This is a post by Sanne Buurma.

This is the second article in a series about finding a better design for the weight needed in a dynamic pool freediving performance. The first article focussed on my discomforts and dislikings about the current design, which I blindly followed when I first started freediving. This article will focus on the way I intend to solve these problems into new solution and the design around it. In the 3rd article I will focus on the testing we’ve done so far with different setups, to see if they actually solve my problems. The 4th article will show how the design evolved through time by incorporating our findings from the test phases. Finally in the 5th article I hope to present a solution with an easy design, so other freedivers can try and build/buy one of their own and see if they benefit from it as much as I do.

Weight placement
To solve the weight placement, I chose to locate the weight around the lung area. It’s a bit of a tricky location and might be disadvantageous due to the flexing of the chest when inhaling and exhaling. Only tests will find out if I find this comfortable or not and if it doesn’t effect my normal breath-up.

Balancing
One of the solutions for unbalanced tilting that caught my eye is already widely used in the shipbuilding industry and is called a keel. The principle behind this solution is to spread the center of gravity, by placing a weight below the structural keel. For ships the use of a keel brings stability and improves the directional movement of the ship. My interest lies with the stability problem it solves; when a sail ship is sailing, the wind will make it tilt, the keel will counter act this by it’s weight. That’s exactly the behavior I want my prototype to have when I’m doing a dynamic performance. So when I tilt over, due to a slightly rotated push-off while turning, the weight underneath the chest will be counteracting this and ensure my alignment in the horizontal plane. So from the balance point of view it is best to place the weight underneath the body, or at least on the lowest point of the chest.

Optimal arm placement
In the 2 preceding points I opted for the placement of the weight around the lung area and at the lowest point of the chest in the water. This will solve my discomfort and inability to fully stretch the arms over my head as well. Because the area around my neck will be clear of any objects what so ever. Ofcourse the question remains; “Will the new weight placement introduce a new discomfort or is it easier to live with?”.

Commence the Testing
As we’re already testing and have been testing with a few different setups, I’m going to continue to test for a while longer to see if he new approach really brings what it should. I will report about my findings in a 3rd article as soon as I think it’s a good point in time to share it with you all. I’ve already shared some insight from my setup through pictures, but my experience still needs to increase a little more to share. How would you like to see the solution tested in comparison to the neck weight? Please leave your ideas in the comments and I’ll see if I can include this in the tests.

PS. Current design lacks the safety feature, so I cannot compare this in the tests.

This is a post by Sanne Buurma.

“Once the technique is dialed in, it’s time for getting some distance in with the monofin.”

…And that time is now, because the past few weeks we’ve been experimenting with technique and alignment, but both seem to be working out good enough to get into some practice. Last night and the past 2 weeks I’ve already dialed in some distance with the monofin, but in the next weeks it’s time to up the distance. Not the performance distance, but many many meters getting used to the monofin on my feet and getting the technique dialed into the core.

Getting ready for the turn

Our Hardcore Trainings Pool

This is a post by Jorg Jansen.

Yesterday evening me, Sanne and Bertrand were forced into freediving between the recreational swimmers. And instead of just putting on our monofin and making a bloodbath between the swimmers with lost finger, toes, or worse, we decided to give ourselves a real old school freediving training once again.

My body was still hurt from the snowboarding of the day before, but men did the training feel good! I can’t help it to just like those intense freediving trainings where you really gasp for air, build up Co2 till headache, burn your legs until you can’t move them anymore. All in all it was great again.

The combination of Apnea crawls, back kicks, different strokes and breathing patterns and around 1200 meter covered underwater felt painful but good. Bertrand is new in our group, but he managed to do an excellent job! Finally someone who is not only able to complete such a training, but even enjoys it as much as Sanne and me. He even managed to do 4 laps of relaxed underwater swimming with his bi-fins in the end! Good stuff and motivational to watch him continue.

We have to do this a lot more!

This is a post by Sanne Buurma. 7BBXWSR4GX4F

Since the new suit arrived I had a great first test run with it last week. The result of this test run was that I had an increase of about 10 meters with my current set of parameters concerning Kick & Glide ratio. As this was tested in the 50 meter pool in Eindhoven, I faced a new challenge last night in the 25 meter pool. With what kind of ratio will I continue,…

The glide phase is definitely longer and more efficient than before, which in turn means that I can make more use of that. On the other hand I’ve always been a high intensity freediver, where long rest periods would just make me restless. So where do you decide on, with what set of parameters do I want to continue? Those are the questions that I’ve been struggling with and discussing it with Jorg led me to the point where we think it’s fair and right that I give this an honest shot.

