To remain ignorant of things that happened before you were born is to remain a child. (Cicero)

Variable Weight Swim Paddles

[repost from]

A couple of weeks ago I wrote a post titled “Things To Consider When Shopping For New Power Training Gear” in which I described three essential properties of training gear to consider when shopping for new equipment. One of the properties described was Effectiveness, which I defined as: A training device is considered effective if it brings about the intended results while not introducing any drawbacks. Recently I came across a picture of swimming paddles that could serve as an excellent example for evaluating effectiveness:

Variable Weighted Paddles-2

The goal of the paddles in the picture, according to the description, is to “teach proper hand entry, relaxed recovery, and to build endurance.” At first glance, these paddles look promising and even effective. After all, the attached weight will force the hand to point down promoting proper hand entry, relaxed recovery, and will help build endurance. However, a closer examination of these paddles reveals serious drawbacks.

First, because of their physical property, these particular weights add weight not only when the swimmer’s arm is out of the water (in the air) but when it is in the water as well. Unfortunately, when the swimmer’s arm enters the water, the weights will keep pulling the arm down, preventing the swimmer from establishing proper catch. Without the proper catch, power generated during the pull phase will be reduced, consequently reducing the swimmer’s speed as well.

Second, when weights (or anything else for that matter) pull the swimmer’s arm down in the water, they inevitably hinder the swimmer’s streamlined body position and balance – two crucial ingredients for the reduction of drag. Increased drag leads to reduced speed.

There might be other drawbacks these paddles introduce, but the two described render these paddles ineffective.

If you are looking for a training tool that will teach swimmers proper hand entry, relaxed recovery, and help develop strength and endurance while not introducing any drawbacks, I invite you to consider ZB Weights:

ZB weights™ _ AquaVolo-2-1

ZB Weights | VoloBlades | AquaVolo-1

ZB Weights are made of special material that soaks in water to create extra weight. They come in two sizes and can be stacked like pancakes for variable weights. The vital difference between ZB Weights and the weights described above lies in the fact that ZB weights create extra weight only when the swimmer’s arm is out of the water (in the air.) When the swimmer’s arm enters the water, the extra weight created by ZB Weights dissipates, water weighs nothing in the water.

ZB Weights, similar to the paddles described earlier, help swimmers develop proper hand entry, relaxed recovery, strength and endurance. In contrast to the paddles discussed above, because the weight created by ZB Weights disappears in the water, swimmer’s catch, streamline body position and balance stay unhampered. Thus, ZB Weights are effective because they bring about the intended benefits without introducing any drawbacks.

As we have just seen, the best way to make sure you are getting the right training equipment, is not only to consider the benefits that a particular training tool claims to deliver but to also carefully evaluate the potential drawbacks that it might introduce. It is important to stress that each time a training device introduces a drawback that negatively amends the swimmer’s technique, there is a danger for a swimmer to acquire a bad habit. The results of bad habits, especially related to technique, can be pernicious.

Caribou, anyone?

A few months ago, SFGate ran an article titled “Wild dinner of caribou meatballs” in which the author, Meredith May, describes her experience of eating caribou meat. The meat was provided by the popular writer Tim Ferris who, in research for his book The 4-Hour Chef, “spent days slogging the tundra learning to hunt.”  The caribou meat apparently tasted delicious:

I chewed. The meat was dense, close to the taste of venison, yet not as gamey as the bear meat. It did not leave a waxy coating on the roof of my mouth, the way corn-fed beef does.

It was pure and direct and wild. Food tastes so much better when you can appreciate how it got to your fork. Ferriss agreed. He butchered and dressed the caribou, and is either eating or giving away every bit of the meat.

“You aren’t what you ate,” he said. “You are what you ate, ate.” (1)

Reading this article reminded me of a wonderful book by Farley Mowat – one of the few white men ever to have lived with the Ihalmiut – titled People of the Deer. One lucid description of Caribou in particular kept popping up into my head:

For the record, and for the enlightenment of any reader who may someday be offered a price roast of caribou, there is a list of the actual parasites I took from one old buck.

