Movement Velocity Research Articles

Enhancing endurance performance predictions: the role of movement velocity in metabolic simulations demonstrated by cycling cadence.

Mader's mathematical model, widely employed for endurance performance prediction, aims to accurately represent metabolic response to exercise. However, it traditionally overlooks dynamic changes in metabolic processes at varying movement velocities. This narrative review examined the effect of cycling cadence on its key input parameters, including oxygen demand per Watt ( ), resting oxygen uptake ( ), maximal oxygen uptake ( ), and maximal blood lactate accumulation rate (vLamax). These findings were integrated into the model to assess cadence-induced variations in predicted power output at maximal aerobic power (MAP), maximal lactate steady state (MLSS), and peak fat oxidation (FATmax). A U-shaped relationship was found between cadence and both and , while remained largely cadence-independent within typical cadences. vLamax exhibited a polynomial increase with cadence, attributed to changes in lactate elimination, suggesting cadence-independent maximal glycolytic flux. Incorporating these findings into Mader's model considering various scenarios revealed significant cadence-induced variations, with power output differences of up to > 100 W. Using cadence-dependent and while maintaining constant and vLamax yielded polynomial power output-cadence relationships, with optimal cadences of 84rpm at MAP, 80rpm at MLSS, and 70rpm at FATmax. Incorporating cadence-dependent vLamax produced implausible results, supporting cadence-independent maximal glycolytic flux. A hypothesized cadence-dependent improved alignment between model predictions and empirical data. Neglecting dynamic changes in metabolic processes across different movement velocities can lead to inaccurate modelling results. Incorporating cadence alongside established parameters enhances the precision of Mader's metabolic model for cycling performance prediction.

Dynamics of dual-orbit rotations of nanoparticles induced by spin–orbit coupling

Abstract Spin–orbit coupling (SOC) in tightly focused optical fields offers a powerful mechanism for manipulating the complex motion of particles. However, to date, such a mechanism has only been applied to the single-orbit motion for particles, while multi-orbital dynamics have not yet been experimentally demonstrated. Here, the theoretical and experimental realization of dual-orbit rotational dynamics of nanoparticles in a tightly focused circularly polarized Laguerre-Gaussian beam is reported. Analyses reveal that the dual-orbit rotation of nanoparticles originates from SOC in a tightly focused vortex beam, with the motion velocity and direction determined by the topological charge of the beam. Experimentally, the dual-orbit rotation of polystyrene nanoparticles was observed for the first time using an inverted optical tweezer. In addition, the rotation velocity showed a clear linear dependence on the topological charge of the incident beam. This work reveals the pivotal role of SOC in enabling precise dual-orbit control at the nanoscale, paving the way for applications in optical sorting, grinding and delivery of microparticles.

Velocity as an overlooked driver in the echolocation behavior of aerial hawking vespertilionid bats.

Moving animals must gather information at sufficient rates, detail, and range relative to their velocity while filtering this information to that essential for a given task.1,2 Echolocators, because of their active sensory system, are exceptional models for investigating how animals filter and adjust information flow to motor patterns.3,4 During airborne prey capture, bats adjust echolocation and, by extension, how they probe for information in distance- and context-dependent ways.5,6,7 We investigated how sensory probing guides movement and how niche specializations shape strategies to integrate information acquisition and motion velocity. Specifically, we recorded three sympatric bats of the same foraging guild (edge-space hawkers), but different niches, as they intercepted airborne prey under identical conditions. When hawking, we find that the trawler, Myotis daubentonii, and the hawker, Pipistrellus pygmaeus, exhibit similar flight and echolocation behavior, whereas the gleaner, M. nattereri, flies slower and produces calls of lower duration and intensity, greater bandwidth and call interval, but similar beam breadth. Strikingly, these differences in echolocation behavior converge when accounting for flight speed. We show that these species move equivalent distances between call emissions and that all bats travel through their respective sonar ranges in the same time interval. Further, each echolocation call's duration is related to the two-way travel time of its sonar range, and thus velocity, the same way across species. The similarity in how these bats sample their environment relative to velocity suggests general mechanisms of information processing and conserved traits underlying auditory attention in vespertilionid bats and, perhaps, other echolocators.

