Kinematic Parameters Research Articles

Introduction of a Framework for the Integration of a Kinematic Robot Arm Model in an Artificial Neural Network - Extended Kalman Filter Approach

The aim of this paper is to introduce a model in which systematic effects can be assigned according to their origin or mode of action. The approach intends to improve the positional accuracy of a robot arm. We show the impact of unaccounted model biases on estimated parameters when applying sequential approaches and conclude the necessity of jointly determining all influencing variables. Therefore, we propose a simultaneous estimation of transformation parameters, robot’s kinematic parameters and non-geometric parameters modelled by an artificial neural network (ANN) in further consequence. Thus, the main contribution of this paper is a new approach of the simultaneous estimation of the geometric and non-geometric components of a robot arm model. The integration of the geometric model (transformations, kinematic robot model) with the non-geometric one (ANN) is realised in the extended Kalman filter. The functionality of the algorithm has been proven on simulated data. The adaptive behaviour of machine learning approaches is made possible by an additional iteration of the ANN. The initialisation of the ANN parameters must not deviate from the nominal parameters by more than 10% so that the ANN can learn the non-geometric part. In this setup, the robot arm position corrections are reduced by 32.5%. A final sensitivity analysis proves the estimability of most kinematic parameters in the course of a future adaptive extension of the approach.

Tire Rubber Based Microplastic Particles Cause Adverse on Quality Parameters of Rainbow Trout Sperm Cells.

In the present study, we aimed to determine the parameters of oxidative stress markers, motility and kinematics of rainbow trout (Oncorhynchus mykiss) sperm cells exposed to different doses (0.001, 0.01, 0.1, 1.0, and 10mg/L, in vitro 4h) of tire rubber based microplastic particles (TRMP-Ps) the leachates procedure of rubber pieces. First of all, TRMP-Ps were prepared by abrasion method in accordance with the literature. Structural and morphological features of TRMP-Ps were determined by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) methods, respectively. Energy dispersive X-ray (EDX) analysis technique was used to characterize the elemental composition of TRMP-Ps. Particle size of microplastic structures was measured hydrodynamically with dynamic light scattering analysis (DLS). After exposure, the effect of TRMP-Ps was defined by the observations of kinematics and antioxidant activities in sperm cells. Our findings showed that the straight line velocity, the curvilinear velocity, the angular path velocity, and the amplitude of lateral displacement of sperm cells decreased. Moreover, while the level of superoxide dismutase decreased dose-dependently against the toxicity of TRMP-Ps, no significant change was observed in the levels of malondialdehyde and total glutathione. The 4-h median effective concentrations (EC50) of TRMP-Ps based on mobility parameters of sperm ranged from 0.31mg/L for reduced straight line velocity of sperm cells to 0.51mg/L for reduced amplitude of lateral displacement of the spermatozoa head. Therefore, we concluded that TRMP-Ps can be a risk for the reproduction cycle of fish in aquatic environments.

Robot error compensation strategy based on error sensitivity

Abstract Due to the errors in manufacturing and assembly, there are differences between the actual model and the theoretical model of the robot, which affects the positioning accuracy of the robot end-effector. In order to improve the accuracy of robot end-effector position, a robot error compensation strategy based on error sensitivity is proposed.Firstly, the robot kinematic model is established by Denavit-Hartenberg (D-H) method, and the sensitivity of end-effector position error is analyzed. According to the influence degree of different kinematic parameters on the robot end-effector position accuracy in the whole workspace, different weights are given to different kinematic parameters. {\color{red}Secondly, the kinematic error model is established, and the redundancy of the error parameter matrix is analyzed to obtain an independent error model. Thirdly, based on the error sensitivity analysis, a Weighted Levenberg-Marquard (WLM) algorithm with adaptive penalty factor is proposed, and the kinematic parameters are iteratively identified.} Finally, an error compensation experiment is carried out by using a universal serial six-degree-of-freedom robot. The experimental results show that the maximum error, mean absolute error and root mean square error of the position error on the test set are reduced by 90.75%, 89.86% and 95.64% respectively. The research in this paper provides a theoretical basis for robot end error compensation.

Effects of treadmill training combined with transcranial direct current stimulation on mobility, motor performance, balance function, and other brain-related outcomes in stroke survivors: a systematic review and meta-analysis.

