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Purpose: The pivot‐shift test is used to clinically assess knee instability in patients with anterior cruciate ligament (ACL) lesions; however, it has low interobserver reliability. Dynamic radiostereometry (dRSA) is a highly precise and noninvasive method for the objective evaluation of joint kinematics. The purpose of this study was to quantify precise knee kinematics during a pivot‐shift test using dRSA imaging. Method: Eight human donor legs, including hemipelvises, were evaluated. Arthroscopic intervention was performed inducing ligament lesions in the ACL, and anterolateral ligament (ALL) section was performed as a capsular incision. The pivot‐shift test was recorded with dRSA on knees with intact ligaments, ACL‐deficient and ACL + ALL‐deficient knees. Results: A pivot‐shift pattern was identifiable after ligament lesion, as a change in tibial posterior drawer velocity from 7.8 mm/s (95% CI: 3.7; 11.9) in ligament intact knees to 30.4 mm/s (95% CI 23.0; 38.8) after ACL lesion to 35.1 mm/s (95% CI 23.4; 46.7) after combined ACL‐ALL lesion. The anterior‐posterior drawer excursion increased from 2.8 mm (95% CI 2.1; 3.4) in ligament intact knees to 7.2 mm (95% CI 5.5; 8.9) after ACL lesion to 7.6 mm (95% CI 5.5; 9.8) after combined lesion. A statistically significant increase in tibial external rotation towards the end of the pivot‐shift motion was observed when progressing from intact to ACL + ALL‐deficient knees (p < 0.023). Conclusion: This experimental study demonstrates the feasibility of dRSA to objectively quantify the kinematic laxity patterns of the knee during the pivot‐shift test. The dynamic parameters obtained through dRSA revealed the kinematic changes from ACL to combined ACL‐ALL ligament lesion. Level of Evidence: Not applicable. [ABSTRACT FROM AUTHOR]

Post-error slowing (PES), the tendency to slow down a behavioral response after a previous error, has typically been investigated during simple cognitive tasks using response time as a measure of PES magnitude. More recently, PES was investigated during a single reach-to-grasp task to determine where post-error adjustments are employed in a more ecological setting. Kinematic analyses in the previous study detected PES during pre-movement planning and within the grasping component of movement execution. In the current study (N = 22), we increased the cognitive demands of a reach-to-grasp task by adding a choice between target and distractor locations to further explore PES, and other post-error adjustments, under different task conditions. We observed a significant main effect of task condition on overall reaction time (RT); however, it did not significantly impact PES or other post-error adjustments. Nonetheless, the results of this study suggest post-error adjustment is a flexible process that can be observed during pre-movement planning and within the onset and magnitude of the reaching component, as well as in the magnitudes of the grasping component. Considering the sum of the results in the context of existing literature, we conclude that the findings add support to a functional account of error reactivity, such that post-error adjustments are implemented intentionally to improve performance. [ABSTRACT FROM AUTHOR]

Background: Optimal management and surgical planning of severe bony deformities and muscle tendon unit contractures demands comprehensive evaluation of all structures including the dynamic muscle tendon length of all muscles around the joint during gait. Objectives: Present study aimed to explore dynamic muscle–tendon length for all muscles around the knee joint along with pelvis, hip, and ankle joint kinematics among adolescent children with varying crouch angle. Methods: Muscle–tendon length of 29 adolescent children with cerebral palsy with varying crouch angles was computed using a full-body musculo-skeletal model and expressed as a percentage of muscle–tendon length during walking compared to resting condition. Results: Children with knee flexion angle greater than 25° demonstrated lower anterior pelvic tilt and 11% greater muscle–tendon length of semimembranosus and biceps femoris during stance phase of gait compared to children with knee flexion angle less than 25° and typically developing children (p < 0.01). Conclusions: The findings of present study reported that routine bedside clinical evaluation in adolescent children with knee flexion angle greater than 25° revealed moderate shortening of hamstring muscle in supine position. Whereas instrumented objective evaluation of gait demonstrated lengthened hamstring muscle and reduced hip extension and relatively lower anterior pelvic tilt. Therefore, it may be valuable to add objective assessment of dynamic muscle–tendon length to kinematics of all lower-extremity joint motion during gait, in order to understand the muscle–joint interactions; particularly in children with severe crouch and plan specific, tailor-made surgical and non-surgical interventions. [ABSTRACT FROM AUTHOR]

Study Background: Mechanical alignment has always been considered as the gold standard in total knee arthroplasty (TKA), but various other coronal alignment strategies have been proposed to enhance native knee kinematics and thus elevate patient satisfaction levels. Coronal plane alignment of the knee (CPAK) classification introduced by MacDessi is a simple yet comprehensive system to classify knees based on their coronal plane alignment. It categorizes knees into nine phenotypes based on medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA). Materials and Methods: This study investigates the distribution of classification of primary arthritic knees (CPAK) types among arthritic knees in the South Indian population and compares the functional outcomes following total knee arthroplasty (TKA) using traditional mechanical alignment among various CPAK types. The research, spanning from September 2021 to August 2023, encompasses a comprehensive analysis of 324 patients with 352 knees in the first part and 48 patients with 72 knees in the second part of the study who underwent TKA, incorporating demographic data and radiological evaluations. Results: Results indicate a predominant distribution of CPAK type 1, followed by type 2 and type 4 among the South Indian population. In the functional outcomes analysis, regardless of CPAK type, patients exhibited significant improvements in Knee Injury and Osteoarthritis Outcome Score (KOOS), Oxford Knee Score (OKS), and visual analog scale (VAS) scores post-operatively. Conclusion: CPAK distribution among the South Indian population is comparable to other Indian study and studies with an Asian population, but varies with studies among the White population. Significant improvement of functional outcome among all CPAK types signifies the robust nature of conventional mechanical alignment strategy. Thus, our study serves as an initial exploration into the knee phenotype of the South Indian population and findings contribute to ongoing research on optimal alignment strategies in knee arthroplasty, paving the way for future, more extensive studies in this dynamic field. [ABSTRACT FROM AUTHOR]

Tennis is a sport in which the surface plays an important role in performance and injury risk. Professional players face an extensive competition calendar in which they must adapt to different types of surfaces. However, unlike other sports, tennis lacks standards that regulate surface properties affecting athlete–surface interaction. The objective of this study was to mechanically evaluate shock absorption, vertical deformation, energy restitution and slip resistance in different types of tennis surfaces, compare them with each other and look for correlations between variables. Thirty-six tennis courts (12 hard court, 16 clay, 8 artificial grass) were evaluated. All variables differed significantly between surfaces (p < 0.001). Shock absorption (1.1 ± 0.5 to 13.9 ± 3.4%) and vertical deformation (0.02 ± 0.04 to 1.07 ± 0.19 mm) were lower on hard court compared to clay and artificial grass; energy restitution (72.5 ± 4.7 to 89.9 ± 1.5%) showed the opposite; and slip resistance (in Pendulum Test Value) was lower on clay (53.6 ± 2.5) compared to grass (61.4 ± 1.3) and hard court (66.6 ± 1.1). No significant correlations between variables were identified in hard court. However, both clay and artificial grass showed a significant positive correlation (p < 0.001) between shock absorption and vertical deformation (0.872 and 0.947, respectively), and a significant negative correlation (p < 0.001) between shock absorption and energy restitution (− 0.807 and − 0.981, respectively). Also, significant negative correlations were found between vertical deformation and energy restitution both in clay (− 0.802; p < 0.001) and artificial grass surfaces (− 0.890; p < 0.01). As for the shock absorption, only a significant negative correlation with vertical deformation in artificial grass (− 0.715; p < 0.05) was identified. This study contributes initial evidence for further research to inform future International Tennis Federation regulations aimed to assess and control the mechanical properties of tennis surfaces affecting athlete–surface interaction. [ABSTRACT FROM AUTHOR]

