We are very pleased with the continued responses to the KA forum. More and more coaches and practitioners are contributing their opinions to the controversial topic of "unstable training". We have the unedited, unabridged response in reference to recent contributions in the KA forum. We would like to thank all the incredibly knowledgeable people who contribute to this forum and encourage all of you to get involved. There is much to be learned from each others experiences.

Brian DeCastro, high performance coach and amateur natural powerlifter shares with us his experiences with CNS fatigue and recovery in this months feature editorial. Make sure to read this incredibly enlightening column. Make sure to look for Mark Mancino's comprehensive marathon training articles in upcoming issues as well.

KA is committed to improving and distinguishing the format of our material. If you have any suggestions as to what you would like to see within the Precision Loading Newsletter or how to improve it, we want to hear from you! Please e-mail us at info@kineticadvantage.com

We look forward to all of your feedback and submissions! Keep em coming!

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Myofascial Stretching Seminar
Presented by: Dr. Guy Voyer

Dr. Guy Voyer has an extensive background in sport, manual therapy and medicine which includes studies and degrees in physical education, physiotherapy, sports medicine, traumatology, osteopathy, biomechanics and various manual therapies. His myofascial stretching seminar offers indispensable information on stretching the fascial components of the multiarticular continuum. The seminar participant will learn how to stretch the envelope of the muscle, through continuum of fascial chains. For more information click here.

Date: Saturday December 6 - Sunday December 7, 2003
Location: Stamford, Connecticut.
Investment : $595 (USD
)

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KA is thrilled to announce our upcoming seminar plans with with world renown practitioner
Peter Rouse,
international performance consultant Mike Adams and athletic development coach Mark Mancino. These three professionals have teamed up to present the latest methods in flexibility and tension release.

Peter, Mike and Mark will introduce you to the theories and practice of neural testing, advanced flexibility assessments, corrective neuromuscular stretching, advanced PNF techniques, neurodynamic stretching and multiple tension release techniques. Participants will receive a comprehensive manual complete with detailed descriptions of range/tension appraisals and other information presented in the seminar.

The coaches expect this seminar to be the most in depth, comprehensive practical seminar ever presented on the topic of flexibility and muscle tension release.

For more information click here

NOTE: In order to bring the coaches over from Australia, a minimum of 15 participants is required to run
the seminar.


 

Vladimir M. Zatsiorsky is a world renowned sport biomechanist and strength and conditioning coach. In his book, "Science and Practice of Strength Training", Zatsiorsky presents the specific physiology behind strength adaptations and offers practical recommendations to optimize strength development. Much of what he presents is based on his experience as a strength and conditioning consultant to the former Soviet Union's Olympic team. This data is supported by the training logs of over 1000 Eastern European and world class athletes. KA believes that "Science and Practice of Strength Training" by Vladimir Zatsiorsky should be in every athletic development coach's library.

 
I still remember my best meet ever... I was prepared really well for the meet, weighed in just under my limit (after breakfast) and felt very well rested that day. I also give credit to my state of mind as all I wanted to do at this meet was lift well. I was not concerned with any other outcome. As a result of that I was not concerned with dropping body weight to compete in any particular weight class.

I had been humbled in a previous meet that in turn changed my attitude for this meet...
The outcome...

Personal best in the squat
Personal best in the bench
Personal best in the deadlift
Personal best in my total!!!

I also went 9 for 9 that day...a perfect day!!!

Normally I would have to take a week to 10 days off after a meet (which I did). But this time I really didn't need to take the time off. I felt ready to train by about Tuesday or Wednesday (the meet being on sat). I would also normally not even want to look at a barbell for days, or even
drive by the gym after a meet. Mentally I would need that break. But not after the "perfect day", I was so jazzed to get lifting right away.

I credit it to upping the volumes in my regular training and adding variety to my training lifts. I avoided loading one neural pattern more than 3 weeks at a time. I also trained in the absolute strength zone, more often due to the constant change in applications. I would train with triples and singles for up to 10+ weeks this way as opposed to only 2-3 weeks in a traditional periodization method. So mentally and physically I was very familiar and better adapted to competitive singles by the time the meet came around. So the mental burn out wasn't there because the heavy loads were no different to me than any other day in the gym. I was also much more aware physically, of
what my body does under those kinds of loads and how it would feel after.