Insights into proprioceptive acuity assessed with a dynamic joint position reproduction task.

This study investigated proprioceptive acuity using the conventional joint position reproduction (JPR) task and a modified version, the Dynamic JPR task (D-JPR), during Concentric and Eccentric muscle contractions. Seventeen participants were recruited and received a tactile stimulus indicating the position cue at Initial (INI), Intermediate (INT), and Final (FIN) phases of movements, during either the concentric or eccentric phases. After the movement, they replicated the position where they received the stimulus. Angular error (AE) and movement velocity were analysed. AE was higher in the D-JPR than in JPR Task, and in Concentric than Eccentric contractions. Within the D-JPR Task, during Concentric contractions, AE was lower at FIN phase compared to INI and INT phases, and at INT phase compared to INI phase, whereas in Eccentric contraction AE was lower in FIN compared to INI phase. Significant correlations between movement velocity at the time of stimulus delivery and AE were found in both types of contractions. Proprioceptive acuity was affected by task type, muscle contraction, movement phase, and movement velocity, highlighting the need to consider these factors for accurate and ecological assessments of proprioception.

Accelerometric assessment of fatigue-induced changes in swimming technique in high performance adolescent athletes

The present study analyzed the kinematic changes under fatigue in highly trained adolescent swimmers during a 50-m all-out front cwal test. Twenty-four girls and fourteen boys aged 12–13 participated in the study. The movement of the hip rim was analyzed using a specialized inertial device equipped with a triaxial gyroscope and accelerometer to measure changes in angular velocity and acceleration. Between the first and second lengths of the pool, the following were observed: a significant (F1.36 = 63.6; p < 0.0001; η2 = 0.64) increase (34%) in maximum pelvic angle, significant (F1,36 = 6.0; p = 0.0193; η2 = 0.14;) increase (12.10%) in angular velocity in rotational motion around a vertical axis, and a significant (F1,36 = 11.29; p = 0.0018; η2 = 0.24) increase (6.86%) in angular velocity in yaw rotation motion around the sagittal axis. Significant (F1,36 = 13.96; p = 0.0006; η2 = 0.28) differences in maximum pelvic angle were observed for lap and side. As unfavourable changes in kinematics are already observed in the second half of the distance, it is therefore suspected that performing frequent high-intensity repetitions may lead to the perpetuation of unfavourable movement patterns. Taking this into account, coaches should limit maximum-speed swimming in adolescent athletes to short distances and an appropriate interval and use training methods to reduce asymmetric work such as training snorkels.

Modeling of turbulent fluid flow based on the solution of the Mathieu equation

Objective. This work examines the problem of fluid flow simulation in a turbulent regime. The main reasons why turbulent flow occurs are due to the existence of high velocities of movement in fluids; besides that, there may be obstacles or changes in the shapes of flows. Method. To determine the characteristics of a flow, it is proposed to use Mathieu’s equation. The main steps of the solution algorithm are presented for Mathieu functions that were used over the course of the computer program execution. Result. Upon evaluating eigenvalues, it is shown that it is necessary to rely on the corresponding transcendental equations. It is illustrated how modified Mathieu functions are calculated. It is indicated how calculations should be carried out in the case of a small parameter value in Mathieu functions. A block diagram of the executed turbulence modeling algorithm is presented. In order to conduct turbulence simulation, a GUI shell based on the Qt library was created in the Qt Creator environment. During the simulation process, the value of the Smagorinsky constant was chosen to be equal to 0.01. For the time step, a length value of 0.05 was selected. During the execution of the simulation, 2000 time steps were used. The simulation results were recorded every 10 steps. The results of the simulation are presented visually. Conclusion. A mathematical model has been created, on the basis of which there are possibilities for modeling turbulent media. The mathematical model has been constructed for various parameters during the flow of solid bodies by turbulent flows.

Investigating Cell-Induced Mixing Dynamics in Microfluidic Droplets Using the Lattice Boltzmann Method.

