combining movement quality assessments with simple tests may improve early detection of subtle neuromotor issues and guide early stimulation strategies. Full article

Introduction: Manual therapists routinely evaluate changes in pain, movement, and function through clinical tests that support clinical reasoning. The Prone Hip Extension Test (PHET) is commonly used as a self-perturbation task to assess lumbopelvic control and hip motion patterns related to gait. Performing the PHET actively and passively may reveal how voluntary activation and passive structures influence joint kinematics and contribute to force production. This study aimed to compare active and passive PHET execution and investigate how initial (IP) and final hip positions (FP) correlate with lower-limb neuromuscular function. Methods: Seven healthy volunteers (24.3 ± 3.4 years; 173.1 ± 7.5 cm; 72.1 ± 9.5 kg) without musculoskeletal conditions participated. Hip kinematics were recorded using a 12-camera Qualisys Oqus system (200 Hz) with 22 reflective markers, processed in Qualisys Track Manager 2.13 and exported to Visual3D. Participants performed three PHET trials in both IP and FP, with mean an-gles considered for analysis. Knee isokinetic performance was assessed on a Biodex System 4 at 180°/s and 300°/s for flexion and extension. Results: Significant differences between active and passive PHET emerged in the FP for rotational movements bilaterally (p = 0.02) and in IP adduction/abduction for both hips (right p = 0.03; left p = 0.02). No side-to-side differences were observed. Passive FP of the right hip showed multiple significant correlations with isokinetic flexion and extension parameters at 180°/s and 300°/s, particularly with torque/body weight, acceleration and deceleration times, and agonist/antagonist ratios (ρ ranging from −0.86 to 0.90). Conclusions: Meaningful differences exist between active and passive PHET performance, especially in frontal-plane IP and rotational FP measures. Additionally, passive FP strongly correlates with several neuromuscular variables, suggesting that PHET kinematics may reflect lower-limb isokinetic function. Full article

The VR-based circular tracking movement evaluation system (CES) was developed to quantitatively assess visuomotor control. The virtual stick, a component of the CES, provides visual cues in the virtual environment and haptic feedback when holding the controller. This study examined the effects of stick presence and presentation order on control accuracy for distance, angle, and angular velocity. Twenty-seven participants (12 females; mean age 23.3 ± 2.3 years) performed tasks in the frontal plane followed by the sagittal plane. In each plane, the stick was visible for the first 1–3 revolutions and invisible for the subsequent 4–6 revolutions in the invisible condition, with the reverse order in the visible condition. In the invisible condition, control accuracy with the stick was 1.10 times higher for distance only in the sagittal plane, and 1.13 and 1.09 times higher for angle and angular velocity in the frontal plane, and 1.11 and 1.08 times higher in the sagittal plane. No significant differences were observed in the visible condition. The improved control accuracy when the stick was visible is likely due to enhanced precision in constructing the reference frame, internal models, body coordinates, and effective multisensory integration of visual and haptic information. Such visual information may enable fine control in virtual environment-based applications, including games and surgical simulations. Full article

The Timed Up and Go (TUG) test is used to assess mobility in older adults, but its reliance on completion time limits its insight into detailed movement patterns that could serve as early indicators of functional decline. This study aimed to identify lower limb and trunk kinematic biomarkers during the TUG test that distinguish between older adults with and without functional disability, emphasizing the potential for wearable sensor applications. Sixty adults aged 60+ participated in this cross-sectional study. Three-dimensional lower limb and trunk range of motion (ROM), velocity, center of mass (CoM) displacement, and velocity were analyzed using an optoelectronic system across TUG subphases: sit-to-walk, walk-forward, turn, walk-back, and turn-to-sit. Principal component analysis identified eleven principal components (PCs), explaining 84.33% of the total variance. PCs included sagittal hip and knee motion and CoM velocity during turn-to-sit and walking (PC1); tri-dimensional trunk velocity during turning, walk-back, and sit-to-walk transitions (PC2, PC4, PC6); sagittal knee and hip velocity in sit-to-walk (PC3); and frontal and transverse plane knee ROM and velocity during turning (PC5). Significant differences between functional disability groups were found for PC1 and PC4. These findings provide benchmark data for developing and validating wearable biosensors aimed at monitoring kinematic biomarkers. Full article

