Search

Introduction: The purpose of our report was to use a Random Forest classification approach to predict the association between transcutaneous electrical nerve stimulation (TENS) and walking kinematics at the stride level when middle-aged and older adults performed the 6-min test of walking endurance. Methods: Data from 41 participants (aged 64.6 ± 9.7 yr) acquired in two previously published studies were analyzed with a Random Forest algorithm that focused on upper and lower limb, lumbar, and trunk kinematics. The four most predictive kinematic features were identified and utilized in separate models to distinguish between three walking conditions: burst TENS, continuous TENS, and control. SHAP analysis and linear mixed models were used to characterize the differences among these conditions. Results: Modulation of four key kinematic features--toe-out angle, toe-off angle, and lumbar range of motion (ROM) in coronal and sagittal planes--accurately predicted walking conditions for the burst (82%accuracy) and continuous (77% accuracy) TENS conditions compared with control. Linear mixed models detected a significant difference in lumbar sagittal ROM between the TENS conditions. SHAP analysis revealed that burst TENS was positively associated with greater lumbar coronal ROM, smaller toe-off angle, and less lumbar sagittal ROM. Conversely, continuous TENS was associated with less lumbar coronal ROM and greater lumbar sagittal ROM. Conclusions: Our approach identified four kinematic features at the stride level that could distinguish between the three walking conditions. These distinctions were not evident in average values across strides. [ABSTRACT FROM AUTHOR]

Introduction: Maximal acceleration and deceleration tasks are frequently required in team sports, often occurring rapidly in response to external stimuli. Accelerating and decelerating can be associated with lower limb injuries; thus, knowledge of joint mechanics during these tasks can improve the understanding of both human high performance and injury mechanisms. The current study investigated the fundamental differences in lower limb joint mechanics when accelerating and decelerating by directly comparing the hip, knee, and ankle joint moments and work done between the two tasks. Methods: Twenty participants performed maximal effort acceleration and deceleration trials, with three-dimensional marker trajectories and ground reaction forces collected simultaneously. Experimental data were combined with inverse dynamics analysis to compute joint moments and work. Results: Net joint work for all lower limb joints was positive during acceleration and negative during deceleration. This occurred because of significantly greater positive work production from the ankle and hip during acceleration and significantly greater negative work production from all joints during deceleration. The largest contributions to positive work during acceleration came from the ankle, followed by the hip and knee joints, whereas the largest contributions to negative work during deceleration came from the knee and hip joints, followed by the ankle. Peak joint moments were significantly greater when decelerating compared with accelerating, except for the peak ankle plantar flexion and hip flexion moments, which were significantly greater when accelerating. Conclusions: Our findings may help to guide training interventions, which aim to enhance the performance of acceleration and deceleration tasks, while also mitigating the associated injury risk. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the immediate effect of Dynamic TapeTM (DT) on hip muscle activation and torque and on lower limb kinematics. Forty-five healthy, recreationally active women were randomly assigned to three groups: 1) submitted to the application of DT in the active form in the gluteus medius (GMed) muscle (BG; n = 15), 2) submitted to the application of DT in the placebo form in the GMed muscle (PG; n = 15), and 3) not submitted to any intervention (CG; n = 15). Participants were evaluated for GMed and gluteus maximus (GMax) muscle activation in a maximal voluntary isometric contraction, simultaneously with the assessment of the hip abductor and extensor torques, as well as during two functional tasks – single leg squat (SLS) and jump landing + maximum vertical jump (VJ) – simultaneously with a 2-D kinematic assessment of the lower limb. After DT application in BG, there was a significant decrease in the hip abductor time to peak torque (P = 0.004), hip extensor torque (P = 0.02), excursion to hip adduction (P = 0.007), and to knee flexion (P = 0.02) during the SLS, as well as in GMed activation during VJ (P < 0.05). DT was able to reduce GMed activation and modify lower limb torque and kinematics. [ABSTRACT FROM AUTHOR]

An unconventional and innovative mechanical transmission component, the curved groove ball bearing without retainer (CGBBR), is introduced in this article to facilitate the conversion between rotational and reciprocating motion. The CGBBR boasts several advantages over conventional motion conversion mechanisms, including a streamlined and compact structure, as well as the mitigation of high-order vibrations. This article delves into the design methodology, structural attributes, kinematic principles, and dynamic response properties of the CGBBR. A novel design method named closed curve envelopment theory is proposed to generate the distinctive spatial surface structure of the CGBBR. Moreover, a design scheme is presented that employs the concept of diameter-stroke ratio for CGBBR implementation. A calculation methodology is also introduced for determining the number of rolling elements within the CGBBR, which serves as the foundation for subsequent optimization design. This article deeply analyzes the kinematics principle of CGBBR and provides a new insight of motion conversion in mechanism. [ABSTRACT FROM AUTHOR]

Limited research exists on the relationship between aesthetic saut de chat performance and muscle-tendon unit (MTU) characteristics of dancers. We developed a weighted parameter ranking (WPR) tool to incorporate aesthetic leaping aspects (i.e., height, peak split angle, average trunk angle and trunk angle range) for correlation with MTU properties. The purpose was to identify the relationship of saut de chat WPR and leap height with maximal plantarflexion strength, medial gastrocnemius (MG) stiffness, Achilles tendon (AT) stiffness and relative peak power (PP). Dancers (n = 18) performed maximal plantarflexion, short-range stretches and isometric ramping contractions on a dynamometer equipped with ultrasound to determine strength, MG stiffness and AT stiffness, respectively. Subjects then performed saut de chat leaps atop force platforms surrounded by motion capture cameras. A principal component analysis (PCA) was performed to compare WPR variable weightings with PCA results and rankings. Moderate–strong relationships were identified among WPR, maximal plantarflexion strength, MG stiffness and PP. Strong–very strong relationships were also identified between leap height and maximal plantarflexion strength, MG stiffness, AT stiffness, peak split angle and PP. A very strong correlation existed between PCA rankings and WPRs. Practitioners may consider developing strength and power capabilities in dancers to improve leaping. [ABSTRACT FROM AUTHOR]

Performance during the baseball pitch is dependent on the flow of mechanical energy through the kinetic chain. Little is known about energy flow during the pitching motion and it is not known whether patterns of energy flow are related to pitching performance and injury risk. Therefore, the purpose of this study was to quantify energy generation, absorption, and transfer across the shoulder and elbow during the baseball pitch and explore the associations between these energetic measures, pitch speed, and traditional measures of upper extremity joint loading. The kinematics of 40 youth baseball pitchers were measured in a controlled laboratory setting. Energy flow between the thorax, humerus, and forearm was calculated using a segmental power analysis. Regression analyses revealed that pitch speed was best predicted by arm cocking phase shoulder energy transfer to the humerus and peak elbow valgus torque was best predicted by arm acceleration-phase elbow energy transfer to the forearm. Additionally, energy transfer across the shoulder and elbow generally exhibited the strongest correlations to pitch speed and upper extremity joint loads. These data reinforce the importance of energy transfer through the kinetic chain for producing high pitch speeds and provide descriptive data for energy flow during baseball pitching not previously found in the literature. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the regularity of the lower limb joint kinematics in runners with and without a history of running-related injuries. The second aim was to verify if the movement pattern regularities are different among the lower limb joints. Eighteen asymptomatic recreational runners with and without a history of running-related injury participated in this study. Lower limb kinematics in the sagittal plane were recorded during running on a treadmill at a self-selected speed. The regularities of the time series of hip, knee, and ankle were analysed using sample entropy (SampEn). A mixed analysis of variance was used to investigate differences between groups and among joints. Runners with a history of injury had lower SampEn values than runners without a history of injury. Ankle kinematics SampEn was higher than that of the knee and hip. Knee kinematics had higher values of SampEn than that of the hip. Runners with a history of running-related injury had greater joint kinematic's regularity. This result suggests that, even in asymptomatic runners, previous injuries could influence the movement pattern regularity. Also, the regularity was different among joints. The ankle demonstrated the lowest regularity, reinforcing the different functions that lower limb joints perform during running. [ABSTRACT FROM AUTHOR]

