DIR fin technique questions

[Rhone Man]

Marc's Third Law of Scubaboardynamics in action again.

I think there is also a theory to be extrapolated about what including "DIR" in a thread title does to the size and content of the thread...

 

[Blackwood]

I think there is also a theory to be extrapolated about what including "DIR" in a thread title does to the size and content of the thread...

Most definitely. Next time I want to sell something I'm putting DIR in the thread title. Instant traffic.

 

[Erku]

It may be a long thread but the discussion of efficiency and kicking has been fascinating and well worth the read. The argument/reiterations on whether or not a frog kick is DIR / invented by DIR divers / other nitpicking, not so much. But the efficiency stuff = great, and something I'm going to experiment with in my pool time now.

 

[Lenaxia]

Most definitely. Next time I want to sell something I'm putting DIR in the thread title. Instant traffic.

Wow, yeah tell me about it. I did not expect this. I leave for a day and come back and the thread has gone nuts.

My humblest of apologies go out to the non-DIR frog kickers. I am still relatively new to scuba (read: I have had 4 post-cert dives and scheduled to but have not taken AOW).

I did not mean to imply that DIR invented frog kick, it is just that frog kick is mentioned in conjunction with DIR in most references and conversations I have overheard.

There is much more that I could say/ask that would continue this discussion but it wouldn't contribute anything more so for the sake of letting this thread die, I shall say no more. As Rhone man said, all my questions were answered to a satisfactory extent within the first few posts.

 

[RU4SKUBA]

As a former competitive swimmer, frog kick is the most inefficient kick of all three because of the repeated fast acceleration and fast deceleration. Even the DIR style flutter kick with 90* bent knees is much more efficient..

a) Where did you get the idea the flutter kick was efficient?

The front crawl is a continuous stroke that has "more propulsion generated from the arms than from the kick" according to the Red Cross "Swimming and Water Safety" Manual. Its an anaerobic workout and it'll suck your gas dry, and its why most advanced divers use the frog kick frequently or as the default kick.

b) The frog kick is actually not recommended for recreational swimming, not used in any strokes, and should not to be confused with either the whip or scissors kicks.

Aquatics professionals generally consider it a common stroke problem to be dealt with after swim students have mastered the timing, breathing, and arms. But for diving it eliminates the large muscle groups, allows for glide between strokes, directs the water behind the diver, and keeps the heart rate considerably lower than the flutter kick, which is a continuous kick.

 

[scjoe]

Guy - (assuming we're talking about forward crawl) go watch some professional swimmers and see how many of them flutter kick. I'll bet you it's roughly zero. The kick most often associated with forward crawl ('freestyle') is a scissor kick. Unlike a lutter kick, it comes from the hips.

Competitive swimmers do not tend to use the terms flutter kick and scissor kick the way you are. From USA Swimming: "The stroke most commonly used is sometimes called the crawl, which is characterized by the alternate stroking of the arms over the surface of the water surface and an alternating (up-and-down) flutter kick."

The sidestroke kick would typically be called a a scissor kick.

 

[Dyno Bill]

In my opinion and I know not many are really interested but that being said. If you want to learn an efficient kick start freediving. See how much ground you cover on a breath of air as a breath is all you have between surface intervals or circuits as I called them. Personally I never saw a hunter doing anything like a frog kick. First you have to get below buoyancy to fall hence kick and then you have to rise above it again hence more kicking. A trend towards use of a mono fin is kind of popular for more purist freedivers but I personally used one. A frog kick is like a stealth kick where you upset nothing, I would use it in an overhead environment like a ship or cave where silt is an issue. Do it breathold for a bit and trim and style start to improve a lot.

 

[Blackwood]

Competitive swimmers do not tend to use the terms flutter kick and scissor kick the way you are. From USA Swimming: "The stroke most commonly used is sometimes called the crawl, which is characterized by the alternate stroking of the arms over the surface of the water surface and an alternating (up-and-down) flutter kick."

The sidestroke kick would typically be called a a scissor kick.

