Kinematic Motion Analysis Research Articles

Is a cork a legal shortcut? – A comparison of the measured and assumed amount of rotation in freestyle tricks

ABSTRACT In snowboard freestyle disciplines, the amount of rotation is commonly determined as the sum of rotations around all board axes and is the most important indicator of the trick difficulty across all snowboard freestyle disciplines. Based on the type of rotation, tricks can be classified as flatspins, corks and flips. It is not yet known whether the type of rotation of a trick can influence the actual amount of rotation. Therefore, the aim of this study was to determine the amount of deviation, defined as difference between measured and assumed amount of rotation as a function of trick classification, using kinematic motion analysis. The amount of deviation was positive for flatspins (median: 21°; min: −4°; max: 49°) and negative for corks (median: −25°; min: −89°; max: 12°) and flips (median: −28°; min: −94°; max: 13°). Our results demonstrate that there are ways of execution where riders perform corks and flips with a shortcut and flatspins with a detour. This should be taken into account by judges, coaches and riders. Further research is needed to investigate how the shortcut can be influenced.

Accuracy of Kinovea-based kinematic gait analysis compared to a three-dimensional motion analysis system in healthy dogs.

The goal of this study was to compare the accuracy of kinematic measurements obtained using the 2-D video-based kinematic motion analysis (KMA) software Kinovea (version 0.9.5; http://www.kinovea.org) with 3-D KMA in healthy dogs. In this prospective study, 3-D marker-based KMA (VICON-Nexus, version 2.12.1, and Procalc, version 1.6; VICON Motion Systems Ltd) was performed on healthy dogs (body weight ≥ 20 kg; height at withers > 50 cm) walking on a treadmill (study period: November 2022). Simultaneously, dogs were video recorded by 1 smartphone (iPhone SE; Apple Inc) at a 1.50-m distance perpendicular to the shoulder (60 frames per second; 1,920 X 1,080 pixels) for KMA using Kinovea. Joint angle and joint angle velocity of the shoulder, elbow, carpus, hip, stifle, and tarsus were calculated for 6 synchronized gait cycles. Each gait cycle was divided into 10 increments. The difference between 3-D KMA and Kinovea was assessed for each parameter using robust linear mixed-effects models. 34 dogs were included. The estimated joint angle difference between 3-D KMA and Kinovea was less than 2° for all shoulder and elbow gait cycle increments. For the carpus, hip, stifle, and tarsus, the difference was less than 2° in 9, 5, 4, and 4 out of 10 gait cycle increments, respectively. Kinovea provides accurate kinematic data for the shoulder and elbow of healthy dogs. Carpal, hip, stifle, and tarsal kinematics were less accurate. The use of Kinovea for clinical and research purposes remains limited. Future Kinovea-based studies are needed to investigate the accuracy of carpal, hip, stifle, and tarsal kinematics.

3D Modelling and Simulation Based on Kinematic Analysis for Hippotherapy

The engineering perspective on the physiology and anatomy of living things has led to the emergence of the science of biomechanics. Developing computer technologies have made it possible to examine the behaviour of living things in more detail and to develop technologies that enable kinetic and kinematic analysis of movements to imitate real limbs. In this study, the natural gaits of horses (Walk, Canter and Trot) were analysed with image processing techniques, kinematic analyses were made and three-dimensional solid models were created. Giving movement ability to the extracted solid models was carried out with the simulation software prepared on the Matlab-SimMechanic platform. By comparing the findings obtained as a result of image processing and simulation, the success of transferring the movements to a developed system was evaluated. After mathematical equations were created in the MATLAB environment, the equations were tested on the developed system and their performance rates were determined. With the developed system, joint angles, ability to reach the correct position and movement ability were analysed and it was shown how the mathematical equations required to perform the movements could be derived. As a result, a design process model for movement analysis, simulation and control of different living groups is presented with the equations obtained by formulating the information obtained from the developed system.

