ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

Dynamic Touch of Effective Golf Swing
W. Kim 1 , A. Veloso 1 , M. Machado 1 , V. Vleck 1 , L. Aguiar 1 , S. Cabral 1 and F.
Vieira 1
1
Biomechanics Laboratory
1
CIPER (Center for the Interdisciplinary Study of Human Performance)
Faculty of Human Kinetics
Technical University of Lisbon
Estrada da Costa, Cruz Quebrada, Portugal
1. ABSTRACT
Researchers have investigated how the dynamics of the golf swing including that
related to wrist function may be affected by the rotation of individual anatomical
segments via a full-body model, rather than in terms of the movement of specific
segments. We are revisiting the classic dogma of “the significance of left-hand
extension during a golfer’s downswing [1].” Recent studies have suggested that the
inertia tensor, a physical property whose values are time- and coordinate- independent,
may be an important informational invariant that is used by the proprioceptive system to
control the movement of our limb. We use this ‘dynamic touch paradigm’ to explain
why much of traditional golf instruction has stressed the importance of a neutral left
wrist position, classically called the ‘flat left wrist.’ We tested the hypothesis that the
aforesaid is important to the efficacy of the golf swing by comparing the perception to
action diagrams of a high- handicap, and a low-handicap, amateur. We found that a
skilled golfer might achieve stronger relationship between perception and action in
terms of their correlation. The implication of our preliminary findings about wobbling
inertia with respect to the functioning of the ‘flat left wrist’, are discussed.
2. INTRODUCTION
Researchers have reported on the kinematics and kinetics of golf swing in terms
of the relative contribution of each of the anatomical structures that are involved. Here,
we asked whether the mechanics of the golf swing could be modeled in terms of a more
simple integration of perception and action rather the customary full-body computer
model. It has been suggested that kinesthetic perception, largely acting through the
detection of deviation from (normally) established pattern(s), plays a major role in the
movement of hand-held objects (such as a racquet, a hammer, or a pencil) by the intact
arm [2]. However, the precise role of kinesthetic perception in the management of a
hand-held club by an intact limb, during the golf swing, has not been reported as yet.
When a hand-held object is wielded, hefted, carried and so on, hand movements,
in conjunction with and related to the physical properties of the object, produce torque
and angular motions. Both the variables, torques and angular motions are related to each
other in terms of one unchanging quantity, i.e. the object’s inertia for rotation about its
principal axes. Seminal work conducted by Solomon et al. [3-4] suggested that the
haptic perception of length during such action is related to the inertia tensor of the
object that is being wielded. Dynamic touch is the label given to the particular kind of
tactile extro-perception that involves a non-spatial input from muscles and tendons [2].
It has been suggested that the inertia tensor provides the domain for two sets of
functions of the “dynamic touch.” One of said functions relates to the principal