This study investigates the impact of cell dynamics on mixing efficiency within a microfluidic droplet, emphasizing the relationship between cell motion, deformability, and resultant asymmetry in velocity and concentration fields. Simulations were conducted for droplets containing encapsulated cells at varying Peclet numbers (Pe = 100-800) and coupling constants (kt = 0.0025, 0.005, 0.0075). The mixing index was significantly enhanced by the presence of the encapsulated cell, particularly at high Peclet numbers, where cell-induced disturbances in the velocity field disrupted symmetrical flow patterns, improving mixing. An asymmetry index quantified deviations in velocity and concentration fields caused by cell motion. Results revealed a complex interplay between cell deformability and fluid-cell interactions. Lower coupling constants corresponded to weaker velocity field asymmetry but, paradoxically, higher mixing indices. This counterintuitive finding was examined by analyzing the asymmetry in the x-component of the velocity field, aligned with the primary concentration gradient. Disturbances in this direction enhanced convective transport across the diffusion interface, crucial for efficient mixing. The study also examined cell trajectory and membrane deformation during droplet generation. Cells with moderate deformability exhibited greater off-center movement, leading to increased rotational dynamics and chaotic flow patterns conducive to enhanced mixing. In contrast, cells with higher or lower deformability followed more constrained paths, resulting in less effective mixing. These findings suggest optimal mixing within microfluidic droplets occurs when cells exhibit moderate deformability, balancing fluid-cell coupling and the ability to induce flow field asymmetry. These insights could inform the design of microfluidic systems for applications requiring precise mixing control, such as biomedical diagnostics and chemical synthesis.

Role of high-intensity exercise interventions in the management of frailty: a short systematic review

ABSTRACT This study aimed to summarize the current evidence on the impact of high-intensity exercise training interventions on frailty and physical function in older adults. A systematic review of controlled trials involving frail and prefrail older adults was conducted, examining resistance, power, and aerobic training, as well as combinations of these methods using loads greater than 70% of maximum capacity or maximal intended movement velocity. The review included eight studies with 437 participants, averaging 78.2 yr old. Results showed that high-intensity exercise significantly improved frailty phenotype scores by 0.3 to 3.0 criteria and enhanced physical function metrics, including the Short Physical Performance Battery (SPPB), usual gait speed, and the five-repetition sit-to-stand test. Concurrent supervised training programs involving power-oriented and aerobic exercises yielded the most substantial benefits, particularly in frailty and SPPB scores. In conclusion, high-intensity exercise, especially concurrent training, effectively improved frailty and physical function in older adults. These programs should be incorporated into routine care to reduce frailty and improve the quality of life in this population. Further research should focus on standardizing protocols and evaluating long-term benefits.

Student physical education teaching achievement test incorporating biomechanics analysis via decision tree algorithm

In the context of China’s economic growth, building a “sports power” is crucial. With the Internet’s development, the nation focuses on physical education curriculum and students’ test results. Currently, Chinese students’ physical education achievements are mainly evaluated by storage, inquiry, and basic statistics. Digital mining is under - utilized, leaving much data unexplored. But digital education’s progress has brought educational data to the fore, enabling schools to find value and patterns for better teaching decisions. In this case, this paper delves into the integration of biomechanics analysis into the assessment of student physical education teaching achievements. Biomechanics offers invaluable insights into the mechanical aspects of human movement during physical activities. By examining biomechanical factors such as joint angles, muscle forces, and movement velocities during various sports, a more profound understanding of students’ physical capabilities and performance can be achieved. Taking the physical test results of students in a specific school as a case study, this research employs data mining technology to explore the rich dataset. The optimized decision tree algorithm is then utilized to analyze the biomechanics - related data. This algorithm enables the identification of key factors that influence students’ physical test outcomes. For instance, it can pinpoint how a student’s running gait mechanics, including stride length, frequency, and leg - muscle activation patterns, affect their performance in track - and - field events. Through this comprehensive approach, the paper not only aims to uncover hidden information within the physical test data but also to elucidate the intricate interplay between biomechanics and students’ overall physical education performance. By dissecting the factors that influence physical test results from a biomechanical perspective, this study provides actionable insights for enhancing physical education teaching methods. Educators can leverage these findings to design personalized teaching programs that cater to the unique biomechanical characteristics of each student, thereby optimizing the effectiveness of physical education and promoting students’ physical development and athletic performance.

