Kinematic

The purpose of this study was to compare key magnitude and timing parameters of the kinematic sequence between amateur recreational players (amateurs) and PGA touring professionals (pros). It was hypothesized that the key magnitude parameters would be significantly higher in the pros than the amateurs, and that the key timing parameters would be significantly different between the two groups. A representative swing from each of 19 amateurs and 19 pros was captured using three-dimensional (3D) motion analysis techniques. Eighteen key kinematic sequence performance variables that occur during the downswing were computed from the data. Student t-test’s were used to compare the group means for each parameter with an experiment-wise level of significance set at p<0.2, and a corresponding test-wise significance of p<0.011. All the magnitude variables including rotational accelerations; rotational decelerations, (except pelvis); peak rotational speeds; rotational speed gains; and lin...

The main purpose of the present study was to investigate the kinematics and kinetics of successful versus unsuccessful basketball free throw shots. Six professional basketball players (age= 23±2.09 years members of Iranian premier basketball league participat in test. Kinematics of arm motion during basketball free throws were recorded by two Casio zr200 camera in frequency of 240 Hz. Wilcoxon test was used for significant differences between successful versus unsuccessful free throws (p ≤ 0/05). Angular velocity of the wrist was found to be significantly higher in successful versus unsuccessful shots at the time of ball release (p ≤ 0/028). Wrist (p ≤ 0/008) and shoulder (p ≤ 0/023) joints were found to have significantly more flexion in successful versus unsuccessful shots while elbow (p ≤ 0/002) remained significantly less flexed in successful shots. Angular displacement of wrist (p ≤ 0/034) and elbow (p ≤ 0/004) was shown to be significantly greater in successful versus unsuccessful shots. Integrated EMG of Anterior Deltoid (AD), Triceps Brachii (TB) and Flexor Carpi Radialis (FCR) muscles was more in successful free throw versus unsuccessful free throw, but the only significant difference was observed in the Integrated EMG of the Triceps Brachii muscle (p ≤ 0/034). In summery, increasing the wrist angular velocity and activity of triceps brachii muscle affected successful free throws.

There are several mundane and repetitive tasks in recent times that call for the development of effective and efficient robots that can be remotely controlled for safety, accuracy and flexibility. In the work reported here, a versatile and low cost "Pick and Place Robot" that can be remotely controlled is developed. The robot uses two Arduino microcontrollers connected in a master/slave configuration. The master controls the robotic arm while the slave controls the robotic base. The arm utilizes servomotors to provide motion in the required axis. The base consists of dc geared motors and tracked wheels for transporting the robotic arm with the griper. The result of this project is a miniature robot that provides pick and place functions that can be used in several applications by changing the program of controller. The structure is designed to lift light loads. The applications of this system include warehousing, performing tasks in factory lines and even it can be employed as a personal helper for people with disabilities

There are several mundane and repetitive tasks in recent times that call for the
development of effective and efficient robots that can be remotely controlled for safety,
accuracy and flexibility. In the work reported here, a versatile and low cost “Pick and
Place Robot” that can be remotely controlled is developed. The robot uses two
Arduino microcontrollers connected in a master/slave configuration. The master
controls the robotic arm while the slave controls the robotic base. The arm utilizes
servomotors to provide motion in the required axis. The base consists of dc geared
motors and tracked wheels for transporting the robotic arm with the griper. The result
of this project is a miniature robot that provides pick and place functions that can be
used in several applications by changing the program of controller. The structure is
designed to lift light loads. The applications of this system include warehousing,
performing tasks in factory lines and even it can be employed as a personal helper for
people with disabilities

This paper extends the results from velocities and accelerations fields of rigid bodies motion to higher-order accelerations. Using the tensor calculus and the dual numbers algebra, a computing method for studying the higher order acceleration field properties is proposed in the case of the general motion. The vector and tensor invariants in the distribution of the n-th order acceleration field are highlighted. For the case of the spatial kinematics chains, an equation that allows the determination of the n-th order field accelerations are given, using a Brockett-like formulas specific to the dual algebra. The results are free of coordinate and in a closed form. In particular cases the properties for velocities, accelerations, jerks, and hyper-jerks fields are given. This approach uses the isomorphism between the Lie group of the rigid displacements 3 and the Lie group of the orthogonal dual tensors.