Treadmill training (TT) is a gait training technique that has commonly been used in neurorehabilitation, and has positive effects on gait, mobility, and related outcomes in stroke survivors. Transcranial direct current stimulation (tDCS) is a non-invasive approach for modulating brain cortex excitability. To evaluate the available scientific evidence on the effects of TT combined with tDCS on mobility, motor performance, balance function, and brain-related outcomes in stroke survivors. Five databases namely the Cochrane library, PEDro, Web of Science, PubMed, and EMBASE, were searched for relevant studies from inception to March, 2024. Only randomized controlled trials were included, and their methodological quality and risk of bias (ROB) were evaluated using the PEDro scale and Cochrane ROB assessment tool respectively. Qualitative and quantitative syntheses (using fixed effects meta-analysis) were employed to analyze the data. The results revealed that TT combined with active tDCS had significant beneficial effects on some mobility parameters, some gait spatiotemporal parameters, some gait kinematic parameters, gait endurance, gait ability, and corticomotor excitability in stroke survivors, but no significant difference on gait speed (P > 0.05), functional mobility (P > 0.05), motor performance (P > 0.05), or some balance functions (P > 0.05), compared with the control conditions. TT combined with active tDCS significantly improves some gait/mobility outcomes and corticomotor excitability in stroke survivors.

Instrumented timed up and go test and machine learning-based levodopa response evaluation: a pilot study

BackgroundThe acute levodopa challenge test (ALCT) is a universal method for evaluating levodopa response (LR). Assessment of Movement Disorder Society’s Unified Parkinson’s Disease Rating Scale part III (MDS-UPDRS III) is a key step in ALCT, which is some extent subjective and inconvenience.MethodsThis study developed a machine learning method based on instrumented Timed Up and Go (iTUG) test to evaluate the patients’ response to levodopa and compared it with classic ALCT. Forty-two patients with parkinsonism were recruited and administered with levodopa. MDS-UPDRS III and the iTUG were conducted in both OFF-and ON-medication state. Kinematic parameters, signal time and frequency domain features were extracted from sensor data. Two XGBoost models, levodopa response regression (LRR) model and motor symptom evaluation (MSE) model, were trained to predict the levodopa response (LR) of the patients using leave-one-subject-out cross-validation.ResultsThe LR predicted by the LRR model agreed with that calculated by the classic ALCT (ICC = 0.95). When the LRR model was used to detect patients with a positive LR, the positive predictive value was 0.94.ConclusionsMachine learning based on wearable sensor data and the iTUG test may be effective and comprehensive for evaluating LR and predicting the benefit of dopaminergic therapy.

Design procedure of reach stacker control system

Reach stackers are efficient and maneuverable machinery for an overload of overall containers in cargo terminals and ports today. Such machinery design determines the practical interest of the engineering industry specialists. However, the lack of information in open sources about structural or kinematic diagrams of equipment control mechanisms and recommendations for their calculation does not allow an effective approach to the creation and update of reach stackers. We developed the design procedure of the reach stacker control system, which considers the kinematic and geometric parameters of the container spreader, as a result of the conducted research. It can be used in the design stages of mechanisms for spreader lateral displacement, extension of the spreader sections, spreader inclination in the vertical plane, container fixation by spreader, spreader rotation, lifting-lowering and telescoping of the boom, as well as during the real operation modes of reach stackers in cargo terminals and ports.

Research on the change of the combined moment of inertia for two-link manipulator with angular coordinate system

The main of the problems of the development of two-link manipulators with an angular coordinate system is the lack of effective and universal control systems capable of implementing energy-intensive modes of movement. This is due to the design features of the pointer system of such manipulators and the methods of their use. During the operation of the manipulator, significant dynamic loads occur in its drive system, which create oscillations of the mechanical system and reduce the accuracy of work. The control system must also effectively compensate for such dynamic variations. Dynamic equations of motion used to build manipulator control controllers, which allow taking into account various features of using manipulators. These mathematical models necessarily contain one of the characteristics in the form of the combined moment of inertia of the mechanical system, which is important in the calculation of differential equations and the determination of kinematic parameters of motion. In this article, the combined moments of inertia of the boom system of a two-link manipulator with an angular coordinate system are determined. A study was carry out and it shown that the nature of the change in the combined moments of inertia influenced by the modes of movement of the boom system links. The results of the study showed that the combined moment of inertia of the boom system of the manipulator is not a constant value, which does not change uniformly under special operating conditions of the machine. To determine the combined moments of inertia, the method of bringing the kinetic energy of the moving system to the drive mechanism was apply. This is relevant, because in the future it will be necessary to adjust the unevenness of the movement of the manipulator links by the drive itself. The study was conduct for a typical linear motion mode and a motion mode with a change in speed along a parabolic trajectory.

