The starting point in any sports vision analysis would be to take care of the hardware system, the ocular and visual status. Evaluation of the hardware refers to a general optometric examination, which must include ocular health, visual acuity, depth perception, fusional abilities (including phorias and fixation disparity) and accommodative abilities. At ProSportsVision we have developed norms for each of these abilities and according to these norms a player receives a rating in each test. The ratings range from “superior”, “above average”, “average”, “ineffective” to “needs immediate attention”. These ratings were developed by testing more than 300 elite athletes and are continuously updated if needed. It is important to remember that the importance of visual abilities is sports- specific. Having been responsible for the sports vision testing in a number of elite players for the last five years, it became apparent that the hardware system in cricket players should be “average” or better.
This
may come as a surprise, but it should be taken into consideration that these
norms are very strict. For example, “average” visual acuity means 6/7.5 to 6/9
vision (test your visual acuity). For accommodative flexibility it means a player needs to achieve 15-23
cycles/minute using a plano/-2.00 flipper with a row of 6/9 letters at 6m
distance. I mention this because there is a school of thought, particularly in
the USA, that demands that all these abilities should be “superior” and should
be corrected with “in-office” visual therapy. Our research does not support
these claims. The problem that stems from this approach is the fact that this
treatment is very general and does not address the sports-specific demands. The
athletes themselves find it difficult to relate these exercises to their sports
and are, therefore, not committed to follow these programmes.
The critical hardware set up is more critical with reference to ocular dominance with the dominant eye being the alignment system. Hence the disproportionate number of cross dominant athletes in sideways on sports where the dominant/lead eye is contra lateral to the handedness. Cricketers and tennis players have a greater than average chance of being left eye and right handed or visa versa. This is therefore crucial to the training or coaching of technique. However the experienced sportsmen have often adapted their technique to compensate this and may give rise to the idiosyncrasy of technique in the same way as the unique bio-mechanics of the human bodies gives rise every athletes individual cadence or “style”.
An in depth knowledge of the sport that you are dealing with is probably the
most important factor in determining the level of intervention. To explain this,
let us return to the game of cricket. Accommodative demand is almost negligible
in cricket and other fastball sports. Bowlers are bowling at speeds of between
80-150km/hour. At the slow speed of 80km/hour (22m/sec) the batsman needs to
make a decision when the ball still needs to travel 10 meters or 0,5 seconds.
The whole process of perception, decision-making and stroke e
xecution takes
approximately 0,45 seconds and, therefore, any action that is initiated later
than this will be ineffective. The accommodative demand at 10 meters is almost
nothing. Having said this, we do often find players that complain of not being
able to pick up the flight of the ball. When tested, we did find poor
accommodative flexibility. Prescribing an intervention programme, that did
improve the skill to “average”, solved the problem. One important aspect of the
intervention programme is to train the player to be less “centrally inclined”
and to be more peripheral orientated. To write numbers on a ball and expect the
player to call out these numbers while the ball is travelling through the air
would be the worst option since this would force the player to be more centrally
focussed. I am aware that there are people that still do this and I would like
to strongly discourage it. It should now also become apparent why cricket
players don’t need 6/4.5 vision. Both visual acuity and accommodation are
elements of the central or
foveal system. If this system dominates, our
perceptual systems will want to deal with small central detail. This is in
conflict with the body’s arousal system! In an arousal situation, the
sympathetic nervous system dominates. As far as vision is concerned, it means
that the pupil dilates and accommodation is suppressed or relaxed which means
that the body favours the ambient or peripheral system. One of the major
functions of the ambient system is the detection of movement and that is what is
required to perceive a ball in flight. Therefore, intervention programmes should
concentrate on stimulating the ambient system.
Interestingly enough, players report this inability to read the flight of the
ball to be more so with the slower spin bowling than with the faster balls.
There may be several reasons for this phenomenon and most of them are vision
related. Through many hours of practice, batsmen develop a system of
anticipation and respond to that. When balls are bowled at speeds in excess of
140km/hour (39m/sec) the batsman must make a decision at the time that the ball
leaves the bowler’s hand and this can only be achieved through anticipation.
