Search Results (86)

This study aimed to investigate the differences in proprioceptive changes at different time points (Pre vs. Post vs. 90 min vs. 24 h) before and after ischemic preconditioning. It followed a within-subject, self-controlled design, and a total of 21 trained male participants were assessed using two-point discrimination threshold tests on thigh and knee joint position sense testing. The results demonstrated that ischemic preconditioning effectively improved proprioceptive accuracy (two-point discrimination, right lower limb, p < 0.001; two-point discrimination, left lower limb, p < 0.001; knee position sense, right lower limb, p = 0.001; knee position sense, left lower limb, p = 0.014) and stability (two-point discrimination, right lower limb, p < 0.001; two-point discrimination, left lower limb, p = 0.002; knee position sense, right lower limb, p < 0.001; knee position sense, left lower limb, p = 0.003), with the optimal time point for enhancement identified at 90 min. This research suggests administering IPC 90 min before warm-up or competition to enhance athletic performance. Full article

Hexapod robots that use external sensors to sense the environment are susceptible to factors such as light intensity or foggy weather. This effect leads to a drastic decrease in the motility of the hexapod robot. This paper proposes a motion control strategy for a blind hexapod robot. The hexapod robot is symmetrical and its environmental sensing capability is obtained by collecting proprioceptive signals from internal sensors, allowing it to pass through rugged terrain without the need for external sensors. The motion gait of the hexapod robot is generated by a central pattern generator (CPG) network constructed by Hopf oscillators. This gait is a periodic gait controlled by specific parameters given in advance. A policy network is trained in the target terrain using deep reinforcement learning (DRL). The trained policy network is able to fine-tune specific parameters by acquiring information about the current terrain. Thus, an adaptive gait is obtained. The experimental results show that the adaptive gait enables the hexapod robot to stably traverse various complex terrains. Full article

Quadruped robots have shown significant potential in disaster relief applications, where they have to navigate complex terrains for search and rescue or reconnaissance operations. However, their deployment is hindered by limited adaptability in highly uncertain environments, especially when relying solely on vision-based sensors like cameras or LiDAR, which are susceptible to occlusions, poor lighting, and environmental interference. To address these limitations, this paper proposes a novel sensor-enhanced hierarchical switching model predictive control (MPC) framework that integrates proprioceptive sensing with a bi-level hybrid dynamic model. Unlike existing methods that either rely on handcrafted controllers or deep learning-based control pipelines, our approach introduces three core innovations: (1) a situation-aware, bi-level hybrid dynamic modeling strategy that hierarchically combines single-body rigid dynamics with distributed multi-body dynamics for modeling agility and scalability; (2) a three-layer hybrid control framework, including a terrain-aware switching MPC layer, a distributed torque controller, and a fast PD control loop for enhanced robustness during contact transitions; and (3) a multi-IMU-based proprioceptive feedback mechanism for terrain classification and adaptive gait control under sensor-occluded or GPS-denied environments. Together, these components form a unified and computationally efficient control scheme that addresses practical challenges such as limited onboard processing, unstructured terrain, and environmental uncertainty. A series of experimental results demonstrate that the proposed method outperforms existing vision- and learning-based controllers in terms of stability, adaptability, and control efficiency during high-speed locomotion over irregular terrain. Full article

This paper presents a learning-assisted approach for state estimation of quadruped robots using observations of proprioceptive sensors, including multiple inertial measurement units (IMUs). Specifically, one body IMU and four additional IMUs attached to each calf link of the robot are used for sensing the dynamics of the body and legs, in addition to joint encoders. The extended Kalman filter (KF) is employed to fuse sensor data to estimate the robot’s states in the world frame and enhance the convergence of the extended KF (EKF). To circumvent the requirements for the measurements from the motion capture (mocap) system or other vision systems, the right-invariant EKF (RI-EKF) is extended to employ the foot IMU measurements for enhanced state estimation, and a learning-based approach is presented to estimate the vision system measurements for the EKF. One-dimensional convolutional neural networks (CNN) are leveraged to estimate required measurements using only the available proprioception data. Experiments on real data from a quadruped robot demonstrate that proprioception can be sufficient for state estimation. The proposed learning-assisted approach, which does not rely on data from vision systems, achieves competitive accuracy compared to EKF using mocap measurements and lower estimation errors than RI-EKF using multi-IMU measurements. Full article

