Folded Knees

[mc42]

Tough conditions to show off your best kicks, but kudos again for putting yourself up for critique. I didn't read any of the other critiques before posting my opinions so you'd have a clean opinion, but we seem to be in agreement.

As you and others have noted, you've got what I consider the breaststroke frog kick, where you bend your knees at the hips before kicking. That might have been learned from normal pool swimming, but the scuba frog kick is different. And this starts your body rocking back and forth. This is an extremely common technique issue and is hard to spot unless you have video.

Instead of bending at your hips, you would load up the scuba frog kick by bending at the knees only, and slightly moving your knees apart. This gives you enough water to grab on to, and also (for me, especially with limited ankle mobility due to wearing rock boots) allows me to get the fin bottoms closer together. The first few seconds of video show pretty decent knee distance and technique.

The rest of the extension stroke looks pretty good. I would emphasize trying to clap the bottom of the fins together at the end, which will get you that extra bit of thrust. Otherwise if you don't, a lot of the power gets wasted.

Agree with others to check your trim. Best way might be to assume a good trim position with knees bent, stopped, don't move anything, and see if you tend to rotate forward or backwards. Then adjust as needed so when you stop finning, you just coast to a stop. A couple of times you seem OK for trim where you stop swimming and other times maybe a little feet heavy, but it's hard to tell if the rotation is due to the knees dropping.

 

[Dody]

not bad. You bend your knees exactly like we discussed in the thread.
First let me tell you, that this is a very good basic you can build on.
After i roasted you on another thread its time to say something positive (completly different topic)
Why dont you like your arm position? Having the arms in front helps with trim. Maybe put them i bit higher, but this is mostly cosmetic

Things you can aprove:
Your trim is leg heavy. Try to move some weigth up, or get a BP/W. You can see in the video, that you start to become legy heavy when u stop finning for a moment.

Your knees hang a bit down. Hard to explain what i mean... i hope you can understand it: your body and your upper legs should be in one line. When you stop finning(between your frog kicks) your upper legs slightly point down. This leads to a leg heavy trim. Maybe fixing this issue is enough to be more in neutral trim.

After watching your video again i saw, that the tank is very low. Maybe moving the tank up for 2-3 cm will help you.
I guess this is a 12l Steel? Is it your own? if you rent them, try a long 12l tank. They give way better trim and overall weigth distribution. Except for small people, they sometimes like to small 12l tanks.

Besides the hanging knees your frog kick is fine. Maybe try to point the fins more together, so you can have more power in your kick. But this depends on the flexability of your ankles. I got problems with that aswell..
For the flutter kick you can use more of your upper legs OR bend the knees and use the modified flutter kick. But since there is current your probably want to do a real, strong flutterkick. If you use more of your upperlegs(which is a huge muscle) you can generate more thrust.

Maybe on this picture you can see what i mean, by saying body and upper legs in a line. Sorry for the bad quality, vis was very bad. Dont have another picture here

View attachment 666834

Yes, I realized that I was folding my knees. It was a surprise. My arms are not aligned with my body although I thought they were so that’s more drag. The 12 l tank is not mine. Depending on the clubs, the cylinders have different sizes and weights. I dived last weekend and the steel cylinders were 2 kg heavier than usual. I will try to put it higher. Continuous improvement is my motto and I will be doing 25 dives in the next 30 days .

 

[MaxTorque]

One thing that helped me to get horizontal was to simply deflate my bcd and lie on the bottom of a pool (or suitable robust sea bed, need to ensure you pick somewhere flat, smooth and ideally pure sand to avoid any environmental damage!) and of course, this forces you to both be truely horizontal, but also to be "all in line" from knees to head. Then carefully inhale/inflate to lift yourself off the bottom slightly, and maintain that position as you do. This can take a surprising amount of muscle strength in your core, depending on the distribution of your weight and weighting! It also shows up any flappy snag hazard kit issues, as lying on your octo or sDMB hurts! lol!

Lying on the bottom still also actively prevents you from kicking, because it's really easy to phantom kick without really realising it, so if you can float up and off the bottom from true stationary you know you must be in trim. If you can do this, literally hover up off the bottom, and then land back on the bottom again and each time land level and straight, your trim is nailed on perfect!

This is certainly a lot easier intially in a pool, thanks to perfect bottom and no currents etc.

 

[MaxTorque]

BTW, the other members of my dive club ribbed me for being lazy and spending the training session "asleep on the bottom"............. ;-)

 

[Dody]

Tough conditions to show off your best kicks, but kudos again for putting yourself up for critique. I didn't read any of the other critiques before posting my opinions so you'd have a clean opinion, but we seem to be in agreement.

As you and others have noted, you've got what I consider the breaststroke frog kick, where you bend your knees at the hips before kicking. That might have been learned from normal pool swimming, but the scuba frog kick is different. And this starts your body rocking back and forth. This is an extremely common technique issue and is hard to spot unless you have video.