In the previous meet...I was in the process of still learning this lesson; chickened out 6 weeks before and went back to the traditional method after only a month or 2 of varying lifts and applying the appropriate loading. My weigh in was shit. I had to drop weight this time. I was worried about my outcome (winning or losing). Mentally, I was totally psyched out. You will get like this if you are not prepared. It becomes a downward spiral of ignorance and self sabotage. It's not a pretty scene...

So I skipped breakfast before weigh in to be sure I would not weigh over. As a result I weighed in light and extra flat. If your weight drops too much, it is sometime much too difficult to bounce back in the 2 hours allowed before the meet starts. My warm up sucked. I was rushed. And I felt cold, even up to the first platform lift.

So my first squat attempt felt like a max! To make a long story short, I missed all my bench attempts and got myself disqualified... Everything felt heavy that day (even the warm ups)..

I feel it was the lack of preparation and allowance left for recovery, based on the sudden ramping up of intensity in training and experimental application previous to the competitive phase.(this is typical of most "old school" lifters)... Had I finished the deadlift that day, not only would I have won the championships but I would have felt like I normally do after a meet...

that is...

Immediately after, I would be really psyched. Then about 30 mins after that, I would feel really burnt out. About 1-1/2 to 2 hours after the meet, I would totally crash, get a huge headache and likely take a nap for a couple hours. I would wake up stiff all over. My joints would ache a little too depending on how I carried the loads on the platform. The next day all I would want to do is relax and eat whatever I felt like (usually junk), as lifters often have post meet depression. I would take a break for about 7-14 days (and need it). When I get back to the gym, I feel so weak that I almost can't believe it was me lifting at the competition 2 weeks ago.

Ever since I have learned the conjugate method of loading, and a variety of ways to load the lifts I compete in, I recover from meets and manage to bounce back in a few days and still keep some of the strength I had at the meet. I still have to allow time to recover as the CNS does take longer than muscle and harder to judge sometimes as you don't feel it like you feel sore muscles. But I am now more aware of my body as it feels heavy and sluggish when I am not recovered as opposed to feeling light and explosive.

If I walk out of the squat rack with the empty bar and I feel the weight on my shoulders – I am not fully recovered. If I walk out and it pops of the rack and I barely feel any load on my shoulders – I am good to go!


KA would like to sincerely thank Brian for sharing his experiences with us. I believe we can all find value in this editorial. We would also like to take the opportunity to congratulate him on his first place finish in the 75 kg weight class at the 2003 St. Thomas Open last month. Here are his result from that competition:

Squat:

1st - 155 kg (341 lbs)
2nd - 167.5 kg (369 lbs)
3rd - 175 kg (385 lbs) - Personal best

Bench:

1st - 110 (242 lbs)
2nd - 117.5 (259 lbs)
3rd - 122.5 (270 lbs) - Personal Best

Deadlift:

1st - 180 (396 lbs)
2nd - 192.5 (424 lbs)
3rd - 202.5 (446 lbs) - Personal best attempt - missed - inches from lockout.

Total: 490 kg (1078 lbs) - Personal best total.

Congratulations on an unbelievable meet Brian! Anyone wishing to find out more or to take advantage of his tremendous knowledge can contact him at the above address.

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KA believes in sharing information openly and honestly. This column was designed to provide opportunities for people who share this value to present their responses to previous articles, questions and answers. It also provides an opportunity for other associates to learn from multiple sources. It goes without saying that this exercise is not to call peoples philosophies into question or attack anyone personally. It is to stimulate thought processes and open the mind to different philosophies and approaches.

If you have something you would like to post in the KA forum, please feel free to contact us at info@kineticadvantage.com Be sure to provide us with your contact info as you would like it
to appear.

The forum submissions received in response to Mark Mancino's article "Will Your Training Become Flat?" continue to pour in. We recently received a forum submission in response to the article and last months forum responses. Let the games begin!

 

submission by: Dennis Lindsay
subject: KA Forum Response

Mark, Shawn, Mike and others,

Good day gentlemen. My name is Dennis Lindsay. I am the director of High Performance Specialists, in Toronto. We are all aware of each other, and each other’s programs.