A System for Collecting and Evaluating Load Information about Bioelectric Signals of the Muscular Apparatus of the Foot of a Person with Cerebral Palsy

The purpose of the research is to develop a system of biomechanical investigation of the volume of movement in the foot and ankle joint for the diagnosis of patients with cerebral palsy in assessing the quality of rehabilitation measures. The process of creating a computer diagnostic system for patients with impaired motor functions of the lower extremities, which is equipped with special bio-measuring devices provided with specialized algorithms for processing the information obtained, is investigated due to the need for scientific research aimed at developing methods and tools for a comprehensive assessment of the results of physical rehabilitation using biomedical indicators.Methods of kinematic analysis of movements in the ankle joint were used, dynamic and static analyses of the forces of the supporting reactions of the foot of the lower extremities were carried out.Results. A motion detection system based on an electronic goniometer implemented on the basis of a B10K resistive potentiometer has been developed. The determination of the absolute rotation angles of the links of the diagnostic system was carried out using the MMA7361 acceleration sensor, which contains three micromachine capacitors mounted on one silicon plate. In the course of research, changing the capacitances of micromachine capacitors makes it possible to fix the recorded value in each direction. Signals passing through low-frequency filters and temperature compensation cascades are sent to the corresponding outputs X, Y and Z. The obtained angulograms allow us to evaluate the gait of the studied patient in two classes ‒ normal and in the presence of pathology.Conclusion. A system for the formation and evaluation of bioelectric signals obtained using the muscular apparatus of the foot of patients with cerebral palsy, assembled on the platform of the Arduino UNO control board and a generalpurpose personal computer, has been developed. The developed system makes it possible to register bioelectric signals with their subsequent processing using a personal computer and making diagnostic decisions.

Rigidity sensing by blood-borne leukocytes: Is it independent of internal signaling?

<abstract> <p>Atherosclerosis is a chronic inflammatory disease that results in the formation of lipid-rich lesions and stiffening of arterial walls. An increasing body of evidence suggests that nearly all members of the leukocyte family accumulate within atherosclerosis-prone arteries and participate in various stages of disease progression. Recently, it has been proposed that progressive changes of the elastic modulus of the arterial wall during plaque development may directly influence the kinematics of leukocyte rolling. In the present study, we propose that rigidity sensing of rolling leukocytes may occur spontaneously due to the stiffness-dependent elastic instability of reversible bonds between rolling leukocytes and the arterial walls. This effect is mechanistic in nature and operates independently of cell biochemical signaling. To partially test this hypothesis, we measured the rolling velocities of functionalized microparticles, comparable in size to leukocytes, interacting with E-selectin coated substrates of controlled stiffness. The kinematic analysis of the particles' motion reveals a larger rolling velocity on softer substrates, aligning with previous reports regarding monocytes. A simple kinetic model for a cluster of reversible bonds formed between a cell and the underlying substrate demonstrates that the critical forces needed for bond disassembly decrease as substrate stiffness decreases. Consequently, bonds are more likely to break on softer substrates, resulting in enhanced cell mobility.</p> </abstract>

Objective assessment of the effects of opicapone in Parkinson’s disease through kinematic analysis

BackgroundOpicapone (OPC) is a third-generation, selective peripheral COMT inhibitor that improves peripheral L-DOPA bioavailability and reduces OFF time and end-of-dose motor fluctuations in Parkinson’s disease (PD) patients.ObjectivesIn this study, we objectively assessed the effects of adding OPC to L-DOPA on bradykinesia in PD through kinematic analysis of finger movements.MethodsWe enrolled 20 treated patients with PD and motor fluctuations. Patients underwent two experimental sessions (L-DOPA, L-DOPA + OPC), separated by at least 1 week. In each session, patients were clinically evaluated and underwent kinematic movement analysis of repetitive finger movements at four time points: (i) before their usual morning dose of L-DOPA (T0), (ii) 30 min (T1), (iii) 1 h and 30 min (T2), and (iv) 3 h and 30 min after the L-DOPA intake (T3).ResultsMovement velocity and amplitude of finger movements were higher in PD patients during the session with OPC compared to the session without OPC at all the time points tested. Importantly, the variability of finger movement velocity and amplitude across T0–T3 was significantly lower in the L-DOPA + OPC than L-DOPA session.ConclusionsThis study is the first objective assessment of the effects of adding OPC to L-DOPA on bradykinesia in patients with PD and motor fluctuations. OPC, in addition to the standard dopaminergic therapy, leads to significant improvements in bradykinesia during clinically relevant periods associated with peripheral L-DOPA dynamics, i.e., the OFF state in the morning, delayed-ON, and wearing-OFF periods.