Rayleigh-type wave in thermo-poroelastic media with dual-phase-lag heat conduction

Purpose The purpose of this paper is to investigate the propagation of Rayleigh-type surface wave in a porothermoelastic half-space. This study addresses the impact of surface pores characteristics, specific heat, temperature, porosity, wave frequency, types of rock frame and types of pore fluids on the propagation characteristics of Rayleigh-type wave. Design/methodology/approach A secular equation is derived, based on the potential functions for both sealed and open surface pores boundary conditions at the stress-free insulated surface of the porothermoelastic medium. Findings Propagation characteristics (velocity, attenuation and particle motions) of Rayleigh wave are significantly influenced by boundary conditions (opened or sealed surface pores) and thermal characteristics of materials. Furthermore, the path of particles throughout the propagation of Rayleigh-type waves is identified as elliptical. Originality/value A numerical example is considered to examine the effect of thermal characteristics of materials on the existing Rayleigh wave’s propagation characteristics. Graphical analysis is used to evaluate the behavior of particle motion (such as elliptical) at both open and sealed surface of the porothermoelastic medium.

Epsilon Canis Majoris: The Brightest Extreme-ultraviolet Source with Surprisingly Low Interstellar Absorption

Abstract The B2 star Epsilon Canis Majoris (ϵ CMa), at parallax distance d = 124 ± 2 pc, dominates the H i photoionization of the Local Interstellar Cloud. At its closer parallax distance compared to previous estimates, ϵ CMa has a 0.9 mag fainter absolute magnitude M V = −3.97 ± 0.04. We combine measurements of distance with the integrated flux f = (41.5 ± 3.3) × 10−6 erg cm−2 s−1 and angular diameter θ d = 0.80 ± 0.05 mas to produce a consistent set of stellar parameters: radius R = 10.7 ± 0.7 R ⊙, mass M = 13.1 ± 2.3 M ⊙, gravity log g = 3.50 ± 0.05 , effective temperature T eff ≈ 21,000 K, and luminosity L ≈ 20,000 L ⊙. These parameters place ϵ CMa outside the β Cephei instability strip, consistent with its observed lack of pulsations. The observed extreme-ultraviolet spectrum yields a hydrogen photoionization rate ΓHI ≈ 10−15 s−1 (at Earth). The total flux decrement factor at the Lyman limit (ΔLL = 5000 ± 500) is a combination of attenuation in the stellar atmosphere (Δstar = 110 ± 10) and interstellar medium (ΔISM = 45 ± 5) with optical depth τ LL = 3.8 ± 0.1. After correcting for interstellar H i column density N HI = (6 ± 1) × 1017cm−2, we find a stellar LyC photon flux ΦLyC ≈ 3000 cm−2 s−1 and ionizing luminosity Q LyC = 1045.7±0.3 photons s−1. The photoionization rate ΓH ≈ (1–2) × 10−14 s−1 at the cloud surface produces an ionization fraction (30%–40%) for total hydrogen density n H = 0.2 cm−3. With its 27.3 ± 0.4 km s−1 heliocentric radial velocity and small proper motion, ϵ CMa passed within 9.3 ± 0.5 pc of the Sun 4.4 Myr ago, with a 180 times higher photoionization rate.

Structural parameter optimization of a fused all-fiber probe for light manipulation and multi-particle capture

We propose and experimentally demonstrate an economical optical tweezers probe based on the fusion of several commercial optical fibers. By optimizing the structural parameters of the probe, non-contact active capture and manipulation of single or multiple biological particles were achieved. First, the probe structural parameter range was analyzed theoretically, and the theory was cross-verified by the finite element method. Second, the influence of the probe structure and length parameters on the laser focusing performance and particle capture ability was studied, and the optimal structural parameters of the probe in particle capture were determined. The measured capture distance exceeded 50 µm, and the movement velocity of the particle during manipulation was measured. Finally, the capture performance before and after parameter optimization was compared with the dynamic effect of the particles, and the generation mechanism of multiple light traps and the mechanical properties of multi-particles during multi-particle capture were studied. The results indicate that this probe is expected to be used in biological or chemical micromanipulation research.