Mark, I have several staff members who receive your newsletter and regularly get an opportunity to read it. Hence the reason I am writing to you now. I do not regularly put out a newsletter, so I certainly would like to say that I respect you for your consistency. I think the topic is a very good one for a round table. I think the issues go much deeper than the forum demonstrated. I also think most people already know much of what was said about specialized balance training. My instincts tell me that the article was written more to get a response than to teach.

Well, Mark, you mention how you are open-minded, and you did an excellent job of allowing Shawn to present his position to you. I can only hope you will do the same with my input. I have attached gentlemen, my input from the recent KA forum. I apologize for the length but, as you are aware I have processed 12 pages of your information into this 9 page response. Hopefully this will be deemed as a professional and thought-provoking critique. As well I trust that this will not appear, as your newsletter suggests will happen, as “debate inspired by jealousy…”.

Well, here goes…

SM: “The object always remains stable, but it is the pressure applied to the object that makes it move.”

Good point, but this could be clarified further to say “It is the reaction of the object to the force which is applied.”

SM: “The more the skier moves away from their base of support, the more unstable the surface becomes to the skier, not because the surface is unstable by itself, but because they are making it that way.”

The more the skier moves away from their base the more unstable the skier becomes to the surface. Agreed they both play a part to make it that way, but the objective of each party is not to move
the skier.

MM: “The skier will experience g-force resistances acting on him that causes his centre of gravity to deviate, on the other hand standing on a swiss ball the increased forces are caused by pressure of our bodyweight against the object. The instability is created by the movement of the body against the device. It's like the chicken or the egg - which came first? In the case of the skier, the g-forces of traveling at high speeds, navigating turns, gulleys etc. come first causing the skier to have to react to them.”

A few clarifications; G-forces can create stress which will alter the skier’s reaction as well as the outcomes of that reaction. Also keep in mind that G-forces create a mode of stability. The instability is caused by rapid adjustments (the lack or abundance) of proprioceptive control/feedback. A skier who cannot balance first will not be skiing, they will be sliding. Without staying “up” a skier cannot generate enough speed to apply technique or mass, which creates G-force. So balance comes first. Note - even good skiers fall, so this is true for all skiers.

MM: “On the swiss ball, the postural deviations occur due to the shifts in the centre of gravity on a moving device, then the g-forces increase due to these deviations. This is an important point as these two skills can be recognized as independent motor skills.”

Postural deviations occur due to shifts around the center of gravity. Arm, leg, head, eye coordination combine to maintain posture of the center of gravity, once the center goes, it very rarely returns to “resting” without assistance of external force.

In regards to G-forces, combining the surface area of a ball at the top, and the surface area of a ball at the bottom, the max weight a ball can handle and the max distance that weight can travel while on the ball… I don’t think there is a significant difference in G-force. Further, any exercise which could increase G-force would have to be considered too high risk vs the benefit.

SM: “As we all know, nothing is totally absolute, and that is what makes it fun to discuss.”

I understand what both of you are saying with these kind words, but it is really more pleasantry to avoid seeming skeptical or confrontational. There have to be some absolutes, otherwise we have no guidelines professionally. Absolute does not mean it can’t be changed.

SM: “and yes these g-forces create a potential for the skier to become unstable, and yes you need to have enough strength to handle these forces…”

Again, G-forces can actually create stability. Your point here Shawn is very good – handling G-forces requires more strength than normal movement. For the sake of this discussion (balance-oriented sport) the strength required is the amount which allows the athlete to move their body to a point of maximum efficiency within the G-forces.

SM: “your body is creating a moving or unstable surface, that if you take away the body would be considered a stable surface.”

I can see where both of you are coming from on this one, and it is a great philosophical debate (like the glass half empty or half full scenario, or if a tree falls in the forest…). This is where I think that having some absolutes is worthwhile.

Elements such as snow and water and oxygen are not solids. With enough of one element compressed into one space, it can act like a solid – but it is in fact, not. This an absolute that we all learned in our first years of formal education.

Avalanches can start due to weight and environment shifts of the snow particles themselves – so, no, snow is not a solid. The mountain/hill under the snow is a solid. Your body does not create a moving surface so much as it applies movement/force to the surface. In this case the surface further applies/distributes the force across itself and possibly to the solid beneath.