This paper proposes the design and control strategy for a four degrees-of-freedom spatial cable-suspended parallel robot for pick and place operations. Pick and place is a repetitive task requiring payload changes for the movement to pickup the object, and the movement to the final pose to release the manipulated object. In this paper, a new robust control strategy has been proposed, together with proper trajectories for the required operation. The control strategy consists on the system decoupling and linearization by means of a feedforward term and a cascade PD controller. The main advantage of the proposed solution is that its design can be scalable in size spanning from centimeters to meters with a relatively good positioning accuracy. Finally, simulations are reported to show the overall performances of the proposed configuration for pick and place operations with a medium size manipulator.

Objective The aim of this study is investigate the core muscles dysfunctions and their consequences in
patients with chronic ankle instability.
Methods In this review study, search was conducted in three online databases of PubMed, Scopus, and
Google scholar based on Patient, Intervention, Comparison, Outcome (PICO) strategy, and using keywords
related to the role and function of core muscles, their electromyography, kinematic patterns of proximal
segments, and postural stability in individuals with chronic ankle instability.
Results Seven studies were finally selected for the review based on the inclusion and exclusion criteria.
The results indicated that individuals with chronic ankle instability in comparison with healthy peers have
different electromyography and kinematic patterns of proximal segments (trunk, abdomen and pelvis).
Conclusion Muscle activity and kinematic patterns of proximal segments in individuals with chronic ankle
instability are different to those of healthy ones. These differences are compensatory strategies for postural
stability. These strategies may not provide the body’s need to maintain and control the poster in
new environments or during complex activities. Further studies are needed to investigate effects of the
correction of core muscle function on the postural control in individuals with chronic ankle instability.

Ida Kovač, Vladimir Medved, Mario Kasović, Željko Heimer, Vesna Lužar-Stiffler, Marko Pećina: Instrumented joint mobility analysis in traumatic transtibial amputee patients, Periodicum biologorum, 112 (2010), 1; 25-31.

Aim: The presented study reports a quantitative gait analysis and different adaptive strategies evaluation on 12 male adults, war trauma transtibial (TT) amputees, fitted with prostheses. Methods: Gait analysis included kinematics (joint mobility variables) prosthetic and healthy legs in 12 TT amputees and 12 able-bodied per-sons/individuals. Results: The results disclose asymmetry in gait parameters between the amputated and sound legs, as well as between transtibial amputees and able-bodied persons. Kinematic results of the amputees and a control group, showed significantly reduced prosthetic maximum ankle plantar flexion (p<0.01), decreased hip adduction (p< 0.05) and increased knee flexion at stance phase (p< 0.1) for the left, healthy legs of amputees. Conclusion: Although adult traumatic TT amputees have great potential for enhancement of function through appropriate rehabilitation and use of effective prosthetic devices, they adapt a unique way of ambulating with the prosthesis. An instrumented gait analysis study is able to provide assessment of the way prosthetic transtibial amputees walk, as objective information to supplement clinical observation.

