Introduction to Sports Biomechanics: Analysing Human Movement ...

INTRODUCTION TO SPORTS BIOMECHANICS
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task solutions and does not interfere with the self-organisational processes of movement
dynamics, in contrast to the use of a movement-focused emphasis. This view has been
supported by research in slalom skiing, tennis and ball kicking in American football.
These provide evidence that ‘less is more’ – better performance results from less frequent
augmented feedback. However, it is still unclear whether these results generalise
to all stages of skill acquisition, particularly for highly skilled performers. The finding
that a focus on movement dynamics is worse than one that places more emphasis on
outcomes shows that movement analysts must be careful not to lose a focus on the
movement outcome and must tailor technique feedback accordingly – this supports the
qualitative approach to movement analysis.
Let us now address issues relating to the question, what is best? It is now technologically
easy to feed back immediately ‘kinetic’ information, such as the forces on
the pedals in cycling or the forces on the oars in rowing, or to use virtual reality, for
example, to simulate bob-sled dynamics. The assumption is often made that immediate
feedback of such information must improve performance. We have already noted that
no real evidence supports this assumption as a retentive element in skill learning.
Providing kinetic information seems to conflict with ecological motor learning research
touched on above. Also, kinetic information might not relate to the performer’s
immediate problem.
Finally, how is best? Well, as simply as possible, using qualitative information that is
easy to assimilate, preferably provided graphically and with appropriate cues, perhaps
supported with some semi-quantitative data, such as phase durations, ranges of movement,
or correctness scores. We should avoid complex quantitative data – if we do
provide quantitative feedback, it should be graphical rather than numerical. Any
feedback needs to be concise. It is very beneficial to compare good and bad performances,
as in qualitative video analysis packages such as Dartfish (Dartfish, Fribourg,
Switzerland; http://www.dartfish.com) and siliconCOACH (siliconCOACH,
Dunedin, New Zealand; http://www.siliconcoach.com). Finally, it is advantageous if
feedback can be provided in a take-away format, using DVDs or video tape, as can be
done with, for example, siliconCOACH.
The final task of this stage is to review the success of the project. This should be done
independently, at least in the first instance, by the movement analyst and the ‘clients’.
The former should evaluate the whole four-stage process in the context of the needs
analysis carried out in the preparation stage. The analyst and practitioners should then
come together to discuss how improvements could be made in future studies. It is worth
noting in this context that very few studies have addressed the efficacy of interventions
by movement analysts. Although this is very difficult to establish, far too little attention
is paid to addressing this important issue; after all, what is the point of the intervention
stage if it doesn’t have some provable benefit to performers?