I think the absolute you are both looking for is a term like “semi-stable” (or perhaps along the lines of “suspended”), realizing that your discussion has left the training arena and moved to the philosophical.

SM: “Now take the ball, have someone kneel on it and grab a 45 pound plate. Now this object becomes unstable because the person on the ball (most likely won't be able to stay still) because they most likely can't stabilize their center of gravity over their base
of support.)”

Now we are getting to the real reason such a topic makes a good forum. This sounds great, it sounds challenging. It also sounds very dangerous for the average person (meaning average stature). 45 lbs is enough to cause injury in even the able athlete. While the debate continues about snowflakes no one seems to question the risk of such a test/exercise.

Once the athlete grasps the weight it becomes a part of them relative to their environment. So, they can’t stabilize their “new” center of gravity.

SM: “we see that the person creates the instability because they create the moving force and cause the object underneath them to move as well.”

Minor correction, but important in the scheme of having, again, some absolutes; A person does “create” instability in this sense. Instability is an absence of stability, which is caused by an absence of controlled force(s). The athlete might attempt to counter-act the movement with force, but now we are having another discussion on the philosophies of the chicken and the egg.

MM: “From this perspective, they encourage unnatural stability patterns that I feel do not contribute to increased performance on a non moving surface.”
SM: “. I would look at it more as a natural stability pattern.”

I am not familiar with terms “natural stability” or “unnatural stability”. Could either of you provide a reference or resource for this so I can become more familiar?

SM: “My point being that the ball gets a bit closer to acting like snow than does just standing on a flat surface. This I think you might agree upon.”

“if you want to mimic moveable surfaces, without bringing snow into your gym (which might get you kicked out) the swiss ball will do just fine… … So here is a great exercise for a skier. Stand on a swiss ball and go into different degrees of a squat or even better a skiers squat. Now move your legs or feet back and forth, while trying to maintain your balance on the ball. Or do the same thing on a fitter ski machine.”

I have to agree with Mark on this one - A physio ball will never mimic snow.

Once again we have an exercise provided which is very high risk. It has never been studied, so I cannot say this definitively; but its transfer to the slopes is very questionable. I can say that I have yet to see a skier do well who can have both their skis placed in a supinated position as would have to occur when standing upon a concave ball.

If the goal is sport specificity, then the balance “might” be bang on, but the stance of the ankles is way off. As professionals, the way an athlete feels about their exercises level or intensity should not be more important than the ethical consideration to determine its implementation.

MM: “My article was meant to suggest that I believe this type of training is being overemphasized in many training arenas with little or complete lack of reason.”

Perhaps the most important point of the original piece, and something most professionals in our industry would agree with, regardless of their certifications/school of thought. I honestly think the discussion should be more about application philosophies/methodologies. To quote you Mark – let’s get to the “reason”.

MM: “we move over top of the ice, as opposed to the ice moving underneath us.”

If a tree falls in the forest…

MM: “When striding, the body is not overcoming the resistance of the ice, it is overcoming the gravitational resistance (mass) of the body thereby propelling you forward.”

The body is using the resistance of the ice to overcome the inert factors on the body.

MM: “In sport the body moves over top of the surface and adjusts to the postural deviations created by the g-forces. The one constant - the surface never actually moves!”

There are not as many postural deviations from G-forces as one might think from this statement. G-forces enhance some aspects of stability. Leaning into the turn is natural, without it there would be a definite loss of balance – unless traveling too slow, in which case, G-forces cannot assist.

As for the surface never actually moving in sports, (and let’s avoid the snow issue); what about water in water sports, grass in field sports, Parallel bars in gymnastics… there are many instances when the surface being used can become “less stable”.

MM: “The skateboarder may in fact find standing on a swiss ball very challenging because it is unfamiliar. They are used to stabilizing their body on the skateboard, it has become second nature. This brings up a separate issue; stabilizing the body on top of a stable structure (skis) moving dynamically over another stable structure (ice) is considerably different than promoting stability on an unstable structure (the ball) moving against a stable structure (the ground).”

Who’s on first?? In regards to the skateboarder’s “second nature”; this appears to be a question/statement of volume. Anything can become easy with practice.