This study was aimed to compare the knee kinematic parameters between dominant and non-dominant legs of adolescent female athletes during change of direction (CoD) in fatigued and unpredictable settings. Knee kinematic parameters on 49 athletes (mean± SD; age = 14.69 ± 0.14 years; mass = 49.05 ± 1.22 kg; height = 1.61 ± 0.08 m) during CoD before and after performing the Bruce protocol and also in predictable and unpredictable setting situations were collected. Kinematic data were recorded at a sampling rate of 200 Hz. The results showed that the dominant leg had significantly 18.7% more flexion (p = 0.001, η = 0.95), 7.1% less valgus (p = 0.001, η = 0.95) and 0.32% lower tibia rotation (p = 0.003, η = 0.16) compared to the non-dominant leg in predictable and pre-fatigue (p < 0.05) conditions. With unpredictable and post-fatigue conditions the dominant limb again demonstrated 17.4% (p = 0.001, η = 0.67), greater knee flexion, 6.8% (0.003,η = 0.97) lower knee valgus and 1.4% (p = 0.001, η = 0.71) less tibiarotation. In conclusion, there may be an increased risk of injury withthe non-dominant leg due to changes in kinematic parameters caused by fatigue and unpredictable CoD manoeuvres. [ABSTRACT FROM AUTHOR]

The study objective is to test general- and sport-specific adaption during a single training on the Flexibility Trainer. The device is designed to trigger residual muscle tone decreases of the hip-joint muscles by providing (nearly) isokinetic resistance during a full range of motion strength training in adduction/abduction and flexion/extension direction. Static hip flexion and abduction as well as kinematics of double side kicks were analysed on 15 participants before and after training (or rest for controls) to assess general flexibility and sport-specific movement range. Tests were recorded by a Vicon® motion capturing system. Static hip flexion and abduction as well as leg vector spreading angles (VSA) at different nodes of the kick were selected to determine adaptions of active and passive flexibility. Normalised hip joint moments, movement velocities and VSA were calculated to evaluate the training with the device. ANOVAs with 4-repeated measures and Friedman tests were performed to identify time differences and Bonferroni post-hoc test to identify between-subject effects. Significant differences were found for both static flexibility tests (Flexion = 13.65%; Abduction = 9.94%) and the VSA at specific action phases (≤15.15%). Results indicate that short-term adaptions when training with the Flexibility Trainer are exceeding comparable literature showing improved flexibility and sport-specific performance. [ABSTRACT FROM AUTHOR]

This study addresses the practical challenges associated with real-time kinematic relative navigation for cube satellites (CubeSats) performing rendezvous missions in a low Earth orbit (LEO). Considering the limitations of CubeSats, we propose a method to achieve precise centimeter-level relative navigation using single-frequency Global Positioning System (GPS) measurements. By using GPS visibility and minimizing errors in the LEO, our approach eliminates the need for additional sensors. We employed range-domain differential GPS with a Hatch filter to enhance the pseudorange accuracy. Double-difference integer ambiguities were resolved epoch-by-epoch using the least-squares ambiguity decorrelation adjustment (LAMBDA) technique without filters, to ensure efficiency. The algorithm was applied to CubeSat hardware, integrating cycle-slip detection and CubeSat-tailored ground plane designs. Simulations validated the algorithm's performance in LEO, and its real-world efficacy was evaluated through ground-based measurements in an open-sky environment. Considering hardware constraints, our method demonstrates the feasibility of achieving centimeter-level relative navigation for CubeSats, effectively and economically addressing a crucial need in autonomous space missions. [ABSTRACT FROM AUTHOR]

Network real-time kinematic (NRTK) coverage is defined as the area inside a station network. In conventional NRTK, the distance between stations is limited to 100 km, thus restricting the coverage of NRTK. In this study, we propose the utilization of an ionospheric-free combination and the application of a Kriging weighting model to mitigate tropospheric delay to extend the coverage of NRTK through network expansion. A network with station distances exceeding 100 km was constructed, and the residual errors, along with the success-fix rate of integer ambiguities, were analyzed on both sunny and rainy days to confirm the potential for network expansion using the proposed method. The results confirm that the success-fix rate increased by up to 44.3% on rainy days, compared with that of the traditional interpolation method. Furthermore, a high level of performance in integer ambiguity resolution can be maintained within the expanded network, regardless of the weather conditions. [ABSTRACT FROM AUTHOR]

We present deep, sub-arcsecond (⁠|$\sim$| 2000 au) resolution ALMA 0.82-mm observations of the former high-mass prestellar core candidate G11.92–0.61 MM2, recently shown to be an |$\sim$| 500 au-separation protobinary. Our observations show that G11.92–0.61 MM2, located in the G11.92–0.61 protocluster, lies on a filamentary structure traced by 0.82-mm continuum and N |$_2$| H |$^+$| (4-3) emission. The N |$_2$| H |$^+$| (4-3) spectra are multipeaked, indicative of multiple velocity components along the line of sight. To analyse the gas kinematics, we performed pixel-by-pixel Gaussian decomposition of the N |$_2$| H |$^+$| spectra using scousepy and hierarchical clustering of the extracted velocity components using acorns. Seventy velocity- and position-coherent clusters (called 'trees') are identified in the N |$_2$| H |$^+$| -emitting gas, with the eight largest trees accounting for |$\gt $| 60 per cent of the fitted velocity components. The primary tree, with |$\sim$| 20 per cent of the fitted velocity components, displays a roughly north–south velocity gradient along the filamentary structure traced by the 0.82-mm continuum. Analysing an |$\sim$| 0.17 pc-long substructure, we interpret its velocity gradient of |$\sim$| 10.5 km s |$^{-1}$|  pc |$^{-1}$| as tracing filamentary accretion towards MM2 and estimate a mass inflow rate of |$\sim 1.8\times 10^{-4}$| to 1.2 |$\times 10^{-3}$|  M |$_\odot$| yr |$^{-1}$|⁠. Based on the recent detection of a bipolar molecular outflow associated with MM2, accretion on to the protobinary is ongoing, likely fed by the larger scale filamentary accretion flows. If 50 per cent of the filamentary inflow reaches the protostars, each member of the protobinary would attain a mass of 8 M |$_\odot$| within |$\sim 1.6\times 10^5$| yr, comparable to the combined time-scale of the 70- μ m- and mid-infrared-weak phases derived for ATLASGAL-TOP100 massive clumps using chemical clocks. [ABSTRACT FROM AUTHOR]

Inspired by the recent algebraic approach to classical field theory, we propose a more general setting based on the manifold of smooth sections of a non-trivial fiber bundle. Central is the notion of observables over such sections, i.e., appropriate smooth functions on them. The kinematics will be further specified by means of the Peierls brackets, which in turn are defined via the causal propagators of linearized field equations. We shall compare the formalism we use with the more traditional ones. [ABSTRACT FROM AUTHOR]

Background During sprinting, the biceps femoris long head predominantly gets injured, while hamstring strengthening exercises predominantly activate the semitendinosus more effectively. Understanding how joint dominance influences hamstring activity may offer clarity on appropriate exercise selection in strengthening programs. Purpose This study compared three hip-dominant hamstring exercises: the rocker, perpetuum mobile fast and slow (PMfast and PMslow) and the Nordic Hamstring exercise (NHE) on their potential to simulate sprint-like activity and kinematics. Methods Muscle activity of the posterior kinetic chain (biceps femoris, semitendinosus, gluteus maximus, and medial gastrocnemius) was measured with surface electromyography (sEMG) during the exercises and treadmill running at 75% of the individual maximal sprint velocity in male athletes. sEMG data were normalized to maximal sprinting. 3D-motion capture was employed to assess hip and knee angles. Results Eight male athletes were included (age: 24.0 years ± SD 2.9; body mass: 76.8 kg ± 7.7; height: 1.79 m ± 0.08). Greater activity of the hamstrings occurred during the explosive exercises ranging from 63.9% [95%CI: 56.3-71.5%] (rocker) to 49.0% [95%CI: 40.4-57.6%] (PMfast) vs. 34.0% [95%CI: 29.1-38.9%] (NHE) to 32.1% [95%CI: 26.9-37.3%] (PMslow). The rocker showed greatest hamstring and gluteus maximus activity. Biceps femoris consistently showed greater activity than the semitendinosus across all exercises in peak (mean difference: 0.16, [95%CI: 0.07-0.26]) and average (mean difference: 0.06, [95%CI: 0.01-0.11]) activity. PMfast, PMslow and NHE demonstrated less hip flexion angle at peak hamstring activity than the rocker and high-speed running and every exercise showed less hamstring elongation stress than during high-speed running. Discussion Hamstring activity is comparable to high-intensity treadmill running for NHE and PMslow, and greater for the rocker and PMfast. Gluteus maximus activity varied, with the rocker and PMfast showing greater activity than in sprinting. All examined exercises demonstrated their peak activity at short hamstring muscle length. Level of evidence 3b [ABSTRACT FROM AUTHOR]