The purpose of the present study was to determine the lower extremities biomechanical differences between prepubescent and adult males during drop jumps (DJs). Twenty-four untrained males (12 prepubescents, 12 adults) performed DJs from 20 cm height. Kinematics of the lower extremities were captured, in addition with vertical ground reaction forces (vGRFs) and EMG activity of the gastrocnemius medialis (GM), soleus (SOL) and tibialis anterior (TA) muscles. The results showed that men jumped higher, as expected, but their knees were more flexed prior to landing, and their preactivation level was higher and longer in duration compared to prepubescent boys. During landing, men had shorter contact times, lower vGRF normalized to body mass, and less maximal knee joint flexion. Regarding EMG activity men presented higher stretch reflex and higher EMG activity during the braking phase but the level of coactivation (TA to GM + SOL ratio) was lower. It is seems that pre-landing and landing patterns during a complex task such as DJ are affected by physical development. There are indications that men had higher performance in a DJ than prepubescent boys because they activated more effectively their muscles during the preactivation and braking phase. The above-mentioned data support the hypothesis that prepubescent boys might be inferior in optimal regulation of their muscle–tendon unit stiffness.

The purpose of this study was to analyze the reproducibility of kinematic, dynamometric and derived mechanical energy parameters in the pole vault as a main precondition for the practical applicability of the concept of energy exchange in the pole vault. A total of 46 vaults of six experienced vaulters were analyzed. On the basis of 3D kinematic data of the athlete and the pole and ground reaction forces measured at the end of the pole in the planting box the reproducibility of parameters that describe the energy transfer into the pole and the energy exchange between the athlete and the pole during the vault was proofed. Intraclass correlation, mean root mean square and the coefficient of variance were determined, additionally the Wilcoxon Test was applied. Parameters of the athlete&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s 3D total mechanical energy, e.g. initial energy and final energy, and the pole energy (maximum pole energy, energy of the pole due to compressive force and bending moment) were highly reproducible. The distribution of the energy transferred into the pole due to compressive force and bending moment, the same as the energy gain of the vaulter-pole system during the vault, which indicates the strategy of interacting with the pole, were also reproducible. With this the concept of energy exchange in the pole vault can be used to analyze the impact of training interventions, changes in movement pattern respectively, on the vaulters performance during different phases of the vault. The analysis of one trial of an athlete should be sufficient to identify changes in the athlete&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s interaction with the elastic pole.

Computing earthwork volumes is a necessary activity for nearly all construction projects and is often accomplished as a part of route surveying, especially for roads, Dredging and highways. If the area of the cross section at each station is known, then multiply that average end area by the known horizontal distance between the stations to determine the volume of cut. We present the results of precise static and kinematic point-positioning solutions obtained in post-processing, with a recursive Kalman filter estimator. The observations are dual frequency GPS carrier phase and pseudo-range, treated as two distinct data types, each with its own measurement equations. The receiver data is double differenced between satellites, to eliminate the receiver clock, and processed using precise satellite ephemerides and clock corrections. While estimating receiver coordinates, ionosphere-free carrier phase Lc biases, and tropospheric refraction model errors were treated accordingly. The motiva...

This study used the self organising map (SOM) as a processing step in reducing the complexity of human movement dynamics obtained from execution of a rowing stroke. The SOM is an artificial neural network (ANN), adapted in an unsupervised manner using a self organising learning process. Three-dimensional joint angles, produced by the rowers, were projected onto a 2 dimensional topological neural map, thereby identifying rowing movement patterns. Unsupervised clustering allowed the time series rowing strokes to be positioned on the map in relation to each other and this enabled movement patterns to be compared. The larger kinematic variation of the novice rowers was observed. The weight vector associated with each SOM cluster illustrated underlying task related changes in the rowing stroke patterns between elite and novice.

Abstract: This paper extends the results from velocities and accelerations fields of rigid bodies motion to higher-order accelerations. Using the tensor calculus and the dual numbers algebra, a computing method for studying the higher order acceleration field properties is proposed in the case of the general motion. The vector and tensor invariants in the distribution of the n-th order acceleration field are highlighted. For the case of the spatial kinematics chains, an equation that allows the determination of the n-th order field accelerations are given, using a Brockett-like formulas specific to the dual algebra. The results are free of coordinate and in a closed form. In particular cases the properties for velocities, accelerations, jerks, and hyper-jerks fields are given. This approach uses the isomorphism between the Lie group of the rigid displacements