All posts by Sanne Buurma

Tingling sensation can mean 2 different things

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The other night I was coaching Jorg while holding his breath at the hottub pool in the Tongelreep Eindhoven. He was experiencing his normal barrier and trying all kinds of different preparation techniques to break out of it as you can read here. As we know from our previous competition and other training sessions in the hottub, it can be very hot in there :D. This high temperature poses a range of problems which seemed easy to explain why they happen, but it turns out I was wrong about 1 of them.

When I was coaching Jorg, the time I spent in the pool doing nothing but coaching increased to a range of 25 minutes orso. That’s when I started sensing the same thing as when I’d have vasoconstriction. But although I assumed it was a free pass into having the vasoconstriction, I learned that it is actually vasodilation and thus the exact opposite of the thing you want happening with freediving.

To prove the theory I decided on doing a schedule to counteract the vasodilation and see after how many times the tingling sensation would fade away. So I did 1 minute 30 seconds breath holds and in the last 5 seconds I’d release all my air, after that I’d surface and immediately take one deep breath again and do another 1m30s. Normally with this schedule you would get the vasoconstriction kicking in at around 6 or 7 times.

The test showed us, that after only 3 times into this schedule the vasodilation was counteracted and I didn’t have the tingling feeling anymore. Theory proven and a lesson learned ;).

Static competition in Nieuw Vennep

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Last night I drove out to Nieuw-Vennep for a static competition organized by Nanja van den Broek’s organization Enker. The traffic didn’t pose a problem as I anticipated, so I was even in time for the inscription and judge speech. Although one judge was sick and one other freediver had called in sick, the cafetaria was filled with competing freedivers. Jorg was supposed to be joining as well, by after having another session with the dentist the pain was just too much to bare and he decided to stay home. It’s great to meet people in real life, after you spoke with them over the internet, although sometimes it takes a few minutes to recognize someone (Sorry Frank 😉 )

After everybody was inscribed and preparations were made to the pool, the competition started with the safety freedivers doing their own static’s first. After that Judith van de Griendt and Mark Keijzers were the organization’s safety. Besides all the gadgetery display, the competition was fun to be competing at. Exchanging experiences and learning from other freedivers is what comes first at these events, even if you don’t compete or compete against the big guns it will always be good thing to join for the learning experience. During the event I also grabbed my Android phone and tried make something out of the live coverage for You can watch the material in my Ustream channel here.

I promised myself the minimum of 3m30s would be satisfactory as I agreed upon with Jorg. Got into my Elios suit, which felt strange as I was almost the only one wearing one of those these days. I watched Eric and Jouke’s performance before I entered the water and eased into the competition area. Had a few laughs with the safety and started my breath up at 2 minutes before official top. Slow breathing with a normal rythem of 5 seconds in and about 20-25seconds air out always feels comforting. One or two seconds after official top I submerged and immediately the thoughts came into my head: “Here we are again, so why am I doing this?” Time to get rid of those thoughts and replace them by the experiences I had during my work day. Worked pretty well. At about 2 minuntes the contractions started and Not much later Mark Keijzers tapped my 1st tap @ 2m30s. Tap 2 and 3 came pretty quickly and I had reached the satisfactory level for myself. It all felt ok and I did two extra taps as I had promised myself and Eric to take a few extra contractions. Came up clean and did my surface protocol, waited for Erik Skoda to present my white card and there it was another mission accomplished.

It all might sound strange for people who used to know me as a guy who could static’s over 5-6 minutes and now not even being able to do so. But this has everything to do with me getting back on my feet after a succesful step back. I take things slowly and keep the fun factor high, hopefully this way I can get myself to fight off some more contractions. As long as I’m willing to do this for my own benefit and not for expectations of others, which is mostly the thing when my head starts thinking on automatic-mode ;).

Nanja thanks for organizing a nice event and let me express myself in your own words: “I always love competitions like these!”

Upping the CWB schedule

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The CWB training progresses in a good way, yesterday I upped the schedule to starting 1min. 45sec., where as last week I started every 2 minutes to do 50 meter lanes. I did 4 lanes and noticed that the last time my legs were not giving me any propulsion, so I had to rely on the last few meters crawling only with my arms. So the focus for next week should be keeping the time at 1m45s, but then trying to do more lanes, testing and pushing my legs for more. Hopefully the recuperation time will be sufficient to let me continue doing 5 or 6 lines of 50m CWB.