Tendon-driven robots offer advantages in terms of their compliance, lightweight design, and remote actuation, making them ideal for applications requiring dexterity and safety. However, existing tendon-driven actuators often suffer from low integration and inaccurate proprioceptive sensing due to their complex pulley-based tension sensors and bulky angle sensors. This paper presents the design and control of a compact and proprioceptive modular tendon-driven actuator. The actuator features a simplified single-pulley tension sensing mechanism and a novel maze-slot fixation method, minimizing friction and maximizing the structural integrity. A 3D Hall effect sensor is employed for accurate estimation of the tendon length with minimal space usage. A feedforward PID controller and a model-based tendon length observer are proposed to enhance the dynamic performance and sensing accuracy. Bench tests demonstrate that the actuator achieves a high power density (0.441 W/g), accurate closed-loop tension control, and reliable tendon length estimations. The proposed design provides a practical and high-performance solution for tendon-driven robots, enabling more agile, compact, and robust robotic systems. Full article

This study explored the impact of a four-week Neuromuscular Electrical Stimulation (NMES)-induced eccentric contraction training on single-leg standing balance and muscle strength in 17 healthy adults. The unique training approach involved active antagonist muscle contraction during NMES. Post-training results revealed significant improvements in balance, with notable reductions in Center of Pressure (CoP) trajectory velocity (mean reduction: 0.07 ± 0.01 cm/s, p < 0.05) and range (mean reduction: 2.98 ± 0.53 cm, p < 0.05) on a firm surface. While increases in dorsiflexion force (mean increase: 21.43 ± 0.79 N, p < 0.05) and muscle activation were observed, these were not statistically significant. Changes in muscle pennation angles were also not significant (mean change: 0.43 ± 0.06 degrees, p > 0.05), underscoring the complexity of muscle adaptation processes. This study highlights NMES’s potential in enhancing balance and proprioceptive sensing, suggesting its promising applications in neuromuscular rehabilitation. However, further research is needed to fully understand its impact. Full article

Background: Glenohumeral joint instability is associated with a proprioception deficit. Joint position sense can be improved through targeted exercises and kinesiology taping (KT). While previous studies have examined the effects of KT on proprioception, most have focused on the knee joint, with limited research on unstable shoulder joints. Most studies have used commonly available equipment (e.g., the Biodex system). An electronic goniometer, the “Propriometer”, is a useful tool for assessing proprioception in shoulder joint instability; however, its application in evaluating the effects of KT on shoulder proprioception remains unexplored. This study aimed to (1) assess the usability of the Propriometer for evaluating the effects of KT on unstable shoulders and (2) determine the impact of a single KT application on joint position sense and limb function in individuals with anterior, post-traumatic shoulder joint instability. Methods and Materials: The study included 30 individuals with anterior, unilateral, post-traumatic shoulder joint instability (8 women, 22 men, mean age 26 years). A control group consisted of 35 healthy volunteers (9 women, 26 men, mean age 24 years). Proprioception assessment (active joint position reproduction evaluation) was performed in both groups using the Propriometer, which measures joint position in real time with an accuracy of 0.1° across all axes. The study methodology was validated and used to examine shoulder proprioception. The current study focused on assessing the effects of KT, which had not been previously tested with this device Assessments were conducted before KT application and three days’ post-application. Additionally, patients completed the Western Ontario Shoulder Instability Index (WOSI) self-assessment questionnaire before and three days after the therapy. Results: Results of the mean joint position reproduction error indicate a proprioceptive deficit in patients with shoulder joint instability. However, the analyzed KT application did not show a significant change in the magnitude of the active joint position reproduction error. Conversely, KT therapy significantly improved patients’ subjective assessment of shoulder function and stability as measured by the WOSI. Conclusions: The Propriometer goniometer and testing methodology are effective tools for assessing the impact of KT on proprioception in shoulder instability. While KT application did not significantly influence shoulder proprioception, it did improve patients’ perceived joint stability and function. Full article