Head and pelvis are the key segments recruited by adult spinal deformity patients during daily life activities

Functional assessment is a key element in evaluating adult spinal deformity (ASD) patients. The multitude of 3D kinematic parameters provided by movement analysis can be confusing for spine surgeons. The aim was to investigate movement patterns of ASD based on key kinematic parameters. 115 primary ASD and 36 controls underwent biplanar radiographs and 3D movement analysis during walking, sit-to-stand and stair ascent to calculate joint and segment kinematics. Principal component analysis was applied to identify the most relevant kinematic parameters that define movement strategies adopted by ASD. Pelvis and head relative to pelvis kinematics were the most relevant parameters. ASD patients adopted four different movement strategies. Class 1: normative head and pelvis kinematics. Class 2: persistent pelvic backward tilt. Class 3: persistent forward shift of the head. Class 4: both pelvic backward tilt and forward shift of the head. Patients in class 3 and 4 presented sagittal malalignment on static radiographs with increased pelvic tilt, pelvic incidence-lumbar lordosis mismatch and sagittal vertical axis. Surprisingly, patients in class 3 had normal pelvic kinematics during movement, showing the importance of functional evaluation. In addition to being key segments in maintaining static global posture, head and pelvis were found to define movement patterns.

Effects of short-term oral letrozole on fresh semen parameters, endocrine balance, and prostate gland dimensions in domestic dogs

BackgroundAromatase inhibitors improve male fertility by modifying the hormonal control of spermatogenesis. The present study aimed to investigate the effects of oral administration of letrozole on testosterone and estradiol concentrations and their ratios in blood serum, seminal plasma, prostatic fluid, sperm quality in fresh semen, and prostate gland dimensions. Seven adult male intact mixed-breed dogs were selected. The animals received letrozole (72 µg/kg, PO) daily for four weeks. Blood samplings and semen collections were carried out on days 0 (control), 14 (treatment), 28 (treatment), and 42 (post-treatment).ResultsOur results showed that letrozole administration resulted in a 4.3 fold significant increase in serum, seminal plasma, and prostatic fluid testosterone levels after 14 days. This remained high until the end of the study. Serum and prostatic fluid estradiol levels did not change significantly over the study period. However, the seminal plasma estradiol level showed a significant increase on day 14. The estradiol: testosterone ratio was significantly reduced on day 14 in serum, seminal plasma, and prostatic fluid samples. Letrozole significantly improved the ejaculated spermatozoa viability and concentration after 28 days of oral administration. However, the sperm plasma membrane functional integrity and kinematic parameters were not significantly affected by the treatment. Transabdominal ultrasound examination revealed a significant increase in the height, width, and volume of the prostate gland after 28 days of treatment.ConclusionsAccording to the present research, oral administration of letrozole for 28 days affects local and systemic sex hormone balance leading to an improvement of the ejaculated canine spermatozoa viability and concentration concurrent with an increase in the prostate gland dimensions.

Problem of Low-Frequency Motion Cueing Along Roll on Flight Simulators

An innovative approach to improve the fidelity of low-frequency lateral motion cueing within full-flight simulators for non-maneuvering aircraft is presented. On the basis of the perception peculiarities by the human vestibular system of movement along the roll, the problem of low-frequency motion cueing of lateral movement by motion systems of flight simulators was formulated and solved. The critical challenge of simulating the set of angular motion cues that pilots perceive during flights is decided. This research highlights two key outcomes. The fourth-order low-pass filter effectively extracts low-frequency motion cues from aircraft motion kinematic parameters, enhancing simulation accuracy. Secondly, proposed method significantly expands the range of simulated motion cues while ensuring their synchronization with high-frequency motion cues along relevant degrees of freedom. This formulation of the problem increases the range of simulated motion cues to ±0,3nz, which practically corresponds to the range of simulated motion cues of a transport aircraft, and thus increases the quality of motion cueing. The implementation of the developed method on the An-72TK-200 full flight simulator confirmed its effectiveness. In conclusion, this study introduces a promising methodology that enhances the quality of motion cueing, thus rendering flight simulations more realistic and beneficial for both pilots and aerospace engineering researchers in the real of non-maneuvering aircraft flight simulators.