How To Create Our Custom Model in CoppeliaSim From 3D File

Purpose: This paper aims to provide a comprehensive guide to creating custom models in CoppeliaSim from 3D files. It equips users with the necessary knowledge and skills to design and simulate their unique robotic systems within the CoppeliaSim environment. By creating it, users can design robots with unique geometries and configurations that align with their specific requirements and research objectives. It enables users to represent real-world robots or prototypes in the virtual environment accurately. It provides a platform to test and validate robot designs before physical implementation. Users can simulate different scenarios, assess the feasibility of their concepts, and identify potential issues or improvements early in the design process, thereby saving time and resources. It equips students, researchers, and robotics enthusiasts with practical knowledge and hands-on experience designing and simulating custom robot models. It also encourages collaboration and knowledge sharing within the robotics community. Design/Methodology/Approach: Download the desired model for Simulation from the website. Import 3D model into the environment. Configures various properties of the model. This includes defining physical properties, and visual appearance, for realistic rendering. The process also determines the kinematic properties of the model. It involves creating linkages, defining joint properties, and establishing parent-child relationships between objects. Add child scripts. Save the model for future use. Findings/Result: Here, we provide the process for importing 3D files into CoppeliaSim. Users could import their necessary models without an issue, ensuring the accurate representation of 3D object geometry in the simulation environment. Users could establish linkages, define joint properties, and set parent-child relationships, allowing for accurate kinematic simulations and motion analysis. Originality/Value: It provides a comprehensive step-by-step guide on creating custom models in CoppeliaSim from 3D files. It covers all the essential aspects and ensures that users understand the entire process clearly, making it a valuable resource for beginners and experienced users. Paper Type: Experimental-based Research.

N°256 – Kinematic analysis of movement to assess GPi-DBS effectiveness in dystonia

N°256 – Kinematic analysis of movement to assess GPi-DBS effectiveness in dystonia

합기도 술기 칼넣기 동작의 운동학적 분석

The purpose of this study is to conduct a kinematic comparative analysis of the hapkido skill Kalnugki motion. To this end, an infrared high-speed camera were used for motion analysis. The Kwon3d program was used for the analysis of kinematic variables. Additionally, an independent t-test was conducted to verify the differences between the skilled and the unskilled, and this time, the statistical significance level was set at .05. The results were as follows. First, the time required for the completion of the Sulki and Kalnugki techniques was short for those skilled in Hapkido. Second, there was no difference in the movement of the COM(center of mass) by event for both the skilled and unskilled. Third, there was no difference in the left/right and forward/backward velocities of the COM during demonstrations of Sulki and Kalnugki between the skilled and unskilled. In event 2, the vertical velocity of the COM in the vertical upward direction was faster in the skilled. Fourth, there was no difference in the hip joint, and ankle joint angles. However, in event 2 and 3 of the right knee joint angle, skilled showed smaller angles than unskilled, and for left knee joint angles in event 1 and 2, skilled showed smaller angles than unskilled.

High-demand tasks show that ACL reconstruction is not the only factor in controlling range of tibial rotation: a preliminary investigation

BackgroundExcessive range of tibial rotation (rTR) may be a reason why athletes cannot return to sports after ACL reconstruction (ACLR). After ACLR, rTR is smaller in reconstructed knees compared to contralateral knees when measured during low-to-moderate-demand tasks. This may not be representative of the amount of rotational laxity during sports activities. The purpose of this study is to determine whether rTR is increased after ACL injury compared to the contralateral knee and whether it returns to normal after ACLR when assessed during high-demand hoptests, with the contralateral knee as a reference.MethodsTen ACL injured subjects were tested within three months after injury and one year after reconstruction. Kinematic motion analysis was conducted, analysing both knees. Subjects performed a level-walking task, a single-leg hop for distance and a side jump. A paired t-test was used to detect a difference between mean kinematic variables before and after ACL reconstruction, and between the ACL-affected knees and contralateral knees before and after reconstruction.ResultsRTR was greater during high-demand tasks compared to low-demand tasks. Pre-operative, rTR was smaller in the ACL-deficient knees compared to the contralateral knees during all tests. After ACLR, a greater rTR was seen in ACL-reconstructed knees compared to pre-operative, but a smaller rTR compared to the contralateral knees, even during high-demand tasks.ConclusionThe smaller rTR, compared to the contralateral knee, seen after a subacute ACL tear may be attributed to altered landing technique, neuromuscular adaptation and fear of re-injury. The continued reduction in rTR one year after ACLR may be a combination of this neuromuscular adaptation and the biomechanical impact of the reconstruction.Trial registration: The trial was registered in the Dutch Trial Register (NTR: www.trialregister.nl, registration ID NL7686).