Whiplash-Associated Disorders (WADs) often result from traffic accidents, leading to persistent symptoms, including neck pain, disability, dizziness, and central sensitization (CS). A key concern is cervical range of motion (cROM) impairment and sensorimotor dysfunction, which contribute to prolonged disability. This study assessed functional performance in individuals with subacute (>1, <3 months) WADs (n = 122) compared to healthy controls (n = 45). Clinical measures included cROM, movement control (Butterfly test), and position sense (Head–Neck Relocation Test, HNRT). Patient-reported outcomes included neck disability, pain intensity, central sensitization, and dizziness. Mixed and linear models evaluated group differences and the influence of demographic and symptom-related factors. WAD patients had significantly reduced cROM and impaired movement control (p < 0.001). Neck disability (p < 0.001) and pain intensity (p = 0.015) affected cROM within the WAD group. Interaction effects revealed greater amplitude accuracy (AA) impairments at greater difficulty levels (p = 0.043), while time on target (TOT) differences decreased (p < 0.001). Dizziness was associated with increased undershoot (p < 0.001), while pain negatively impacted both AA (p = 0.003) and TOT (p = 0.037). Position sense did not differentiate WAD patients from controls. Findings suggest task-dependent sensorimotor deficits, highlighting the need for multimodal assessment. Early CS screening may optimize rehabilitation and prevent chronic disability. Full article

Proprioceptive deficits can lead to impaired motor performance. Therefore, accurately measuring proprioceptive function in order to identify deficits as soon as possible is important. Techniques based on deep learning to track body landmarks in simple video recordings are promising to assess proprioception (joint position sense) during joint position reproduction (JPR) tests in clinical settings, outside the laboratory and without the need to attach markers. Fifteen typically developing children participated in 90 knee JPR trials and 21 typically developing children participated in 126 hip JPR trials. Concurrent validity of two-dimensional deep-learning-based motion capture (DeepLabCut) to measure the Joint Reproduction Error (JRE) with respect to laboratory-based optoelectronic three-dimensional motion capture (Vicon motion capture system, gold standard) was assessed. There was no significant difference in the hip and knee JRE measured with DeepLabCut and Vicon. Two-dimensional deep-learning-based motion capture (DeepLabCut) is valid to assess proprioception with respect to the gold standard in typically developing children. Tools based on deep learning, such as DeepLabCut, make it possible to accurately measure joint angles in order to assess proprioception without the need of a laboratory and to attach markers, with a high level of automatization. Full article

Background and Objectives: The aim of the study was to compare the effectiveness of proprioceptive studies according to radiological stages in patients with knee osteoarthritis and to determine at which stage of the disease it should be added to the rehabilitation program. Materials and Methods: This study is a prospective clinical trial. The study was registered with ClinicalTrials.gov (name of the registry: Evaluation of the Effectiveness of Proprioceptive Training According to Radiological Stages in Patients with Knee Osteoarthritis; trial registration number: NCT06150170; date of registration: 21 November 2023). The patients were divided into two groups, which were Grade 1–2 (Group 1) and Grade 3–4 (Group 2) knee osteoarthritis. Both groups underwent a strengthening plus proprioception exercise 3 times a week for 4 weeks. Our primary scale was the Western Ontario and McMaster Universities Arthritis (WOMAC) scale. The secondary outcome measures were pain intensity level, proprioception, range of motion, muscle strength, physical performance, physical activity, quality of life and patient satisfaction. All evaluations were performed twice, before treatment and after 4 weeks of treatment. Conclusions: After treatment, there were significant improvements in pain, range of motion, proprioception, muscle strength, functionality, physical performance and quality of life in both groups (p < 0.05). There was no significant difference between the total WOMAC scores among groups after treatment (p = 0.086). There was more improvement in hip external rotation range of motion in Group 1 (p = 0.022). No significant difference was found in other secondary outcomes (p > 0.05). As a result of this study, we found that proprioceptive training was effective on pain, joint position sense, range of motion, muscle strength, functionality, physical performance and quality of life in patients with knee osteoarthritis in all radiological stages. However, there was no difference between the groups, except for hip external rotation angles. Full article