To find the proper parameters we set out 3 different types of K&G-ratio’s for the 25 meter pool:

• 2 * Kick-Kick-Kick-Glide
• 3 * Kick-Kick-Glide
• 2 * Kick-Kick-Glide

2KKKG
2KKKG was the first one I tested, I suited up the gear and went for it. I could easily make the 25 meters with this ratio, where I couldn’t do that without the suit in the weeks before. A big difference lies in the push-off, where I can glide a proper distance before even starting the first K&G-cycle.

3KKG
3KKG was next and surprisingly I was almost doing the 2KKG. If I just had a little bit more patience and let the glide phase be a little longer I could reach the other side by only doing a 2KKG. So got eager to try it in a more real situation by trying a 75 meter run with a 2KKG ratio.

2KKG over 75 meter
The first lap was like I did in the run before, I barely made it but with enough patience it worked, then the second lap I was a little bit less patient and had to a one kick to reach the wall. The 3rd lane was yet again a little less patient and I had to make 2 kicks at the end to reach the wall.

Concluding
By testing these different parameters I’d like to give the 2KKG a good test over the months to come. I believe that I just need to adapt to the new style of waiting a little longer in the glide phase before I start a KG-cycle. Eagerness should be tamed and restlessness turned into confidence. So my plan for a period of 2-3 month’s of training will be to focus on this 2KKG ratio and see to which level I can tweak this ratio. If this works out like I want it to, then it saves me a great deal of energy and for sure my confidence will grow. Let’s wait and see what the month’s ahead have in store.

This is a post by Sanne Buurma.

Today I brought my new Blue Seventy suit to the training pool Tongelreep in Eindhoven. It was time to put it to work in the training to get used to freediving with it. I’ve tried the suit on several occasions, I tried Eric van Riet Paap’s suit at the RMC in Wiesbaden just before my actual run and I tried using the same suit twice at our own dynamic competition. On both occasions I was not able to fully test it before the competition, so in Wiesbaden I decided to go with the familiair – without suit – and at our own competition I did try it in the comp, but then I had other side-effects keeping me from properly putting it to use.

Last week I picked up my suit at Eric’s home, while I was in the area for work related stuff. Today I could finally put it up for a test run and see how it flows through the water. I set my distance to the usual 97,5 meter and went for it without any breathup or preparation. It felt like I was doing my normal rhythm and agreed with myself I’d turn at 50 meters to see how I felt. Somehow it did feel that I was generating more speed and had longer glide phases. Kind of startled to see I was almost at the 100 meter mark I gave the abort sign – like I agreed upon with Jorg – and resurfaced. Looked around a bit and actually everything was very OK.

Jorg gave me the feedback that it looked like I was trying to sprint – as opposed to my normal speed – but I could sustain this tempo longer. I told him that I was just doing my normal rhythm and not exaggerated the motion in any way. So to see what the difference was between without suit and with the suit, I agreed to do 2 test runs where I’d do three kick-kick-kick-glide cycles. Normally this will take me to 25 meters, but now it took me to 35 meters !! Some suit I got here, very glad I gave it a good try finally.

Was it flow? Or did I just cheat time itself?

Today I was looking back at the week and I noticed that somehow I didn’t do any freediving at all. The Tuesday swimming sessions with Sanne haven’t take place at all during the last week, this due to a planning conflict between this session and my son’s skateboarding lessons. And the Thursday training got canceled due to the fact that Sanne was very late at home after some hours in a traffic jam and me being totally depleted from energy because of a family trip to the swimming pool.

So, while the sun was shining hard this afternoon, I decided to fill up the blanks with some dry walks, while my son was riding in the skate park. After sitting on a bench for 2 minutes and breathing lightly I started with my first walk. Normal pace and just strolling along. After 45 seconds I got my first contraction and stopped. It felt terrible, as usual. I walked back to the bench and prepared again for 4 minutes. Started walking and at 43 seconds I got my first contraction and at 48 seconds I just couldn’t hold it anymore. This time it felt even worse and I almost pissed in my pants. Why am I doing this?

Back to the bench and forget about the dry walks! Just relax, enjoy the sun and watch my son skateboard. What a great day, I was thinking. After 20 minutes or so, and nearly falling asleep, I was thinking about why my dry walks always suck so much. I just don’t know why this is. I decided to do one more dry walk, but this time I would stop at the contraction and I wouldn’t promise myself that I would go on a little longer. Just walk until contraction and that’s it!

Instead of using the bicycle lane, I know decided to walk around the skatepark, and instead of looking down the whole time I decided to look at my son and what was happening in the busy skatepark. With the same speed I started the walk, just enjoying the sun, the people, everything. After a lap of walking I felt the contraction coming and stopped the timer. I just couldn’t believe it when I looked at my stopwatch. 1:35 minutes. What just happened?