Anticipatory postural adjustments and kinematic analysis of step ascent and descent in adults with Down syndrome.

Step ascent and descent is one of the most common daily tasks. Although it is generally considered a rather simple movement, it may not be so easy for participants with Down syndrome. A kinematic analysis of step ascent and descent was conducted, and a comparison between 11 adult participants with Down syndrome and 23 healthy participants was carried out. This analysis was accompanied by a posturographic analysis with the aim of evaluating aspects relating to balance. The principal aim of postural control was to investigate the trajectory of the centre of pressure, while the kinematic analysis of movement included the following: (1) the analysis of anticipatory postural adjustments, (2) the calculation of spatiotemporal parameters and (3) the evaluation of articular range of motion. A general instability for participants with Down syndrome, highlighted in the postural control by an increased anteroposterior and mediolateral excursion, when the test was conducted with both open and closed eyes, was found out. Regarding anticipatory postural adjustments, this deficit in balance control was revealed by the execution of small steps before completing the movement and by a much longer preparation time anticipating the movement. In addition, the kinematic analysis reported a longer ascent and descent time and a lower velocity, accompanied by a greater rising of both limbs in ascent, which indicates an increased perception of the obstacle. Finally, a wider trunk range of motion in both the sagittal and frontal planes was revealed. All the data confirm a compromised balance control that could be associated with damage to the sensorimotor centre.

ANÁLISE POSTURAL NO BASQUETEBOL BASEADA NAS HABILIDADES ESPORTIVAS

ABSTRACT Introduction The continuous development of basketball provides greater demands on its players. The traditional method of practical education hardly adapts to the current situation of rapid development, requiring updated teaching strategies. Objective Explore the teaching method concerning the posture taught in basketball based on sports training and skills. Methods Under a particular protocol, the outstanding sports skills of each athlete were analyzed kinematically with a marker ball, deficiencies in their sports skills were checked and corrected, and new tests were performed from the corrections. After the training, the kinematic data of the motor skills were obtained again. The before and after data were compared, analyzed, and discussed. A group of experts discussed a scientific training scheme dedicated to each practitioner’s sports skills. Results Using the kinematic movement analysis model, we can find in detail the athletes’ deficiencies in the sport process and adjust them, optimizing the outstanding aspects of each player. Conclusion The use of the mechanical model to analyze basketball sports skills and movements can complement scientific teaching programs for athletes, and further studies are recommended for its popularization. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

Motion Kinematic Analysis of the Palestinian Athletics Team Players Under 20 Years in 1500 m Race

This study identifies the kinematic analysis of the Palestinian athletics team players under 20 years in a 1500 m race by calculating the kinematic variables, identifying the relationship between them and the performance stages, and identifying the differences between the kinematic variables of the performance stages and the time of the 1500 m race. The researchers followed the analytical descriptive approach and selected a purposive sample; the Palestinian athletics team players under 20 years who participated in 1500 m races from the southern governorates (i.e. three players). The research main results were identifying the kinematic variables and their values (step length, step frequency, contact time, flight time, step time, step speed, average speed and center of pressure position). There are no statistically significant relationships between the values of the kinematic variables and the 1500 m race time. Statically significant differences at 0.05 are observed for the values of the kinematic variables: step length, contact time, and flight speed. However, there are no statistically significant differences for the values of the other variables. The researchers recommend the Palestine Athletic Federation to benefit from the results of the study for each of the race’ stages to identify the strengths and weaknesses of players and hence improve their skills. Keywords: motion analysis, kinematic analysis, 1500 m race. https://doi.org/10.55463/issn.1674-2974.50.2.14

The kinematic analysis of the lateral airflip motion on the balance beam apparatus of the 2008 world champions

