The increasing amount of discussion focussing on supplementary ball training 
to enhance almost anything in sport suggests that it might be appropriate to 
share with you something that I wrote in my "Facts and Fallacies of Fitness" 
book (Siff, 2000).

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BALL BALANCE TRAINING

The Ball, variously known as the physio ball, the stability ball or the Swiss 
ball (although it was used in Germany before it was ever used in 
Switzerland), has been used successfully for several decades by physical 
therapists for various forms of rehabilitation, motor education and trunk 
exercises.  Now we are reading about claims that the execution of weights 
exercises on the Ball can improve strength, power, balance and other motor 
qualities more effectively than many  other traditional methods.

Certainly, any form of novel, challenging exercise may play a role in 
offering some specific from of conditioning, but to unquestioningly accept 
many of the claims being made for its effectiveness is rash.    How do we 
decide if the claims are true or not?  There has been little or no scientific 
research to back up the claims, so almost all the evidence comes from 
anecdotal tales by happy users or fitness professionals who have become as 
competent as performing seals on their balancing balls.

Feedforward vs Feedback

The ability to execute any rapid skilled movement which involves dynamic 
balance has much to do with the visualised and internalised (kinaesthetic) 
image produced in advance of the movement.  This is known as 'feedforward', 
as opposed to 'feedback', during which one obtains ongoing information fed 
back from the joint and muscle receptors and other senses (Siff, 
"Supertraining", 2000, Ch 1.8). 

Athletes like baseballers, tennis players, high jumpers, field athletes and 
many others have to develop highly developed feedforward skills in order to 
perform successfully.  They have to see and feel in advance in their 'mind's 
eye' exactly where they want to aim themselves or implements, since the 
rapidity of their actions does not allow for much or any use of feedback.

Balance Training and Feedforward 

This is a point that nobody in the Ball balancing game or the instability 
training environment seems to mention.  All of their arguments so far have 
been based on using stabilising drills in positions which are very close to 
the fixed, static posture and which allow for considerable ongoing 
communication between the proprioceptors, the eyes and the central nervous 
system.  This sort of training does not address the highly dynamic, often 
ballistic, actions which necessitate the use of feedforward processes.

Advances In Instability Research

What they are doing is relying on incomplete and traditional methods of 
analysing and managing conditions of 'instability'.  In 1977, Dr Ilya 
Prigogine received the Nobel Prize for his work on the dynamics of 
non-equilibrium systems, the realm in which the Ball balance training folk 
presume to have specialist knowledge.  He said that wherever instability may 
occur, one has to determine the threshold and the current distance from 
equilibrium at which fluctuations may produce a new state of behaviour. 

One cannot assume that deviations from a certain equilibrium position will 
necessarily be progressive, linear and repeatable.  There can be sudden 
changes of state which seem to develop chaotically or catastrophically, in 
glaring contrast to the situations of classical symmetry and order which so 
have captivated so many theorists.  
Prigogine even went as far as to say that non-equilibrium may be a source of 
order.  He added that the stability of the stationary state, or its 
independence from fluctuations, can no longer be taken for granted and that 
stability is no longer the automatic consequence of the laws of mechanics.  
Sometimes, we may be led to conclude that a given state is 'unstable' and 
that certain fluctuations, however slight, may actually be amplified and take 
over the entire system, forcing it to leap to a totally new state which is 
very far removed from the original state of static equilibrium that was 
presumed initially to be the most stable and efficient.

The idea of a highly deterministic state of static stability to which a 
disturbed body has to return in order for efficiency to be maximised is no 
longer regarded as highly in science as it is among those extolling the 
universal validity of Ball instability training.   There is not one simple 
state of static equilibrium, nor one way in which any given state of 
equilibrium may be reached.   Static stability is far less prevalent in 
nature and in sport than dynamic stability, metastability, multistability and 
even non-equilibrium, so methods of training based on this limited basis need 
to be revised.