In the body muscles there was a concentration of tapeworm cysts that averaged two per cubic inch of meat. No part of the muscle tissue was free of these abhorrent things, and in addition to them, there was a liberal sprinkling of the cysts of nematode worms. The lungs also were very active even after death. I counted and removed 17 nematode worms, most of them over six inches in length. In the liver there were tapeworm cysts of two species, some of them the size of a tennis ball. The intestines yielded one adult tapeworm of great length and antiquity, and even in the heart muscles I found 6 tapeworm cysts. Of minor parasites, there were 190 warble-fly larvae under the hide and about 75 bott-fly larvae cozily ensconced within the throat and nasal passages.  … This particular deer was no exception. … all deer which I have examined … have yielded a corresponding count of parasites. (2)

And as I kept reading about how much Tim and Meredith enjoyed their Caribou, I recalled another interesting fact from People of the Deer. “All the nematodes and tapeworms [found inside Caribou] have at least two-stage life cycles. That is, they need another host, apart from the deer, to complete their lives. Encysted parasites reach maturity only when the flesh they are lurking in is eaten by another animal.” (3)  That other animal “is often man.” Caribou, anyone?



(2) People of the Deer, Farley Mowat (1952), p.74
(3) Ibid, 75

Things To Consider When Shopping For New Power Training Gear

[My re-post from]

What things should you consider when shopping for new power training gear? Which equipment will be the most beneficial for you or your team? Making the right decision while trying to weed out marketing hype from essential data can be challenging, but, you can simplify the task by evaluating each training device against three essential properties: effectiveness, convenience and price. In this article I will walk through an example of such an evaluation and discuss the merits and disadvantages of a power tower, a parachute, old running shoes, and DragSox. Hopefully, by the time you are done reading, you will have a clear idea of what questions to ask when shopping for new training equipment.


Effectiveness is a crucial property of training gear. I use the following definition for effectiveness: A training device is considered effective if it brings about the intended results while not introducing any drawbacks. The second aspect of this definition is as important as the first because introduced drawbacks may negate any benefits gained and diminish intended results. Bearing this definition in mind, we are now ready to evaluate the effectiveness of power tower, parachute, running shoes, and DragSox.

Power Tower
Swimmers have been using power towers to develop strength and power for a long time. One of the earlier mentions of a power tower as a training device for swimmers was made in the 1973 patent application for “Swimmer Training Device”:

Power Tower Patent US3861675

“Apparatus having variable weights which may be attached to a line connected to a belt worn about the waist of a swimmer for applying weight to provide a restraining force against a swimmer attempting to swim away from the device which helps build, condition and tone the various muscles of the human body employed in swimming.“ [1]

This is an accurate description of the benefits that a power tower claims to provide. And indeed, true to its claim, power tower does help swimmers develop stronger and more powerful muscles thus fulfilling the first factor of effectiveness. While doing that, however, it introduces one drawback: it alters the swimmers body position so that it is no longer streamlined. The following image illustrates this point:


The line that connects the swimmer to the tower, together with the surface of the water (marked in blue) form an angle (marked A). As the athlete swims away from the tower, the restraining force of the power tower starts to pull her back and up along the connecting line (indicated by the black arrow) effectively compromising the swimmer’s streamlined body position. Because of this drawback, power tower fails the second aspect of effectiveness.

Conceptually, a parachute and a power tower are similar: both connect a swimmer to a resistance-generating component with the means of a line. The methods by which they generate resistance are, however, different. Power tower uses variable weights to generate restraining force, whereas a parachute uses actual water to generate resisting drag. The objective of training with a parachute is to help swimmers develop stronger and more powerful muscles. Similarly to the power tower, parachute does meet the first factor of effectiveness: it helps swimmers get stronger. But, it introduces two drawbacks. First, a parachute, like a power tower, negatively affects swimmer’s streamlined body position. Again, let’s use an image to clarify this point:


