377346.pdf (25.88 MB)
The mechanics of twisting somersaults
thesis
posted on 2010-12-03, 11:36 authored by Maurice R. YeadonTwisting movements are categorised into three mechanical types,
named as DIRECT, COUNTER-ROTATION and TILT TWIST. Twisting techniques
are studied using mathematical models.
A mathematical inertia model is constructed to enable the
determination of segmental inertia parameters from anthropometric
measurements. A film analysis program is developed so that the angles,
which specify the orientation and configuration of the body, may be
derived from digitised film data. A computer simulation model,
comprising 11 segments and 17 degrees of freedom, is constructed to
represent the human body in free fall. The combined use of the three
computer programs results in maximum errors of 3% for somersault and
9% for twist in ten filmed movements.
The mechanics of twisting techniques are explained using simple
mathematical models. An analysis of rigid body motions shows that
there are two distinct modes of motion, named as the ROD MODE and the
DISC MODE. It is shown that it is possible to change from one mode
to the other by varying the angle of pike and this permits the twist
to be increased or stopped or even reversed.
The capacities of twisting techniques are determined using
simulations. For twists from a piked position, delaying the extension
from the pike can increase the twist rate although this does depend
upon the particular technique used and the initial direction of
somersault.
The contributions of twisting techniques used in the filmed
movements are determined using simulations based upon modifications of
the film data. It is found that counter-rotation techniques made
small contributions and that aerial techniques, which increased the
angle of tilt, were the major contributors, even in movements where
the twist was apparent at take off.
Using the simulation model it is shown that the build up of twist
in the unstable double layout somersault may be controlled by means of
small asymmetrical arm movements during flight.
History
School
- Sport, Exercise and Health Sciences
Publisher
© Maurice Raymond YeadonPublication date
1984Notes
Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.EThOS Persistent ID
uk.bl.ethos.377346Language
- en