Non-Stability Theory and The Ball

How does this apply to the Ball? Well, if the ball is not fixed, then there 
is only one state of stability for a person balancing on it and this is 
attained when the weight of the person acts through the geometric centre of 
the Ball.  If the person intentionally tries to propel the ball in erratic 
patterns with one's feet while rolling in all directions far from the 
starting point, then the issue of dynamic stability starts to receive some 
meaningful attention.  

However, this is neither possible, nor safe if one is trying to squat, bench, 
clean etc on the Ball, so one is restricted to the unrealistic and highly 
limited model of static, highly deterministic stability.

Sport Specific Stability Training

So, how does one enhance stability?  Certainly the Ball and many other 
similar strategies can train the general stabilising capabilities of the 
body, but research has not shown that this sort of static training 
significantly enhances dynamic stability in real sporting situations.  Some 
years ago, I discussed one method of instability training that I saw used in 
1979 by Russian lifter Rachmanov.  In crucial positions of the Olympic lifts 
(e.g. the lowest squat position of the snatch), he would deliberately shift 
around into unbalanced positions and then restabilise himself. 

Later, while writing the first edition of "Supertraining" with Dr 
Verkhoshansky, I raised this topic with him and he confirmed that this method 
of deliberate unbalanced sport specific training provided superior 
improvement in sporting performance to more general methods of training such 
as balancing on 'unstable' objects such as Balls, wobble boards and 
trampolines.

Ball Benefits and Detriments

There is no doubt that science and practice will prove that some aspects of 
Ball training are ineffective, ineffectual and dangerous, but the same 
results also will be found regarding almost any other form of training. That 
has never stopped us from using any activity - the sensible approach is 
simply to acknowledge these weaknesses and risks and to apply that method of 
training with great circumspection.  The Ball may certainly be used safely 
and effectively for several genuine purposes, such as some types of trunk 
training, flexibility training, partial squatting (as an alternative to ‘Box 
Squats’), pushups and motor education, but if is to be applied as a form of 
balance training, the following issues need to be borne in mind:

1.  Balance training on a moving and deformable surface does not necessarily 
enhance balancing skill on a fixed and rigid surface

2.  Ball training  may disrupt sport specific nervous programs, and alter the 
profile of force-time, rate of force development (RFD) or other biomechanical 
curves for sport specific applications

3. The Ball might be less effective than other forms of more conventional 
training in achieving specific motor skill goals

4.  Ball training deals with relatively slow displacements from positions of 
balance and does not necessarily equip one to handle the more rapid 
disturbances under different conditions of loading encountered in actual 
sport.

5.  Ball training can possibly disrupt the delayed training effects produced 
by other forms of training, so that its use needs to be carefully integrated 
into other forms of training.

6.  Balance training on the ball may cause accidental injury by inappropriate 
range of movement or dubious balancing drills, which is especially 
inappropriate and legally unwise if you happen to be prescribing such 
exercises for valuable professional athletes 

7.  Ball balance training may inappropriately modify the musculoskeletal and 
kinaesthetic systems

8. Time spent on Ball training may be better spent on more directly 
appropriate training

9. The Ball may play a useful role at some stages of training and not at 
others

10.  Very few, if any, of the world's top athletes in any sport have ever 
used the Ball for anything other than a bare minimum of exercises at best, 
and this has been a matter of choice, not ignorance

11.  The ability to execute fairly slow balancing skills on The Ball do not 
necessarily enhance coordination and balance in sports where high speed 
skills in very different patterns are necessary

12.  Anecdotal evidence is inadequate to convince everyone of the merits of 
the Ball and that their reports could lay the foundation for genuine research 
which might resolve the issue in a more acceptable way

13.  Some athletes have used or do use the Ball for certain exercises but not 
for others because experience has allowed them to select exercises which are 
most appropriate to achieve a given physical goal

14.  Overemphasis on Ball balance training may create limited attitudes which 
prevent one from investigating using other alternatives to balance training

15.  Highly emotive praise of extensive Ball use tends to create the 
suspicion that commercial interests are closer to the heart of the issue than 
scientific proof or objectivity.           

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Dr Mel C Siff
Denver, USA
http://groups.yahoo.com/group/Supertraining/