You, no doubt, noticed the similarities between this image and the image used during the power tower evaluation earlier. Both images show how the connecting line and the surface of the water (marked by a blue line) form an angle (marked A), but, there is a difference in the position of connecting lines. Power tower’s connecting line extends above the surface of the water, while the parachute’s line extends below. Therefore, unlike the power tower that pulls a swimmer back and up, the parachute pulls the swimmer back and down, along the connecting line. This “pull down” hinders swimmers streamlined body position and leads to a deteriorating technique. The second drawback that a parachute introduces is, again, related to the position of the connecting line. Because it is extended underwater, along the swimmer’s legs, the line can’t help but be in the way of a swimmer’s kick. As a result, swimmer’s feet get snared in the line as she tries to kick. This incessant entanglement of swimmer’s feet in the line hampers swimmer’s technique. Thus, because of these drawbacks, parachute fails the second factor of effectiveness.

Running Shoes

The purpose of swimming in running shoes is to develop strong legs and a powerful kick. Because wet shoes are heavy, kicking with the extra weight is like training with weights at the gym. Like the power tower and the parachute, running shoes do fulfill the first portion of effectiveness: swimming in old running shoes does make swimmer’s legs stronger. But, running shoes introduce several drawbacks. First, because of their weight, running shoes tend to pull swimmer’s legs down therefore encumber streamlined body position and balance. Second, running shoes restrict ankle movement and minimize the range of motion of swimmer’s feet resulting in a less efficient kick. And finally, swimmers training with running shoes loose the “feel” of the water with their feet. This drawback is more psychological than physical, nevertheless it is very important. Without the “feel” of water, it’s hard to swim with a good rhythm and learn how to be more efficient. Because of their weight, restriction of movement and impediment to sensory input, running shoes fail the second aspect of efficiency.

Finally, let’s evaluate the effectiveness of DragSox. DragSox – a relatively new power training device – were specifically designed to obviate the limitations and drawbacks described above.


DragSox are simple, small and light. They are worn around the swimmer’s ankles, feel natural and allow swimmers to maintain their natural body position and balance with complete freedom of movement. DragSox generate resistance by utilizing available natural resources: water and air. In order for a swimmer to move forward, she needs to expend energy to “pull the water apart against its own cohesive forces to make room … to pass through. The energy expended varies with the shape of the object moving through the fluid. If the fluid is pulled a part in such a way as to force it into eddies and other unevennesses of motion (turbulence) the energy expended is multiplied …” [3] This description precisely explains how DragSox work. DragSox, due to their special design and material, pull water apart by forcing it into “eddies and other unevennesses of motion” and in doing so, they generate a lot of drag. To overcome this drag, a swimmer has to expend a lot more energy, eventually becoming stronger and more powerful.

In contrast to a power tower and a parachute, DragSox require neither a belt nor a connecting line. The absence of a connecting line makes DragSox immune to the drawbacks of a power tower and a parachute, or any other device that requires a connecting line for that matter. Moreover, because DragSox are soft and light, they don’t have the drawbacks introduced by running shoes: DragSox do not pull swimmer’s legs down or restrict the ankle’s range of motion. Thus, DragSox have none of the drawbacks that other power training devices carry. Adam Cremieux, the head coach at Westmont Swim Club, put it this way: “we’ve tried everything we could think of to increase our power of our kick from, fins, zoomers, power towers, parachutes and med balls and nothing matches the DragSox. Everything we’ve tried always had a set back from loss of technique or wasn’t efficient enough for a large group.“ [2] DragSox are effective because they make swimmers stronger and more powerful while not introducing any drawbacks.


Before we begin evaluating convenience of a training device, let me define convenience as a combination of size, weight, storage, maintenance, portability and usefulness in crowded pools. There might be other factors that each swimmer or team needs to consider based on their own unique training environment. The given definition, however, is a good starting point for the purpose of this evaluation.

Power Tower
Power tower is one of the least convenient training devices available for swimmers. It is bulky, heavy, consists of many parts, and requires special tools to assemble and extra space for storage. It is essentially a static training device: once it is installed at your pool, you cannot easily take it with you to another pool. Furthermore, only two people per lane at the most can use a power tower at the same time. This is a serious limitation, especially for those who train in crowded pools.