Purpose: This clinical fluoroscopy study investigated knee kinematics of two different cemented fixed‐bearing, posterior‐stabilised (PS) total knee arthroplasty (TKA) designs: an asymmetric tibial component including an asymmetric insert designed to optimise personalised balance and fit and its precursor symmetrical design with symmetric insert. Methods: A consecutive series of patients (16 TKAs from each treatment group) participating in a randomised controlled trial comparing TKA migration was included. The exclusion criterion was the use of walking aids. Flat‐panel fluoroscopic recordings of step‐up and lunge motions were acquired 1‐year postoperatively. Medial and lateral contact points (CPs) were determined to calculate CP displacement, femoral axial rotation and pivot position. Using linear mixed‐effects modelling techniques, kinematics between TKA designs were compared. Results: During knee extension between 20° flexion and full extension, the CPs moved anteriorly combined with a small internal femoral rotation (a screw‐home mechanism). Whereas CP movement was reversed: femoral rollback, external femoral rotation while flexing the knee between full extension and 20° knee flexion, At larger flexion angles, femoral axial rotation (FAR) occurred around a lateral pivot point both during step‐up and lunge. The symmetric design had a 2.3° larger range of FAR compared to the asymmetric design during lunge (p = 0.02). All other kinematics were comparable. Conclusion: Despite the differences in design, this study showed that the asymmetric and symmetric PS TKA designs had mostly comparable knee kinematics during step‐up and lunge motions. It is therefore expected that the functionality of the successor TKA design is similar to that of its precursor design. Level of Evidence: Level II, prospective comparative study. [ABSTRACT FROM AUTHOR]

Handover actions are part of our daily lives. Whether it is the milk carton at the breakfast table or tickets at the box office, we usually perform these joint actions without much conscious attention. The individual actions involved in handovers, that have already been studied intensively at the level of individual actions, are grasping, lifting, and transporting objects. Depending on the object's properties, actors must plan their execution in order to ensure smooth and efficient object transfer. Therefore, anticipatory grip force scaling is crucial. Grip forces are planned in anticipation using weight estimates based on experience or visual cues. This study aimed to investigate whether receivers are able to correctly estimate object weight by observing the giver's kinematics. For this purpose, handover actions were performed with 20 dyads, manipulating the participant role (giver/receiver) and varying the size and weight of the object. Due to the random presentation of the object weight and the absence of visual cues, the participants were unaware of the object weight from trial to trial. Kinematics were recorded with a motion tracking system and grip forces were recorded with customized test objects. Peak grip force rates were used as a measure of anticipated object weight. Results showed that receiver kinematics are significantly affected by object weight. The peak grip force rates showed that receivers anticipate object weight, but givers not. This supports the hypothesis that receivers obtain information about the object weight by observing giver's kinematics and integrating this information into their own action execution. [ABSTRACT FROM AUTHOR]

Background: Running biomechanics is considered an important determinant of running economy (RE). However, studies examining associations between running biomechanics and RE report inconsistent findings. Objective: The aim of this systematic review was to determine associations between running biomechanics and RE and explore potential causes of inconsistency. Methods: Three databases were searched and monitored up to April 2023. Observational studies were included if they (i) examined associations between running biomechanics and RE, or (ii) compared running biomechanics between groups differing in RE, or (iii) compared RE between groups differing in running biomechanics during level, constant-speed, and submaximal running in healthy humans (18–65 years). Risk of bias was assessed using a modified tool for observational studies and considered in the results interpretation using GRADE. Meta-analyses were performed when two or more studies reported on the same outcome. Meta-regressions were used to explore heterogeneity with speed, coefficient of variation of height, mass, and age as continuous outcomes, and standardization of running shoes, oxygen versus energetic cost, and correction for resting oxygen or energy cost as categorical outcomes. Results: Fifty-one studies (n = 1115 participants) were included. Most spatiotemporal outcomes showed trivial and non-significant associations with RE: contact time r = − 0.02 (95% confidence interval [CI] − 0.15 to 0.12); flight time r = 0.11 (− 0.09 to 0.32); stride time r = 0.01 (− 0.8 to 0.50); duty factor r = − 0.06 (− 0.18 to 0.06); stride length r = 0.12 (− 0.15 to 0.38), and swing time r = 0.12 (− 0.13 to 0.36). A higher cadence showed a small significant association with a lower oxygen/energy cost (r = − 0.20 [− 0.35 to − 0.05]). A smaller vertical displacement and higher vertical and leg stiffness showed significant moderate associations with lower oxygen/energy cost (r = 0.35, − 0.31, − 0.28, respectively). Ankle, knee, and hip angles at initial contact, midstance or toe-off as well as their range of motion, peak vertical ground reaction force, mechanical work variables, and electromyographic activation were not significantly associated with RE, although potentially relevant trends were observed for some outcomes. Conclusions: Running biomechanics can explain 4–12% of the between-individual variation in RE when considered in isolation, with this magnitude potentially increasing when combining different variables. Implications for athletes, coaches, wearable technology, and researchers are discussed in the review. Protocol registration: https://doi.org/10.17605/OSF.IO/293ND (OpenScience Framework). [ABSTRACT FROM AUTHOR]

Background: Historically, kinematic measures have been compared across injured and non-injured groups of runners, failing to take into account variability in kinematic patterns that exist independent of injury, and resulting in false positives. Research led by gait patterns and not pre-defined injury status is called for, to better understand running-related injury (RRI) aetiology and within- and between-group variability. Objectives: Synthesise evidence for the existence of distinct kinematic sub-groups across a population of injured and healthy runners and assess between-group variability in kinematics, demographics and injury incidence. Data Sources: Electronic database search: PubMed, Web of Science, Cochrane Central Register of Controlled Trials (Wiley), Embase, OVID, Scopus. Eligibility Criteria: Original, peer-reviewed, research articles, published from database start to August 2022 and limited to English language were searched for quantitative and mixed-methods full-text studies that clustered injured runners according to kinematic variables. Results: Five studies (n = 690) were included in the review. All studies detected the presence of distinct kinematic sub-groups of runners through cluster analysis. Sub-groups were defined by multiple differences in hip, knee and foot kinematics. Sex, step rate and running speed also varied significantly between groups. Random injury dispersal across sub-groups suggests no strong evidence for an association between kinematic sub-groups and injury type or location. Conclusion: Sub-groups containing homogeneous gait patterns exist across healthy and injured populations of runners. It is likely that a single injury may be represented by multiple movement patterns, and therefore kinematics may not predict injury risk. Research to better understand the underlying causes of kinematic variability, and their associations with RRI, is warranted. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to examine head acceleration event (HAE) propensity and incidence during elite-level men's and women's rugby union matches. Methods: Instrumented mouthguards (iMGs) were fitted in 92 male and 72 female players from nine elite-level clubs and three international teams. Data were collected during 406 player matches (239 male, 167 female) using iMGs and video analysis. Incidence was calculated as the number of HAEs per player hour and propensity as the proportion of contact events resulting in an HAE at a range of linear and angular thresholds. Results: HAE incidence above 10 g was 22.7 and 13.2 per hour in men's forwards and backs and 11.8 and 7.2 per hour in women's forwards and backs, respectively. Propensity varied by contact event, with 35.6% and 35.4% of men's tackles and carries and 23.1% and 19.6% of women's tackles and carries producing HAEs above 1.0 krad/s2. Tackles produced significantly more HAEs than carries, and incidence was greater in forwards compared with backs for both sexes and in men compared with women. Women's forwards were 1.6 times more likely to experience a medium-magnitude HAE from a carry than women's backs. Propensity was similar from tackles and carries, and between positional groups, while significantly higher in men than women. The initial collision stage of the tackle had a higher propensity than other stages. Conclusion: This study quantifies HAE exposures in elite rugby union players using iMGs. Most contact events in rugby union resulted in lower-magnitude HAEs, while higher-magnitude HAEs were comparatively rare. An HAE above 40 g occurred once every 60–100 min in men and 200–300 min in women. Future research on mechanisms for HAEs may inform strategies aimed at reducing HAEs. [ABSTRACT FROM AUTHOR]