In complete disbelief I walked back the exact route and the time was correct. My best dry walk time ever was 1:25 minutes from 6 years ago or so. And I remember that one as one of the most painful breath holds ever! And now… no pain, no contractions, nothing! And this time? I guess this was one of those famous ‘flow’ performances, the one that happens only every thousand times, the one where I ‘lost’ time. I just hope that it will happen to me again in the next session…

I was looking back on this site for some older posts and what we’ve been doing. It was fun to read back what we have done already and especially what we have accomplished. Great stuff and so glad that we started this blog already so many years back. While our Sharkbait blog is 99% filled with freediving stuff, it is not only freediving that keeps Sharkbait occupied. It has been more about the way we do sports in general and how we enjoy doing it. Besides freediving, we also enjoy swimming, running, cycling, track & field, freerunning (Parcours), trampoline jumping, skateboarding, inline skating and especially snowboarding as well.

So, our philosophy about how we experience sport is not just freediving specific, but can be layered upon many other sports. Maybe it is time to update and republish our Sharkbait philosophy post again and see where we are standing today. Good times!

The first is to increase monofin technique. We already came from far with this one. The first quarter of this year was really dedicated to using the monofin and I’m glad to say that both Sanne and I are finally using the monofin in such an easy way that turning back to bifins for dynamic performance dives would only be done of nostalgia.

The basic technique is there and there is even room to play around and experiment with this technique in the form of amplitude changes, body position adjustment, power and kick cycles. We both agree that for the moment our best strategy to go by is a kick-kick-kick-glide cycle in the pool we are using now. As this is a 25 meter pool we need 3 complete kkkg cycles for one length, which feels good compared to effort put in.

Now we need to start working on our weighting stuff. With the technique in the body, it is time to start fine tuning it and because a neck weight is even more uncomfortable for me then it is for Sanne, it is time to fix this this month.

Our preferred way of propulsion: Waterway Glide Fin

The second part is increasing comfortable performance (CP) so that it reaches closer to our maximum distance (MX). Increasing performance is always a trick by itself, and we tried already a lot of methods in the past for this. Reading back all our training logs from the past years one thing comes to mind; speed! The one variable we didn’t use to much is the speed were we would go to the next step. We used weeks, number of repeated performances and other variables to determine if we could make the next step, and the one thing that comes to top that still could be tweaked is going slower with the steps we take.

We still maintain the idea that we should be able to perform near our limits all the time without any big warm-ups and strange techniques. So that together with a program of increasing our CP nearer to our MP, brings us the current schedule we are  doing.

My own comfort distance is a 40-45 meter dive. No contractions, still good technique and the ability to relax underwater at the end. As soon as I turn at 50, I tense my body but especially my mind. So my task is to make sure I can do 45 meter dives without any tension and yesterday was the first time I could accomplish this, which I’m very happy with. I’ve never been able to keep so relaxed at this distance, so a big break through for myself. As I’m not as experienced myself with the no warm-up routine as Sanne is, I do a total of 4 dives like this with around 2 minute rests between and that’s it for me. So at the moment my CP=45 while my MP=75, which brings my CP/MP ratio to 60%

Sanne is already much further with his no warm-up routine and his CP. Yesterday he did 95 meters and make it look so easy. He stopped underwater at 95, made a stop gesture with his arms and slowly surfaced. His MP=125 meters, so his CP/MP ratio is 0,76 which is already great. And we are just getting started. This one dive is everything Sanne does for performance training. He is already so tuned in this no warm-up routine that this is sufficient for him.

The rest of our training is dedicated to technique and helping other freedivers improve. So still a minimum time invested in performance training for maximum results and still a lot of time left to enjoy the water. I just love this method!

This is a post by Sanne Buurma.

This is the first article in a series about finding a better design for the weight needed in a dynamic pool freediving performance. This article focusses on my discomforts and dislikings about the current design, which I blindly followed when I first started freediving. The next article in the series will focus on the way I intend to solve these problems into a new solution and the design around it. In the 3rd article I will focus on the testing we’ve done so far with different setups, to see if they actually solve my problems. The 4th article will show how the design evolved through time by incorporating our findings in the test phases. Finally in the 5th article I hope to present a solution with an easy design, so other freedivers can try and build one of their own and see if they benefit from it as much as I do.