(1) Background: Hemiparetic patients after stroke have deficits on the side of the body opposite to the brain lesion. The aim of this study is to assess the occurrence of deficits in the ipsilesional lower limb. (2) Methods: Twenty-nine stroke patients (SG) and 29 healthy volunteers (CG) were recruited for this study. Passive (PROM), active (AROM), fast range of motion (FROM), and joint position sense (JPS) in the knee joint were measured using a wireless motion system. Participants were also assessed using the step test, balance platform, and the isometric protocol of measuring the strength of the extensor and flexor muscles of the knee. We compared non-paretic lower limb outcomes to the paretic side and a control group. (3) Results: The results showed a difference between the results of the ipsilesional side of the body of stroke patients and the control group. In the non-paretic limb, we observed deficits in PROM (p = 0.018) and AROM (p = 0.048), a lower average (p < 0.001) and maximum speed (p < 0.001) in FROM, worse proprioception (JPS, p < 0.001), and a lower number of repetitions in the step test (p < 0.001) compared to the control group. We also observed a decrease in the average isometric strength of the extensor (p < 0.001) and flexor (p = 0.040) muscles of the non-paretic knee joint compared to the CG. The balance assessment on a balance platform showed worse postural control in people after stroke in all tested conditions (eyes open and closed on a firm and foam surface; p < 0.001). (4) Conclusions: The non-paretic lower limb in stroke patients is characterized by limited ROM at the knee joint, reduced movement speed, decreased proprioception, weakness of the knee flexors and extensors, and resulting impaired balance. The deficits identified require improvement and should be considered when planning rehabilitation. Full article

This study examined the association between knee proprioception, strength, and functional symmetry in healthy individuals using isokinetic strength tests, proprioception assessments, and hop tests. Twenty young, healthy adults (mean age 26.5 ± 4.1 years, 85% right-limb dominant) participated. Knee extensor and flexor strength were measured at 60°·s⁻¹ and 240°·s⁻¹. Proprioception was assessed by measuring passive joint position sense (JPS1: position recognition; JPS2: repositioning) and kinesthesia (threshold to detection of passive motion, TTDPM). Functional performance was evaluated using the single-leg hop test (SLH), triple-hop test (TH), and crossover hop test (COH). Symmetry was calculated using the limb symmetry index (LSI) as the ratio of non-dominant to dominant limb values. The results showed that THT (p = 0.011) and COH (p = 0.032) performance was superior on the dominant limb. A correlation analysis revealed strong positive correlations between hop test distances and knee extensor strength (r = 0.56–0.70, p < 0.001). JPS symmetry was negatively correlated with hop test symmetry (JPS1: SLH, r = −0.53; THT, r = −0.49; COH, r = −0.70). The participants with poorer position sense on the non-dominant leg were 2.7 times more likely to show LSI < 90% (p = 0.035). In conclusion, proprioception—particularly joint position sense—is associated with functional symmetry during dynamic tasks, highlighting the importance of proprioceptive assessments in rehabilitation and injury prevention. Full article