Rotator cuff injuries are a leading cause of shoulder disability, directly impacting joint mobility and overall quality of life. Effective recovery in these patients depends not only on surgical intervention, when necessary, but also on accurate and continuous monitoring of joint movements during rehabilitation, especially across multiple anatomical planes. Traditional tools, such as clinical assessments or motion capture systems, are often subjective or expensive and impractical for routine use. In this context, wearable devices are emerging as a viable alternative, offering the ability to collect real-time, non-invasive, and repeatable data, both in clinical and home settings. This study presents innovative wearable sensors, developed through 3D printing and integrated with fiber Bragg grating technology, designed to detect the shoulder’s planes of motion (sagittal, scapular, and frontal) during flexion–extension movements. Two wearable sensors made of thermoplastic polyurethane (TPU 85A and 95A) were fabricated and subjected to metrological characterization, including strain and temperature sensitivity, hysteresis error, and tear resistance, and tested on eight healthy volunteers. The results demonstrated high discriminative ability, with sensitivity values up to 0.76 nm/mε and low hysteresis errors. The proposed system represents a promising, cost-effective, and customizable solution for motion monitoring during shoulder rehabilitation. Full article

Background: Movement symmetry in the lower limbs is critical for biomechanical efficiency, injury prevention, and athletic performance. Lateral (sideways) jumping challenges force production and control in the frontal plane and provide a unique assessment of neuromuscular coordination that may not be detected through sagittal-plane tasks such as running or vertical jumping. This study aimed to evaluate limb asymmetries in isometric knee muscle torque and ground reaction forces (GRFs) during lateral jumps in healthy young women, using the Symmetry Index (SI) to quantify differences between limbs. Methods: Twenty right-limb dominant females (mean age: 20.65 ± 4.51 years) participated in the study. Isometric torque of the knee flexors and extensors was measured using a dynamometric testing station. Lateral jumps were performed onto dual force platforms, with GRF components (vertical (PD), anterior–posterior (AP), mediolateral (ML)) recorded separately for rightward and leftward jumps. SI was calculated for all parameters to determine side-to-side asymmetries, and paired Student’s t-tests were used for statistical comparisons. Results: Right-limb dominance was evident in both knee flexor and extensor torque. Significant asymmetries were observed across all GRF components, varying with jump direction. The trailing limb in each jump direction typically generated greater propulsion forces. In lateral jumps, the trailing limb is generally the leg positioned opposite to the direction of travel, playing a primary role in generating propulsion and absorbing forces during take-off. SI values revealed both inter-individual variability and consistent direction-dependent asymmetry patterns. Conclusions: The or-posterior and vertical components, with greater loading on the dominant leg. Muscle torque measurements also revealed imbalances, with flexors showing more symmetry than extensors. These findings underline the importance of assessing load symmetry to prevent injury and guide rehabilitation. Full article

This paper presents the development, modeling, and analysis of an autonomous active ankle prosthesis with two degrees of freedom (2-DoF), designed to reproduce movements in the sagittal (dorsiflexion/plantarflexion) and frontal (inversion/eversion) planes in order to enhance the stability and naturalness of the user’s gait. Unlike most commercial prostheses, which typically feature only one active degree of freedom, the proposed device combines a lightweight mechanical design, a screw drive with a stepper motor, and a microcontroller-based control system. The prototype was developed using CAD modeling in SolidWorks 2024, followed by dynamic modeling and finite element analysis (FEA). The simulation results confirmed the achievement of physiological angular ranges of ±20–22 deg. in both planes, with stable kinematic behavior and minimal vertical displacements. According to the FEA data, the maximum von Mises stress (1.49 × 10⁸ N/m²) and deformation values remained within elastic limits under typical loading conditions, though cyclic fatigue and impact energy absorption were not experimentally validated and are planned for future work. The safety factor was estimated at ~3.3, indicating structural robustness. While sensor feedback and motor dynamics were idealized in the simulation, future work will address real-time uncertainties such as sensor noise and ground contact variability. The developed design enables precise, energy-efficient, and adaptive motion control, with an estimated average power consumption in the range of 7–9 W and an operational runtime exceeding 3 h per charge using a standard 18,650 cell pack. These results highlight the system’s potential for real-world locomotion on uneven surfaces. This research contributes to the advancement of affordable and functionally autonomous prostheses for individuals with transtibial amputation. Full article