An analytical study for predicting incipient motion velocity of sediments under ice cover

This study investigates the critical impact of incipient sediment motion on sediment transport estimation and riverbed evolution prediction. In this research, we examine the effects of ice cover on the vertical distribution of flow velocity, establishing a mathematical relationship between the vertical average flow velocities in open channel and ice-covered flows. This leads to the derivation of a formula for incipient motion velocity under ice cover. Additionally, the study analyzes the riverbed evolution process under ice jam conditions. The proposed formula is applicable to both open channel and ice-covered flows, effectively capturing the characteristics of incipient sediment motion for non-cohesive and cohesive sediments. The calculated incipient motion velocities closely align with the empirical data from existing literature. The study reveals that the roughness of ice cover significantly influences the incipient motion velocity of sediment, with higher ratios of ice cover roughness to riverbed roughness promoting sediment initiation under more favorable hydraulic conditions. Furthermore, the riverbed beneath ice jams experiences significant scouring. Field observations indicate that when ice jams form in localized sections of the river, the displacement of the main flow can substantially increase flow velocity in areas away from the ice jam, leading to scouring in non-ice-jammed areas and sedimentation in ice-jammed areas. The uneven distribution of ice jam is likely a critical factor contributing to discrepancies between theoretical predictions and observed outcomes. The complexity and limited data associated with the initiation of cohesive sediments pose challenges in validating the proposed formula for these sediment types.

Automated Detection of Isolated REM Sleep Behavior Disorder Using Computer Vision.

Isolated rapid eye movement (REM) sleep behavior disorder (iRBD) is, in most cases, an early stage of Parkinson's disease or related disorders. Diagnosis requires an overnight video-polysomnogram (vPSG), however, even for sleep experts, interpreting vPSG data is challenging. Using a 3D camera, automated analysis of movements has yielded high accuracy. We aimed to replicate and extend prior work using a conventional 2D camera. The dataset included 172 vPSG recordings from a clinical sleep center, 81 patients with iRBD and 91 non-RBD healthy controls (63 with a range of other sleep disorders and 28 healthy sleepers). An optical flow computer vision algorithm automatically detected movements during rapid eye movement (REM) sleep, from which features of rate, ratio, magnitude and velocity of movements, and ratio of immobility were extracted. Patients with iRBD exhibited an increased number of shorter movements and immobility periods. Accuracies for detecting iRBD ranged from 84.9% (with 2 features) to 87.2% (with 5 features). Combining all 5 features but only analyzing short (0.1-2 second duration) movements achieved the highest accuracy at 91.9%. Of the 11 patients with iRBD without noticeable movements during vPSG, 7 were correctly identified. This work improves prior art by using a 2D camera routinely used in sleep laboratories and improving performance by adding only 3 features. This approach could be implemented in clinical sleep laboratories to facilitate and improve the diagnosis of iRBD. Coupled with automated detection of REM sleep, it should also be tested in the home environment using conventional infrared cameras to detect and/or monitor RBD. ANN NEUROL 2025.

From Motion to Prevention: Evaluating Ergonomic Risks of Asymmetrical Movements and Worker Well-Being in anAssembly Line Work