The lower hook mechanism is one of the key mechanisms in netting machine. The weft reel diameter of the new generation netting machine has doubled to the original one, resulting in a large route change of lower hook, thus the lower hook mechanism needs to be redesigned. By comparing the fitting results under different methods, the hook tip trajectory with smaller acceleration is determined. By using the closed vector method, the inverse and forward kinematic models of the mechanism is established and solved. By using NSGA-II genetic algorithm, the transmission performance parameters of the mechanism are effectively optimized. The kinematic simulation of the optimized mechanism is completed in Adams to verify the correctness of kinematic models and the effectiveness of optimization results. The comparison result of the simulated and initial fitted trajectory shows that the lower hook mechanism designed in this paper could meet the technical requirements of the position and posture of the lower hook. [ABSTRACT FROM AUTHOR]

In order to reduce the cost of milling ultra-precision microlens arrays and improve its efficiency, a fast tool servo-assisted microlens milling method is proposed which combines a fast tool servo (FTS) and a traditional three-axis displacement platform. The FTS-assisted microlens arrays milling path generation algorithm is established and the milling surface simulation model based on milling kinematics and grid discretization principle is constructed. A high precision FTS system is developed based on which a FTS-assisted microlens arrays milling platform is built. For verifying the effectiveness of this new method, a series of experiments are carried out. The minimum surface roughness and surface PV error of the machined micro-lenses are 0.046 µm and 0.673 µm, respectively. The results of tests with various cutting parameters illustrate that feed rate is the main cutting parameter to affect the milling quality of micro-lens array. [ABSTRACT FROM AUTHOR]

Normal aging often results in an increase in physiological tremors and slowing of the movement of the hands, which can impair daily activities and quality of life. This study, using lightweight wearable non-invasive sensors, aimed to detect and identify age-related changes in wrist kinematics and response latency. Eighteen young (ages 18–20) and nine older (ages 49–57) adults performed two standard tasks with wearable inertial measurement units on their wrists. Frequency analysis revealed 5 kinematic variables distinguishing older from younger adults in a postural task, with best discrimination occurring in the 9–13 Hz range, agreeing with previously identified frequency range of age-related tremors, and achieving excellent classifier performance (0.86 AUROC score and 89% accuracy). In a second pronation–supination task, analysis of angular velocity in the roll axis identified a 71 ms delay in initiating arm movement in the older adults. This study demonstrates that an analysis of simple kinematic variables sampled at 100 Hz frequency with commercially available sensors is reliable, sensitive, and accurate at detecting age-related increases in physiological tremor and motor slowing. It remains to be seen if such sensitive methods may be accurate in distinguishing physiological tremors from tremors that occur in neurological diseases, such as Parkinson's Disease. [ABSTRACT FROM AUTHOR]

Over the past 30 years, research on meniscal kinematics has been limited by challenges such as low-resolution imaging and capturing continuous motion from static data. This study aimed to develop a computational knee model that overcomes these limitations and enables the continuous assessment of meniscal dynamics. A high-resolution MRI dataset (n = 11) was acquired in 4 configurations of knee flexion. In each configuration, the menisci were modeled based on the underlying osseous anatomy. Principal Polynomial Shape Analysis (PPSA) was employed for continuous meniscal modeling. Maximal medial anterior horn displacement occurred in 60° of flexion, equaling 6.24 mm posteromedial, while the posterior horn remained relatively stable. At 90° of flexion, the lateral anterior and posterior horn displaced posteromedially, amounting 5.70 mm and 6.51 mm respectively. The maximal observed Average Surface Distance (ASD) equaled 0.70 mm for lateral meniscal modeling in 90° of flexion. Based on our results, a strong relation between meniscal dynamics and tibiofemoral kinematics was confirmed. Expanding on static meniscal modeling and employing PPSA, we derived and validated a standardized and systematic methodological workflow. [ABSTRACT FROM AUTHOR]

Training load quantification methods may help optimize soccer performance. However, whole-body indicators potentially underestimate biomechanical load. A new inertial sensor setup allows joint-specific biomechanical load quantification. Good discriminative validity further supports the use of this method, and therefore the purpose of this study is to assess the discriminative validity of this method during soccer-specific activities. Twelve national and sixteen regional soccer players wore an inertial sensor setup and performed countermovement jumps, soccer kicks, and 30 m sprints. Between-group differences in angular acceleration-based biomechanical load indicators Knee Load, Hip Load, and performance were assessed using MANOVAs and Cohen's effect sizes. Furthermore, relationships with performance were explored. National players showed higher Knee Load during jumping (mean difference: 0.11 A.U., ES = 0.93, p = 0.02), kicking (mean difference: 1.94 A.U., ES = 0.94; p = 0.02), and almost during sprinting (mean difference: 12.85, ES = 0.77; p = 0.05). Hip Load did not differ between groups across all tasks, although national players outperformed regional players on all tests. Significant relationships between Knee Load (rjump = 0.41, rkick = 0.65), Hip Load (rjump = 0.42), and performance were observed with 95% confidence intervals ranging from trivial to large. The results confirm discriminative validity of Knee Load for jumping and kicking, but not for sprinting and Hip Load in general. The confidence intervals of the established relationships suggest that the biomechanical loads might not entirely explain between-group differences in performance. The results can be used as reference values for biomechanical load quantification in the field. [ABSTRACT FROM AUTHOR]

Belle II collects data at the asymmetric electron-positron collider SuperKEKB, which operates with a centre-of-mass energy at, or close to, the mass of the Υ (4 S) resonance. The Υ (4 S) lies just above the kinematic threshold for B-meson-pair production, so Belle II collects a large sample of B + B - and B 0 B ¯ 0 pairs that are unaccompanied by other particles. The low-multiplicity final state and constrained kinematics allow many measurements with missing energy and neutral mesons in the final state that complement the B-physics measurements made by LHCb. In addition to B mesons, this center-of-mass energy has a similar cross section for electron-positron annihilation to c c ¯ and τ + τ - pairs, meaning Belle II also makes measurements of charm hadron and tau lepton properties. Finally, unique searches for hypothesized dark-sector particles with masses in the range 100 MeV–10 GeV are possible. This article reviews the current results from the Belle II experiment. [ABSTRACT FROM AUTHOR]

Lattice QCD offers the possibility of computing parton distributions from first principles, although not in the usual MS ¯ factorization scheme. Calculations are therefore matched to MS ¯ using a perturbative procedure which is the source of significant uncertainty within the currently accessible kinematics. We present the possibility of computing the z2 evolution of non-singlet pseudo-parton distribution functions within the short factorization scheme in a numerically improvable way. The goal is to have tools to evolve a calculation to a scale where perturbative uncertainties are less pronounced. We compare a numerical extraction of the evolution operator from lattice data to the computation of z2 dependence in perturbation theory. Finally, we discuss how this numerical work may be extended to address the two-scale problem that arises when the Ioffe time range must be made large to extend the reach of the calculation of the pseudo-PDF to smaller values of the momentum fraction. [ABSTRACT FROM AUTHOR]