Background Sidestep cutting technique is highly individual and has been shown to influence knee joint loading. However, studies assessing whether individualized technique feedback improves technique and ACL injury-relevant knee joint loads instantly in a sport-specific task are lacking. Purpose To determine the instant effects of individualized augmented technique feedback and instructions on technique and the peak external knee abduction moment (pKAM) in a handball-specific sidestep cut. Additionally, to determine the effects of technique modifications on the resultant ground reaction force and its frontal plane moment arm to the knee joint center. Study Design Controlled laboratory cohort study Methods Three-dimensional biomechanics of 48 adolescent female handball players were recorded during a handball-specific sidestep cut. Following baseline cuts to each side, leg-specific visual and verbal technique feedback on foot strike angle, knee valgus motion, or vertical impact velocity using a hierarchically organized structure accounting for the variables' association with performance was provided. Subsequently, sidestep cuts were performed again while verbal instructions were provided to guide technique modifications. Combined effects of feedback and instructions on technique and pKAM as well as on the resultant ground reaction force and its frontal plane moment arm to the knee joint center were assessed. Results On average, each targeted technique variable improved following feedback and instructions, leading to instant reductions in pKAM of 13.4% to 17.1%. High inter-individual differences in response to feedback-instruction combinations were observed. These differences were evident in both the adherence to instructions and the impact on pKAM and its components. Conclusion Most players were able to instantly adapt their technique and decrease ACL injury-relevant knee joint loads through individualized augmented technique feedback, thereby potentially reducing the risk of injury. More research is needed to assess the retention of these adaptations and move towards on-field technique assessments using low-cost equipment. Level of Evidence: Level 3 [ABSTRACT FROM AUTHOR]

BACKGROUND: There is a lack of information about the optimal setup of multiple screen configurations in virtual reality (VR) office work. OBJECTIVE: The objective of this study was to evaluate the effects of different screen configurations on neck flexion, rotation, neck muscle activity, and simulator sickness symptoms during Virtual Reality (VR) office work. METHODS: Twelve participants (7 males; 21 to 27 years old) performed copy-paste and drag-drop tasks in three different screen configurations (single screen, primary-secondary screen, and double screen) in a randomized order. Optical motion capture system, electromyography (EMG) device, and simulator sickness questionnaire (SSQ) were used to measure the users' responses. RESULTS: Neck rotation angles, muscle activities, and VR sickness were significantly affected by the screen configurations (p < 0.021). The primary-secondary screen showed the highest right rotation angle (median: -33.47°) and left sternocleidomastoid (SCM) muscle activities (median: 12.57% MVC). Both single (median: 22.42) and primary-secondary (median: 22.40) screen showed the highest value of SSQ. CONCLUSIONS: The screen configurations in VR could be an important design factor affecting the users' physical demands of the neck and VR sickness symptoms. Asymmetric neck rotations caused by the primary-secondary screen conditions should be avoided. [ABSTRACT FROM AUTHOR]

Concentric tube robots (CTR) have gained popularity in robotic research due to their potential for smaller instrument sizes, enhanced dexterity and reduced trauma. However, CTR control can be complex, with tip direction and curvature being kinematically coupled. To address this, a symmetric eccentric tube robot (ETR) is presented, where three identical pre-curved wires are arranged in parallel and constrained by an outer sheath. Instrument curvature is controlled by a single input angle. This study aims to demonstrate the suitability as manually actuated instrument. A model for curvature as a function of input angle is presented, and a prototype ETR with an outer diameter of 1 mm is assembled and evaluated. The results show that the ETR follows the expected shape, the curvature decreasing with the separation angle in an almost linear way that may be perceived as intuitive and predictable by the human user. However, some unsteady behavior (snapping) is observed, which may be addressed by preventing torsion of the wires through mechanical means. The simplified model neglecting the sheath stiffness provides precise enough predictions for the working space of a manual ETR. The findings suggest that manual ETRs have potential applications in superficial interventions, such as injections, arthroscopy, or ophthalmic surgery, where their curved section can be beneficial in comparison to current straight needles. Further research could explore interlocking mechanical designs to prevent torsion or modular setups for enhanced functionality. [ABSTRACT FROM AUTHOR]

For the system containing multiple adjustable degree-of-freedom modular units, a mathematical description of the modular robot topology including a standardized process and a kinematics parallel modeling method are proposed. Firstly, a library of the modular unit motion transfer is established, and a mathematical description of the modular robot topology based on the quadruple matrix with the standardized process is proposed. Then, based on the kinematics model of one modular unit, considering the coupling effect between the branches of the modular robot with multiple motion branches, a position level and speed-level kinematics model is established, which is suitable for chain modular robots. Subsequently, a kinematics parallel modeling method of modular robots is proposed. Both theoretical analytics and stimulation results show that this method can be adapted to the rapid modeling of modular robots with various types of topologies. The introduction of topology mathematical description and parallel computing reduces the difficulty of modular robot modeling and improves modeling efficiency. [ABSTRACT FROM AUTHOR]

Hyper‐redundant manipulators have strong flexibility that benefits from their redundant limb structure. However, a large number of redundant degrees of freedom will also lead the solution of inverse kinematics much more difficult, which restricts their motion performance to some extent. Inspired by the FABRIK (Forward and Backward Reaching Inverse Kinematics) method, an improved inverse kinematics solution method for the hyper‐redundant manipulator is proposed. Based on the space vector method, the kinematic model of the manipulator is established to dynamically acquire its endpoint position, and the workspace is further obtained by using the Monte Carlo method. The original search method is optimized, the include angle decoupling mechanism between adjacent links is established to obtain the rotation angles of each joint, and the joint angle limitation is introduced to meet the actual manipulator structural restriction. On this basis, the pose constraint mechanism is established to realize the control of the end‐link pose, and the linear degree of freedom is introduced to realize the solution after the directional expansion of the manipulator's workspace. A series of simulation experiments are carried out. In the experiments, the position error of the manipulator's endpoint is always less than 10−6 mm. Meanwhile, the comparative experimental results show that compared with the original method, the proposed method exhibits higher position accuracy under the condition that the computation time is almost the same. In addition, in the end‐link pose constraint experiment and path motion experiments, the pose error of the end‐link is always less than 10−7°, indicating that the end‐link pose can also meet the high accuracy requirements under the premise of ensuring high position accuracy. Finally, the prototype experiment further verifies its performance. [ABSTRACT FROM AUTHOR]