Surface Topography Analysis of BK7 with Different Roughness Nozzles Using an Abrasive Water Jet.

This study investigated the effect of abrasive water jet (AWJ) kinematic parameters, such as jet traverse speed and water pressure, abrasive mass flow rate, and standoff distance on the surface of BK7. Nozzle A reinforced with a 100 nm particle-sized coating of titanium alloy has more wear resistance compared to Nozzle B coated with nothing. Through analysis of variance and measurement of BK7 surface quality, it is concluded that the grooving and plowing caused by abrasive particles and irregularities in the abrasive water jet machined surface with respect to traverse speed (3, 7.2, 7.8, and 9 mm/min), abrasive flow rate (7 L/min and 10 L/min, 80 mesh) and water pressure (2 and 3 MPa) were investigated using surface topography measurements. The surface roughness (15.734 nm) of BK7 results show that a nozzle coated with titanium alloy has more hardness, which protects BK7 undamaged and super-smooth. The values of selected surface roughness profile parameters-average roughness (Ra) and maximum height of PV (maximum depth of peak and valleys)-reveal a comparatively smooth BK7 surface in composites reinforced with 2% titanium alloy in the nozzle weight at a traverse speed of 7.8 mm/min. Moreover, abrasive water jet machining at high water pressure (3 MPa) produced better surface quality due to material removal and effective cleaning of lens fragmentation and abrasive particles from the polishing zone compared to a lower water pressure (2 MPa), low traverse speed (5 mm/min), and low abrasive mass flow rate (200 g/min).

The efficacy of the Novel Hybrid Passive Spring Damper Ankle Foot Orthosis regard to kinetic and kinematic parameters of patients with Multiple Sclerosis: An intervention study

ABSTRACT Drop foot is a common consequence of Multiple Sclerosis (MS), which may be improved somewhat by an ankle-foot orthosis (AFO). This study aimed to examine the immediate effect of using the recently developed Novel Hybrid Passive Spring Damper AFO (the novel HPSDAFO) on the kinetic and kinematic parameters of patients with MS (PwMS) in the sagittal plane. Twelve PwMS who suffered a unilateral drop foot participated in this study and fitted with the novel HPSDAFO. They walked with the novel HPSDAFO on the affected side and shoe on the affected side at a self-selected speed. Walking by the novel HPSDAFO, the symmetry of all of the evaluated sagittal kinetic and kinematic parameters improved noticeably. The range of ankle plantarflexion and knee flexion increased significantly at the stance phase. Power generation increased at all three joints. The peak of ankle dorsiflexion at early stances and the first peak of knee extension moments increased significantly but decreased at the hip joint. Changes in sagittal ROM, moment, and power generation in the plane and the improved symmetry revealed a more normal walking by using the novel HPSDAFO on the affected limb of PwMS.

Biomechanical Gait Analysis Using a Smartphone-Based Motion Capture System (OpenCap) in Patients with Neurological Disorders.

This study evaluates the utility of OpenCap (v0.3), a smartphone-based motion capture system, for performing gait analysis in patients with neurological disorders. We compared kinematic and kinetic gait parameters between 10 healthy controls and 10 patients with neurological conditions, including stroke, Parkinson's disease, and cerebral palsy. OpenCap captured 3D movement dynamics using two smartphones, with data processed through musculoskeletal modeling. The key findings indicate that the patient group exhibited significantly slower gait speeds (0.67 m/s vs. 1.10 m/s, p = 0.002), shorter stride lengths (0.81 m vs. 1.29 m, p = 0.001), and greater step length asymmetry (107.43% vs. 91.23%, p = 0.023) compared to the controls. Joint kinematic analysis revealed increased variability in pelvic tilt, hip flexion, knee extension, and ankle dorsiflexion throughout the gait cycle in patients, indicating impaired motor control and compensatory strategies. These results indicate that OpenCap can effectively identify significant gait differences, which may serve as valuable biomarkers for neurological disorders, thereby enhancing its utility in clinical settings where traditional motion capture systems are impractical. OpenCap has the potential to improve access to biomechanical assessments, thereby enabling better monitoring of gait abnormalities and informing therapeutic interventions for individuals with neurological disorders.