Background: Balance and proprioception are essential elements in postural control and injury prevention. Proprioception, the body’s sense of position and movement, is closely tied to balance, which depends on input from the visual, vestibular, and somatosensory systems. This article explores the link between trauma experiences and proprioceptive dysfunction, emphasizing how heightened muscle tone, dissociation, and altered sensory processing contribute to balance issues and the risk of injury. Method: The study included 48 participants, aged 18–25. Participants completed the Emotional Regulation Scale, Dissociative Experiences Scale II, and Childhood Trauma Questionnaire, after which they had to stand on a BTrackS Balance Plate while being exposed to images that are designed to evoke emotions from the OASIS image set. The balance plate software calculated outcomes of the participants’ postural sway (total sway, sway area, root mean square (RMS) to the mediolateral (ML) and anteroposterior (AP) way, and excursion to ML and AP ways). Results: Dissociative experience shows significant correlation with RMS ML when viewing positive pictures (rτ = 0.207, p = 0.045) and when viewing negative pictures again; scores with RMS ML (rτ = 0.204, p = 0.049) but also with RMS AP (rτ = 0.209, p = 0.042) and with Excursion ML (rτ = 0.200, p = 0.049) were significant. Experiences of physical abuse affected certain indicators of postural sway when viewing positive images compared to participants with no such experience (sway area: U = 374.50, p = 0.027; RMS AP: U = 383.50, p = 0.016; Excursion ML: U = 397.00, p = 0.007). Similarly, physical neglect affected postural sway during viewing of negative images (sway area: U = 366.50, p = 0.003; RMS AP: U = 371.00, p = 0.004; Excursion ML: U = 347.00, p = 0.034; and Excursion AP: U = 353.00, p = 0.010). Conclusions: The study highlights that dissociation disrupts balance in trauma survivors, especially under emotional stress which highlights the potential for motor-based treatments. Full article

Background: The presence of sensorimotor control deficits in adolescent idiopathic scoliosis compared to typically developed adolescents is supported by the literature but lacks reliability studies for assessment in this population. This study aimed to assess the reliability of eight sensorimotor control tests, in terms of static and dynamic balance, joint position sense (JPS) tests of the extremities and the spine, and a functional upper extremity proprioceptive test in adolescent idiopathic scoliosis subjects. Methods: Sixty adolescent idiopathic scoliosis subjects were divided into four groups. Each group underwent two tests by the same examiner, repeated at 15 min intervals. Reliability was measured using the intraclass correlation coefficient (ICC), standard error of measurement (SEM), and smallest detectable difference (SDD). Results: The results showed high reliability for the upper extremity functional proprioception test, for the dynamic and static balance test, and for the spinal lateral flexion joint position sense test in both directions. On the other hand, the shoulder external rotation, knee extension, elbow flexion, and spinal flexion joint position sense tests demonstrated poor reliability in adolescent idiopathic scoliosis subjects. Conclusions: Therapists are recommended to use the functional upper extremity proprioception test, the Fukuda test, the static balance test using a force footplate, and the spinal lateral flexion joint position sense test for assessing treatment progress in this population. Full article

Previous studies have revealed decreased proprioception and perception of joint position in elderly adults. Joint position sense, indicating an individual’s ability to perceive the position of limbs without visual aid, is essential for everyday movements. A few studies have shown a positive effect of muscle stretching on joint position sense (JPS). However, these studies have only been conducted with younger participants. The impact of stretching on JPS in elderly adults remains unclear. Therefore, the aim of this study is to compare the acute effects of muscle stretching on joint position sense in young and elderly adults. An experimental group of younger adults (n = 15; 25.4 ± 2.9 years) and an experimental group of active, healthy elderly adults (n = 15; 64 ± 3.5 years) stretched their knee flexor muscles. The absolute error (AE) of the joint position sense was calculated before and after muscle stretching. The results indicated no significant difference in the AE between groups (p > 0.05) after the stretching intervention. The similarity in the physical activity status of the subjects may have influenced the results. Even though no significant age-specific differences were found in this study, its results may not be applicable to non-active elderly adults. Full article