Background: One mechanism by which exercise interventions may be effective in reducing anterior cruciate ligament (ACL) injury risk is through changes in lower limb biomechanics. Understanding how training programmes affect lower-limb kinematics and kinetics may help refine injury prevention programmes. Objective: The aim of this systematic review and meta-analysis was to assess the effect of injury prevention programmes on kinematics and kinetics during tasks related to ACL injury in female team field and court sports. Data Sources: Five databases were searched in October 2022. Eligibility Criteria: Randomised controlled trials assessing the effect of injury prevention programmes compared with usual training/no training on lower limb kinematics and kinetics in female team field and court sports were eligible for review. Results: Sixteen studies were included. A total of 976 female athletes were included. Most of the studies included interventions with multiple components (12/16). Commonly used components were plyometrics (12/16), strength (8/16), and balance/stability (7/16). Thirteen studies had routine training or sham interventions as the control group and three studies had no training. Very low certainty evidence suggests that injury prevention programmes increase knee flexion angles (mean difference = 3.1° [95% confidence interval 0.8–5.5]); however, very low to low certainty evidence suggests no effect on hip flexion angles/moments, knee flexion moments, hip adduction angles/moments, knee adduction angles/moments, hip internal rotation angles/moments, ankle dorsiflexion angles, and ground reaction forces, compared with usual training/no training. Conclusion: Injury prevention programmes may be effective in increasing knee flexion angles during dynamic landing and cutting tasks but may have no effect on other lower limb biomechanical variables. As such, the benefits of injury prevention programmes may be mediated by factors other than altered biomechanics and/or may happen through other biomechanical measures not included in this review. [ABSTRACT FROM AUTHOR]

The Triassic outcrop in the Bazina structure is known among the largest massif in northern Tunisia. Its tectonic setting and sub-surface geometry are related to geodynamics and kinematics in North Africa and western Mediterranean domains. Gravity data processing and interpretation over the Hedil region highlight deep faulting and the geometry of Bazina structure and the neighboring ones. Enhancement of the residual anomaly, which represents the gravity response of sedimentary cover, mainly horizontal gradient map and its maxima, reveals varied oriented lineaments. The E–W conspicuous direction covers and delimits the outcropping Triassic body. However, the NE–SW major direction, highlighting eastward and southward of the Bazina structure, coincides with Cretaceous exposures. Furthermore, less extended N- and NW-trending features were highlighted. Limits and depth of deep gravity causative bodies were located using the Euler deconvolution method. 3D inversion and 2D forward gravity modeling combined with geological outcrops enabled the reconstruction of the Triassic bodies and surrounding structures. The study area reveals piercing diapiric structures and salt wrinkles. This Bazina evaporite exposure corresponds to a deep-rooted diapir marked by a southward evaporite lateral outpouring related to the Eocene Pyrenean compressive tectonic phase. The evaporite lateral flow should be controlled by reactivation of preexisting regional faults with its thermodynamic conditions and asymmetrical basin geometry. [ABSTRACT FROM AUTHOR]

Utilizing an updated dataset of 145 GNSS surface velocities, this study examines the fault slip rate and fault geometry along the Main Himalayan Thrust (MHT) in the central Himalaya. Employing a Bayesian inversion model, the present analysis reveals that the upper portion of the MHT ramp exhibits full locking, while the lower flat displays creeping motion. The estimated locking depth and fault depth of MFT range from 4.3 ± 2.6 km to 9.7 ± 2.2 km and 13.5 ± 3.1 km to 15.8 ± 1.9 km, respectively, along the central Himalaya. Further, the slip rate along the transition zone lies in the range of 1.4 ± 0.8 mm/yr to 2.7 ± 0.5 mm/yr. Considering the amount of uncertainties as ~1–2 mm/yr in GNSS velocities, the study suggests that the transition zone along the middle flat of the MHT also exhibits locking behavior. Thus, the estimated locking depth extends to ~15.0 km down-dip and covers a horizontal distance of ~90 km (locking line) on the surface, reaching the foothills of the Higher Himalaya. Furthermore, along the deeper flat of the MHT, the slip rate ranges from 19.4 ± 2.5 mm/yr in the west to 12.8 ± 1.6 mm/yr in the east along Nepal Himalaya. The analysis also calculates the slip deficit rate along the MHT fault plane, revealing values of ~15.1 mm/yr in western Nepal, ~12.7 mm/yr in central Nepal, and ~10.6 mm/yr in eastern Nepal. These slip deficit rates across different segments of central Nepal indicate the potential for large earthquakes in the region. The results are further supported by a resolution test using a checkerboard synthetic model, demonstrating the capability of the GNSS network to capture the slip rate along the MHT. These findings inevitably contribute to a comprehensive assessment of the seismic hazard potential in the central Himalayan region. [ABSTRACT FROM AUTHOR]

The stretching of the lithosphere leading to back-arc basins formation generally develops behind arc-trench systems and is considered the consequence of slab retreat relative to the upper plate. Here, we examine the deformation regime evolution within the overriding plate due to subduction processes, using thermo-mechanical numerical simulations. We explore the north-eastern Eurasia plate boundary and the mechanisms of subducting Pacific plate since 57 Ma. During this time interval, several extensional basins formed along the Eurasia margin, such as the East China Sea, the Japan Sea, and the Kuril basin. Here, we increased the simulation complexity, with the inclusion of (i) the kinematic variability of the Pacific plate over the geological past with respect to a fixed Eurasia, incorporating time-dependent (i.e., temporally evolving) velocities computed from plate motion reconstructions; (ii) a Low-Velocity Zone within the asthenosphere, and (iii) a horizontal eastward mantle flow. Our results show a crucial role of the mantle flow for the development of lithospheric extension and back-arc basin opening, and a main kinematic control of the subduction trench position, which advances and retreats, into distance intervals in the order of ∼ 100 km, and providing stages of compression and extension in a back-arc basin. [ABSTRACT FROM AUTHOR]

Surface roughness has a significant influence on the mechanical properties and service life of a component. During face milling, surface roughness greatly varies in the tool step direction and can be controlled by using a surface roughness prediction model. However, the issues of accuracy and efficiency of surface roughness prediction models have not been adequately addressed. This study aims to address these research constraints. An improved surface roughness prediction model is proposed, taking into consideration the influences of insert back cutting and stepover ratio. First, the profile-forming mechanism is analyzed based on geometry and kinematics. Subsequently, an improved surface roughness prediction model is established. Thereafter, the influence of feed per tooth, stepover ratio, corner radius, and minor cutting edge angle on surface roughness are analyzed through numerical simulation. Finally, the experiment of face milling aerospace aluminum alloy 7075 is suggested to verify the improved model, and the Z-Map model is introduced for comparison. Results show that the surface roughness is nonlinear with a feed per tooth and stepover ratio, a monotonic variation with corner radius, and a minor cutting edge angle. The predicted values of the improved model and the Z-Map model for the Rsm are equal to the experimental values. However, the improved model reduces the prediction error of Ra from 11.2 to 4.2% in the non-overlapping compared with the Z-Map model and from 62.58 to 13.34% in the overlapping. In addition, the improved model performs better than the Z-Map model in predicting the shape parameters. This work serves as a significant reference for selecting and optimizing the milling parameters to enable machining quality control. [ABSTRACT FROM AUTHOR]

To assess the skiing economy (SE) and kinematics during double poling (DP) roller skiing between two groups of skiers in a field setting. Five experienced and five novice male skiers performed a SEDP test at 16 km∙h−1 on an outdoor athletics track. Gas exchange parameters were measured to determine SEDP. A two-dimensional video was filmed to measure the kinematics variables. Experienced skiers exhibited a 21% lower oxygen cost than novice skiers (p = 0.016) in DP, indicating a strong association between SEDP, cycle length and cycle rate (p < 0.001). Additionally, before the poling phase, experienced skiers manifested significantly greater maximum hip and knee extension angles than novice skiers (p < 0.001). During the poling phase, experienced skiers with a greater pole plant angle (p = 0.001), longer flexion time (p < 0.001) and higher flexion angular velocity in the elbow joint (p < 0.05) demonstrated better SEDP. There was an interaction effect of the one-repetition maximum bench press × group in SEDP (b = − 0.656, SE = 0.097, t = − 6.78, p = 0.001). Therefore, experienced skiers with better SEDP demonstrated more efficient cycles, potentially accomplished using dynamic full-body DP motion to ascertain effective propulsion. Combined upper body strength and ski-specific skill training may enhance SEDP in novice skiers. [ABSTRACT FROM AUTHOR]