The prototype I had recently tested, started out with an idea to get rid of my discomfort in wearing a weight belt around my neck. There are a few reasons why I dislike the neck-weight solution;

1. Weight placement
2. Unbalanced alignment
3. Blocking optimal arm position

Weight placement
Why I think the weight placement at the neck is wrong, comes from the lung placement in a human body. The center of mass for a human being is located in the lower abdominal regoin, where as the center of buoyancy of the body immersed in water is located in the middle of the lung area. Which is a substantial distance apart when placed horizontally, besides the fact that it differs a between different body types. If you want to compensate this and bring balance to the scale, next thing you want to think about is weight placement.

When a person of average build tries to float horizontally on the back with arms along the sides of the body, the center of mass is nearly level with the center of buoyancy. Many people have more body weight in their legs and hips because of the high proportion of muscle tissue there, so their center of mass is near the hips. Thus when trying to float in a horizontal position, gravity pulls the hips and legs downward while the buoyant force of the water pushes the chest area (center of buoyancy) upward. The body rotates until the center of mass is directly below the center of buoyancy, resulting in a diagonal body position. At that point, the person should float motionless.

A human bodies’ center of buoyancy is a point around which the buoyancy forces are balanced. My problem with the neckweight is that my back-muscles are over compensating to keep a straight back. Compare it to holding a crate of beer out in front of you with straight arms or holding it close to the chest, you’ll find that holding it closer will require less effort to keep your back straight. Now imagine the same for the dynamic freediving position of the body with arms fully stretched; would you hold a weight for compensation in your hands? My point is not that the neck location is wrong, but focusses more with being able to last longer if the weight is located closer to the point around which the buoyancy forces are balanced.

Unbalanced alignment
The second reason for disliking the neck weight is the unbalance it introduces into the glide phase. It’s a fact that it is hard to ensure the lead to be equally distributed throughout the tube and requires proper craftsmanship. If it is not equally distributed, in the glide phase I find myself tilting left or right depending on which side has a little bit more weight. Even when the weight is distributed equally, I still find myself tilting, but this is caused by different strength in my arms or imprecise arm movement.

These phenomenons would pose no problem to the dive, if they were corrected by the weight. But the tilting during a glide phase is not corrected by the neck weight, because of the equally distributed lead. If I am to introduce a correcting & dampening factor for the neck weight, that would solve the problem of tilting, which is now neglected by the old designs.

Lately some improved neck weights, the one Daan calls the ‘Big Fat Bastard’ version 3, already solves a part of these problems, but introduces another discomforting factor; when you make a powerful arm stroke the weight is accelerated a tat slower than your body and lags behind your motion, than when it is accelerated it swings back giving your lower jaw a nice blow.

Blocking optimal arm position
The third problem I have with a neck weight is that in most cases the tube filled with lead will make it close to impossible to strive for optimal arm position. I myself don’t have a particular large gap between my arms when I place them in optimal position. Which is making it very hard for me to fully stretch my arms out without choking myself with the neck weight.

Although this sounds a minor detail, swimming with comfort is an important factor, the BFB 3 solves the problems with the old design by keeping the parts around the neck very thin. But a thin wire like solution, introduces a smaller surface area which has to distribute the weight on to your neck.

My 2 cents
These are just my dislikings with the current and old designs, there’s nothing wrong with them as people are swimming extremely far with them. I just hope to set sail on a journey to improve the sport of freediving by sharing my ideas. I am not the only one out here trying to improve this, so let yourself be heard and post your ideas in the comments.

I’ll share my thoughts on how I think I’m able to solve my problems & dislikes with the neck weight in the next article in this series.

This is a post by Sanne Buurma.

Since last weeks training the distance of 87,5 meters is the set distance to go by for the coming 2 weeks after the holiday. Yestrday night and last tuesday I did them without any real problems and my mindset was prepared for a distance like that. I like to keep it that way and start freediving with a comfortable distance and build from there. If I up the distance to a new one it’ll be somewhere around 90-95 meters the next distance after that must be 105-110 meters, as I don’t want to end a run at the wall. Mentally a bad thing to have and I’ll keep in mind the words “a wall is there to make a turn” which I believe are the words from Danny Matherus.

Getting comfortable with the new monofin is the best thing that is happening at the moment. The technique is developing itself every time I try a new run and will only become more effective as I make more meters. The one thing that is making it uncomfortable at the moment is the neckweight. Because of the natural body reflex of making a contraction to get some air in, it also initiates the muscles in my neck to tense and by doing so the neckweight’s fit becomes unpleasant. Even if I would loosen the neckweight’s fit, it will still ‘choke’ me because my arms are pushing against them. So I have to start focussing on perfecting the design for my own weight system again and start training with that.

Overall I’m very pleased with the new monofin and training strategy, besides that it’s great to teach some diver students (who join us on Thursdays) the basics and fundamentals of freediving.