MM: “Therefore, by the same token, stabilizing the body on skis moving dynamically over a solid surface requires significantly different neural input (brain, muscles etc..) than attempting to stabilize a static position on the ball. Sure you can add small movements, but the end result is you do not create significant movement (as in skiing down a hill).”

As you stated later Mark – just go skiing, then.

MM: “teaches the individual to fight gravity by attempting to remain static over top an unstable surface, rather than adjusting your posture to allow gravity to work with you.”

I don’t think you can really have one without the other – can you? Walking is classified as a controlled act of losing balance and regaining balance. As well, using the word “fight” gives the impression of resistance, rather, the whole exercise category is about co-ordination (intrinsic and extrinsic), perhaps coordination is more appropriate word.

MM: “When skiing downhill, gravity not only acts downward (in a frontal plane) upon you to keep you in contact with the ground, it also acts directly against you (in a sagittal and transverse plane) as you move. Standing on a ball, gravity only acts in one direction - downward.”

I disagree, both instances demand and therefore require complete 3 dimensional abilities.

MM: “if balance and stability on skis is your goal, the best way to achieve that is on the hills.” “Attempting to create those specific adaptations in the gym is futile. The exercises should support these goals; for example by increasing lower body strength and power.”

I think you are correct, but we cannot forget balance, even you have used words such as “leaning to carve a turn on the hill.”, so apparently balance is still a factor.

MM: “P.S. The feedback from your client is duly noted as I believe that athlete feedback is a tremendous measure of the efficacy of a program; critical to the success of
the individual.”

Efficacy does have it’s place… but I worry that feedback of this nature has a placebo element and can be dangerous to include as a statement of “reference”.

SM: “I am sure you can come up with 10 things that you can take out of that exercise and correlate to improving a skiers performance. I will give you three to start with:

1) the exercise can be challenging
2) the exercise demands alertness
3) the exercise takes coordination”

A good point, that there are various benefits to various exercises, but I might suggest that if any exercise does not have the three “things” listed above then it is not an exercise. These qualities will not “improve a skier’s performance” unless the exercise creates a need to adapt equal to, or greater than, skiing actually does. (Mark, you often quote Selye – GAS principle)

SM: “I sometimes look at different health and wellness forums on the internet, and in my mind, something that drives people in circles more than anything else are articles that are continuously written outlining the negative or trying to come up with negative reasons for certain methods. Someone will always find a positive, it just goes round and round.”

Well, I hope my points don’t seem negative. I also believe in sharing information, as well as that discussion leads to greater understanding and more open-mindedness.

I also, however, look for points of reference, research and valuable statistics which allow me the opportunity to provide a client with correct, peer reviewed information which can be accomplished repeatedly but still allow for individualized creativity in program implementation.

MM: “The real question is whether we believe that training in unstable environments creates carryover to greater performance in sport. I appreciate your opinion but I have to say that generally speaking (recognizing every athlete is unique), it is not as effective as other means in increasing performance in the sport. This is not to suggest these tools do not have there place by any means. This is suggesting that I do not believe that using them to create an unstable environment will contribute to greater stability in the sport
(generally speaking).”

There are loads of peer-reviewed articles which specifically study or serve to educate the reader specifically about Balance in sport (with amazing references from Physiotherapy, Rehab, and Athletic Training Journals and magazines).

I think it is great that you have stated your opinion Mark, but how about supporting it with something. As you can see, much of what was originally published is sketchy and has each of you contributing to 12 pages of great discussion with no firm resolution or points.

MM: “On the contrary, what you have presented is well though out, sound reasoning for why you choose to use certain modes of training. What I am trying to say is, the industry has been influenced to believe that training in an unstable environment must be part of your athletic development program. Like you, I do not believe in unequivocals, instead I attempt to overcome them.”

What modes of training? What Reason? Sorry guys, but once gain, I fail to see what the beginning person in our industry is going to retrieve from all this. Why not present concrete items along with your opinions?

“Unequivocals” (no such word) are, in sport science, the absolutes which form the basis of decision making. These are important to resource and help to achieve specific goals when performing ground-breaking or creative programming.