ﻤن ﺨﻼﻝ ﺨﺒرة اﻟﺒﺎﺤﺜﺔ ﻓﻲ ﻤﺠﺎﻝ اﻟﺠﻤﻨﺎﺴﺘك ﻛﺎﻟﻼﻋﺒﺔ وﻤدرﺒﺔ وﺤﻛﻤﺔ دوﻟﻴﺔ ﻻﺤظت إن اﻟﺘﻐﻴﻴر اﻟﻤﺴﺘﻤر ﻓﻲ ﻤﻬﺎ ارت وﺤرﻛﺎت اﻟﺠﻤﻨﺎﺴﺘك اﻟﻔﻨﻲ ﻴﺘم ﺒزﻴﺎدة اﻟﺼﻌوﺒﺔ واﻟﺘﻨوﻴﻊ ﻓﻲ ﻤﺨﺘﻠف اﻷﺠﻬزة ﻤن ﺤرﻛﺎت اﻟطﻴ ارن أو اﻟﻘﻠﺒﺎت واﻟدو ارن ﻟذا وﺠدت اﻟﺒﺎﺤﺜﺔ أن ﻤﻬﺎرة اﻟﻘﻠﺒﺔ اﻟﻬواﺌﻴﺔ اﻟﺠﺎﻨﺒﻴﺔ ﻤن اﻟﻤﻬﺎ ارت اﻟﺼﻌﺒﺔ واﻟﻘﻠﻴﻠﺔ اﻻﺴﺘﻌﻤﺎﻝ ٬ ﺒﻐض اﻟﻨظر ﻋن دﺨوﻟﻬﺎ ﻤن ﻀﻤن اﻟﺴﻼﺴﻝ اﻹﺠﺒﺎرﻴﺔ ﻓﻲ ﺠﻬﺎز ﻋﺎرﻀﺔ اﻟﺘوازن ٬ إذ أﻨﻬﺎ ﺘﻤﺘﺎز ﻋن اﻟﻬواﺌﻴﺎت اﻟﺨﻠﻔﻴﺔ واﻷﻤﺎﻤﻴﺔ ﻤن ﻨﺎﺤﻴﺔ اﻟﺘﻛﻨﻴك ودو ارن اﻟﺠﺴم ﻟﻠﺠﺎﻨب ٬ ﻟذا ﻗﺎﻤت اﻟﺒﺎﺤﺜﺔ ﺒﺈﺠ ارء اﻟﺘﺤﻠﻴﻝ اﻟﻛﻴﻨﻤﺎﺘﻴﻛﻲ ﻋﻠﻰ أﻓﻀﻝ ﺴﺘﺔ ﻻﻋﺒﺎت ﻓﻲ اﻟﻌﺎﻟم ﻋﻠﻰ ﺠﻬﺎز ﻋﺎرﻀﺔ اﻟﺘوازن وﻓﻘﺎ ﻟﻨﺸرة اﻻﺘﺤﺎد اﻟدوﻟﻲ ﻟﻠﺠﻤﻨﺎﺴﺘك اﻟﻔﻨﻲ ﻟﻠﺘﻌرف ﻋﻠﻰ اﻟﻤﺘﻐﻴ ارت اﻟﻛﻴﻨﻤﺎﺘﻴﻛﻴﺔ ﻷداء ﻤﻬﺎرة اﻟﻘﻠﺒﺔ اﻟﻬواﺌﻴﺔ اﻟﺠﺎﻨﺒﻴﺔ ٬ واﻻﺨﺘﻼف ﺒﻴن اﻟﻼﻋﺒﺎت ﻟﻠوﺼوﻝ إﻟﻰ أﻓﻀﻝ اﻨﺠﺎز ﻟدﻴﻬن. ﻟذا ﻫدف اﻟﺒﺤث إﻟﻰ اﻟﺘﻌرف ﻋﻠﻰ أوﻀﺎع اﻟﺠﺴم ﺨﻼﻝ ﻤ ارﺤﻝ أداء ﻤﻬﺎرة اﻟﻘﻠﺒﻴﺔ اﻟﻬواﺌﻴﺔ اﻟﺠﺎﻨﺒﻴﺔ ﻋﻠﻰ ﺠﻬﺎز ﻋﺎرﻀﺔ اﻟﺘوازن. واﻟﺘﻌرف ﻋﻠﻰ اﻟﻤﺘﻐﻴ ارت اﻟﻛﻴﻨﻤﺎﺘﻴﻛﻴﺔ ﻷوﻀﺎع اﻟﺠﺴم ﺨﻼﻝ ﻤ ارﺤﻝ أداء ﻤﻬﺎرة اﻟﻘﻠﺒﻴﺔ اﻟﻬواﺌﻴﺔ اﻟﺠﺎﻨﺒﻴﺔ ﻋﻠﻰ ﺠﻬﺎز ﻋﺎرﻀﺔ اﻟﺘوازن.