During this Cricket World Cup, one often heard the sports commentators say, “the
batsman has a good eye” which, in essence, refers to a batsman with excellent
anticipation skills that he developed from an ambient visual system that
dominates.
In general terms, it means that the batsman will look at the bowler’s torso
while he is running in to bowl and will move his gaze to the bowler’s hand just
before the ball is delivered. The batsman needs to perceive several visual
clues. (This is akin to the anticipation and reaction speed in order to "read" a
tennis serve, i.e. when a player starts to read his opponents serve and gives
critical cues to the direction and likely bounce/spin of the ball almost before
it is delivered). Amongst others, the bowler’s action, the speed that he swings
his arm, whether he turns his body or drops his shoulder. All this information
will be used to anticipate the speed, line and length of the ball. If a batsman
would only focus on the ball in the bowler’s hand, he would loose all this
information or, vice versa, the ambient system (Magnocellular Pathway) needs to
dominate to allow him to correctly perceive all this information. This has been
well known with ball handing sports and juggling alike where the look through,
rather than tracking is a successful strategy. Allowing for adjustment in the
unexpected whilst core task is being maintained.
To the question, “Why are batsman more often deceived by the slower ball?” Well,
first of all, let us look at the fast bowler that slips in a slower ball (by the
way, it is only recently that fast bowlers have started to bowl the slower ball
as a surprise ball). The bowlers that have success with this ball are the ones
that manage to keep their action exactly as if the were going to bowl a
fastball. The batsman, anticipating a fast ball, would then make his decision as
to the shot that he is going to play at the moment the ball leaves the bowler’s
hand. By the time he realises that it is a slower ball he often does not have
enough time to change his decision. The consequence is that he is too early on
the shot, resulting in the ball being scooped up in the air.
When it comes to spin bowling, the answer is a bit more complicated. First of
all, the batsman expects the ball to be slow and then tends to allow his foveal
or central visual system to dominate. The slower ball (80km/hour or 22m/sec)
does allow him to maintain foveal fixation and decision-making is delayed until
the ball has travelled halfway down the pitch. By concentrating on the ball
only, he again loses all the other information such as the bowler’s action, the
position of fielders close to him and, very important, and his anticipation of
the line and length of the ball. The key in playing spin bowling is the ability
to judge where the ball is going to pitch and that requires information from the
ambient visual system. Furthermore, good spin bowlers are continuously varying
the flight of the ball and that makes it even more difficult for the batsman to
anticipate where the ball is going to pitch. Good spin bowlers are also those
bowlers that can flight the ball higher through the air. This results in the
batsman lifting his head to track the flight of the ball and that immediately
effects his balance and, therefore, also his body position. Batsmen need to be
taught not to move their heads, but only their eyes and, again, by letting the
ambient system dominate, the batsmen should maintain their balance.
I am well aware that I have only scratched the surface and that there are many
other issues to be discussed. Issues such as the importance of fusional reserves
that may explain why all the top right-handed batsmen, through the years, have
one thing in common and that is their relatively diminutive stature, all being
between 1.63m (5’4”) and 1.73m (5’8”), while most of the top left- handed
batsmen are much taller. Also, remember that I have stated in a previous article
that elite athletes do not have superior hardware systems when compared to the
normal population, but it is the software systems that distinguish experts from
novices. What are these software skills and how can it be enhanced or trained?
ProSportsVision has focused
on the peripheral lock, movement and location receptive system (mango-cellular
visual system). The specific stimulation of the
paramacular
encourages
peripheral visual system and allows adjustment to variation in the critical task
analysis.
This unique approach has proven advantageous across a number of sports involving
fast moving projectile sports. This is a characteristic of Cricket.
This is just an overview and expresses the opinion formed by an accumulation of evidence from a number of sports sharing similar sporting tasks.
Note: The excellent pictures used in this article come from the Oxford University Department of Chemistry website, the record of a match 14th May 2004. The University of Oxford have no responsibility for this website, nor does it in anyway endorse it.
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