Unequivocal defn: adj : admitting of no doubt or misunderstanding; having only one meaning or interpretation and leading to only one conclusion.

These are not rules to be seen as obstacles, or walls of prejudice to hide behind, they do not tolerate being abused to gain selfishly – because everyone else (peers, colleagues and mentors) adhere to some aspect of them.

MA: “There exists two primary responses in the brain to deal with balance in both the unstable and stable environments. The Tilting response has been identified as specific activity/firing in the brain to deal with proprioception and balancing when a person is on an unstable environment. The Righting response, is again identified by significant firing patterns in the brain and relates to stable land training where the person becomes unstable on the ground.”

I have heard of the Righting Reflex. I have heard of an element of the Reflex which is responsible for controlling “Tilt”. I have not heard of these responses as Mike defines them. Any references for such information, would be appreciated.


Now I realize that this will seem negative, but I must point out one thing: The main article in the newsletter before this, and now most of this one, has been dedicated to this topic. I have read these pieces, but do I come away from them with any more tangible knowledge than before?

KA’s purpose to writing was reflected in statements from previous newsletters like this:
“Our number one goal is "to provide a high quality resource for fitness professionals and enthusiasts seeking further development in the industry.” I’m sorry – I don’t see this. Show me the resource! Challenge the rest of us in the industry. Please.

Before I end, I should probably provide you with a brief version of what I mean by my own statements – so here goes;

In my view, many of the programs today which utilize stability balls and sissel cushions etc. are more focused on selling the client on the training fad rather than the results. I believe this because there is not much research information out there to support any of the claims made about the equipment or training parameters used. With most other specialty equipment modes of training (over-speed, overload, hypergravity, weighted implements…) there is research which will at least allow a professional to take a position.

These tools do have their place in training and rehab, based on research into vestibular and thalamus control points of balance, however the study of specific transfer of training is still in its infancy. The most common example of this might be the Physio Ball Squat. It has been an icon of “talent” in the world of practitioners who implement primarily “stability” based programs. In fact, Paul Chek’s website opens with a picture of a standing ball squat with 135lbs on his back.

First, standing on a ball will make you good at standing on a ball. Unless you are an athlete in the Chinese circus or cirque de soleil (of which I’ve trained both) this will most likely not come in handy. At best, a neat gym trick.

Second, standing on a ball means there is a chance (no matter how good you are) of falling off a ball. Due to the height of the ball, the height of an athletes CG above the ball, and the minimal surface area of the ball actually applied to the athlete or the floor, if an athlete was to fall it could certainly involve trauma to the upper body (or specifically, the head). Adding weight to this only compounds the risks.

We need to review the aspect of risk vs. benefit. If I knew through proper study that there was a direct transfer to sports actions then maybe I would consider it for certain athletes (based only on using the other identification models such as maturity, experience, skill acquisition and physical…). Until then I do not want to even appear as though I condone it, so not even with assistance in the squat rack – No standing on the ball, at all.

Besides I can refer to other equipment which has been studied. The BOSU board, while not researched, follows the guidelines of balance boards. Interestingly, regardless of the angle of the ankles while squatting on the ball (extreme rotation – not common in many sports actions), there is also the element of height. Using the lowest balance board is harder than using the largest ball, due to the fact that the amount of response time is almost explosive when the board is 1/8 inch off the floor. Plus I can add weight with significantly less risk, and I can do so in the squat rack to further prevent risk. The final touch – on a balance board the feet don’t supinate and the ankle does’t rotate like on the ball or in a non-functional pattern.

With just these points of reference, why would Paul Chek even have such a display on his website? It sells. Paul is a smart man, he knows all these points and even has sold courses which incorporate these points, but there it is on the front of the website.

At HPS we have a progression of training exercises which allow us to introduce varying levels of tasks which can incorporate balls, boards, rockers, med balls etc… . The progression looks like this; unilateral, ipsilateral, bilateral, then bilateral w balance, ipsilateral balance, mixed ipsilateral balance and finally unilateral balance. Balance could involve any of the different tools listed (based on the results of the original assessment, and progress).

As well, using “sport specific implements” never exceeds 10% of our program. This number is selected based on length of programs, number of training sessions per program, goal response or adaptation expected from training, and the need to focus on critical factors. We maintain this philosophy with all of our clients, but it comes from information specific to elite athletes.