The objective was to investigate the effects of running shoes with midsole hollow structure span and height on the biomechanics of the lower limbs during running. We collected 21 adults with running habits who wore two pairs of running shoes with different midsole hollow structures and ran at a speed of 3.3m/s on a force-measuring treadmill. The lower limb kinematics, ground reaction force (GRF) and lower limb muscle activation characteristics were simultaneously captured by a motion capture system, a 3D force treadmill, and a surface electromyography (sEMG) system. Paired t-tests were performed on data for the two shoe conditions that fit the normal distribution assumptions; otherwise, Wilcoxon signed-rank tests were used. The statistical parameter mapping (SPM) technology was used for the analysis of 1D parameters of kinematic, dynamic, and sEMG activation characteristics. The result showed that the time to the peak impact force at touchdown of Hollow shoe2 was significantly increased (P<0.01), the maximum loading rate (P<0.01) and average loading rate (P<0.05) were significantly reduced, braking time (P<0.05), push time (P<0.05), contact time (P<0.01) of Hollow shoe2 were significantly increased compared with Hollow shoe1. Hollow shoe2 push phase of the tibialis anterior muscle activation characteristics was significantly lower (SPM, P<0.05) than Hollow shoe1. Our conclusion is that running shoes offer the solution as they have the advantage of the complex structure of the hollow midsole. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) bubble structure of the Sgr-B molecular-cloud complex is derived by a kinematical analysis of CO-line archival cube data of the Galactic Centre (GC) observed with the Nobeyama 45-m telescope. The line-of-sight depth is estimated by applying the face-on transformation method of radial velocity to the projected distance on the Galactic plane considering the Galactic rotation of the central molecular zone (CMZ). The 3D complex exhibits a conical-horn structure with the Sgr-B2 cloud located in the farthest end on the line of sight at radial velocity |$v_{\rm lsr} \sim 70$|  km s |$^{-1}$|⁠ , and the entire complex composes a lopsided bubble opening toward the Sun at |$v_{\rm lsr}\sim 50$| to 30 km s |$^{-1}$|⁠. The line-of-sight extent of the complex is |$\sim 100$|  pc according to the large velocity extent for several tens of km s |$^{-1}$| from Sgr-B2 to the outskirts. The entire complex exhibits a flattened conical bubble with full sizes |$\sim 40 \ {\rm pc} \times 20 \ {\rm pc} \times 100 \ {\rm pc}$| in the l, b and line-of-sight directions, respectively. Based on the 3D analysis, we propose a formation scenario of the giant molecular bubble structure due to a galactic bow shock, and suggest that the star formation in Sgr-B2 was enhanced by dual-side compression (DSC) of the B2 cloud by the Galactic shock wave from up-stream and expanding H  ii region from the down-stream side of the GC Arm I in Galactic rotation. [ABSTRACT FROM AUTHOR]

Motion analysis has played a crucial role in providing gait analysis for prosthetic users. Understanding kinematics in motion analysis allows for the evaluation of the effects of prostheses and the development of a prosthetic component design that aids in walking within the community. However, there are currently limited open datasets available to study the locomotion of individuals using transtibial prostheses, and most research studies involve a limited number of participants. This dataset shows 30 transtibial prosthesis users walking comfortably on a 10-meter walkway inside a laboratory. We offer a set of joint ankles obtained from the inertial measurement unit (IMU) signals in CSV file format. We also provide the optical motion capture (OMC) system's raw trajectory marker data in C3D file format and joint angle in CSV file format. This open dataset will provide resources for professionals interested in amputee gait for research in amputee gait detection and tracking algorithms. Moreover, the data will be the control data for comparison in developing advanced prosthetic components. [ABSTRACT FROM AUTHOR]

In rivers worldwide, multiple scales of dunes coexist. It is unknown how the larger, primary dunes interact with secondary bedforms that are superimposed. We test the hypothesis that streamwise variability in the sediment flux inferred from the downstream migration of secondary bedforms explains migration of the host dune, based on bathymetric data from a lowland, sand‐bedded river. Results indicate that transport estimated from secondary bedform migration increases along the host dune stoss, eroding the stoss slope. When the superimposed bedforms disintegrate at the primary lee slopes, results indicate that all sediment transport associated to secondary bedform migration is arrested in the lee of the host dune, explaining migration of the host dune. When secondary dunes persist however, only part of the sediments transport linked to secondary dunes contributes to the migration of the host dune. This study gives novel insight into the fundamental mechanisms controlling the kinematics of compound dunes. Plain Language Summary: Dunes are undulating features that can develop on a sandy river bed. They migrate downstream as a result of sediments moving from the stoss, the upstream facing slope of the dune, to the lee, the downstream slope of the dune. Sometimes, multiple scales of dunes coexist, where trains of small dunes travel over larger dunes. In this study we investigate how two dune scales interact and how they contribute to the downstream transport of bed sediments. This is done based on a series of field campaigns in the River Waal. The results indicate that migrating secondary dunes contribute to the displacement of the host dune, the dune over which they migrating. In some cases, secondary dunes travel over the host dune stoss and disintegrate at the host dune lee, depositing sediment there. In other cases, secondary dunes travel over the full length of the host dune toward the next, downstream dune. In this case, part of the sediments transport linked to the secondary dunes contributes to the downstream displacement of the host dune, and part of the sediments are transported to the next primary dune. Key Points: Secondary bedforms are omnipresent and are key to understanding primary dune behaviorSediment transport rates linked to migration of superimposed river bedforms increase over the host dune stoss and decrease over the lee sideSecondary bedforms control migration of the host dune, both when they persist over the host dune and when they disintegrate at the lee side [ABSTRACT FROM AUTHOR]

This study evaluates the effects of object weight and hand dominance on the end-point kinematics of the hand-to-mouth (withdrawal) movement in a functional reach-to-drink task for typically developing school-aged children. Using 3D motion capture, speed (average velocity and peak velocity), straightness (ratio), and smoothness (number of velocity peaks and log dimensionless jerk) of hand movements were calculated for the withdrawal motion with three different bottle weights (empty, half-filled, and full). Average velocity (550.4 ± 142.0 versus 512.1 ± 145.6 mm/s) and peak velocity (916.3 ± 234 versus 842.7 ± 198.4 mm/s) were significantly higher with the empty versus half-filled bottle and with the non-dominant (average: 543.5 ± 145.2 mm/s; peak: 896.5 ± 207 mm/s) versus dominant (average: 525.2 ± 40.7 mm/s; peak: 864.2 ± 209.2 mm/s) hand. There were no differences in straightness or smoothness. These findings indicate that increasing weight in reach-to-drink task puts greater constraints on the task. The slower movements with the dominant hand might denote better precision control than the non-dominant hand. The quantitative motion capture results show average values for the kinematic variables for a functional reach-to-drink task in a typically developing population of school-aged children with changing weights of the bottles that are relevant to a real-life scenario. These results could inform the design of individualized therapeutic interventions to improve functional upper-extremity use in children with neurodevelopmental motor disorders. [ABSTRACT FROM AUTHOR]

Boots are widely used by many people for various purposes, but their impact on gait biomechanics and injury risk is not well understood. This study investigated the effects of boots on walking biomechanics, compared to casual footwear. The lower limb joint kinematics and kinetics of 20 healthy male participants aged 20 to 30 years old were compared during self-paced walking with boots and shoes. The results showed that walking with boots is associated with greater hip extensor (P = 0.009) and ankle dorsiflexor (P < 0.001) moments in early stance, hip power generation (P < 0.001) and knee power absorption (P < 0.001) in early swing phase, hip abductor (P < 0.001) and knee adduction (P < 0.001) moments in the entire stance, net concentric work for the hip joint in sagittal (13.9%, P = 0.001) and frontal (21.7%, P = 0.002) planes. In contrast, the subtalar supinator moment in the entire stance (P < 0.001), ankle angular velocity in late stance (P < 0.001), and net concentric (− 42.7%, P < 0.001) and eccentric (− 44.6%, P = 0.004) works of subtalar joint were significantly lower in the boot condition. The compensatory adjustments in the hip and knee joints may result from ankle restrictions. While boots may aid those with ankle disorders, lower limb loading and the risk of musculoskeletal injuries and osteoarthritis could be increased. This study offers new perspectives on the biomechanical impact of boots on gait, potential prevention and treatment strategies of related injuries, and advancing footwear design. [ABSTRACT FROM AUTHOR]