Wearable resistance (WR) and weighted vests (WV) can be used in almost all training conditions to enhance sprint performance; however, positioning and additional mass are different in WV and WR strategies, affecting performance and kinematics differently. We aimed to systematically review the literature, searching for intervention studies that reported the acute or chronic kinematic and performance impact of WV and WR and comparing them. We analyzed Pubmed, Embase, Scopus, and SPORTDiscuss databases for longitudinal and cross-over studies investigating sprint performance or kinematics using an inverse-variance with a random-effect method for meta-analysis. After the eligibility assessment, 25 studies were included in the meta-analysis. Cross-over WR and WV studies found significantly higher sprint times and higher ground contact times (CT) compared to unloaded (UL) conditions. However, WR presented a lower step frequency (SF) compared to UL, whereas WV presented a lower step length (SL). Only one study investigated the chronic adaptations for WR, indicating a superiority of the WR group on sprint time compared to the control group. However, no difference was found chronically for WV regarding sprint time, CT, and flight time (FT). Our findings suggest that using WV and WR in field sports demonstrates overload sprint gesture through kinematic changes, however, WR can be more suitable for SF-reliant athletes and WV for SL-reliant athletes. Although promising for chronic performance improvement, coaches and athletes should carefully consider WV and WR use since there is no supporting evidence that WV or WR will impact sprint performance, CT, and FT. [ABSTRACT FROM AUTHOR]

Purpose: Tourniquet use during total knee arthroplasty (TKA) remains controversial. There are limited data demonstrating the effect of tourniquet use on flexion and extension gaps. The use of a tourniquet can theoretically affect the kinematics of the knee joint, specifically the extension and flexion gaps and the laxity, by mechanically compressing the soft tissues including the muscles above the knee joint. Therefore, this study was designed to prospectively evaluate changes in flexion and extension gaps with and without the use of a tourniquet. Methods: The following prospective study included 50 consecutive patients who underwent TKA using a surgical robot. The inclusion criteria were advanced osteoarthritis (OA) and varus‐alignment or valgus‐alignment <3° (hip‐knee‐ankle angle, standing long‐leg X‐ray), and the exclusion criteria were BMI >35 kg/m2 and mechanical axis in >3° valgus. A CR‐TKA was performed, and the medial and lateral gaps (in mm) throughout the full range of motion in 10° increments were recorded. The procedure was conducted both with and without an applied tourniquet (350 mmHg). Results: No significant differences were observed in the medial joint space. By contrast, the lateral gap showed significant differences in 10–20° of flexion (with a tourniquet 1.9 mm vs. without a tourniquet 2.1 mm, p = 0.018), 20–30° (1.6 vs. 1.8 mm, p = 0.02), 100–110° (0.9 vs. 1.1 mm, p = 0.021), and 110–120° (0.8 vs. 1 mm, p = 0.038). Thus, at the above degrees of flexion on the lateral side, there was a decrease in the mean of 0.2 mm with the use of a tourniquet. Conclusion: Although the use of a tourniquet showed a detectable change in the lateral gap in four 10° segments of flexion, clinical relevance with an average difference of 0.2 mm is not achieved. Thus, the use of a tourniquet in TKA can still be advocated based on the presented data. Level of Evidence: Level I. [ABSTRACT FROM AUTHOR]

Self-propelled oscillating foils provide an effective model system to explore the intricacies of oscillatory and undulatory bio-locomotion, particularly the coupled thrust and drag mechanism that enable self-propulsion. Here, we explain the design, construction, and working of an experimental apparatus that can achieve self-propulsion. Our apparatus utilizes a long, freely rotating arm pivoted on one end and houses the airfoil on the other. The novelty of the apparatus is a spiral-spring-based crank rocker mechanism employed to provide the necessary sinusoidal actuation to the airfoil. We discuss the kinematics of a four-bar crank-rocker mechanism and identify the conditions under which the rocker motion can be approximated as sinusoidal. We describe the mechanism's design and construction with these kinematic constraints, test it under various loading conditions, and observe that it can produce sinusoidal actuation up to 20°. As a characterization, we use the apparatus to record the self-propulsion speed in two airfoil models – rigid (NACA0015) and hybrid (NACA0015 with flexible flap). Our results demonstrate high repeatability and less than a 2% error in all cases. The apparatus can attain self-propelling speeds ranging from 1 cm/s to almost 45 cm/s. Additionally, we explore potential applications for the mechanism, such as in large robotic fishes. [ABSTRACT FROM AUTHOR]

Purpose: Performance is the benchmark to assess the level of an athlete: in this respect, a more precise qualitative and quantitative evaluation of the performance represents an important target to be achieved. Methods: The work presents a possible method, based on the biomechanical evaluation of the motor exercise with an optoelectronic system, to characterise single or multiple repetitions of pull-ups of 12 athletes of sport climbing and sportive healthy subjects, monitoring and scoring the performance and the safety of the executions. The analysis includes the time courses of the segmental kinematics and some newly developed synthetic indices in the form of performance and safety scores. Results: The time courses make it possible to analyse the linear and angular kinematics district-by-district and have a direct overview of the ranges of motion, the patterns of task execution, together with the possible strategies adopted to complete the exercise in terms of compensations. The proposed characterisation provides a condensed summary of the global execution quality and offers the possibility to identify which single biomechanical parameters are modified. Conclusion: The method is intended as a practical tool to enrich the training schedule in terms of the qualitative and quantitative evaluation of the performances and to increase the self-awareness while training. [ABSTRACT FROM AUTHOR]

Purpose: Exercise intensity during walking can be increased by attaching an external load or accelerating the walking speed. However, the combination of these effects on the human body remains unclear. To investigate the influence of different walking speeds and ankle weight loads on metabolic and neuromuscular responses and lower limb kinematics during walking. Methods: Twelve healthy participants walked on a treadmill under eight conditions (speed: 4 and 7 km/h × ankle weight loads: 0, 2, 4, and 6 kg). We recorded V ˙ O 2 , heart rate (HR), lower limb neuromuscular activities, and kinematic data. Results: The interaction effect of speed and ankle weight load on V ˙ O 2 and HR was significant (p < 0.05). V ˙ O 2 and HR were higher during walking at 7 than 4 km/h (p < 0.05). V ˙ O 2 rapidly rose with an increase in ankle weight loading from 4 to 6 kg during walking at 7 km/h compared with that at 4 km/h (p < 0.05). Rectus femoris proximal activity with 6 kg ankle weight loading was higher than that under the no-loading condition during walking at 7 km/h (p < 0.05). During walking at 4 km/h, medial gastrocnemius muscle activity with 4- and 6 kg ankle weight loading was significantly higher than under the no-loading condition (p < 0.05). All targeted lower limb muscle activity and the maximum hip flexion angle were greater during walking at 7 than 4 km/h. Conclusion: Our results suggest that the effect of ankle weight loading on metabolic and neuromuscular responses is potentiated by a faster walking speed. [ABSTRACT FROM AUTHOR]

Purpose: Increasing access to marker-less technology has enabled practitioners to obtain kinematic data more quickly. However, the validation of many of these methods is lacking. Therefore, the validity of pre-trained neural networks was explored in this study compared to reflective marker tracking from sagittal plane cycling motion. Methods: Twenty-six cyclists were assessed during stationary cycling at self-selected cadence and moderate intensity exercise. Standard video from their sagittal plane was obtained to extract joint kinematics. Hip, knee, and ankle angles were calculated from marker digitisation and from two deep learning-based approaches (TransPose and MediaPipe). Results: Typical errors ranged between 1 and 10° for TransPose and 3–9° for MediaPipe. Correlations between joint angles calculated from TransPose and marker digitalization were stronger (0.47–0.98) than those from MediaPipe (0.25–0.96). Conclusion: TransPose seemed to perform better than MediaPipe but both methods presented poor performance when tracking the foot and ankle. This seems to be associated with the low frame rate and image resolution when using standard video mode. [ABSTRACT FROM AUTHOR]