Instead of bending at your hips, you would load up the scuba frog kick by bending at the knees only, and slightly moving your knees apart. This gives you enough water to grab on to, and also (for me, especially with limited ankle mobility due to wearing rock boots) allows me to get the fin bottoms closer together. The first few seconds of video show pretty decent knee distance and technique.

The rest of the extension stroke looks pretty good. I would emphasize trying to clap the bottom of the fins together at the end, which will get you that extra bit of thrust. Otherwise if you don't, a lot of the power gets wasted.

Agree with others to check your trim. Best way might be to assume a good trim position with knees bent, stopped, don't move anything, and see if you tend to rotate forward or backwards. Then adjust as needed so when you stop finning, you just coast to a stop. A couple of times you seem OK for trim where you stop swimming and other times maybe a little feet heavy, but it's hard to tell if the rotation is due to the knees dropping.

Back in the days, 3 decades ago, I used to be a competitive swimmer. So, yes, my frog kick is pretty much close to backstroke. I hated frog kick at first. Couldn’t do it properly and move forward. It’s way better now even though sometimes I realize that My hips are unnecessarily jerking.

 

[Dody]

You do bend your legs, like many of us.

You have classic rocking from top to bottom. Notice how your head to knee position swings up and down during each kick cycle? When you stop kicking, you rotate knees down. This rocking is interfering with developing a stable platform and having control over your fin movements.

The tank looks quite low. Can you reach the valve in that position? If you move some ballast up on your body, like the tank and/or some of your weight or use lighter fins, you should be less foot heavy and avoid the rocking and rotating from top to bottom.

Body positioning can help refine your position in the water as well. Stretch out, put your arms more forward, glutes tight (yup, I said it), and keep your knees up, in line with your chest.

Once you take care of the rotating, everything will become much easier.

I can’t reach the valve but I am pretty stiff too. I regularly exercice taking off my BCD within a couple of seconds to access my valve hoping that I will never have to do this in real. Last two things I systematically do before going into the water is inflating my BCD and taking three deep breathes checking the SPG so I should be fine there. If I get a free flow underwater, I won’t bother closing my valve.

 

[Joris Vd]

Welcome to the bad back club:
We have special pillows, office chairs and weird excuses as to why we no longer carry groceries.

The point of folding knees is clear: Prevent from kicking up silt when you're pretty close to the bottom.
It's also a pretty stable position for a very good trim
The problem with the modern position of diving that is suggested by most is not the knees folding. It's the exagerrated hyperextension of the spine when diving in that perfectly flat position. Especially when squeezing the butt muscles the hyperextension is quite severe.
It puts the back in an insanely vulnerable position, especially when you're then gonna put weight on that back.

It's good for trim, good for diving in general, but anyone who will tell you it's a good position for the back is just flat out lying.
The thing is, if you have a normal functional back without too many issues, you could probably do this for 30 years without any issues.

One thing you could do if you insist on diving this way is not hyperextending the spine as much but going more into a semi-straight position.

You might get some people who will tell you you should probably sign up to redo your fundies and your photos will look less cool...
It's not pretty, and certainly not DIR, but it'll sure put less stress on your back.

( just randomly picked this off google to show what I mean with like a not hyperextended trim).


or you could just trim out with your legs straight and make sure you don't dive too close too the bottom so you don't kick up ****, that's probably the easiest solution.

(again not my picture, but I guess you're pretty anonymous with scuba stuff on).

 

[Ayisha]

I can’t reach the valve but I am pretty stiff too. I regularly exercice taking off my BCD within a couple of seconds to access my valve hoping that I will never have to do this in real. Last two things I systematically do before going into the water is inflating my BCD and taking three deep breathes checking the SPG so I should be fine there. If I get a free flow underwater, I won’t bother closing my valve.

Actually, when I asked if you could reach your valve, I meant it even as an indicator of tank height. The tank looks really low, even if you had good mobility, and that rocking is interfering with every kick. It is important to be able to reach your valve or at least have a plan to access it if need be, especially if your valve is accidentally closed and you need to open it. Yes, you can avoid jumping in with it closed by doing your breathing/SPG watching, but those DG's can be pesky sometimes.

BTW, if you had to, you don't have to take your rig off to help you reach the valve. You can just loosen the waist cummerbund (or keep it not too tight) and "hitch" the rig up with your body or just lift the bottom of your tank with your left hand and manipulate the valve with your right hand. Easy peasy.

Having said that, I still think the tank or other ballast should be moved higher on your body so that you're balanced head to toe in order to stop the rocking and rotating during the kick cycle and when you stop moving. You should try it, you'll be so much more stable.

 

[Blackcrusader]

Maybe Dody can move his tank like I do. Works for me. Maybe minus a small o ring leak.

 

[Dody]

Maybe Dody can move his tank like I do. Works for me. Maybe minus a small o ring leak.

View attachment 667453

Well! No risk of hitting the back of the head on the valve ?