A-15 Generating mechanism of racket head-speed for the upper limb in tennis serve motion : The influence of skill level on the contributions in forward dynamics analysis

In the high-velocity tennis serve, the contributions that the upper limb segments' anatomical rotations make to racket head speed at impact depend on both their angular velocity and the instantaneous position of the racket with respect to the segments' axes of rotation. Eleven high-performance tennis players were filmed at a nominal rate of 200 Hz by three Photosonics cameras while hitting a high-velocity serve. The three-dimensional (3-D) displacement histories of 11 selected landmarks were then calculated using the direct linear transformation approach, and 3-D individual segment rotations for the upper limb were calculated using vector equations (Sprigings, Marshall, Elliott, & Jennings, 1994). The major contributors to the mean linear velocity of the center of the racket head of 31.0 m · s-1 at impact were internal rotation of the upper arm (54.2%), flexion of the hand (31.0%), horizontal flexion and abduction of the upper arm (12.9%), and racket shoulder linear velocity (9.7%). Forearm extension at the elbow joint played a negative role (-14.4%) and reduced the forward velocity of the center of the racket at impact.

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Technique effects on upper limb loading in the tennis serve

Journal of Science and Medicine in Sport ◽

10.1016/s1440-2440(03)80011-7 ◽

2003 ◽

Vol 6 (1) ◽

pp. 76-87 ◽

Cited By ~ 143

Author(s):

B Elliott ◽

G Fleisig ◽

R Nicholls ◽

R Escamilia

Keyword(s):

Upper Limb ◽

Limb Loading ◽

Tennis Serve

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Comparison of Endpoint Data Treatment Methods for the Estimation of Kinematics and Kinetics Near Impact During the Tennis Serve

Journal of Applied Biomechanics ◽

10.1123/jab.28.1.93 ◽

2012 ◽

Vol 28 (1) ◽

pp. 93-98 ◽

Cited By ~ 17

Author(s):

M. M. Reid ◽

Amity C. Campbell ◽

B. C. Elliott

Keyword(s):

Upper Limb ◽

Treatment Method ◽

Biomechanical Analysis ◽

Quintic Spline ◽

Tennis Serve ◽

Analysis System ◽

Endpoint Data ◽

Spline Filter ◽

The Impact ◽

Kinematics And Kinetics

Tennis stroke mechanics have attracted considerable biomechanical analysis, yet current filtering practice may lead to erroneous reporting of data near the impact of racket and ball. This research had three aims: (1) to identify the best method of estimating the displacement and velocity of the racket at impact during the tennis serve, (2) to demonstrate the effect of different methods on upper limb kinematics and kinetics and (3) to report the effect of increased noise on the most appropriate treatment method. The tennis serves of one tennis player, fit with upper limb and racket retro-reflective markers, were captured with a Vicon motion analysis system recording at 500 Hz. The raw racket tip marker displacement and velocity were used as criterion data to compare three different endpoint treatments and two different filters. The 2nd-order polynomial proved to be the least erroneous extrapolation technique and the quintic spline filter was the most appropriate filter. The previously performed “smoothing through impact” method, using a quintic spline filter, underestimated the racket velocity (9.1%) at the time of impact. The polynomial extrapolation method remained effective when noise was added to the marker trajectories.

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Dynamic Modeling of Overconstrained Parallel Robot

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.373-375.34 ◽

2013 ◽

Vol 373-375 ◽

pp. 34-37

Author(s):

Jian Xin Yang ◽

Zhen Tao Liu ◽

Jian Wei Sun

Keyword(s):

Dynamic Modeling ◽

Virtual Work ◽

Parallel Robot ◽

Tree Structure ◽

Kinematics And Dynamics ◽

Dynamics Analysis ◽

Forward Dynamics ◽

Principle Of Virtual Work ◽

Closed Form Solutions ◽

Dynamics Models

The dynamic modeling method for parallel robot based on the principle of virtual work and equivalent tree structure is proposed by taking off the platform and the chains as well as degenerating parallel robot into a tree structure, the closed-form solutions for the inverse and forward dynamics models of parallel robot are derived. The method is applied on kinematics and dynamics analysis of a representative 3-RRR spherical parallel robot.

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