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

perturbation in e3 whereas player B produced e3 whose shape is more uniformly aligned
to the path of ISA (Figure 2 (a) and 3 (a)). Greater congruency was observed in the
alignment of the two surfaces in Player B compared to player A. Moreover, by virtue of
positioning the ISAs alongside with e3 of the club, Player B achieved a skill that the
ISAs could be somewhat connected with the principal inertia axes e . 3
Figure 3: : Player B produced a three-dimensional spatiotemporal view on the
instantaneous screw axe (ISA, solid lines) and the instantaneous principal axes
of inertia (e3, dashed lines) for small motion step (300Hz) that were projected
onto the postero-medial side of the player (a) and onto the superior side of the
player (b). In a verification effort positioning perception and action relation in
time-sequence of motion data, the club ISA screws are shown to regularly
projective to the e3. This representative analysis indicates a close connection
(Spatial-temporal representation of ISA versus the e3) during the down swing for
the player B.
If e3, the principal axes are not aligned with ISAs, the instantaneous location of
rotational axes in player A, then the perturbation is observed as the club wobbles. A
practical example of this phenomenon is the routine automobile task of balancing a tire,
which basically means adjusting the distribution of mass of a car wheel such that its
principal axis of inertia is aligned with axle so the wheel does not wobble. This
occurrence of the wobbling inertia is indicative of how player A swings the club in
conjunction with an idiosyncrasy in wrist extension/flexion (as noted in the method
section, e3 and the joint axis are located in the same reference body). The dynamics of
the player-club interaction dictate that these events result in changes to the forces
applied to the golfers by the club. Thus mal-alignment of two screw surfaces is
indicative of how a higher handicap player swings the club in a manner of wobbling
inertia. Collectively, the results suggest that the wobbling inertia may explain the
dynamic performance of the golf swing in holistic terms.
5. DISCUSSION
The purpose of this study was to obtain the desired perception to action
diagrams that can be used to connect the golfer to the club together in the sense of
“dynamic touch” paradigm. We demonstrated that said perception to action diagram,
which was generated in terms of two screw axes surfaces during the downswing, is a
purely geometric representation of the player-club interaction. Therefore, the shape of
the perception to action diagram can be regarded as the “genome” of swing performance