Fins for Frog Kick

[dherbman]

Good link...

I actually missed the video comment in herbie's original post... when people write a novel, I tend to ignore them... or perhaps it's an author thing...

- ChillyWaters

lol
Sounds like a great thread for the whine and cheese forum.

 

[SparticleBrane]

How about the modified flutter? It doesn't go straight behind nor hanging down.
I think both modified frog and and modified flutter are kind of elevated.
Still, I agree that, the modified frog kicks may use less energy.

Influencing other's vision.... I guess that's the reason why modified flutter is being invented, maybe?

If we are on the same page, the modified flutter came out mainly to get through tight squeezes in overhead environments where you can't frog kick, but don't want to silt the place up. It's also not a kick you want to do for very long, because I haven't found it to be hugely effective on a per stroke basis.

 

[ChillyWaters]

The flutter kick tends to propel you upwards. The frog kick is a forward propellsion. Fighting againsts an upward thrust is gonna effect your trim and use alot more energy.

Hmmm... I've never felt this upward motion before.

How would someone dive if they were kicking "upwards." I mean, wouldn't that cause a _lot_ of problems?

It would be interesting to videotape oneself, and understand what they are doing right/wrong. We did this in basketball a lot, both for games, and during practice. It's very useful way to get better.

Though, I still think I'd notice if I was propelling myself upwards, no?

- ChillyWaters

 

[runamonk]

Just curious as to how the frog kick allows you to keep a better trim?

- ChillyWaters

When you're moving your legs up and down you're moving the rear of your body out of trim. When you do the frog kick you're only moving your feet and lower half of your leg, it's hard to explain really. Our instructor explained it with a drawing that really put it all into perspective for us. Neither me or my wife can really do the kick yet but we're working on it.

In any case there is alot less overall movement with the frog kick than that of the flutter. Which helps to keep you in trim and horizontal. There is a great deal of control, it's impressive.

Check out Frogkickdiving.com there is great information there.

 

[runamonk]

Sorry to see that...

1. http://www.divetekadventures.com/Images.htm
2. I guess the experts replied to your question have suggested some very good fins...

Good luck for your search!!!

EXCELLENT LINK! Thanks! I've been looking for something like that!

 

[BDub]

How would someone dive if they were kicking "upwards." I mean, wouldn't that cause a _lot_ of problems?

Yes, it can cause a lot of problems, beyond just kicking up silt.

There is an inherent upward thrust with the flutter kick. While it is propelling you forward, the upward thrust on the "down cycle" has a great tendency to push the diver up as well. That's why many divers achieve neutral buoyancy when they are kicking, but when they stop, they start to sink.

If you're in trim, the effect isn't so great, but if you're out of trim (plow position), your kicks will now propel you up and forward as your body is in a diagonal attitude, facing up and forward.

 

[dherbman]

Just curious as to how the frog kick allows you to keep a better trim?

- ChillyWaters

Chilly:
Think of it like a see-saw? It starts out balanced and adding length to one side or the other will cause that side to drop. Extending your legs to flutter adds length to one end of your body.


Extending your legs to flutter shifts the COG(center of gravity) towards the feet. This causes the feet and legs to drop and trim tends to become diagonal.

This can be offset by shifing the tank towards the head, adding tank weights near the top of the tank or by shifting the weight back towards your head by using the frog kick to shorten leg extension.

The diagonal trim causes your body to act as a wing, which cuts upward through the water if you are in strong current or actively kicking. The counter for this is typically dumping air, resulting in negative buoyancy. At this point, you have continue kicking or you will sink.

 

[ChillyWaters]

Yes, it can cause a lot of problems, beyond just kicking up silt.

There is an inherent upward thrust with the flutter kick. While it is propelling you forward, the upward thrust on the "down cycle" has a great tendency to push the diver up as well. That's why many divers achieve neutral buoyancy when they are kicking, but when they stop, they start to sink.

If you're in trim, the effect isn't so great, but if you're out of trim (plow position), your kicks will now propel you up and forward as your body is in a diagonal attitude, facing up and forward.

Okay, I could see this with blades, but is the same true with splits?

With split fins, the kick isn't as exaggerated, and the propelling motion is more behind you, reducing silt, and presumably the "upward thrust" as well.

- ChillyWaters

 

[ChillyWaters]

Extending your legs to flutter adds length to one end of your body.

Why would you extend your legs? Usually legs are kept bent...

Actually, wouldn't your legs extend more for the frog kick? Though, admittedly, only for a short period of time.

- ChillyWaters

 

[alo100]

If we are on the same page, the modified flutter came out mainly to get through tight squeezes in overhead environments where you can't frog kick, but don't want to silt the place up. It's also not a kick you want to do for very long, because I haven't found it to be hugely effective on a per stroke basis.

Got you, thanks!
But then, besides stirring mud at the bottom, why is it good for the divers to bend their legs? I thought if the kick is right behind you, the trim would be the best, right?

Another question is, it seems to me that when modifed frog kicks are used, e.g. as shown in that clip, the user has to move the fins such that the water at the middle are squeezed. Do you think this movement is done best with L and XL Jets?
I looked at the small size and medium size, just wondered if they can perform it as effective. Again, I am not a regular Jets user....

Today I found some old Jets somewhere, old Jets, full foot, the "old rubber" model. Actually they got the old Cressisub Rondine, some narrower Jets by SP, Beuchat Contact, then finally a pair of Jets made by Beuchat (Jets label at the front, at the back "Beuchat"). They are all very similar designs.