Jorg also upped his schedule and made it worth his time as well. After the schedule of 25 meters, I spotted for him while he did a few maximum attempts of CWB. Starting out with about 30 seconds of CWB, he upped it by grueling himself to 39 seconds and about 44 meters CWB. Good intense training where the mental factor was the winner for Jorg.

After the nice schedules it was time for some small monofin technique training. Without any weights and holding the arms alongside the body, we tried training for the proper execution of the motion. The points I have to work on are trying to start the motion in the pelvis area, where I now start the motion somewhere half-way my back, it should start at the pelvis and then work the rest.

CWB: 75m – where did that come from!?

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Yesterday I went out for a training in the Tongelreep with Jorg and CWB was the exercise on the schedule. We both started out doing our own type of CWB-exercise; Jorg did the version where he’d do 25 meters and start every 1m25s, I did 5 x 50 meters and starting every 2 minutes.

Then it was time for me to coach Jorg and see what he was capable of in maximum attempts of CWB. Very impressive to see he’s improving a lot in training. He started out with a 35 meters CWB and after that he did a 40m. To trigger that extra bit for him, we varied the approach a bit and swopped to trying to swim a full lane (50m) with only one breath or two breath’s, which made it in all a very good training for him.

Finally Jorg wanted me to do a 60 meters CWB, which has been a while since I’d done that, I started out as planned for the 60 meters, having some trouble approaching the 50 meter mark, but after the turn it all felt good again. I just kept in the same pace and thin I just had a safety stop at 75 meters, just to be sure. Where the hell did that come from 😮 ;). Overall it felt very good and certainly room for more, so maybe next week I’ll be upping the game and try for a longer Crawl Without Breath.

Never test new things in a competition

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This is the wisest lesson I can learn from my little mishaps last Saturday. Although the bad luck came from a totally unexpected angle, this is usually how it works with testing out new setups in a competition for the first time. Everything from my prototype to a borrowed suit from Eric van Riet Paap, went fine and was no problem what so ever. It actually went wrong when I used a swim cap in combination with my normal swim goggles. As it turned out the cap-material was to slippery for the head band to not fully hold the swim goggle cups against my eyes. Immediately after take off, they started making water. Normally a little bit of water is no problem, but it kept going until fully filled and yet it kept on passing by my eyes. After 33 meters of little disorientation I called off the first attempt and surfaced somewhat flabbergasted, it was only at my second attempt I realized it was actually due to the swim cap. So having to call that one off as well. So after my both failed attempts I got rid of the swim cap and did a quick 50 meters with only my trusted swim goggles and all was fine. Lesson learned 😉

Besides all that I had a great time safetying all other competitors doing very great performances & national records and running around for the live coverage to happen. All in all I’m very pleased with my new prototype and I will shed some light on that with more details in a next post.

Shark Sports: Dynamic Competition

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As you might have read in my previous posts, I am preparing to compete in the Shark Sports dynamic competition, this Saturday in Tongelreep, Eindhoven. I have no set goals for this competition, but I just have to prove my self a minimum I agree upon on the day itself. Furthermore I’ll be swimming with a new prototype for better alignment. In combination with the new monofin we now use, it’s going to be interesting for myself to just compete with the new setup!

Besides the fact of competing I’ll be doing safety as well, gives me a chance to wear my Gara 3000’s again.

Yesterday I’ve been setting up the streaming ability for the camera, which we are going to place behind the window at the 100 meter turn point in the pool. This should deliver a few nice images of competitors making their turn against the window. Hopefully the wireless connection is strong enough to reach that basement the Tongelreep created to view/analyze what athletes are doing underwater.

So if all is proceeding according our plans, than the competition will start at 14:00 CET, this is also the time that the LIVE internet broadcast will start. If you’re unable to join us at the Tongelreep in real life, then surf to I’ll start the first run, so I can do the safety for the other competitors. Hopefully it will be lot’s of fun and good atmosphere, see you all on Saturday 14:00 CET.

First impressions: Waterway Glide vs Leaderfins Flyer Pro

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Last night Jorg and I had the chance to test our new Waterway Glide fin from and it’s hard to not like it instantly. Although I’ve already tested with Daan and Judith’s Glide fin, we now had the chance to properly train some more with it. Although the technique to use for both these fins differs, I’ll try and put down my findings for both monofins independent from the technique used.