(1) Background: This study examines the association between asymmetrical movements of an assembly line and machining workers and their overall well-being. The primary aim is to quantify the extent to which asymmetrical movements serve as predictors of work-related musculoskeletal disorders (WMSDs) among these workers and their overall well-being. The study emphasises the predictive relationships between asymmetry metrics and health outcomes. (2) Methods: The study included 86 employees from an automotive manufacturing plant, categorised into machining workers (MWEs) and assembly workers (AWEs). The employment duration spanned from 6 months to 40 years. Inertial motion capture technology was employed alongside the Goldberg 28-item General Health Questionnaire for a retrospective observational analysis and assessment of worker well-being. Movement dynamics were evaluated using a Motion Activity Index (MAI) to measure movement intensity, asymmetry, and quality. (3) Results: The machining group demonstrated nearly double the range of motion (median ROM: 36.6° vs. 25.5°, p = 0.019) and peak angular velocities up to eight times higher (median: 40°/s vs. 5°/s) in lumbar and thoracic rotations compared to the assembly group. Significant differences in ROM and movement speeds were observed (p &lt; 0.001). The MAI showed higher dynamic and symmetrical movements in the machining group (36.6% vs. 25.5%, p = 0.019). No significant mental health issues were identified, aside from complaints related to somatic symptoms. (4) Conclusions: This study highlights significant occupational risks due to movement asymmetry in industrial settings, revealing substantial differences in joint angular displacements, velocities, and accelerations between machining and assembly workers. The findings emphasise the importance of targeted ergonomic interventions to enhance worker well-being and advocate for preventive health measures in occupational environments.

Asymmetry in the Onset of Paraspinal Muscles Activity Differs in Adolescents With Idiopathic Scoliosis Compared With Those With a Symmetrical Spine.

Adolescent idiopathic scoliosis (AIS) is characterized by an asymmetrical formation of the spine and ribcage. Recent work provides evidence of asymmetrical (right versus left side) paraspinal muscle size, composition, and activation amplitude in adolescents with AIS. Each of these factors influences muscle force generation. The timing of paraspinal muscle activation may also contribute to an asymmetry in the timing of forces applied to the spine. The main objectives were to determine (1) whether the timing and asymmetry of erector spinae muscle activation during a rapid bilateral arm raise task differs between adolescents with AIS and those without AIS and (2) whether the magnitude of erector spinae activation asymmetry in AIS is associated with scoliosis curve severity (Cobb angle) or skeletal development level (Risser stage). Finally, (3) we investigated potential kinematic confounders to determine whether symmetry of bilateral rapid arm movements differed between those with and without AIS, and whether any asymmetry in arm movement was associated with erector spinae activation asymmetry. All patients were made aware of the project through flyers at one outpatient spine clinic and a scoliosis rehabilitation clinic in Brisbane, Australia. They were invited between August 2022 and September 2023 to contribute if they met the selection criteria. This cross-sectional study included females with AIS who agreed to participate (n = 24, mean ± SD age of 14 ± 2 years). They all had a primary right-thoracic curve, diagnosed by an orthopaedic specialist. Twenty age- and sex-matched controls (age 13 ± 2 years) who did not have AIS were recruited from the local community. Volunteers (from either group) were excluded if they had any history of spinal surgery, neurological disorders, or musculoskeletal disorders (other than AIS). The experimental task required participants to perform a bilateral rapid arm flexion in response to a visual cue. Muscle activation was recorded using surface electrodes, placed bilaterally on the anterior deltoid and erector spinae adjacent to the C7, T9 (the curve apex for AIS), T12, and L5 vertebrae. Muscle activation onsets were determined from 6 of 10 trials with the quickest deltoid onset for each participant. A linear mixed model (with fixed factors) was used to determine whether activation asymmetry (left-right onset difference) differed between groups (AIS, control) and vertebral level (C7, T9/apex, T12, and L5). Where a group difference in onset asymmetry was identified, the relation of the Cobb angle and Risser stage with the magnitude of asymmetry was evaluated in the AIS cohort using a linear mixed model. Task kinematics, including peak angular arm movement velocity and deltoid onset relative to the light signal, were analyzed using a linear mixed model with group and side as fixed factors. Erector spinae activation timing asymmetry differed between groups at the T9/apex (mean difference 14 ± 23 ms; p < 0.01). In the AIS group, muscle activation was 6 ± 17 ms earlier on the right (convex) relative to the left side of the spine, whereas in controls, activation was 8 ± 19 ms earlier on the left relative to the right side. This difference in activation timing asymmetry between groups was explained by later activation of the T9 level erector spinae muscles on the left (concave) side of the spine in AIS compared with controls (mean group difference of left T9/apex erector spinae onset 13 ± 26 ms; p = 0.01). There were no between-group differences at other vertebral levels. Within the AIS group, no association was observed between the magnitude of the erector spinae activation asymmetry measured at T9/apex and Cobb angle or Risser stage. There were no differences between groups in either the bilateral deltoid onset relative to light or arm peak velocity. Erector spinae muscle activation is asymmetrical at the T9/apex vertebral level during a rapid bilateral arm raise task. This asymmetry was opposite between the AIS and control cohorts, with left-side activation delayed in AIS. It is well established in conditions such as cerebral palsy that muscles forces can influence bone development in children. In children with AIS, there is growing evidence of asymmetrical paraspinal muscle size, composition, and activation amplitude. Each of these factors contribute to paraspinal muscle force generation. Our findings add to what we know by identifying an asymmetry in the timing of erector spinae activation during a well-controlled, bilateral movement task. Combined with previous research, these results support further investigation into whether asymmetrical paraspinal muscle forces might contribute to the curve progression and asymmetrical bony development in AIS. This is important as muscle forces are modifiable through targeted rehabilitation.