Background: Hemiparetic gait is characterized by reduced limb shortening during swing, increasing the risk of tripping and leading to compensatory strategies. Despite 3D gait analysis being the gold standard for gait assessment, there is no consensus on relevant kinematic biomarkers for limb shortening and compensatory movements. Methods: Systematic review querying five databases (PubMed, Cochrane, Scopus, PEDro, and Web of Science). We included articles that described at least one kinematic biomarker of the lower limb in the sagittal plane and at least one biomarker of the lower limb or pelvis in the transversal or frontal plane, or pelvis in the sagittal plane. Then, we collected kinematic biomarkers from these studies and identified those that seemed relevant to describe limb shortening and compensatory movements during the swing phase. Results: We included 40 studies and collected 385 biomarkers. Among them, 15 described limb shortening, 22 compensations, and 3 toe clearance. Analysis of 12 interventional studies showed that some biomarkers of shortening and compensation were more sensitive to change than others. Conclusions: This review highlights the lack of standardized description for limb shortening and compensatory movements in hemiparetic gait. A set of 13 relevant biomarkers is proposed to improve the interpretation of gait analysis and support consistent evaluation of therapeutic interventions. Full article

Accurate range of motion (ROM) assessment is essential for evaluating musculoskeletal function and guiding rehabilitation, particularly in pediatric populations. Traditional methods, such as optical motion capture and handheld goniometry, are often limited by cost, accessibility, and inter-rater variability. This study evaluated the feasibility and accuracy of the Microsoft Azure Kinect-powered Monitored Augmented Rehabilitation System (MARS) compared to Kinovea. Sixty-five pediatric participants (ages 5–18) performed standardized shoulder and elbow movements in the frontal and sagittal planes. ROM data were recorded using MARS and compared to Kinovea. Measurement reliability was evaluated using intraclass correlation coefficients (ICC3k), and accuracy was evaluated using root mean squared error (RMSE) analysis. MARS demonstrated excellent reliability with an average ICC3k of 0.993 and met the predefined accuracy threshold (RMSE ≤ 8°) for most movements, with the exception of sagittal elbow flexion. These findings suggest that MARS is a reliable, accurate, and cost-effective alternative for clinical ROM assessment, offering a markerless solution that enhances measurement precision and accessibility in pediatric rehabilitation. Future studies should enhance accuracy in sagittal plane movements and further validate MARS against gold-standard systems. 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

This study aims to develop and evaluate a cycling-specific marker protocol that minimises the number of markers while accounting for the unique biomechanics of cycling. Although movements in the frontal and transverse planes during cycling are limited, they are clinically relevant due to their association with overuse injuries. Existing gait-based marker protocols often fail to consider cycling-specific factors such as posture, range of motion, marker occlusion, and muscle-induced artifacts. The proposed protocol (PP) uses 15 physical and 8 virtual markers. In the absence of a gold standard for 3D pedalling kinematics, the PP was evaluated by comparing it with established gait analysis protocols. The protocol demonstrated high correlation in gait (CCC > 0.98 for hip and knee in the sagittal plane), low intra-subject variability (CV < 15% for hip, knee, and ankle), and high repeatability. During pedalling, position, velocity, and acceleration were measured in all three spatial directions. Notably, angular velocity and linear acceleration showed significant components outside the sagittal plane, particularly for angular velocity. These findings highlight the importance of considering 3D motion when estimating forces, joint moments, and joint-specific powers in cycling biomechanics. Full article

Background: Knee injury risk screening protocols predominantly employ high-impact tasks (HIT), but there is a need for low-impact movement screening alternatives. This study aimed to investigate kinematic carryover between low-impact tasks (LIT) and HIT. Methods: This study employed a cross-sectional design. Eighteen healthy, active females with no history of injury within the last six months, aged between 18–35 years completed three trials of LIT (stand-to-sit, single-leg stand-to-sit) and HIT (drop vertical jump, single-leg drop vertical jump). Hip and knee three-dimensional kinematics were evaluated during LIT and HIT. Pearson correlation analyses were used to assess kinematic relationships between LIT and HIT. A post-hoc exploratory analysis examined the consistency of kinematic directionality across tasks. Results: In the frontal plane, the dominant hip, dominant knee, and non-dominant knee during LIT demonstrated a strong positive correlation and directional consistency with the corresponding values during HITs (p < 0.001). In the transverse plane, non-dominant hip, dominant knee, and non-dominant knee kinematics during LITs demonstrated directional consistency and a strong positive correlation with respective kinematics during HITs (p < 0.001). Conclusion: The similarities in hip and knee kinematic patterns suggest that motor responses may generalize across varying task intensities. Thus, LITs may be a useful tool in early knee injury risk identification. Full article