Red Geysers are galaxies with low-star formation rates and galactic scale ionized outflows likely driven by low-luminosity active galactic nuclei (AGN). We investigated the impact of AGN winds on the oxygen abundance using integral field spectroscopic data from Mapping Nearby Galaxies for Red Geysers, control galaxies (quiescent galaxies without outflows), and AGN hosts within the inner 1.5 kpc radius. Red Geyser galaxies have higher W |$_{80}$| values compared to those of AGN and controls, with 64 per cent showing W |$_{80}\gt 500$|  km s |$^{-1}$| that is indicative of outflow. Only 40 per cent of controls and 31 per cent of AGNs reach this value. We found a small tendency of the oxygen abundance distribution of controls to be biased towards higher values than those of Red Geysers. However, Red Geysers do not show a correlation between H |$\alpha$| width (parametrized by the W |$_{\rm 80}$|⁠) and oxygen abundance, which indicates that AGN winds are not significantly impacting the chemical abundance of the nuclear region of these galaxies. The oxygen abundance distribution mean value for the tree samples is |$\rm 12+log(O/H)\sim$| 8.7 (⁠|$\mathit{Z}\sim \rm Z_{\odot })$|⁠. On the other hand, AGN hosts show a positive correlation between W |$_{80}$| and O/H which could be due to star formation that outflows from the active nuclei could induce; or to the reservoir of gas that makes the nucleus active, and its is also used in the star formation. [ABSTRACT FROM AUTHOR]

This paper reports an application of the Lie algebra s e (3) of the Euclidean group S E (3) , which is isomorphic to the theory of screws in the velocity and acceleration analyses of serial manipulators. The symbolic computation of the infinitesimal kinematics allows one to obtain algebraic expressions related to the kinematic characteristics of the end effector of the serial manipulator, while in the case of complex manipulators, numerical computations are preferred owing to the emergence of long terms. The algorithm presented enables the symbolic computation of the velocity and acceleration characteristics of the end effector in serial manipulators in order to allow the compact and efficient modeling of velocity and acceleration analyses of both parallel and serial robotic manipulators. Unlike other algebras, these procedures can be extended without significant effort to higher-order analyses such as the jerk and jounce. [ABSTRACT FROM AUTHOR]

Simple Summary: Equestrian sports have evolved beyond traditional disciplines, embracing specialised events that showcase breed-specific abilities. The Criollo horse breed, a product of centuries of genetic refinement, stands out in South America and internationally, particularly in events like the Freio de Ouro. This competition highlights the breed's versatility and skills, emphasising manoeuvres like the esbarrada and volta sobre patas, which demonstrate agility, coordination, and balance. Despite the breed's success, there is a lack of quantitative kinematic studies on these manoeuvres and their relation to horse morphology. Our study aims to fill this gap by using kinematics to analyse the esbarrada and volta sobre patas, exploring any connections between static goniometry and manoeuvre dynamics. Understanding these movements not only enhances our appreciation of equine biomechanics but also informs breeding and training practices, ultimately benefiting both horses and riders in various equestrian disciplines. The esbarrada and volta sobre patas manoeuvres are critical in Criollo horse equestrian activities, yet their kinematics remain largely unexplored. This observational study aimed to kinematically describe the manoeuvres in Criollo breed horses and explore the relationship between static goniometry and dynamics. A 2D kinematic analysis was conducted on 31 Criollo horses performing the manoeuvres using high-speed cameras. Joint angles were measured using static goniometry and analysed in relation to dynamic performance. The esbarrada covered a distance of 4.28 ± 0.99 m in 1.15 ± 0.11 s at a velocity of 3.77 ± 0.55 m/s. Joint angles showed a mean fetlock extension of 75.4° ± 5.3° and hock flexion of 43.2° ± 4.1°. In the volta sobre patas, significant differences were found in turn duration (first: 0.96 ± 0.07 s, second: 1.12 ± 0.09 s, p = 0.03) and thoracic limb suspension (first: 0.23 ± 0.02 s, second: 0.28 ± 0.03 s, p = 0.02). Static goniometry indicated that limb conformation did not significantly correlate with protraction angles during the esbarrada (p = 0.27). The volta sobre patas demonstrated prolonged duration and increased thoracic limb suspension in the second turn. Also, the findings suggest that static conformation does not predict dynamic limb movement during the esbarrada. [ABSTRACT FROM AUTHOR]

Simple Summary: Water treadmill (WT) exercise is popular for cross-training of sport horses. The nature of the horse's adaptation to WT exercise could be influenced by the type of session used and how often it is conducted. The study's aim was to compare the gait characteristics of 48 sport horses during a standardised WT exercise test (WTSET) at the start, i.e., 'week 0', and after 20 and 40 weeks of WT exercise incorporated within their normal training programme. Horses were recruited from the existing client populations of two commercial water treadmill venues for the purpose of this longitudinal, observational study. Measurements of limb, back, poll, wither, and pelvic movement were taken during the WTSET at weeks 0, 20, and 40. Compared to week 0, the results showed changes in gait characteristics during the WTSET at weeks 20 and 40 that reflected adaptation to walking in water, including increased protraction and decreased retraction of the fore and hind limbs. Kinematic responses were primarily dependent upon water depth, but previous experience of the horses with WT exercise, the number of WT exercise sessions carried out per month, and the type of the WT exercise session used during training with respect to speed and depth used were also influential. The WT session design and frequency of use can influence the nature of the kinematic responses to water walking seen over time, suggesting that WT exercise sessions within a normal sport horse training programme could be designed in accordance with specific training goals. Repeated exposure to water treadmill (WT) exercise could elicit kinematic responses reflecting adaptation to WT exercise. The study's aim was to compare the responses of a group of sport horses to a standardised WT exercise test (WTSET) carried out at three time points, week 0 (n = 48), week 20 (n = 38), and week 40 (n = 29), throughout a normal training programme incorporating WT exercise. Horses were recruited from the existing client populations of two commercial water treadmill venues for the purpose of this longitudinal, observational study. Limb, back, poll, wither, and pelvic kinematics were measured during the WTSET using videography, optical motion capture, and inertial motion sensors. Forelimb and hindlimb protraction increased (p < 0.001 for both), and forelimb and hindlimb retraction decreased (p < 0.001 for both) at week 40 compared to week 0. Caudal thoracic flexion–extension and lateral bend ranges of movement were greater at week 40 compared to week 0 (p < 0.001 and p = 0.009, respectively). Increased training speed was associated with increased craniocaudal poll movement (p = 0.021), decreased forelimb protraction (p = 0.008), and increased forelimb retraction (p = 0.021). In addition to characteristic changes in kinematics due to increasing water depth, regular WT exercise resulted in kinematic adaptation to movement in water. Factors such as the frequency of WT sessions and the type of session used with respect to depth and speed were seen to influence the nature of the adaptation. The results suggest that WT exercise sessions could be designed in accordance with specific training goals when used within a normal sport horse training programme. [ABSTRACT FROM AUTHOR]

Background: Characterizing the condition of patients suffering from knee osteoarthritis is complex due to multiple associations between clinical, functional, and structural parameters. While significant variability exists within this population, especially in candidates for total knee arthroplasty, there is increasing interest in knee kinematics among orthopedic surgeons aiming for more personalized approaches to achieve better outcomes and satisfaction. The primary objective of this study was to identify distinct kinematic phenotypes in total knee arthroplasty candidates and to compare different methods for the identification of these phenotypes. Methods: Three-dimensional kinematic data obtained from a Knee Kinesiography exam during treadmill walking in the clinic were used. Various aspects of the clustering process were evaluated and compared to achieve optimal clustering, including data preparation, transformation, and representation methods. Results: A K-Means clustering algorithm, performed using Euclidean distance, combined with principal component analysis applied on data transformed by standardization, was the optimal approach. Two unique kinematic phenotypes were identified among 80 total knee arthroplasty candidates. The two distinct phenotypes divided patients who significantly differed both in terms of knee kinematic representation and clinical outcomes, including a notable variation in 63.3% of frontal plane features and 81.8% of transverse plane features across 77.33% of the gait cycle, as well as differences in the Pain Catastrophizing Scale, highlighting the impact of these kinematic variations on patient pain and function. Conclusion: Results from this study provide valuable insights for clinicians to develop personalized treatment approaches based on patients' phenotype affiliation, ultimately helping to improve total knee arthroplasty outcomes. [ABSTRACT FROM AUTHOR]