Muscle power is associated with higher levels of walking capacity and self-reported gait performance and physical activity in individuals with cerebral palsy.

The purpose of this study was to investigate the relationships between a Power Leg Press test (PLP) with walking capacity and self-reported performance and participation in individuals with Cerebral Palsy (CP), and to compare the strength of the associations between two power tests (PLP and isokinetic (IsoK)) with walking capacity. Ambulatory individuals with CP (n = 33; age 17.89 ± 7.52 years) performed five inclined power leg presses at 40%-50% of their 1-repetition maximum "as fast as possible". A linear position transducer was attached to the weight bar, and the displacement, total load, and angle of the sled were used to calculate peak power for each trial. Isokinetic knee extensor power was measured at 60 deg/sec. Walking capacity was measured using the 10-m walk test fast (FS) and self-selected (SS) speeds and the 1-min walk test (1MWT). Self-reported performance and participation measures were the Activities Scale for Kids-performance (ASKp), Patient-Reported Outcomes Measurement Information System (PROMIS®), and the Gait Outcomes Assessment List (GOAL). Pearson's correlation coefficients determined relationships between power measures with walking capacity and self-report measures (α < 0.05). PLP and IsoK power were significantly correlated to SS (r = 0.361, r = 0.376), FS (r = 0.511, r = 0.485), and 1MWT (r = 0.583. r = 0.443), respectively (p < 0.05). There was no significant difference between the strength of the associations between walking capacity and each test of power (PLP and Isok) (p > 0.05). PLP power was significantly correlated to composite scores on the ASKp (r = 0.690) and GOAL (r = 0.577) and to four components of the PROMIS, including physical function (r = 0.588) (p < 0.01). The Gait and Mobility subscale of the GOAL (r = 0.705) and the Locomotion (r = 0.636), Transfers (r = 0.547), and Standing (r = 0.521) subscales of the ASKp had strong relationships to peak power produced during the PLP test (p < 0.01). PLP power was significantly correlated with walking capacity and self-reported walking performance and mobility-based participation in ambulatory individuals with CP. Higher movement velocities associated with the PLP test may explain the significant associations of power with faster gait speeds. Self-reported mobility performance and physical activity also showed moderate to strong relationships with lower extremity power. Overall, these results suggest a strong link between decreased muscle power generation and walking limitations in individuals with CP.

The acute effects of dynamic stretching on the neuromuscular system are independent of the velocity