The computation of master integrals from their differential equations requires boundary values to be supplied by an independent method. These boundary values are often desired at singular kinematical points. We demonstrate how the auxiliary mass flow technique can be extended to compute the expansion coefficients of master integrals in a singular limit in an analytical manner, thereby providing these boundary conditions. To illustrate the application of the method, we re-compute the phase space integrals relevant to initial-final antenna functions at NNLO, now including higher-order terms in their ϵ-expansion in view of their application in third-order QCD corrections. [ABSTRACT FROM AUTHOR]

In this work, we present a complete theoretical framework for analyzing the distribution of polarized hadrons within jets, with and without measuring the transverse momentum relative to the standard jet axis. Using soft-collinear effective theory (SCET), we derive the factorization and provide the theoretical calculation of both semi-inclusive and exclusive fragmenting jet functions (FJFs) under longitudinal and transverse polarization. With the polarized FJFs, one gains access to a variety of new observables that can be used for extracting both collinear and transverse momentum dependent parton distribution functions (PDFs) and fragmentation functions (FFs). As examples, we provide numerical results for the spin asymmetry A TU , T cos ϕ S − ϕ ̂ S h from polarized semi-inclusive hadron-in-jet production in polarized pp collisions at RHIC kinematics, where a transversely polarized quark would lead to the transverse spin of the final-state hadron inside the jet and is thus sensitive to the transversity fragmentation functions. Similarly, another spin asymmetry, A TU , L cos ϕ q − ϕ S from polarized exclusive hadron-in-jet production in polarized ep collisions at EIC kinematics would allow us to access the helicity fragmentation functions. These observables demonstrate promising potential in investigating transverse momentum dependent PDFs and FFs and are worthwhile for further measurements. [ABSTRACT FROM AUTHOR]

Maximal sprinting in humans requires the contribution of various muscle–tendon units (MTUs) and joints to maximize performance. The plantar flexor MTU and ankle joint are of particular importance due to their role in applying force to the ground. This narrative review examines the contribution of the ankle joint and plantar flexor MTUs across the phases of sprinting (start, acceleration, and maximum velocity), alongside the musculotendinous properties that contribute to improved plantar flexor MTU performance. For the sprint start, the rear leg ankle joint appears to be a particularly important contributor to sprint start performance, alongside the stretch–shortening cycle (SSC) action of the plantar flexor MTU. Comparing elite and sub-elite sprinters revealed that elite sprinters had a higher rate of force development (RFD) and normalized average horizontal block power, which was transferred via the ankle joint to the block. For the acceleration phase, the ankle joint and plantar flexor MTU appear to be the most critical of the major lower limb joints/MTUs. The contribution of the ankle joint to power generation and positive work is minimal during the first stance, but an increased contribution is observed during the second stance, mid-acceleration, and late-acceleration. In terms of muscular contributions, the gastrocnemius and soleus have distinct roles. The soleus acts mainly as a supporter, generating large portions of the upward impulse, whereas the gastrocnemius acts as both an accelerator and a supporter, contributing significantly to propulsive and upward impulses. During maximum velocity sprinting the ankle joint is a net dissipater of energy, potentially due to the greater vertical loading placed on the plantar flexors. However, the ankle joint is critical for energy transfer from proximal joints to ground force application to maintain velocity. In terms of the contribution of musculoskeletal factors to ankle joint and plantar flexor performance, an optimal plantar flexor MTU profile potentially exists, which is possibly a combination of several musculoskeletal factors, alongside factors such as footwear and technique. [ABSTRACT FROM AUTHOR]

Geomorphological and sedimentological characteristics are key evidences for understanding the emplacement mechanisms of rock avalanches. Based on remote sensing, photogrammetry, and field surveys, the depositional characteristics of the Alasu rock avalanche (ARA) in southern Tianshan, China, were investigated in detail. It is reached that the ARA has a detached rock mass volume of ~ 93 × 106 m3 and propagated 3874 m on rugged terrain with a drop height of 1030 m. Large rock blocks (95,598 rock blocks with sizes ≥ 0.5 m) are widely distributed on the deposit surface. There is no decreasing trend in block size with travel distance for these rock blocks, while jigsaw and sibling structures of megablocks commonly occur in the carapace facies. The size and structural features of megablocks demonstrate that the carapace facies underwent a passive emplacement process with low degrees of fragmentation and disturbance. Furthermore, a series of surficial landforms, including irregular platforms, minor scarps, lateral levees, run-ups, ridges, and troughs, are preserved in the rock avalanche deposit. The most remarkable features are the large, subparallel, curved longitudinal ridges with continuous directional variations and three run-up traces. Extensions of these ridges indicate that the avalanche mass experienced a continuous extension-dominated process in emplacement due to its momentum transfer effect and high energy propagation. These observations and analyses may elucidate the emplacement mechanisms of rock avalanches in rugged landscapes. [ABSTRACT FROM AUTHOR]

Task conditions significantly impact human motor control. We investigated how task type, difficulty, and constraints influence the kinematics of goal-directed arm reaching. Non-disabled young adults performed two distinct goal-directed arm reaching tasks: pointing and picking up an object with chopsticks. These tasks were carried out under various conditions, including constrained and unconstrained elbow extension and two different task difficulties. We collected kinematic data using a 3-D motion capture system and analyzed the effects of different task conditions on kinematic variables using linear mixed-effects regression analysis. Our findings revealed statistically significant differences in kinematics between the two tasks. Arm reaching during the picking-up task was slower and exhibited jerkier movements compared to the pointing task. Additionally, when arm reaching was performed with constrained elbow extension, it led to slower and jerkier movements, with an increased involvement of trunk movements compared to the unconstrained condition. These findings show that complex manipulative motor tasks requiring higher hand dexterity necessitate feedback-based control of arm reaching, but simple pointing tasks requiring less hand dexterity do not. In conclusion, our study sheds light on the influence of task conditions on goal-directed arm reaching kinematics and provides valuable insights into the motor control strategies involved in different tasks. [ABSTRACT FROM AUTHOR]

The research on state estimation for quadruped robots is critical. Its result passed to motion controller makes the robot navigate autonomously and adjust the gait to a more stable motion. The current research depends on a multi-sensor fusion of cameras, lidars or other proprioceptive sensors, such as Inertial Measurement Unit (IMU) and encoders. The high-frequency data are generally derived from body sensors, which is to be fused with data from external sensors directly, or preprocessed with EKF first. Due to its unguaranteed convergence and robustness of tracking state mutations, EKF is insufficient. Therefore, we study state estimation for hydraulic quadruped robot based on the fusion of IMU measurement and leg odometry in this paper, and Invariant Extended Kalman Filter (IEKF) is successfully applied to quadruped robots by using this method. Besides, neural networks are utilized to train the weight functions of foot force and the state of leg odometry, and our trained functions improve the accuracy of observation compared with common weight average methods. Finally, our experiments of accuracy show that the root mean square error of our method is significantly reduced and the absolute trajectory error is reduced by 30% compared to traditional IEKF. The algorithm achieves the drift per distance travelled below 4 cm/m. Moreover, it has good robustness. [ABSTRACT FROM AUTHOR]