Weird. I always thought scissor kick was pretty much a flutter that comes from the hips. Either way...

 

[Guy Alcala]

I think the frog kick, to some extent, is habit forming. Because it incorporates a rest phase, it isn't very fatiguing -- I can and have frog kicked for a couple of hours in caves in MX without getting tired. It also gives you a buoyancy check with each kick, because of the glide. In still water, it's really a lovely kick, and we all had to practice it to learn it, so we acquired the habit.

You are quite right that there are circumstances where it's not ideal, and the problem with people getting stuck on frog kicking has become severe enough that GUE has issued a technical bulletin to make sure their instructors work with students enough on the modified flutter. Flutter IS better when swimming into current or flow, because there is a constant stream of propulsion directed forward, and you don't have the glide phase to lose velocity and momentum.

Bent leg kicks are just plain better when you are swimming above a fine silt floor, unless you are way up in the water column. I have seen flutter kickers six or eight feet up in the water column and still leaving a silt trail, here in the Sound. If you are swimming above sand, no big deal -- if you are even a few feet off the bottom, you will raise little dust and it will settle quickly behind you. Over fine silt, things are different.

Agreed with the last, which is why I stressed local (i.e. Mocal) divers, which the OP and I are. I find 5 feet above the bottom to be more than enough over our sandy bottoms, and 3 feet is often enough if I'm not trying to get somewhere. In a high-silt environment the equation's very different.

I do disagree with Guy. If I am doing a long transit, and am not in current, I will frog kick, because I won't get tired. If I am doing a VERY long transit over largely uninteresting terrain . . . well, that is one of the few situations where I get out the scooter. Diving, for marveling at things, is best done slowly.

Lynne, on the few occasions when I've tried to do very long transits with my size XL Jets, I've gotten tired (and cramped) doing flutter too, even when I've been swimming laps on a regular basis. My size Large Jet blades are small enough and/or fit my feet better that this isn't a problem, but I can only use them with 3mm or thinner wetboots, not the turbosoles on my drysuit. My Bio-fins fit my feet better than my XL jets and cause little if any cramping, nor do they make me tired while doing flutter kicks.

In addition, since I'm often doing long compass nav. swims over barren sand in surge between points of interest, I also find it easier to count kick cycles with a flutter kick (than a frog), as I prefer using K.C.s to time for estimating distance. My single tank dives at moderate depth often involve covering a distance of 1/2-3/4 mile underwater plus a long surface swim before/after. On the few occasions I've done that with my XL jets I've been cramped and hurting. Not so with my splits. It may be, as I get more practice doing bent-knee frogs, that my efficiency will improve to the point that I can cover the same ground with equal or better speed, gas usage and physical stress as I can using my splits and flutter-kicking. That is not currently the case.

As far as scooter use, my recreational sports all share one common theme - they're human powered. To the extent physically possible, I won't use a motor to accomplish what I can do under my own power. This is a personally-imposed handicap for the game I play with myself, and it forces me to stay in decent shape, as I won't use a motor to get to a site if I've done it under my own power (until I'm so physically decrepit from age/injuries that I have no choice, at which point I'll have to decide whether to give in or stop going to that site).

For me, I'd only use a scooter if there were no other way to accomplish a task, which is pretty much the progression used in cave exploration. But that's a matter of personal philosophy, although it does surprise me that so many DIR-trained divers use scooters routinely for recreational OW dives that don't need them, as that seems to me to violate both the minimalism and the physical fitness that GUE stresses. Obviously, scooter use boosts time underwater owing to lower gas consumption, and is presumably safer from a decompression standpoint owing to the lower workload, but to me it violates the KISS principle as well as being a needless expense. But then, I still dive air when I think it makes sense and often solo, so who am I to talk?

Guy

 

[Doc Harry]

BTW

I did a swimming efficiency test for myself a couple of years ago. I set 100 feet of line at a fixed depth and did timed swimming trials back and forth along its length. I tried different kick styles and different speeds.

By far, the most efficient kick was a slow flutter kick, significantly more efficient (in terms of SAC) than the frog.