AbstractThis study examined the acute effects of dynamic stretching at different velocities on the neuromuscular system. Fourteen participants underwent four experimental sessions in random order: (1) control (lying at rest with the ankle in a neutral position); (2) slow velocity dynamic stretching (50 beats/min; SLOWDS); (3) moderate velocity dynamic stretching (70 beats/min; MODDS); and (4) fast velocity dynamic stretching (90 beats/min; FASTDS). The stretching protocols consisted of four sets of 10 repetitions and targeted the plantar flexor muscles of the right ankle. Assessments included corticospinal excitability (via motor‐evoked potential—MEP/Mmax), spinal reflex activity (via H‐reflex—Hmax/Mmax), muscle contractile properties (peak twitch torque; PTT), maximal voluntary contraction (MVC), and maximal range of motion (ROMmax). Dynamic stretching did not affect MEP/Mmax and MVC of the plantar flexor muscles (P &gt; 0.05). All stretching protocols similarly reduced soleus Hmax/Mmax (P &lt; 0.05), and increased PTT (P &lt; 0.05). Additionally, all conditions, including control, similarly increase ROMmax (P &lt; 0.05, and Cohen's d value of −0.39, −0.28, −0.38 and −0.29 for CON, SLOWDS, MODDS and FASTDS, respectively). Therefore, dynamic stretching reduces spinal reflex activity and enhances muscle contractile properties irrespective of movement velocity without impairing corticospinal excitability and MVC.

Cellular automata modelling of leukaemic stem cell dynamics in acute myeloid leukaemia: insights into predictive outcomes and targeted therapies.

Acute myeloid leukaemia (AML) is a haematologic malignancy with high relapse rates in both adults and children. Leukaemic stem cells (LSCs) are central to leukaemopoiesis, treatment response and relapse and frequently associated with measurable residual disease (MRD). However, the dynamics of LSCs within the AML microenvironment is not fully understood. This study utilized three-dimensional cellular automata (CA) modelling to simulate LSC behaviour and treatment response under induction chemotherapy. Our study revealed: (i) a correlation between LSC persistence post-induction chemotherapy and risk of AML relapse; (ii) MRD negativity based on LSC count may not reliably predict outcomes, supporting clinical evidence that patients with MRD-negative status can still be at risk of relapse; (iii) prolonged persistence of LSCs post-chemotherapy without disruption of normal haematopoiesis, aligning with clinical observations of dormant AML clones; (iv) early LSC dynamics post-induction chemotherapy, characterized by stochastic behaviours and movement velocities, are insufficient predictors of long-term prognosis; and (v) a distinct spatiotemporal organization of LSCs in later phases post-induction chemotherapy is correlated with long-term outcomes. Our modelling results provide a theoretical and clinical framework for AML research, and future clinical data validation could refine the utility of CA modelling for oncological studies.

The PSO-IFAH optimization algorithm for transient electromagnetic inversion.

As a non-contact method, the transient electromagnetic (TEM) method has the characteristics of high efficiency, small impact of device, no limitation of site range, and high resolution, and is a hot topic in current research. However, the research on the refined data processing method of TEM is lag, which seriously restricts the application in superficial engineering investigation and is a key problem that needs to be solved urgently. The particle swarm optimization (PSO) algorithm and firefly algorithm (FA) were successful swarm intelligence algorithms inspired by nature. However, the accuracy and efficiency of the algorithm restrict its further development. In this paper, the particle moving velocity of FA algorithm is defined according to the concept of particle moving velocity in PSO algorithm, so as to improve the local fast convergence ability of FA algorithm. On this basis, the appropriate velocity of particle movement is improved, so that the improved algorithm can overcome the oscillation problem around the optimal solution and improve the computational efficiency. And finally, an improved PSO-IFA hybrid optimization algorithm (PSO-IFAH) was proposed in the paper. The proposed algorithm can exploit the strong points of both PSO and FA algorithm mechanisms. A typical layered model was established, and the PSO algorithm, FA algorithm, and PSO-IFAH algorithm were applied to inversion calculations. The results show that the PSO-IFAH algorithm improves calculation accuracy by more than 80% and efficiency by over 60% compared to the PSO and FA algorithms, respectively. The PSO-IFAH algorithm also exhibits high inversion accuracy and stability, with superior anti-noise properties compared to the other algorithms. When implemented in ground TEM measurement data processing, the PSO-IFAH algorithm enhances the resolution of anomalies and low-resistance details, aligning well with actual excavation results. This highlights the algorithm's capability to depict underground electrical structures and karst developments accurately, thereby improving the precision of TEM data processing and interpretation.