We study the role of 1 → 2 and 1 → 3 processes in triple charmonium production in the leading logarithmic approximation (LLA). We see that the ratio of effective cross sections of TPS and DPS only moderately depends on charmonium transverse momenta, but the total DPS and TPS cross sections each separately may have rather strong dependence on charmonia transverse momenta in the central kinematics region that can be studied experimentally. [ABSTRACT FROM AUTHOR]

Objective: Numerous factors affect abductor strength after Total hip arthroplasty (THA), including surgical technique, prosthesis type, postoperative rehabilitation program, and preoperative patient condition. We prospectively investigated the effects of the modified Hardinge approach on hip muscle strength, which was evaluated using the isokinetic test, functional results, and gait function of patients who underwent primary THA. Methods: The hip muscles strength were measured using an isokinetic dynamometer. The primary outcomes of the present study were measurement of isokinetic strength of hip abductor muscle strengths using an isokinetic evaluator and gait analyses preoperatively and at 6 months postoperatively in 27 patients. Results: Isokinetic muscle strength test, abductor and other hip circumference groups achieved the preoperative muscle strength at 3 months postoperatively, and the postoperative sixth month values showed a statistically significant improvement compared with the preoperative and third month values. In gait analyze, our temporospatial data showed a slight regression at postoperative 3 months but reached the same values at 6 months postoperatively. Kinematic data showed a significant regression, but the data were not compared with those in the preoperative period. Conclusions: Adequate muscle strength and physiological gait pattern, similar to the preoperative status, can be achieved at 6 months postoperatively. Level of evidence: Level III. [ABSTRACT FROM AUTHOR]

Purpose: Running at a given speed can be achieved by taking large steps at a low frequency or on the contrary by taking small steps at a high frequency. The consequences of a change in step frequency, at a fixed speed, affects the stiffness of the lower limb differently. In this study, we compared the running mechanics and kinematics at different imposed step frequencies (from 2 step s−1 to 3.6 step s−1) to understand the relationship between kinematic and kinetic parameters. Methods: Eight recreational male runners ran on a treadmill at 5 different speeds and 5 different step frequencies. The lower-limb segment motion and the ground reaction forces were recorded. Mechanical powers, general gait parameters, lower-limb movements and coordination were investigated. Results: At low step frequencies, in order to limit the magnitude of the ground reaction force, the vertical stiffness is reduced and thus runners deviate from an elastic rebound. At high step frequencies, the stiffness is increased and the elastic rebound is optimised in its ability to absorb and restore energy during the contact phase. Conclusion: We studied the consequences of a change in step frequency on the bouncing mechanics of running. We showed that the lower limb stiffness and the intersegmental coordination of the lower-limb segments are affected by running step frequency rather than speed. The runner rather adapts their lower limb stiffness to match a step frequency for a given speed than the opposite. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to find a standard of the vertebra kinematics during functional weight-bearing activities in degenerative lumbar scoliosis (DLS) patients. Methods: Fifty-four patients were involved into this study with forty-two in DLS group and twelve in the control group. The three-dimensional (3D) vertebral models from L1 to S1 of each participant were reconstructed by computed tomography (CT). Dual-orthogonal fluoroscopic imaging, along with FluoMotion and Rhinoceros software, was used to record segmental vertebral kinematics during functional weight-bearing activities. The primary and coupled motions of each vertebra were analyzed in patients with DLS. Results: During flexion–extension of the trunk, anteroposterior (AP) translation and craniocaudal (CC) translation at L5–S1 were higher than those at L2–3 (9.3 ± 5.1 mm vs. 6.4 ± 3.5 mm; P < 0.05). The coupled mediolateral (ML) translation at L5–S1 in patients with DLS was approximately three times greater than that in the control group. During left–right bending of the trunk, the coupled ML rotation at L5–S1 was higher in patients with DLS than that in the control group (17.7 ± 10.3° vs. 8.4 ± 4.4°; P < 0.05). The AP and CC translations at L5–S1 were higher than those at L1–2, L2–3, and L3–4. During left–right torsion of the trunk, the AP translation at L5–S1 was higher as compared to other levels. Conclusions: The greatest coupled translation was observed at L5–S1 in patients with DLS. Coupled AP and ML translations at L5–S1 were higher than those in healthy participants. These data improved the understanding of DLS motion characteristics. [ABSTRACT FROM AUTHOR]

Ground reaction force and moment (GRF&M) measurements are vital for biomechanical analysis and significantly impact the clinical domain for early abnormality detection for different neurodegenerative diseases. Force platforms have become the de facto standard for measuring GRF&M signals in recent years. Although the signal quality achieved from these devices is unparalleled, they are expensive and require laboratory setup, making them unsuitable for many clinical applications. For these reasons, predicting GRF&M from cheaper and more feasible alternatives has become a topic of interest. Several works have been done on predicting GRF&M from kinematic data captured from the subject's body with the help of motion capture cameras. The problem with these solutions is that they rely on markers placed on the whole body to capture the movements, which can be very infeasible in many practical scenarios. This paper proposes a novel deep learning-based approach to predict 3D GRF&M from only 5 markers placed on the shoe. The proposed network "Attention Guided MultiResUNet" can predict the force and moment signals accurately and reliably compared to the techniques relying on full-body markers. The proposed deep learning model is tested on two publicly available datasets containing data from 66 healthy subjects to validate the approach. The framework has achieved an average correlation coefficient of 0.96 for 3D ground reaction force prediction and 0.86 for 3D ground reaction momentum prediction in cross-dataset validation. The framework can provide a cheaper and more feasible alternative for predicting GRF&M in many practical applications. [ABSTRACT FROM AUTHOR]

Biting to obtain attached benthic prey characterizes a large number of fish species on coral reefs, and is a feeding mode that contributes to important ecosystem functions. We use high-speed video to reveal the mechanisms used by a surgeonfish, Acanthurus leucosternon, to detach algae. After gripping algae in its jaws, the species pulls it by ventrally rotating both the head and the closed jaws, in a novel use of the intra-mandibular joint. These motions remain in the plane of the fish, reducing the use of a lateral head flick to detach the algae. The novel ability to bite and pull algae off the substrate without bending the body laterally minimizes exposure to high water flows, and may be an adaptation to feeding in challenging reef habitats such as the crest and flat. Therefore, our results could potentially represent a key milestone in the evolutionary history of coral reef trophodynamics. High-speed video of feeding in a surgeonfish reveals novel functions, and suggests an adaptation to feeding in high flow environments, as well as how fish interact with the substrate [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to compare the long‐term objective biomechanical and functional parameters of a high‐flexion total knee arthroplasty (TKA) design against healthy older adults to determine whether knee biomechanics are comparable in both populations. Methods: One cohort of patients with a primary TKA, and a cohort of healthy adults over 55 years old with no musculoskeletal deficits or arthritis participated. Bilateral knee range of motion (RoM) was assessed with a goniometer, and gait patterns were analysed with a three‐dimensional‐motion capture system. An arthrometer quantified the anterior‐posterior laxity of each knee. Statistical analyses were performed in SPSS software (α = 0.05). Results: Twenty‐three knees were replaced in 20 patients. At 9.8 ± 3.1 years postoperatively, patients' knees had a statistically significantly poorer RoM than healthy controls' knees (n = 23) due to limited flexion; p < 0.0001. Patients also failed to achieve the same degree of knee flexion as controls during downhill gait. No kinematic differences were observed during mid‐flexion in level nor downhill gait; a state that has been associated with instability (p = 0.614; not significant [n.s]). There were no differences between groups in knee laxity (n.s). Conclusion: Patients in this study had similar gait patterns to healthy older adults during mid‐flexion and were no more likely than the healthy controls to exhibit anterior‐posterior translation of the knee > 7 mm; a known risk factor of instability. However, the knee flexion range was poorer. This likely led to bilateral pathological knee flexion patterns during downhill gait. Level of Evidence: Level III. [ABSTRACT FROM AUTHOR]