Contrast-enhanced ultrasound tracking of helical propellers with acoustic phase analysis and comparison with color Doppler.

Medical microrobots (MRs) hold the potential to radically transform several interventional procedures. However, to guarantee therapy success when operating in hard-to-reach body districts, a precise and robust imaging strategy is required for monitoring and controlling MRs in real-time. Ultrasound (US) may represent a powerful technology, but MRs' visibility with US needs to be improved, especially when targeting echogenic tissues. In this context, motions of MRs have been exploited to enhance their contrast, e.g., by Doppler imaging. To exploit a more selective contrast-enhancement mechanism, in this study, we analyze in detail the characteristic motions of one of the most widely adopted MR concepts, i.e., the helical propeller, with a particular focus on its interactions with the backscattered US waves. We combine a kinematic analysis of the propeller 3D motion with an US acoustic phase analysis (APA) performed on the raw radio frequency US data in order to improve imaging and tracking in bio-mimicking environments. We validated our US-APA approach in diverse scenarios, aimed at simulating realistic in vivo conditions, and compared the results to those obtained with standard US Doppler. Overall, our technique provided a precise and stable feedback to visualize and track helical propellers in echogenic tissues (chicken breast), tissue-mimicking phantoms with bifurcated lumina, and in the presence of different motion disturbances (e.g., physiological flows and tissue motions), where standard Doppler showed poor performance. Furthermore, the proposed US-APA technique allowed for real-time estimation of MR velocity, where standard Doppler failed.

Kinematics of Hooke’s Joint

Problem. An analysis of the literature has shown that some issues of the kinematics and dynamics of the Hooke’s joint are not fully covered. In particular, this applies to the determination of the kinematic characteristics of the relative movements of the links in the movable joints of the crosspieces and cardan yokes, as well as the acceleration of the crosspiece in the study of the hinge. These kinematic characteristics are the basis for dynamic analysis of the cardan transmission; they are used at research of operation of the bearings of a cardan joint cross; they are necessary to determine the energy expended to overcome the forces of friction in these kinematic pairs; they form the basis for evaluating transmission efficiency. Goal. The goal of this work is to determine the kinematic characteristics of the cross in its absolute and relative motions. Methodology. The research is based on the graphical and analytical method of kinematic analysis of spherical motion of a rigid body. At the initial stage, the calculated dependences for determining the angular velocity of the cross in its absolute and relative motions were obtained. The relative angles of rotation of the links in the movable joints of the crosspiece and cardan yokes were determined by integrating the corresponding differential equations. To determine the angular acceleration of the crosspiece, the theorem on the addition of angular accelerations of a rigid body rotating around two non-parallel axes was used. Results. The study of the kinematics of the cardan joint made it possible to identify and eliminate ambiguities in determining the relative angular velocities of the elements of the kinematic pairs of the cross and cardan yokes. Functional dependences for determination of angular acceleration of a crosspiece in absolute and relative movements, and also relative angles of rotation of links in kinematic pairs of a crosspiece and cardan yokes were received. It was shown that the angular acceleration of the crosspiece is a periodic function of the angle of rotation of the input link. During the operation of the hinge, the crosspiece creates insignificant periodic dynamic loads, which should be taken into account in accurate calculations of high-speed cardan transmissions. Practical value. The work is devoted to the study of the kinematics of the asynchronous hinge, which is the foundation for its dynamic analysis and ultimately aimed at improving the output performance of the cardan transmission. The research method combines mathematical calculations with simplicity and clarity of graphic constructions, which contributes to a deeper understanding of the kinematic features of a hinge of uneven angular velocities. The obtained results can be used in the design and study of motor-transmission units, which include the Hooke’s joint.

Performance analysis of quadruped robot designed with Desai’s walking leg mechanism

ABSTRACT The simulation studies performed on walking quadruped robot, with 8 link coplanar Desai’s walking leg mechanism, is conducted using SAM 6.1 software along with the kinematic analysis and motion analysis of a quadruped robot performed in SOLIDWORKS software. The optimised link lengths of each leg in Quadruped robot are obtained based on motion along a straight path and a staircase. The foot profile of optimised model is compared with Desai’s, Theos Jansen’s, and Joe Klann’s walking leg mechanisms.

