Computer simulation of a full twisting dive

Journal of Sports Sciences

1993

At the 1991 World Student Games, eight reverse 1 1 2 somersault dives with 2 1 2 twists were recorded during the men's finals in the 1m and 3m springboard diving competitions using two video cameras. Angles describing body configuration were determined from video data and were input, together with initial orientation angle values and angular momentum components, into a computer simulation model of aerial movement in order to predict body orientation in space. Mean absolute deviations between simulation and video after the completion of one twist were 0.02 rev for somersault, 2.3• for tilt and 0.04 rev for twist. Contributions to the tilt angle after one twist were used as measures of the twisting potential of various techniques and were determined using simulations based on modifications of the video data. Seven of the eight competitors produced the majority of the tilt using aerial techniques which were predominantly asymmetrical movements of the arms and hips, although the mean contribution from contact techniques amounted to one-third of the total tilt.

Section: Introductionmentioning

confidence: 99%

Twisting techniques used by competitive divers

Journal of Sports Sciences

1993

“…The weakness of this approach is that often neither the model nor the hypothetical movements are shown to be adequate representations of actual performances, as in Pike (1980) and Ramey and Yang (1981).…”

Section: Introductionmentioning

confidence: 99%

The simulation of aerial movement—IV. A computer simulation model

Journal of Biomechanics

Atha

Hales

1990

A computer simulation model of human airborne movement is described. The body is modelled as 11 rigid linked segments with 17 degrees of freedom which are chosen with a view to modelling twisting somersaults. The accuracy of the model is evaluated by comparing the simulation values of the angles describing somersault, tilt and twist with the corresponding values obtained from film data of nine twisting somersaults. The maximum deviations between simulation and film are found to be 0.04 revolutions for somersault, seven degrees for tilt and 0.12 revolutions for twist. It is shown that anthropometric measurement errors, from which segmental inertia parameters are calculated, have a small effect on a simulation, whereas film digitization errors can account for a substantial part of the deviation between simulation and film values.

“…Scher and Kane (1969) used a two-segment model to show that it is theoretically possible to convert a pure twist into a pure somersault by repeatedly abducting and adducting one arm. Pike (1980) showed that a full twist may be introduced into a plain dive by means of asymmetrical arm movements.…”

Section: Introductionmentioning

confidence: 99%

The biomechanics of twisting somersaults Part III: Aerial twist

Journal of Sports Sciences

1993

A simulation model and a rigid body model are used to evaluate aerial twisting techniques. It is found that when somersault is not present, a number of cycles of segment counter-rotation are required to produce one twist. When somersault is present, twist may be introduced by producing tilt using asymmetrical movements of the arms, chest or hips about the sagittal plane. The same asymmetrical movements may be used to remove tilt, although the effectiveness of these techniques is dependent upon body configuration and the direction of somersault.