I could elaborate more, but I have already become long winded.

Professionals can have their agendas based on the school of thought to which they belong (Poliquin, Chek, Siff, Tate, etc… ), just don’t let it over-ride common sense and absolutes which are the foundation for the science which is our business and our devotion. Question and Challenge everything, but be prepared to answer at the same time.

Dennis Lindsay
Director of High Performance
High Performance Specialists
416 481 1601 x210
highperformance@rogers.com

 

submission by: Paul and Michael Lamey
subject: Math Response

Mark,

After reading your forum, I got a great question out of it ... whether the swiss ball is stable or unstable (I always assumed it was unstable). So I figured this to be a math question ... out of my league, fortunately my brother is a physics major (grad student) I had him read the article and asked him what he thought. He asked a few of his friends and this is his conclusion.

"First I will define what stable and unstable systems are:

A system is STABLE if it returns to its original position following an outside disturbance. The classical example is of a ball at the foot of two hills. If you try to roll it up is comes back to the bottom of the hill.

A system is UNSTABLE if the system continues to moves away from its original position following an outside disturbance. The classical example is a ball at the top of a hill if you push it slightly it will roll down the hill.

A system is NEUTRALLY STABLE if the system stays where ever its placed. Classical example is a ball on a flat surface.

So the swiss ball before we stand on it would be described as neutrally stable.

My first comment is the example about placing the 45lb weight on the swiss ball, this is ABSOLUTELY NOT a stable equilibrium. If you were to just nudge the weight a bit it would fall over. The weight would not return to the top of the ball. This is called an unstable equilibrium position. The condition for stability is not whether or not one can balance the weight on the ball, but whether or not it comes back to its ORIGINAL POSITION after being SLIGHTLY DISPLACED, and it must come back every time. Another classical example is that of an egg one can balance the egg on one of its ends but this does not mean it is stable. Once displaced slightly it will fall over.

The question of a person on a ball to me is hard to describe because the person adds a dynamical quantity. In order to stay on top of the ball you have to exert what is known as negative feedback. Negative feedback is a force which tends to move the system back to its original position, this is what your body does to compensate for any displacements of you on the ball. Negative feedback is a condition for stability but it doesn't guarantee stability. In the case of a ball at the base of two hills gravity provides the negative feedback. In the case of a person this feedback is always changing, that is it may not always be of the same magnitude and is thus hard to describe. For the person on the ball to be stable the person must always be able to exert enough of a restoring force to stay on the ball. The question to me is how big is a small force or a small displacement on the ball in the definition of stability? Obviously with a big enough displacement anyone will fall off the ball.

I would consider a person on a ball as unstable, but I cant quantify it exactly. I'm sure there may be some more precise definitions of stability one can find, those interested should investigate themselves."

Hope this provides some insight.

Paul Lamey
Fitness Manager / Personal Trainer
The Boulevard Club
416-532-3341 ext.150
fitness@boulevard.com

 

upcoming KA forum

NOTE: KA would like to thank Paul and Michael for their time and efforts on this topic. We would also like to thank Dennis for his candid feedback and sharing his philosophies. The saga continues next month when Mark Mancino drops the gloves in response to the above forum contributions. Stay tuned for next month's Precision Loading Newsletter!


To learn more about the philosophies presented in this forum, feel free to contact the individual coaches and practitioners that submitted responses. These individuals possess tremendous knowledge and have much to add to our industry. E-mail addresses and websites are included below each submission.

The above written opinions do not necessarily reflect those of Kinetic Advantage Inc. We assume no liability, copyright or otherwise for the information presented.

i have a question or response for an upcoming KA Forum column.

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KA provides information not only in an effort to share our methods, but to learn from others along the way. We share this knowledge not to convince, but to stimulate thought and further investigation. We encourage our associates to question information and formulate their own opinions. Seek other sources and test all methods in an effort to support these beliefs whether in line with ours or not. Then look to share these opinions and beliefs openly so others may benefit from your knowledge and further contribute to the evolution of thought and practice. It is with this philosophy in mind that I leave you with this final thought…


“Convinced myself, I seek not to convince.”

Edgar Allen Poe

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