Waterway Glide Fin - Freediving
The first difference I noticed between the Leaderfin Flyer Pro and the Waterway Glide is the difference in buoyancy. The Leaderfins monofin has been built with 5 kilograms of lead in the arch, which contributes to the motion by stimulating it by lagging the motion. The Glide fin on the other hand has a positive buoyancy, which stimulates the glide phase by leveling the monofin out horizontally. I experienced the difference in buoyancy by trying to stay balanced through a 25 meter lane run. Where the Flyer Pro tends to start whirling left and right, the Glide seemed to stay at course. I checked with Jorg runs if these findings were also happening to him in the runs, which they did. So either this means, that the Flyer Pro needs more getting used to or more specific strength put into the blade. But out of the box it seems that the Glide does a better job at being balanced.


Leaderfins - Flyer
Leaderfins - Flyer
After swimming with the Flyer Pro I got used to having the weight from the arch help me in swinging the fin around and planting it against the wall quite effortless. But when I tried the Glide for a turn, I noticed that I needed to help out with my arms to swing around and plant the fin on the wall. Now of course this just needs some getting used to turning with the Glide fin, but it was a point which both Jorg and me immediately pointed out after trying it. Next training sessions will have more focus on making proper turns with the Glide, if we want to use it properly and not loose too much energy by pretending to be a bird underwater.

Having a tight fit into the foot pockets is essential with both monofins, to keep the efficiency of the throughput of power into the fin optimal. Both fins go at this a different way and of course in that way it’s not fair to compare these versions. But as we’re giving our first impressions on the difference in these fins, we’ll do it anyway ;).

The Flyer Pro doesn’t really feature an internal profile of a foot, but just a pocket with a tight band around the heel. Where as the glide does feature a more profiled inside pocket, which genuinely has advantages over just having a tight fit like the Flyer Pro. Even though both fins do have a proper tight fit and do not loose a lot of energy that way, the profile in the Glide fin makes it overall more comfortable to swim with.

Overall performance
If I compare the first thing I noticed between the two fins, it’s the fact that I need far less kick cycles to reach 25 meters. Where I use 3 kick cycles or more to reach the 25 meters with the Flyer Pro, I now seemed to be able to reach the other side by only using 2 kick cycles and one arm stroke. This is due to the fact that one fin is a glide fin and the other fin for a continuous motion, but I did want to point it out. As I believe it felt less of a hard performance to reach 50 meters if I compare both fins. Which in the end matters most, because with less energy wasted it will leave you with more distance in the end.

I believe that the Flyer Pro is a very good fin, but it doesn’t work out good the way I seem to be able to utilize it. (Also the reason to put the fin up for sale.) So for the time ahead we will try and optimize the use of the new Waterway Glide fin and I will write a more detailed impression about the experience with the fin when I have been training with the fin for an extended period of time.

Dynamic Exercise: Crawl without Breath

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We’ve had this exercise for quite a while now and I’ll take this opportunity to further explain the crawl without breath exercise, as it’s an exercise which really helps in building endurance levels and also builds confidence for doing dynamic performances.

It’s an idea that we came up with about a year ago when we were in the project 13 schedule, where I had to be able to train on by myself due to circumstances where Jorg would not be able to make it to the pool. The idea is simple, just do a normal crawl like the swimmer do at the surface, but then without breath and we mix it up into a build-up-, exhale- and an endurance schedule.

Build-up schedule (interval)
At first we were unfamiliar with how much and how far we should be alternating the not breathing part in the crawling at the surface. This is how the build-up schedule first originates, we would set out a schedule of 500 meters. Were I would try to do 100 meters of breathing every 6 strokes, where we count a stroke as after both arms had made a full motion. The second 100 meters I’d up it to breathing only every 10 strokes and so on. I gradually got to a point where  I would almost do full lanes of crawl without breath. Although rest times in between the almost full lanes (50m) had to be somewhat longer than at the start of the schedule.

Example schedule:

  1. 2 x 50 meter: breath every 3 strokes
  2. 2 x 50 meter: breath every 5 strokes
  3. 2 x 50 meter: breath every 7 strokes
  4. 2 x 50 meter: breath every 9 strokes
  5. 2 x 50 meter: breath every 11 strokes

Exhale schedule (slowly exhaling)
To mix things up with the static O2 tables, the next step we tested as part of a good training would be a O2 training. Getting rid of the CO2 building up during the lane by slowly exhaling the air within a set amount of arm-strokes.

Example schedule:

  1. 2 x 50 meter: 5 exhales
  2. 2 x 50 meter: 4 exhales
  3. 2 x 50 meter: 3 exhales
  4. 2 x 50 meter: 2 exhales
  5. 2 x 50 meter: 1 exhale
  6. 1 x 50 meter: 0 exhaling

Endurance schedule
This came into play when Jorg got curious into how it would work out if I’d just do a full lane without breath, as we had been upping it since the Build-up schedule, this was a thought we’d both been playing with and this actually would be the next schedule we’d go by, focussed on endurance.