Unlike a power tower, parachute is small, light, dries quickly, doesn’t require extra space for storage and is easily portable. On the other hand, because it has a relatively long connecting line extended behind a swimmer, parachute is not convenient for swimmers training in crowded pools. Swimmers in crowded lanes have to stay closer behind each other when they swim, thus, the parachute gets in the way of the person swimming behind. Overall, parachute is a convenient training tool as long as you don’t train in a crowded pool.

Running Shoes
Compared to a parachute, running shoes are bigger, heavier and require a significantly longer time to dry. In fact, running shoes might not even get completely dry between workouts. Perpetually wet shoes become pungent and start to disintegrate. In addition, running shoes are not portable. Swimmers might be able to use them at their own pools, but it is unlikely that other swimming pools will allow people to swim in shoes. On the plus side, running shoes work well in crowded pools. On the whole, though, running shoes are not convenient.

Like a parachute, DragSox are small, light, easy to dry, require no extra space for storage and are highly portable. In contrast to parachute, because of their small size, DragSox can be used in crowded pools. As Chris Plumb, the head coach at Carmel Swim Club, said: [DragSox] are simple to put on and take off, are easy to store, and have been a terrific tool for the Carmel Swim Club to use.” [4] What’s more, DragSox can be used in any size pool and during meet warm-ups. By and large, DragSox are considerably more convenient than the other items evaluated here.


The only training gear property that we haven’t considered yet is price, which also happens to be the easiest to evaluate. All you need to do is to look at the prices and decide whether the price reflects your perceived value of the device and whether it is within your budget.

Power Tower: $2,000+
Parachute: $25-$90
Running shoes: $50-$100
DragSox: $29.95


Rarely are potential drawbacks of training equipment outlined online or elsewhere. However, any swimmer or coach can evaluate gear against the three essential properties – effectiveness, convenience and price – described in this article. We have looked at four popular power training devices for swimmers – Power Tower, Parachute, Running Shows, DragSox – and evaluated these properties. Hopefully, having read this article, you are now armed with the right questions and will be able to pick the best training gear for you or your team. Good luck!




[1] Hopper, R. T. (1973). Patent No. 3861675. US.
[2] Cremieux, A. (2012, 12 14). AquaVolo Testimonials. Retrieved 04 20, 2013, from AquaVolo:
[3] Asimov, I. (1993). Understanding Physics. New York: Barnes & Noble, Inc.
[4] Plumb, C. (2011, 06 26). AquaVolo Testimonials. Retrieved 04 13, 2013, from AquaVolo:

Motivation to Read

Do you read books? If not, consider this:

To get some idea of what reading meant in the two centuries following Gutenberg’s invention, consider the case of two men – one by the name of William, the other by the name of Paul. In the year of 1605, they attempted to burglarize the house of the Earl of Sussex. They were caught and convicted. Here are the exact words as given by presiding magistrate: “The said William does not read, to be hanged. The said Paul reads, to be scarred.” Pauls’s punishment was not exactly merciful; it meant he would have to endure the scarring of his thumbs. But Paul survived because he had pleaded what was called “benefit of clergy,” which meant that he could meet the challenge of reading at least one sentence from an English version of the Bible. And that ability alone, according to English law in the seventeenth century, was sufficient grounds to exempt him from the gallows. I suspect the reader will agree with me when I say that of all the suggestions about how to motivate people to learn to read, none can match the method of seventeenth-century England. (1)

(1) Building a Bridge to the 18th Century, Neil Postman (1999), 188

Google’s Keep and User’s Trust

Google released “Keep” today which sounds like an app that I would actually use. But I will not.  After what Google did to “Reader”, can you trust that “Keep” won’t have the same fate a year or two from now? You can’t. Google completely lost my trust after they shut down “Reader” and once user’s trust is gone, it is very difficult to get it back.

We Are Google’s Products

We are its [Google's] product. We – our fancies, fetishes, predilections and preferences – are what Google sells to advertisers.

Siva Vaidhyanathan

Today’s news about Google shutting down Reader clearly shows that we are indeed Google’s products and not its customers.