Comparison of 2-D and 3-D Analysis of Running Kinematics and Actual Versus Predicted Running Kinetics

Background Providing clinicians with an accurate method to predict kinetic measurements using 2D kinematic motion analysis is crucial to the management of distance runners. Evidence is needed to compare the accuracy of 2D and 3D kinematic measurements as well as measured and estimated kinetic variables. Purposes The objectives of this study were to (1) compare 2D video analysis of running kinematics with gold standard 3D motion capture and, (2) to evaluate published equations which estimate running kinetics using 2D kinematic and spatiotemporal values and modify these equations based on study findings. Design Controlled laboratory study, cross-sectional design Methods Runners who averaged at least 20 miles per week were invited to participate. Athletes ran on an instrumented treadmill at their preferred training pace for a 6-minute warm-up. Markers were placed over designated anatomical landmarks on both sides of the pelvis as well as the left lower extremity. Subjects then ran at their preferred speed and kinematic data were recorded using both the 2D and 3D camera systems at 240 frames/second. Additionally, ground reaction forces were recorded at 1200Hz. 2D and 3D kinematic values were compared and published kinetic prediction formulas were tested. Linear regression was used to develop new prediction equations for average loading rate (AVG_LR), peak vertical ground reaction force (VERT_GRF), and peak braking force (PK_BRK). Paired t-tests were used to assess differences between the 2D and 3D kinematic variables and the measured (MEAS) and calculated (CALC) kinetic variables. Results Thirty runners (13 men and 17 women) voluntarily consented to participate in this study and the mean age of the participants was 31.8 years (range 20 to 48 years). Although significant differences existed, all 2D kinematic measures were within 2°-5° of 3D kinematic measures. Published prediction equations for AVG_LR and VERT_GRF were supported, but new prediction equations showed higher R2 for AVG_LR (0.52) and VERT_GRF (0.75) compared to previous work. A new prediction equation for PK_BRK was developed. No significant differences were found between the MEAS and CALC kinetic variables using the new equations. Conclusion Accurate predictions of kinetic variables can be made using spatiotemporal and 2D kinematic variables. Level of Evidence Level 2

Modulation of biological motion perception in humans by gravity

The human visual perceptual system is highly sensitive to biological motion (BM) but less sensitive to its inverted counterpart. This perceptual inversion effect may stem from our selective sensitivity to gravity-constrained life motion signals and confer an adaptive advantage to creatures living on Earth. However, to what extent and how such selective sensitivity is shaped by the Earth’s gravitational field is heretofore unexplored. Taking advantage of a spaceflight experiment and its ground-based analog via 6° head-down tilt bed rest (HDTBR), we show that prolonged microgravity/HDTBR reduces the inversion effect in BM perception. No such change occurs for face perception, highlighting the particular role of gravity in regulating kinematic motion analysis. Moreover, the reduced BM inversion effect is associated with attenuated orientation-dependent neural responses to BM rather than general motion cues and correlated with strengthened functional connectivity between cortical regions dedicated to visual BM processing (i.e., pSTS) and vestibular gravity estimation (i.e., insula). These findings suggest that the neural computation of gravity may act as an embodied constraint, presumably implemented through visuo-vestibular interaction, to sustain the human brain’s selective tuning to life motion signals.

Magnetic field-assisted batch superfinishing on thin-walled components

Thin-walled components have been widely used in different kinds of fields such as aviation, automobiles, medical, etc. However, it is difficult to strike a balance between polishing efficiency and accuracy in the polishing of such components. Hence, this paper presents a novel magnetic field-assisted batch superfinishing (MABS) process which makes use of a magnetic field applied by two pairs of magnetic poles rotating outside an annular chamber mounted with a number of workpieces concurrently. The rotating magnetic brushes comprise magnetic particles and abrasives formed inside the chamber which impinge and remove materials from the workpiece. A theoretical and experimental investigation of the material removal in MABS is conducted on typical thin-walled components, including kinematic analysis of the brush motion, simulation of the magnetic field distribution and material removal distribution model. The experimental results indicate that the MABS process can be successfully used for batch polishing of thin-walled components while obtaining nanometric surface roughness. The developed material removal distribution model can be used to predict the material removal, so as to provide theoretical guidance of process optimization.