A Kinematic Comparison of Dive Fins

[Thalassamania]

To clarify: If as the sample size rose the variance assignable to the block effect due to pretrial preference were to drop and then level off (which is what one would expect) it would either level off at a statistically significant or statistically insignificant value. At an insignificant value that would indicate that the diver's (and I'd look at this by diver rather than in the aggregate) fin choice had no bearing on the most efficient fin for the diver. If, on the other hand, the variance remained significant that would indicate that the fin the diver used before the experiment was a predictor of the outcome of the experiment and would also permit a quantification of how important this influence was.

 

[meesier42]

lets assume that you are correct that you can overcome bias by increasing the sample size. But how do you plan to overcome the problem of exercise theory, that will introduce a statistically significant error unless you allow weeks of acclimatization with a single fin.

I will say, I have had to eliminate people (or at least their data) from test that I have done in the past, as even though they claimed they were at max effort using certain fins, it was obvious they were not. For example 2 divers similar in speed with 3 fins, but the 4th fin one diver was became much faster and the other slowed. Obviously somebody is fudging the data and people this is always going to happen.

 

[Bob Evans]

Deco, I have a wonderful way to test my new models of fins and compare them to others. First, I pour Makers Mark into a large glass, with ice. I finish that drink and make another. As I sip my way through the second glass, I line up a variety of fins on the side of the pool. By this point things fall into the random mode. I take a few more sips, close my eyes and slip on a fin. Sometimes I am real surprised to look at the fin that felt good and it is a model other than Force Fin. By that point I figure my objectivity is affected, so those results are thrown out the window.

This system of testing is not recommended for anyone other than me. I have years of experience that allow me to do this safely and accurately. When I put on the Jet fin I knew it all too well, even when numb, it hurts. I will never know how I was able to use that fin for over 20 years.

Seriously, a fin is about moving you in the water. The best test I have found is to remove the fin strap, and kick. If the fin stays on your foot, then it is pushing you forward. If it falls off, it is working against you. Force Fin Challenge.

 

[Blair Mott]

At age 17 Dr. Havrvey Barnett decided he was going to do something about infant drowning and since then he has saved many lives. He is the founder of the Infant Swimming Resource which developed the first and only drowning prevention strategy that has earned a 100% safety record.

He is also a Force Fin user and I keep listening to his video and what he has to say about Force Fins. Diving equipment can be a very personal choice, but when people really test their gear, to his extent, it is interesting to hear what they find.

 

[uncleavi]

Test Diver #1 will have to check on the Infant swimming as My little test Diver is taking lessons and I see there is one of his Instructors close by.
Also, think new Foils. I am going back to My Great Lakes Hometown for Thanksgiving and I belive a bit of diving will happen.

 

[Blair Mott]

Uncleavi,
Infant Swimming Resource would be great for your little one!

 

[Blair Mott]

Bob,
We need to contact Ryan Lindsey so we can present his study to anyone who wants to read it. An outside link , 3rd party, away from our site as we have had multiple inquires to read and review his study. I know I learned a lot from reading it. Of course we also need to contact him to schedule some upcoming dives out at the islands.

 

[Thalassamania]

The basic error of the study is identified in the opening paragraph of Methods Section: "Using a single subject, two category, two variable design, ..." Such a design means that the results and conclusions can not be applied to any but the single subject that was tested, drawing any conclusions by extrapolation of the findings to other individuals or to a population as a whole is simply bad statistics and thus bad science.

Further more, unreferenced claims such as, "For measures under 180 degrees, there is no damage to the body, where measures beyond 180 degrees force the ankle joint beyond their designed end ROM and cause micro trauma to the muscles on the front side of the lower leg and cause an over contraction of the muscles on the back side of the lower leg. This over contraction causes spasm in the muscle and the spasm induces a cramp." are more like snake oil sales pitches than science, where are the studies that demonstrate, "micro trauma to the muscles on the front side of the lower leg ... ", etc.?

As far as the conclusions that were reached, even if you grant all the unsupported claims, the comparison was with one set of "intermediate conventional fins" (whatever that might be) and one set of, pro model conventional fins (what ever that might be) yet the implications is that all fins that are out there (except the Forcefin) perform identically, something that common sense and experience runs counter to.

 

[Bob Evans]

Dear High Pressure, Before I stream up, I was wondering.... someone who sits on our "Nukes" in the Pacific Ocean, and has logged 5,000 plus dives what Fin do you use? Best Bob

 

[Thalassamania]

My choice of fins has no relevance to the study that is the topic of this thread. I would be happy to discuss the fins that I like (and dislike) in a thread on that topic, in fact I suspect that I've done that in the past.