Dynamic knee valgus is a biomechanical condition often linked to an increased risk of knee injuries, particularly in female athletes, due to greater hip adduction, internal rotation, and knee abduction during dynamic movements. This study aimed to assess the impact of neuromuscular fatigue on dynamic knee valgus in female basketball players during single-leg drop jumps (DJ-SL) and change of direction (COD) tests at 45° and 90°. Thirty-three athletes, divided into national and regional performance groups, performed these movements before and after a fatigue protocol. Fatigue was induced through a series of anaerobic exercises, and frontal plane projection angle (FPPA) was used to measure knee valgus. The results showed that dynamic knee valgus increased with the angle of directional change (from 24.77° ± 8.25 at 45° to 34.55° ± 10.40 at 95° pre-fatigue, and from 26.59° ± 12.30 at 45° to 35.87° ± 10.37 post-fatigue), but was not significantly affected by neuromuscular fatigue. The national group demonstrated lower valgus angles compared to the regional group, indicating potential performance differences based on competitive level. These findings suggest that while neuromuscular fatigue does not notably impact knee valgus, the higher valgus angles during directional changes warrant attention in injury prevention programs for female basketball players. Further research is needed to explore other factors influencing knee mechanics and injury risk. Full article

(1) Background: Dynamic knee valgus (DKV) is a common biomechanical risk factor for knee injuries, particularly in sports involving high-intensity movements, such as basketball. While neuromuscular control and structural alignment contribute to DKV, recent evidence indicates that lower limb muscle power (LLMP) and cardiorespiratory fitness (CRF) may significantly influence DKV. This study aims to examine the relationship among LLMP, CRF, and DKV in adolescent basketball athletes. (2) Methods: A total of 104 adolescent basketball athletes (63.5% boys), 12 to 17 years old (13.87 ± 1.46 years) participated in this study. Anthropometric and demographic characteristics such as sex, age, height, weight, and body mass index (BMI) were recorded. The Counter Movement Jump (CMJ) was used for the evaluation and prediction of the LLMP, the 20 m shuttle run test (20mSRT) was used for the evaluation and prediction of CRF, and the single-leg drop jump (SLDJ) was used for the evaluation of DKV via a two-dimensional (2D) kinematic analysis. Statistical analysis included Pearson and Spearman correlations, as well as multiple linear regression, to determine the relationship among LLMP, CRF, and DKV. (3) Results: A statistical analysis revealed strong correlations among LLMP, CRF, and DKV. Pearson’s correlation coefficients demonstrated significant associations between the VO₂max and frontal plane projection angle (FPPA) (r = 0.78, p < 0.001), as well as between LLMP and FPPA (r = 0.82, p < 0.001). Multiple linear regression analysis showed that VO₂max and LLMP together accounted for 85% of the variance in FPPA (R² = 0.85, p < 0.001). (4) Conclusions: The findings highlight that both aerobic capacity and lower limb muscle power significantly contribute to knee valgus control among adolescent basketball players. Implementing training programs focused on improving lower limb muscle power and cardiorespiratory fitness may enhance knee stability and reduce the risk of lower limb injuries. Given the strong predictive value of VO₂max and LLMP for knee control, targeted training programs focusing on neuromuscular conditioning and aerobic capacity may be effective for injury prevention. Full article

Single-leg jumping is a fundamental movement in sports and is frequently used for performance assessment and injury risk evaluation. However, the specific kinetic and kinematic factors influencing jump performance remain unclear. This study aimed to examine the relationships between sagittal and frontal plane kinematic variables, maximal and explosive isometric hip strength, and single-leg countermovement jump (SLCMJ) performance. We assessed eighty elite handball players who performed SLCMJs on force plates, with jumps being video recorded from both the sagittal and frontal planes. Maximal and explosive hip adduction, abduction, extension, and flexion strength were assessed using an isometric dynamometer. Correlation analysis revealed significant relationships (p < 0.05) between maximal hip abductor strength and sagittal plane hip flexion angle (r = −0.23), femur inclination (r = −0.27), and shin inclination (r = 0.23). Explosive adduction strength was significantly correlated (p < 0.05) with frontal plane trunk angle (r = −0.29) and trunk inclination (r = −0.33). A significant negative correlation (p < 0.05) was also observed between femur inclination and jump height (r = −0.30). However, no significant relationship (p > 0.05) was found between hip strength variables and jump height. These findings suggest that while isometric hip strength influences movement kinematics during SLCMJs, its direct impact on jump height is limited. Based on the results of the present study, other factors likely contribute to jump performance outcomes and should be investigated further. Full article