The meniscus plays a crucial role in the proper functioning of the knee joint, and when it becomes damaged, partial removal or replacement is necessary to restore proper function. Understanding the stress and deformation of the meniscus during various movements is essential for developing effective materials for meniscus repair. However, accurately estimating the contact mechanics of the knee joint can be challenging due to its complex shape and the dynamic changes it undergoes during movement. To address this issue, the open-source software SCONE can be used to establish a kinematics model that monitors the different states of the knee joint during human motion and obtains relevant gait kinematics data. To evaluate the stress and deformation of the meniscus during normal human movement, values of different states in the movement gait can be selected for finite element analysis (FEA) of the knee joint. This analysis enables researchers to assess changes in the meniscus. To evaluate meniscus damage, it is necessary to obtain changes in its mechanical behavior during abnormal movements. This information can serve as a reference for designing and optimizing the mechanical performance of materials used in meniscus repair and replacement. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Gait dysfunction (GD) is a common impairment of Parkinson's disease (PD), which negatively impacts patients' quality of life. Among the most recent rehabilitation technologies, a lower-limb powered exoskeleton (LLEXO) arises as a useful instrument for gait training in several neurological conditions, including PD. However, some questions relating to methods of use, achievable results, and usefulness compared to traditional rehabilitation methodologies still require clear answers. Therefore, in this review, we aim to summarise and analyse all the studies that have applied an LLEXO to train gait in PD patients. Literature research on PubMed and Scopus retrieved five articles, comprising 46 PD participants stable on medications (age: 71.7 ± 3.7 years, 24 males, Hoehn and Yahr: 2.1 ± 0.6). Compared to traditional rehabilitation, low-profile lower-limb exoskeleton (lp-LLEXO) training brought major improvements towards walking capacity and gait speed, while there are no clear major benefits regarding the dual-task gait cost index and freezing of gait symptoms. Importantly, the results suggest that lp-LLEXO training is more beneficial for patients with an intermediate-to-severe level of disease severity (Hoehn and Yahr > 2.5). This review could provide a novel framework for implementing LLEXO in clinical practise, highlighting its benefits and limitations towards gait training. [ABSTRACT FROM AUTHOR]

This study aimed to assess the validity and reliability of a commercially available inertial measurement unit (Enode) for measuring barbell kinematics and kinetics during a snatch. In order to assess validity and within- and between-session reliability, thirteen competitive weightlifters conducted two snatches on two separate occasions at 85% of their one-repetition maximum. The Enode sensor was attached to the barbell, with each lift recorded via the device's native application concurrently with an 11-camera motion capture system. Passing–Bablok regression indicated fixed and proportional bias in some horizontal measures of barbell mechanics but showed no bias in all but one vertical variable. Collectively, this suggests that the Enode is a valid tool in the measurement of vertically derived, but not horizontally derived, variables from barbell kinematics. Within- and between-session reliability showed moderate to excellent ICCs, with trivial to small differences between repetitions and between sessions. However, between-session reliability showed lower levels of variability and, thus, may help coaches identify changes in technique over time (between sessions) with good accuracy. Overall the Enode offers a practical and affordable option for coaches seeking to monitor weightlifting technique in training environments. [ABSTRACT FROM AUTHOR]

This paper presents a procedure for estimating the motion capabilities of an omnidirectional mobile platform with three omni wheels arbitrarily distributed and oriented. This procedure is based on the analysis of the bidirectionality compliance between the inverse and forward kinematics of a mobile platform for a wide set of discrete motion commands. This procedure has been applied to analyze eleven alternative mobile platform configurations with three omni wheels. The estimation of the omnidirectional motion capabilities of these platforms agrees with state-of-the-art methods while providing new differentiated information on the translational capabilities of each platform. The procedure can be applied in the design stage of new omnidirectional mobile platforms in order to verify the motion capabilities of new designs with omni wheels. [ABSTRACT FROM AUTHOR]

Soccer referees are at risk of injury due to the physical demands of their role. This study evaluated the impact of the 24-week FIFA 11+ Referees training program on the quality of change of direction (COD) maneuvers in elite soccer referees. Eighty-one male referees were randomly assigned to either the 11+ referee group (n = 40) or a control group (n = 41). The intervention group replaced their usual warm-up routines with the FIFA 11+ program, while the control group continued their standard training. Both groups were assessed using the cutting movement assessment score (CMAS) before and after the intervention. The results demonstrated significant improvements in CMAS scores for the 11+ referee group at all tested angles (45°, 70°, and 90°), with the most notable improvements observed at 90° angles. These findings indicate that the FIFA 11+ Referees program enhances COD maneuver quality, which is critical for injury prevention. Implementing this program may therefore improve movement quality and reduce injury risks among soccer referees. Further research should explore the program's long-term efficacy and applicability across different populations and injury factors. [ABSTRACT FROM AUTHOR]

This paper proposes a calculation method for the optimal solution of the inverse kinematics of redundant robots. Specifically, eight sets of vector solutions of redundant robots are solved by the D-H parameter method. Then, an objective function is designed to measure the accuracy of the robot's inverse kinematics solution and the smoothness of the robot's joint motion. By adjusting the weights of each item, the optimal solution that meets different requirements can be selected. In addition, this paper also introduces an improved artificial potential field method to solve the problem of discontinuous changes in gravitational potential in path planning and the problem of excessive joint torque caused by excessive gravitational potential. Finally, the application of the rapidly exploring random tree (RRT) algorithm in robot path planning and obstacle avoidance is introduced. The above-mentioned calculation method and path planning algorithm were verified in the joint simulation environment of MATLAB Robot Toolbox and CoppeliaSim. The proposed inverse solution method is compared with the inverse solution generated in the CoppeliaSim simulation environment, and the angle error of each joint is less than 0.01 rad. [ABSTRACT FROM AUTHOR]

This study investigated the influence of impact height and competitive level on racket speed and stroke accuracy by analysing segmental angular kinematics under a random ball condition. High- (HQ, n = 7) and low-quality (LQ, n = 7) groups were determined by k-means clustering of the ratio of ball landing in the target (accuracy) and racket speed decrease. HQ showed higher accuracy (48.3% vs. 32.4%), less speed decrease at lower impact heights (−4.4% vs. −10.3%) and better competitive level ranking [median (1st–3rd quartiles); 4 (2–7)] than LQ [10 (8–13)]. HQ produced greater racket speed (24.4 vs. 21.6 m/s), especially with a notable horizontal velocity (23.8 vs. 20.8 m/s) of the racket at lower impact height, which was attributed to the central role of greater angular velocity of pelvis and thorax in the hitting direction. Both groups showed similar adjustment mechanisms that due to the decrease in angular velocity of pelvis, players increased the relative rotation angle between pelvis and thorax to maintain angular velocity of thorax when transitioning from low to high impact heights. Our findings suggest that players should emphasise the coordination between pelvic and thoracic rotations according to impact heights to maintain racket speed while controlling ball landing position. [ABSTRACT FROM AUTHOR]

Individuals with neuromuscular pathologies are often prescribed an ankle-foot orthosis (AFO) to improve their gait mechanics by decreasing pathological movements of the ankle and lower limb. AFOs can resist or assist excessive or absent muscular forces that lead to tripping, instability, and slow inefficient gait. However, selecting the appropriate AFO with mechanical characteristics, which limit pathological ankle motion in certain phases of the gait cycle while facilitating effective ankle movement during other phases, requires careful clinical decision-making. The aim of this study is to propose an explicit methodology for the adjustment of multi-function articulated AFOs in clinical settings. A secondary aim is to outline the evidence supporting this methodology and to identify gaps in the literature as potential areas for future research. An emerging class of AFO, the multi-function articulated AFO, offers features that permit more comprehensive, iterative, and reversible adjustments of AFO ankle alignment and resistance to ankle motion. However, no standard method exists for the application and optimization of these therapeutic devices in the clinical setting. Here we propose an evidence-guided methodology applicable to the adjustment of multi-function articulated AFOs in the clinical setting. Characteristic load-deflection curves are given to illustrate the idealized yet complex resistance-angle behavior of multi-function articulated AFOs. Research is cited to demonstrate how these mechanical characteristics can help mitigate specific pathologic ankle and knee kinematics and kinetics. Evidence is presented to support the effects of systematic adjustment of high resistance, alignable, articulated AFOs to address many typical pathomechanical patterns observed in individuals with neuromuscular disorders. The published evidence supporting most decision points of the algorithm is presented with identified gaps in the evidence. In addition, two hypothetical case examples are given to illustrate the application of the method in optimizing multi-function articulated AFOs for treating specific gait pathomechanics. This method is proposed as an evidence-guided systematic approach for the adjustment of multi-function articulated AFOs. It utilizes observed gait deviations mapped to specific changes in AFO alignment and resistance settings as a clinical tool in orthotic treatment for individuals with complex neuromuscular gait disorders. [ABSTRACT FROM AUTHOR]