The Googlization of Everything, Siva Vaidhyanathan (2010)

Loyal Customers vs. Groupon Customers

A loyal customer is the best customer a business can hope for. The more loyal customers your business has, the more likely it is to succeed. To build customer loyalty takes skill, time and patience. Many books have been written about customer loyalty and ways to build it, so I will not talk about that (see reference to two excellent books below). Instead, I will describe the worst customer for a business. And I will do that by quoting from Frederick F. Reichheld’s excellent book The Loyalty Effect. Hopefully, by understanding who the worst customer is, you will be able to make right decisions for your business.

So, who are the worst customers? Here is how F. Reichheld describes them:

If your business decides to … scour the marketplace for the worst imaginable customers with the lowest possible coefficient of loyalty – you could hardly do better than choose price discounts or mass distributions of coupons.

When I first read this, the name Groupon immediately popped up into my head. Groupon’s entire business is built on discounts and mass distribution of coupons. Think about it for a second. Their entire business is built on finding the “worst imaginable customers” for your business (assuming you are doing business with Groupon, obviously).

And why is this customer so bad for a business you might ask? Again, I’ll let Frederick F. Reichheld answer this question:

Customers who glide into your arms for a minimal price discount are the same customers who dance away with someone else at the slightest enticement. Coupons and price discounts find these customers like heat-seeking missiles. Why would you want customers who will renounce their loyalty to save a dime, or even a dollar?

and here is more:

Discounts and coupons train customers to shop for price while teaching them they cannot trust company to deliver consistent value… They foster adverse selection, do little or nothing to inspire loyalty in new customers, and actually discourage in old customers.

If you are trying to grow your business, you should not rely on companies like Groupon to help you build loyal customers. It won’t work. Discounts and coupons don’t build loyalty, even if they show you stats like these:


(image source:





The Loyalty Effect: The Hidden Force Behind Growth, Profits, and Lasting Value , Frederick F. Reichheld (2001)

Customers for Life: How to Turn That One-Time Buyer Into a Lifetime Customer, Carl Sewell (2002)

Telephone, Fax and Hubris

Vance Trimble in “Overnight Success” briefly mentions how around 1986 Fred Smith (the founder of FedEx) conceived an idea for ZapMail. The plan was to take advantage of rapidly emerging technology: facsimile transmission. By incorporating it into FedEx overnight document delivery business the delivery time would be reduced from overnight to two hours. ZapMail would work like this:

  1. Customer would schedule a pickup of a document for overnight delivery.
  2. FedEx would pickup the document and take it to a FedEx office.
  3. The document would be faxed to a FedEx office closest to the destination.
  4. FedEx would deliver the document to the recipient.

Three years and 357 million dollars later, Fred Smith admitted defeat. ZapMail failed because Fred Smith didn’t foresee that within a short period of time every company would be able to afford a fax machine of their own essentially eliminating the need for ZapMail.

This story by itself is not very interesting, except maybe for the fact that a huge amount of money was wasted. However, it reminded me of a strikingly similar event that took place 100 years earlier and that could have, at least in theory, predicted the failure of ZapMail.

Around 1880 the fastest way to transmit information was telegraph. At the same time a new technology, called the telephone, was rapidly evolving. The telegraph experts predicted that the telephone would be used in the following way:

  1. Customer comes to the telegraph office.
  2. Customer gives a written message to be delivered to a telegraph operator.
  3. Telegraph operator reads the message over the telephone to the telegraph operator at the destination point.
  4. Telegraph company then delivers the message to the recipient.

Needless to say that the telegraph experts failed miserably in their predictions. In a short period of time every household could afford a telephone and people were able to make calls without involving a telegraph operator.

If you replace telegraph with FedEx and the telephone with fax the above-mentioned two events become identical. Just like telegraph experts assumed that a telegraph operator would be needed to place a call from point A to point B, Fred Smith assumed that FedEx would be needed to fax a document from point A to point B. History proved both wrong.