Optimization of kinematic parameters of dragonfly wing section in forward flapping flight

A numerical investigation is conducted on the two-dimensional corrugated wing section of the dragonfly Aeshna cyanea in forward flapping flight mode. The analysis aimed to determine the impact of various kinematic parameters on the aerodynamic performance and to identify the optimal kinematic conditions for achieving maximum mean lift ([Formula: see text]) and minimum mean drag coefficient ([Formula: see text]). In forward flapping flight mode, the insect moves forward by flapping its wings, and the forward velocity is not zero. The study used the QUICK (Quadratic Upstream Interpolation for Convective Kinetics) scheme for spatial discretization of convective terms and first-order accurate implicit for temporal discretization. The dynamic mesh method following the Arbitrary Lagrangian Eulerian (ALE) formulation is used to track the moving interface of rigid wing section in the fluid domain. It has been observed that the maximum of lift and drag occur during the downstroke of flight. The vortical structures are larger in size at the leading and trailing edges when the peak of lift occurs. The larger leading-edge vortex on the lower surface of the airfoil creates a low-pressure region, thus increasing the peak drag. The kinematic parameters of best performance varied depending on the performance parameter being considered. The Pareto optimal front (POF) is obtained using multi-objective optimization method using surrogate models, which is a set of various design points obtained considering the maximum mean lift and lowest mean drag as objectives. From the POF, one can obtain the corresponding drag and optimum kinematic parameters for a particular lift, and vice versa, for an optimum design.

Enhancing canine semen quality through a second centrifugation after 48 hours of storage: a comparative study

BackgroundCentrifugation is a common procedure to improve the quality of chilled and frozen canine semen by removing debris and seminal plasma and adding semen extenders. The aim of this study was to evaluate the efficacy and influence of a second centrifugation after 48 h of storage at 5 °C on the sperm quality of canine semen. The ejaculates of 45 healthy male dogs, divided into three groups according to body weight, were analyzed for macro- and microparameters such as ejaculate volume, sperm concentration, kinematic parameters, morphology, and integrity of plasma membrane. Samples were analyzed at baseline conditions (T0), after 24 h (T24) and after 48 h (T48) to assess the effects of the different treatments on sperm quality.ResultsThe results showed a significant effect of a second centrifugation on the improvement of chilled sperm quality compared to the other techniques, especially up to 48 h.ConclusionsAnalysis of the data showed that the semen samples centrifuged and then cooled at 5 °C had acceptable semen parameters, especially in terms of motility, with a gradual decrease in serial evaluations after 24 and 48 h. A second centrifugation after 48 h of storage may lead to better semen quality and improve the kinetics of sperm parameters, the percentage of morphologically normal sperm and the percentage of sperm with intact membranes.

Higher abundance of DLD protein in buffalo bull spermatozoa causes elevated ROS production leading to early sperm capacitation and reduction in fertilizing ability