Introduction: Advancements in technology have recently made it possible to implement effective training solutions across different environmental conditions. This study evaluated the reliability and validity of measures obtained from the innovative motorized device, Alex7 (Inosportas, Lithuania), and differences in speed and kinematic characteristics between resisted and assisted sprinting in young football players. Methods: Twenty-seven male athletes (mean age: 16.5 ± 0.8 years; height: 179.5 ± 6.9 cm; body weight: 67.7 ± 8.3 kg) each performed 30-m sprints twice under three different conditions: regular, resisted, and assisted sprinting. The Alex7 device provided the assistance and resistance during sprints. Results were compared with those from Witty timing gates. Ground contact time, flight time, stride length, and pace were measured using the OptoJump system. Reliability was assessed using two-way mixed intraclass correlation coefficients (ICCs) for single measures, the standard error of the mean (SEM), and the coefficient of variation (CV). Pearson's correlation coefficient determined the associations between Alex7 and Witty timing systems. Criterionreferenced validity was based on the mean difference and CV. Systematic bias was determined by limits of agreement using Bland-Altman analysis. Results: Running times obtained using the Alex7 equipment exhibited good to excellent test-retest reliability between sessions (ICC, 0.83-0.94) and good to excellent correlation (Pearson's r = 0.88-0.98) between the Alex7 and Witty systems in both assisted and resisted running conditions. However, the Alex7 device consistently produced longer running times than the Witty device (up to 0.16 s difference, p < 0.001). The different running conditions produced substantial variations in kinematic variables, such as stride length, ground contact time, and running speed (p < 0.001 for all), but the effects on flight time and running pace were smaller. Discussion: The Alex7 device shows high reliability for creating resisted and assisted running conditions for young football players. However, it tends to overestimate running time, necessitating caution when assessing the time parameters. [ABSTRACT FROM AUTHOR]

Barbell squats are commonly utilized in resistance training for rehabilitation, daily living enhancement, and improving sports performance. The current study investigated the kinematic and electromyographic (EMG) parameters in the squat between sexes across different repetition ranges (1-, 3-, 6-, and 10-RM) among recreationally strength-trained subjects. A total of 26 subjects (13 men: age 25 ± 3.5 years, height 178.2 ± 5.8 cm, weight 82.3 ± 9.1 kg; 13 women: age 24 ± 4.1 years, height 165.4 ± 6.3 cm, weight 68.2 ± 8.7 kg) participated in the study. The level of significance was set at p<0.05. The findings revealed no sex-specific differences in average barbell velocity across repetition ranges. However, the 1-RM showed a significantly lower average velocity compared to the final repetition of other repetition ranges (p<0.001), with the last repetition at 10-RM revealing a significantly higher velocity (p<0.001). Women had greater maximal angular hip extension velocity in the final repetitions of the 6- and 10-RM (p≤0.035, ηp2≤0.20), while both sexes displayed lower maximal angular knee extension velocity in the final repetition of the 10-RM (p = 0.028, ηp2 = 0.15). Moreover, men had lower EMG amplitude in the rectus femoris (3- and 10-RM), soleus, and lateral vastus (10-RM) compared to women (p≥0.011, ηp2≥0.26). It was concluded that 10-RM differed greatly in kinematics and EMG, suggesting different fatigue mechanisms compared to other repetition ranges with heavier loads. Furthermore, sex differences in EMG and angular hip extension velocity might imply sex-specific fatiguing mechanisms during high-repetition squats. These considerations could be important when prescribing training programs. [ABSTRACT FROM AUTHOR]

Reconfigurable structures can perform multiple functions and are useful in confined environments with complicated access. To extend the complexity of configurations achievable with reconfigurable mechanisms, remotely reconfigurable mechanisms are explored. Magnetically responsive phase change materials are selected for actuation, and origami backbones as the structure. Modulating the mechanism's coupling and constraints, multiple configurations are achieved. Three functional aspects of in situ reconfiguration are demonstrated. First, selective attachment and actuation enable remote mechanisms to deploy and actuate. Second, reconfiguration that modifies the constraints allows for new kinematics even in confined environments. Third, the actuator can construct and change the configuration of an origami structure, allowing subsequent functions to emerge. Tetherless interface reconfiguration is demonstrated with an in situ needle puncture and escape room puzzle, which can benefit existing robotic applications in confined spaces. [ABSTRACT FROM AUTHOR]

Purpose Methods Results Conclusion Level of Evidence The aim of this study was to analyse clinical, functional and shoulder kinematics results using subacromial balloon spacer in nonreparable massive rotator cuff tears. Subacromial balloon spacer was hypothesised to improve shoulder kinematics and increases clinical and functional outcomes scores in nonreparable massive rotator cuff tears.This is a prospective study in massive rotator cuff tears. From October 2021 to October 2022, a total of 127 shoulders suffering massive rotator cuff tears were initially evaluated. All patients were evaluated preoperatively, at 6 and 12 months. Patients' patient‐reported outcome measures (PROM) subjective values using visual analogue scale (VAS) and the Spanish Western Ontario Rotator Cuff Index (WORC) version were analysed. We also evaluated objective outcomes: constant score, range of movement and kinematic shoulder analysis (isokinetic test to evaluate internal and external rotation forces). Statistical analysis was conducted using SPSS software; continuous variables were presented as means and standard deviations (SDs).Seventeen nonrepairable massive rotator cuff tears were finally included. Three patients required reverse shoulder arthroplasty before 6 months postoperative. After 1‐year follow‐up, objective and subjective (PROM) outcome scores and isokinetic measurements improved in 13 patients. Preoperative VAS improved from 6.5 ± 2.1 to 2 ± 1.9 points on average at 1‐year follow‐up and WORC index from 1603 ± 217.3 to 699 ± 361.6. Constant score from 42.1 ± 13.1 on average and at 1‐year follow‐up increased to 60.8 ± 14.7. Range of movement also improved in elevation 122.2 ± 39.3 to 166.9 ± 25.8, abduction 120.3 ± 38.6 to 134.6 ± 21.1, external rotation 30.3 ± 19.7 to 86.1 ± 13.8 and internal rotation L4–T12 on average at 1‐year follow‐up. Isokinetic evaluation showed functional improvement 1 year after implantation. Both internal and external rotation improved compared with their healthy shoulder. External rotation improved from 30.3° ± 19.7° preoperatively to 86.1° ± 13.8° (43.7% in the isokinetic study) and internal rotation from L4 preoperatively to L1 (49.8% in isokinetic study) on average.Among the different alternatives for irreparable rotator cuff injuries surgical treatment, subacromial balloon spacer is an effective alternative in selected patients, both in terms of clinical‐functional improvement and short‐term isokinetic results.Level II [ABSTRACT FROM AUTHOR]