The telegraph/telephone evolution occurred 100 years before FedEx/ZapMail. The question that begs asking is whether the telegraph/telephone history could have predicted the failure of ZapMail. Considering how similar telephone and fax technologies are, I believe that it would have been reasonable to assume that what had happened with the telephone would happen with the fax machine. In a short period of time people were able to afford a telephone in their houses, eliminating the need for telegraph operators. Similarly, one could have predicted that in a short period of time people could afford their own fax machines, eliminating the need for ZapMail. Of course, hindsight is 20/20, but had they looked at the history of technology innovations in communication could they have prevented spending 357 million dollars on an idea that was doomed for failure? Or was it hubris to think that they could avoid a similar fate?


FedEx was not the only company trying to incorporate fax technology in their delivery process. Larry Hillblom and DHL also tried it but quickly failed for the same reasons, but I don’t think they spend 357 millions dollars!


Overnight Success: Federal Express And: Frederick Smith, It’s Renegade Creator (by Vince Trimble)

The Telephone Patent Conspiracy of 1876: The Elisha Gray-Alexander Bell Controversy and Its Players (by A. Edward Evenson)

King Larry: The Life and Ruins of a Billionaire Genius (by James D. Scurlock)

Sports Innovations Created by Participants Not by Product Manufacturers

I recently read a book by MIT professor Eric Von Hippel “Democratizing Innovation.”  The book talks about the difference between user-centric and manufacturer-centric innovation. According to several studies discussed in the book, most new products developed by manufacturers are commercial failures. Only 1 out of 4 new products developed by product manufacturers succeeds. That’s a 75% failure rate! The main reason for such a striking failure of manufacturer-developed products, according to the book, is a poor understanding of users’ needs. What was particularly interesting to me was the data related to the sports industry which showed that most innovations in the sports industry are created by users and not by product manufacturers.

In this post I wanted to talk about a couple of popular swimming products and the people who invented them. Since most products are sold through large companies, you might get the idea that it’s companies doing the innovating, but in reality it’s usually the users. In the case of swimming, it’s usually swimmers and coaches, and not equipment manufacturers.

Swimming paddles

The first swimming paddles were invented by Benjamin Franklin around 1717.  Since then, manufacturers have made numerous incremental improvements to design and material.  Most of the paddles that are currently on the market look very similar with two exceptions: anti-paddles and bolster paddles.


The anti-paddles were invented by a Hungarian swim coach in 1990s.  Anti-paddles take away the resistance during the pull phase which forces the swimmer to concentrate on the proper technique in order to move forward.  These types of paddles are currently produced by several swimming equipment manufactures.

Bolster paddle:

Bolster paddle were invented by a swim coach Brian Bolster.  These paddles insure proper high-elbow catch.  They are currently produced by Finis Inc.

Swimming fins

Swimming fins were also invented by Benjamin Franklin around 1717 and ever since there have been a lot of incremental improvements.  One of the notable changes in design and functionality was the Zoomers fins.


Zoomers were invented Dr. Marty Hull who was a Stanford NCAA Champion in the 200 Breaststroke.  Zoomers have a smaller fin that promotes a faster and more propulsive kick. Later Dr. Marty Hull licensed Zoomers to Finis Inc for distribution.

Center-mount snorkel

The earliest center-mount snorkel that I was able to find was invented in 1863.  However, the most popular center-mount snorkel was designed by Dean Garraffa in 1996.  Dean Garraffa is a co-founder of Atomic Aquatics, a well known scuba company that produces high quality scuba products.  The patent for this snorkel was later assigned to Finis Inc.

As you can see, none of these well known swimming products were invented by the product manufacturer.  These examples show exactly what Eric Von Hippel talks about in his “Democratizing Innovation:” in the sports industry, most innovation comes from sports participants, not from product manufacturers.  Product manufacturers do develop new products, but most of them either fail to succeed because manufacturers don’t understand user needs or these new products are mere incremental improvements on existing products.

“The Process of Innovation” (Andy Bechtolsheim)

Lessons from the Web Innovations

  • Time from invention to adoption is short
  • You don’t have to be the first to succeed
  • What matters is to solve the right problem
  • Being first at that extremely important
  • Ongoing innovation is also absolutely key
Why Do New Products Fail?
  1. Too early
  2. Too late
  3. Too difficult
  4. Not relevant
  5. Too expensive

Video: Andy Bechtolsheim “The Process of Innovation”


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