BackgroudBefore fertilization, spermatozoa undergo a crucial maturation step called capacitation, which is a unique event regulates the sperm’s ability for successful fertilization. The capacitation process takes place as the spermatozoa pass through the female reproductive tract (FRT). Dihydrolipoamide dehydrogenase (DLD) protein is a post-pyruvate metabolic enzyme, exhibiting reactive oxygen species (ROS) production which causes capacitation. Additionally, other vital functions of DLD in buffalo spermatozoa are hyperactivation and acrosome reaction. DLD produces the optimum amount of ROS required to induce capacitation process in FRT. Depending on physiological or pathophysiological conditions, DLD can either enhance or attenuate the production of reactive oxygen species (ROS). Aim of this study was to investigate whether changes in the production of ROS in sperm cells can impact their ability to fertilize by triggering the capacitation and acrosome reaction.ResultsIn this study, abundance of DLD protein was quantified between high (n = 5) and low fertile bull (n = 5) spermatozoa. It was found that compared to high-fertile (HF) bulls, low-fertile (LF) bulls exhibited significantly (P < 0.05) higher DLD abundances. Herein, we optimised the MICA concentration to inhibit DLD function, spermatozoa were treated with MICA in time (0, 1, 2, 3, 4, and 5 h) and concentrations (1, 2.5, 5, and 10 mmol/L) dependent manner. Maximum DLD inhibition was found to be at 4 h in 10 mmol/L MICA concentration, which was used for further experimentation in HF and LF. Based on DLD inhibition it was seen that LF bull spermatozoa exhibited significantly (P < 0.05) higher ROS production and acrosome reaction in comparison to the HF bull spermatozoa. The kinematic parameters of the spermatozoa such as percent total motility, velocity parameters (VCL, VSL, and VAP) and other parameters (BCF, STR, and LIN) were also decreased in MICA treated spermatozoa in comparison to the control (capacitated) spermatozoa.ConclusionsThe present study provides an initial evidence explaining the buffalo bull spermatozoa with higher DLD abundance undergo early capacitation, which subsequently reduces their capacity to fertilize.

The Effect of Metallic Nanoparticles Supplementation in Semen Extender on Post-thaw Quality and Fertilizing Ability of Egyptian Buffalo (Bubalus bubalis) Spermatozoa.

Nanomaterials offer several promising prospects in the field of farm animal reproduction, encompassing a broad range of applications such as transgenesis and the precise delivery of substances to sperm cells, antimicrobial, antioxidants properties as well as their potent role in improving cryopreservation methods. The aim of the present study is to explore the effect of supplementing the semen extender with 10µg/mL nano gold (Au-NPs10), 10µg/mL nano silver (Ag-NPs10), 1µg/mL nano selenium (Se-NPs1), and 100µg/mL nano zinc oxide (ZnO-NPs100) on sperm characteristics and kinematics parameters, acrosome integrity, oxidative biomarkers, morphological and apoptosis-like changes of frozen-thawed buffalo bull sperm, and, ultimately, their fertilizing capacity. The results revealed that all aforementioned nano materials significantly improved viability, progressive motility, membrane integrity, acrosome integrity, and kinematic parameters as well as apoptosis-like changes of post-thawed buffalo bull sperm compared to the control (p < 0.05). No discernible effects were observed on sperm ultrastructure morphology measures as a response to the addition of these metallic nanoparticles to the extender. The values of caspase 3 significantly decreased by 64.22, 45.99, 75.59, and 49.39% in Au-NPs10, Ag-NPs10, Se-NPs1, and ZnO-NPs100treated groups, respectively, compared to the control. The addition of 100µg ZnO-NPs to the extender significantly decreased the total count of bacteria, fungi, and yeast compared to the control (p < 0.05). The AuNPs10 and SeNPs1 treated groups showed lower content of malondialdehyde, hydrogen peroxide, and nitric oxide concentrations and higher values of total antioxidant capacity of post-thawed extended semen (p < 0.05). Pregnancy rates increased by 17.5, 20, and 30% in buffalo cows inseminated with sperm treated with ZnO-NPs100, Se-NPs1, and Au-NPs10, respectively, compared to the control group. The present results indicate that the freezing extender supplemented with metallic nanoparticles can be an effective strategy to enhance the cryotolerance and fertility potential of buffalo bull sperm.

Effects of minute oscillation stretching training on muscle and tendon stiffness and walking capability in people with type 2 diabetes.

we investigated the effects of a 10week training program (i.e., minute oscillatory stretching; MOS) on the mechanical responses and walking capability in people with type 2 diabetes (T2D). seventeen T2D patients performed maximum voluntary contractions of the plantar flexor muscles during which Achilles tendon stiffness (kT) and muscle-tendon stiffness (kM) were evaluated at different percentages of the maximum voluntary force (MVC). In addition, each participant was requested to walk at different walking speeds (i.e. 2, 3, 4, 5, and 6kmh-1) while their net energy cost of walking (Cnet), cumulative EMG activity per distance travelled (CMAPD) and kinematic parameters (step length, step frequency, the ankle/knee range of motion) were evaluated. maximum tendon elongation increased after MOS training, and kT significantly decreased (between 0 and 20% of MVC). No differences were observed for muscle elongation or kM after training. Cnet decreased after training (at the slowest tested speeds) while no changes in CMAPD were observed. Step length and ankle ROM during walking increased after training at the slowest tested speeds, while step frequency decreased; no significant effects were observed for knee ROM. these results indicate the effectiveness of 10weeks of MOS training in reducing tendon stiffness and the energy cost during walking in people with T2D. This training protocol requires no specific instrumentation, can be easily performed at home, and has a high adherence (92 ± 9%). It could, thus, be useful to mitigate mechanical tendon deterioration and improve physical behaviour in this population.