This note provides a new point of view for bootstrapping the tree amplitudes of the nonlinear sigma model (NLSM). We use the universality of single soft behavior, together with the double copy structure, to completely determine the tree amplitudes of the NLSM. We first observe Adler's zero for four-point NLSM amplitudes, by considering kinematics. Then we assume the universality of Adler's zero and use this requirement to construct general tree amplitudes of the NLSM in the expanded formula, i.e., the formula of expanding NLSM amplitudes to bi-adjoint scalar amplitudes, which allows us to give explicit expressions of amplitudes with arbitrary numbers of external legs. The construction does not require the assumption of quartic diagrams. We also derive double soft factors for NLSM tree amplitudes based on the resulting expanded formula, and the results are consistent with those in the literature. [ABSTRACT FROM AUTHOR]

Two-dimensional simulations are performed to investigate the effects of flexible vortex generators (FVGs) on thermal performance using the immersed boundary method to consider the fluid-structure interaction. The two FVGs are mounted on the upper and lower walls, respectively, with a symmetric arrangement. The asymmetric feature of the system is obtained by adjusting their inclination angles differently. The kinematics of FVGs are analyzed, revealing deflected and flapping modes depending on their inclination angles. The heat transfer system with the deflected mode of FVGs shows a decreased thermal performance as compared to that of the system without the FVGs. For the inclination angle greater than 0.5π, the FVGs show the flapping mode, and the thermal performance is observed to be improved by about 2 ~ 11% except for the cases where the inclination angles are identical. The enhancement of the thermal performance is stably reached by adopting asymmetric FVGs with inclination angles greater than 0.5π. The vorticity and temperature fields are analyzed in detail to elucidate the mechanisms through which the asymmetric FVGs improve thermal performance. By spectral analysis, the relations between the flapping kinematics of the FVGs, heat transfer, and energy loss are clarified. [ABSTRACT FROM AUTHOR]

Objective: CT imaging precisely and quantitatively analyzes the kinematics of the carpal bones to evaluate the etiology of related osteoarthritis. Previous studies have investigated the kinematics of the trapeziometacarpal joint using static CT scans of various postures including the pinch position. This study analyzed the in-vivo kinematics of the trapeziometacarpal joint during dynamic pinch motion in young healthy volunteers using four-dimensional CT. Materials and methods: Twelve healthy young volunteers participated in this study. Each participant held the pinch meter between their thumb and index finger and pinched it with maximum force for a period of 6 s. This series of movement was recorded using a four-dimensional CT. The surface data of the trapezium and first metacarpal of all frames were reconstructed, and bone movement at the trapeziometacarpal joint was calculated using sequential three-dimensional registration. The instantaneous pinch force of each frame was measured using a pointer on a pinch meter that was reconstructed from the CT data. Results: The first metacarpal was abducted (15.9 ± 8.3°) and flexed (12.2 ± 7.1°) relative to the trapezium, and significantly translated to the volar (0.8 ± 0.6 mm) and ulnar directions (0.9 ± 0.8 mm) with maximum pinch force. This movement consistently increased with the pinch force. Conclusion: This study successfully employed 4D-CT to precisely demonstrate changes in rotation and translation at the trapeziometacarpal joint during pinch motion for various instantaneous forces. [ABSTRACT FROM AUTHOR]

Oriented by the demands on high-speed and large-load picking up/handling in textile, electronics and other industries, a novel parallel manipulator (PM) achieving SCARA motion was designed. First, the mobility of the PM was obtained by dual space theory. Thereafter, the kinematic model was deduced in detail, and a dynamics model was developed using the Lagrangian formulation. The validity of the above models was verified by ADAMS software. Furthermore, the singularity existing in the workspace was analyzed. Subsequently, a homogeneous Jacobian matrix was constructed by the characteristic length factor, based on which dexterity index was defined. Aiming at the optimal performance in the singularity-free task workspace, a dimensional synthesis model incorporating kinematics and dynamics performance is proposed, which is efficiently tackled by differential evolution (DE) algorithm. The obtained result provides a sound foundation for the development of an engineering prototype. [ABSTRACT FROM AUTHOR]

The article presents the discussion on reviewing a paper by Carl Woods, Duarte Araújo, and Keith Davids, emphasizing the importance of joining an ongoing conversation in sport science rather than providing a traditional review. Topics include challenges faced by sport and human movement scientists in understanding complex philosophical texts, and the value of participant observation in research.

Homotopy Lie algebras are a generalization of differential graded Lie algebras encoding both the kinematics and dynamics of a given field theory. Focusing on kinematics, we show that these algebras provide a natural framework for the description of generalized gauge symmetries using two specific examples. The first example deals with the non-commutative gauge symmetry obtained using Drinfel'd twist of the symmetry Hopf algebra. The homotopy Lie algebra compatible with the twisted gauge symmetry turns out to be the recently proposed braided L ∞ -algebra. In the second example, we focus on the generalized gauge symmetry of the double field theory. The symmetry includes both diffeomorphisms and gauge transformation and can consistently be defined using a curved L ∞ -algebra. [ABSTRACT FROM AUTHOR]

An algorithm for automatic approximation of the time dependence x(t) is built for the observed coordinate of the coronal mass ejection (CME) front from the admissible starting point to the first appearance in the field of view of the LASCO coronagraph and further, up to a heliocentric distance of ~25 solar radii (RS). In the region from the starting point to the first appearance of the CME, two sections are assumed, with uniform (impulsive) acceleration and with uniform motion; then, the motion is approximated by observations. At the beginning of the approximation, either the CME start time is found through the appearance of certain frequencies of radio emissions (RSTN data) and type II and IV radio emissions (sequence characteristics are determined by machine learning), or the start time is determined by averaging over the allowable takeoff area; then the polynomial-ballistic model is optimized. The first and second derivatives x(t) determine the speed and acceleration of the CME at any point of its trajectory. Such an algorithm is necessary to obtain the most accurate kinematic characteristics of CMEs, which can allow one to study the physical, spatial, and temporal relationships between flares and CMEs in all their diversity. Widely used approximation techniques simplify the real CME trajectories x(t), thereby possibly discarding important features of the CME kinematics and flare development in the posteruptive phase. The algorithm was trained and tested on 17 solar flares and associated CMEs, which are known for their powerful proton events with proton energies greater than 300 MeV. The rate of the first occurrence of CMEs turned out to be different from the average rate given in the LASCO catalog, which is important for estimating the energy of flares and CMEs. In 7 out of 17 events, there was acceleration only in the impulsive phase (and then deceleration), while acceleration in the impulsive and posteruptive phases occurred in 10 events. In 4 out of 17 events, CME velocities greater than 2000 km/s were reached at a distance of 20RS. The accuracy of determining the kinematic characteristics of CMEs can be improved by using additional observations, for example, SDO AIA in the September 10, 2017 event. [ABSTRACT FROM AUTHOR]

A highway embankment founded on a sloping tectonised marly-sandstone flysch formation located in the Apennines chain (Italy) has been affected for about 30 years by continuous slow movements. Given the strategic importance of the involved infrastructure, different investigation and monitoring campaigns have been carried out to get information about the properties of the involved soils and collect data about the displacements and piezometric regime. Field monitoring, in particular, reveals that the observed displacements result from a failure mechanism involving both the embankment and the foundation soils. However, significant gaps in monitoring jeopardize the possibility to assess the long-term trends in the displacements and piezometric regime and the significance of weather forcing in regulating the phenomena. To address such research questions, a procedure, easily transferable in different contexts, is proposed and applied to the test case: a simple hydrological proxy indeed permits evaluating the rate of movement featured by weatherinduced seasonal variability. Such a mechanical response has been confirmed by the results of a simplified numerical model aimed at finding out the main features of the observed kinematics accounting for a hydrological balance of the involved area. [ABSTRACT FROM AUTHOR]