Background: The preservation of semen quality and kinematic characteristics during cryopreservation is crucial for the reproductive success and genetic management of livestock, particularly in Bali bulls. Aim: This study aimed to investigate the effect of adding purified green tea extract antioxidant Epigallocatechin-3- gallate (EGCG) in tris egg yolk diluent on the quality and kinematic characteristics of frozen semen from Bali bulls. Methods: Fresh and frozen semen samples were obtained from Bali bull and divided into four different treatment groups. P0 contained semen samples + diluent, while P1 to P3 consisted of semen samples + diluent supplemented with EGCG levels of 0.1, 0.15, and 0.2 mg/100 ml, respectively. Data were analyzed using One-way ANOVA and followed by Duncan’s test if significant differences were found (p<0.05). Parameters observed included the assessment of fresh semen quality, kinematic analysis, post-thawing sperm viability, and abnormality. Results: The results indicated that the assessment of fresh semen quality showed macroscopic and microscopic semen quality according to SNI 4869-1:2021. Kinematic analysis revealed significant differences in DSL and STR parameters between P0 and P3 (p<0.05). EGCG supplementation also caused significant differences in motility between P0 and P3 (p<0.05). Viability and spermatozoa abnormality with EGCG supplementation did not show significant differences (p>0.05). Conclusion: The best results for motility, kinematics, and sperm morphology variables were found in P1 as it did not exhibit a decrease in motility, kinematics, and sperm morphology. Viability did not show significant differences between P1, P2, and P3, but the best results were found in P2 as it did not exhibit a decrease in viability with mean and standard deviation (66.84 ± 7.88). Abnormality variables also did not show significant differences between P1, P2, and P3, but the best results were found in P2 as it did not exhibit a decrease in abnormality with mean and standard deviation (23.80 ± 7.36). [ABSTRACT FROM AUTHOR]

We investigated the temporal variability of the surface velocity of 30 glaciers in the Mont Blanc massif (European Alps). We calculated the monthly velocity between 2016 and 2024 using digital image correlation of Sentinel-2 optical imagery. The main objectives of the study were (i) to characterize the variability of the velocity fields of such glaciers (referring to both their temporal seasonal and inter-annual and spatial variations) and (ii) to investigate relationships between the morphology of glaciers and their kinematics. We measured monthly velocities varying from 12.7 to 487.4 m yr -1. We observed an overall decrease in the velocity between 2016 and 2019 and an unexpected rise in 2020–2022, which are especially visible in most glaciers on the southern side of the massif. Considering the whole period, half of the glaciers showed positive acceleration, which reached values > 4 m yr -2 in three glaciers. In general, the trend's absolute value in the cold season is higher in the case of positive acceleration and lower in the case of negative acceleration. We found that smaller glaciers have a more pronounced seasonality, with winter–summer velocity differences of 50 %–100 %. Finally, in 2016, 2018, and 2022, we observed an exceptionally high winter–summer velocity difference in the 0.3 km 2 wide Charpoua Glacier, when summer velocities increased by 1 order of magnitude. [ABSTRACT FROM AUTHOR]

The suspended parallel mechanism, due to the use of gravity as a virtual rope to provide both geometric and force constraints, leads to coupled kinematics and statics of the mechanism (geometrico-static), whose under-constrained relationship makes the coupled kinematic/hydrostatic solution very challenging. In order to solve its geometrico-static problem, this paper proposes an inverse kinematic solution algorithm and conducts an experimental study on the equilibrium configuration of the end of the two-rope robot. First, the geometric constraint equations of the force system are derived from the force system equilibrium conditions. Second, motion simulation of the end of the mechanism is carried out to analyze its motion characteristics. Finally, the trajectory similarity between the motion control test and the theoretical calculation is compared. The experimental results show that the solution algorithm proposed in this paper has high accuracy and solution efficiency. [ABSTRACT FROM AUTHOR]

People with Parkinson's disease often exhibit improvements in motor tasks when exposed to external sensory cues. While the effects of different types of sensory cues on motor functions in Parkinson's disease have been widely studied, the underlying neural mechanism of these effects and the potential of sensory cues to alter the motor cortical activity patterns and functional connectivity of cortical motor areas are still unclear. This study aims to compare changes in oxygenated haemoglobin, deoxygenated haemoglobin and correlations among different cortical regions of interest during wrist movement under different external stimulus conditions between people with Parkinson's disease and controls. Ten Parkinson's disease patients and 10 age‐ and sex‐matched neurologically healthy individuals participated, performing repetitive wrist flexion and extension tasks under auditory and visual cues. Changes in oxygenated and deoxygenated haemoglobin in motor areas were measured using functional near‐infrared spectroscopy, along with electromyograms from wrist muscles and wrist movement kinematics. The functional near‐infrared spectroscopy data revealed significantly higher neural activity changes in the Parkinson's disease group's pre‐motor area compared to controls (p = 0.006), and functional connectivity between the supplementary motor area and pre‐motor area was also significantly higher in the Parkinson's disease group when external sensory cues were present (p = 0.016). These results indicate that external sensory cues' beneficial effects on motor tasks are linked to changes in the functional connectivity between motor areas responsible for planning and preparation of movements. [ABSTRACT FROM AUTHOR]

Introduction: The upper body Wingate Anaerobic Test (WAnT) is a 30-smaximal effort sprint against a set load (percentage of body mass). However, there is no consensus on the optimal load and no differential values for males and females, even when there are well-studied anatomical and physiological differences in muscle mass for the upper body. Our goal was to describe the effects of load, sex, and crank position on the kinetics, kinematics, and performance of the upper body WAnT. Methods: Eighteen participants (9 females) performed threeWAnTs at 3%, 4%, and 5%of body mass. Arm crank forces, 2D kinematics, and performance variables were recorded during eachWAnT. Results: Our results showed an increase of ~49% effective force, ~36%peak power, ~5° neck flexion, and ~30° shoulder flexion from 3% to 5% load (P < 0.05). Mean power and anaerobic capacity decreased by 15%, with no changes in fatigue index (P < 0.05). The positions of higher force efficiency were at 12 and 6 o'clock. The least force efficiency occurred at 3 o'clock (P < 0.05). Sex differences showed that males produced 97% more effective force and 109% greater mean power than females, with 11.7%more force efficiency (P < 0.001). Males had 16° more head/neck flexion than females, and females had greater elbow joint variability with 17°morewrist extension at higher loads. Males cycled ~32%faster at 3%versus 5%WAnT load with a 65%higher angular velocity than females. Grip strength, maximal voluntary isometric contraction, mass, and height positively correlated with peak and mean power (P < 0.001). Conclusions: In conclusion, load, sex, and crank position have a significant impact on performance of theWAnT. These factors should be considered when developing and implementing an upper body WAnT. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to determine associations between running economy (RE) and running sagittal plane kinematic and kinetic parameters. Method: A total of 30 male recreational runners (age: 21.21 ± 1.22 yr, VO2max: 54.61 ± 5.42 mL·kg-1·min-1) participated in two separate test sessions. In the first session, the participant's body composition and RE at 10 and 12 km·h-1 were measured. In the second session, measurements were taken for the sagittal plane of hip, knee, and ankle angles and range of motion (ROM), as well as ground reaction force. Results:Moderate correlations were found between lower energy costs at 12 km·h-1 and smaller hip flexion at toe-off (r = 0.373) as well as smaller peak hip flexion during stance (r = 0.397). During the swing phase, lower energy costs at 10 km·h-1 were moderately correlated with smaller peak knee flexion and smaller knee flexion and extension ROM (r = 0.366-0.443). Lower energy costs at 12 km·h-1 were moderately correlated with smaller peak hip and knee flexion as well as knee extension ROM(r = 0.369-0.427). In terms of kinetics, there was a moderate correlation between higher energy costs at 10 km·h-1 and larger peak active force, as well as larger peak braking and propulsion force (r = -0.470-0.488). Lower energy costs at 12 km·h-1 were moderately to largely correlated with smaller peak impact and braking force (r = 0.486 and -0.500, respectively). Regarding the statistical parametric mapping analysis, most outcomes showed associations with RE at 10 km·h-1, including knee flexion (42.5%-65.5%of the gait cycle), ankle plantarflexion (32.5%-36%of the gait cycle), active force (30.5%-35%of the stance phase), and propulsion force (68%-72.5% of the stance phase). Lower energy costs at 12 km·h-1 were correlated with smaller hip flexion (5.5%-12% and 66.5%-74%) and smaller knee flexion (57%-57.5%) during the running gait cycle. Conclusions: This study indicates that biomechanical factors are associated with RE in recreational runners. To design effective training methods to improve RE, coaches and runners should focus on the sagittal plane kinematics of the hip, knee, and ankle, as well as lower vertical and horizontal kinetic parameters. [ABSTRACT FROM AUTHOR]