A force-velocity relationship in overarm throwing was determined using ball weights varying from 0.2 to 0.8 kg. Seven experienced handball players were filmed at 240 frames per second. Velocity of joints of the upper extremity and ball together with the force on the ball were derived from the data. A statistically significant negative relationship between force and maximal ball velocity, as wel...

This paper presents an Abaqus/Explicit simulation of the impact event when a golf club hits a golf ball. This is a challenging subject for finite element simulations because of it is characterized by high strain rate behavior. The simulation emphasizes accurate material characterization and realistic model construction. Specifically, an advanced nonlinear viscoelastic material model from Veryst...

This work is motivated by a staple carnival game. A player throws a ping-pong ball onto a grid of cups with the goal of having the ball land in a cup. Though there are many variations to this game, there is a common underlying characteristic. As the ball bounces on the cup grid, its sequence of bouncing trajectories becomes nonlinear. It is this nonlinearity which makes it impossible for an obs...

objectives: the incidence of stereotyped behaviors is one of the major symptoms of diagnosis of individuals with autism spectrum disorder that causes disruption in daily life. this study aimed at evaluating the effectiveness of ball exercises on the reduction of stereotypical behavior of children with autism spectrum disorder. methods: in this study, 16 children (boys) with autism spectrum diso...

This study investigates the control involved in a task where subjects rhythmically bounce a ball with a hand-held racket as regularly as possible to a prescribed amplitude. Stability analyses of a kinematic model of the ball-racket system revealed that dynamically stable solutions exist if the racket hits the ball in its decelerating upward movement phase. Such solutions are resistant to small ...

When a tennis ball rests on top of a basketball and both drop to the floor together, the tennis ball is projected vertically at high speed. A mass-spring model of the impact, as well as air track data, suggest that the tennis ball should be projected at relatively low speed. Measurements of the forces on each ball and the bounce of vertically aligned superballs are used to resolve the discrepan...

We construct a massive non-abelian N = 1 SYM theory on R. This is achieved by using a non-local gauge and Poincare invariant mass term for gluons due to Nair. The underlying supersymmetry algebra is shown to be a non-central extension of the Poincare algebra by the spacetime rotation group so(3). The incorporation of Chern-Simons couplings in the formalism is also presented. The dimensional red...