Environmental Conditions Associated with Long-Track Tornadoes

Abstract Reanalysis proximity vertical profile attributes associated with long-track tornadoes [LTTs; pathlength ≥48 km (30 mi)] and short-track tornadoes [STTs; pathlengths &lt;48 km (30 mi)] for a total of 48 212 tornadoes with pathlengths ≥0.16 km (0.1 mi) from 1979–2022 in the United States were examined. Both longer- and shorter-track tornadoes were associated with vast ranges of mixed-layer convective available potential energy, together with relatively low mixed-layer lifted condensation level heights and minimal convective inhibition. A large range of 500–9000-m wind speeds and bulk wind differences, 500–3000-m streamwise vorticities, storm-relative helicities, and storm-relative wind speeds were found for STTs. In stark contrast, LTTs only occurred when these kinematic attributes were larger in amplitude through the troposphere, supporting previously documented associations between observed longer-track tornado pathlengths and faster-propagating parent storms. A novel parameter, heavily weighted by kinematic parameters and lightly weighted by thermodynamic parameters, outperformed the significant tornado parameter in differentiating environments that were more supportive of both LTTs as well as tornadoes rated &lt;EF5. The high correlation values R2 = 0.79 between tornado pathlength and Bunkers’ approximate tornado duration (pathlength / VBunkers) calls for improved understanding of mesocyclone periodicities, which impact tornado longevity, to improve tornado pathlength diagnoses and forecasts. Pragmatically, diagnosing LTT environments using vertical profile attributes, perhaps, is not so much a problem of determining when there might be higher expectations for LTTs, but rather a problem of when there might be lower expectations for LTTs, e.g., weaker kinematic attributes in the lower troposphere.

Association between movement speed and instability catch kinematics and the differences between individuals with and without chronic low back pain

Studies reported the existence of instability catch (IC) during trunk flexion in patients with chronic low back pain (CLBP). However, different movement speeds can cause different neuromuscular demands resulting in altered kinematic patterns. In addition, kinematic characterization corresponding to clinical observation of IC is still limited. Therefore, this study aimed to determine (1) the association between movement speed and kinematic parameters representing IC during trunk flexion and (2) the differences in kinematic parameters between individuals with and without CLBP. Fifteen no low back pain (NoLBP) and 15 CLBP individuals were recruited. Inertial measurement units (IMU) were attached to T3, L1, and S2 spinous processes. Participants performed active trunk flexion while IMU data were simultaneously collected. Total trunk, lumbar, and pelvic mean angular velocity (T_MV, L_MV, and P_MV), as well as number of zero-crossings, peak-to-peak, and area of sudden deceleration and acceleration (Num, P2P, and Area), were derived. Pearson’s correlation tests were used to determine the association between T_MV and L_MV, P_MV, Num, P2P, and Area. An ANCOVA was performed to determine the difference in kinematic parameters between groups using movement speed as a covariate. Significant associations (P < 0.05) were found between movement speed and other kinematic parameters, except for Area. Results showed that L_MV significantly differed from the P_MV (P = 0.002) in the CLBP group, while a significant between-group difference (P = 0.037) was found in the P_MV. Additionally, significant between-group differences (P < 0.05) in P2P and Area were observed. The associations between movement speed and kinematic parameters suggest that movement speed changes can alter kinematic patterns. Therefore, clinicians may challenge lumbopelvic neuromuscular control by modifying movement speed to elicit greater change in kinematic patterns. In addition, the NoLBP group used shared lumbar and pelvic contributions, while the CLBP group used less pelvic contribution. Finally, P2P and Area appeared to offer the greatest sensitivity to differentiate between the groups. Overall, these findings may enhance the understanding of the mechanism underlying IC in CLBP.