Example schedule:

  1. 2 x 50 meter: 2 minute rest time
  2. 2 x 50 meter: 1 minute 30 seconds rest time
  3. 2 x 50 meter: 1 minute 15 seconds rest time
  4. 2 x 50 meter: 1 minute rest time
  5. 2 x 50 meter: 45 seconds rest time

Maximum attempts
200706_Project13_TrainingAs we were progressing pretty good with this exercise and it was really fun to do as well, Jorg added the mental factor again by letting me push my limits into trying a maximum performance with crawl’s without breath. To be honest at the time it was not really a success for my mental state, but doing a maximum performance of almost 75 meters in crawl was enough to prove it’s a serious exercise.

Looking back at 2009

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Looking back at 2009 shows us that we’ve really gotten the best out of ourselves by finding the roots of our fun for freediving. Both Jorg and I had been searching for this important factor for a while, but it seems we both found it and are very much motivated for a new year of freediving. As Jorg already posted a set of goals for the new year, I need not say more that he’s motivated and ready to go.

Fun & Lessons learned
For myself when I look back at the last year it started out with my search for fun in freediving and I had no real distance and time goals set out. During the search, which lasted from January to about October, I was getting more and more interested in competing again. But as I really wanted to find out if that was really what I wanted, I had to hold myself off from competing. The first part of the year I spent a lot of time relaxing in the water and doing the other stuff I love to do, filming, producing and writing about it. I wrote a lot of “How-to” articles, which are very popular when I check the Google Analytics panel.

In september I could not keep myself from starting project “The Number 23” and thus inscribing to the Wiesbaden competition, which posed as a good marker to see if was capable of competing again. Wiesbaden turned out to be very succesful and I showed myself that I could do statics again without bailing early. Next test on the list was to see if I was able to cope with results that were not as high as I can, but werre still results I could live with as I did my best for them. So I went to Belgium with no high expectations and pure for fun and meeting up with everybody and it turned out I can easily live with performances I did my best for and not as far or long as I should be capable of. A big lesson learned in this year and the start of a new approach.

Furthermore a lot has happened and changed throughout the year, I got my balance for DNF sorted out better, made my first steps into actually competing with a monofin and improved a few monofin personal bests along the way. As I think back of the travelling I’ve done it’s quite a list: Austria Cuba, Belgium, Germany, Scandinavia (Norway, Denmark & Sweden) & Slovenia. Not all of them have been for freediving, but that’s not the point of all my travelling ;).

2010 – This year
We’re on the virge of getting into more monofin training and thourougly testing a Waterway Glide more intensively. This will bring new motivations along and a lot of nice training we’re both looking forward to. My goals are to enjoy freediving with my new mindset and see which distances and times it will bring me. Sounds like a no goal year, but it’s a real goal for me ;). The first test will be on the 23rd or January when is organizing a nice dynamic competition, let’s see what I can do with the Glide monofin.

Even though we had a hick-up on our Google Analytics account, the statistics counting from 2nd half of May to the end of this year shows the trend of our visitor’s Country of origin. In total 4,606 visits came from 102 countries, I’ll post the top 10 countries:

  1. 2009-StatisticsUnited States
  2. Netherlands
  3. United Kingdom
  4. Germany
  5. Poland
  6. Czech Republic
  7. Belgium
  8. Australia
  9. Canada
  10. Spain

The top 5 referring sites, without shark-freediving and social sites like Twitter & Facebook are:


The top 5 Search terms were:

  1. monofin technique
  2. freediving materials
  3. finning technique
  4. wiesbaden aida freediving
  5. freediving mask

Thank you
It’s very motivating to see so many people know and find their way to our site and articles. We really appreciate all the feedback through comments and e-mail. We love answering your questions and continue to do so if they are related to us & freediving that is ;). We plan to continue on this course in 2010 as well. although the start for sharkbait is a bit different, as the website is ported over to the portal and now has a different address: Which had also been the reason for me not to post any stories until the site had been fully ported over into the new environment. If you might spot any irregularities please contact us.

Minor tweaking and getting some distance

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Tonight the freediving training consisted of a small introduction to freediving for a few new divers and the last part we focussed on minor tweaking details and getting some distance with the monofin. So the first 30 minutes we spent learning a few new guys from Scubacity the few basic steps into the world of freediving. They were both highly motivated and looking forward to their next session. Both performed well and will learn a lot in the time to come.

20091203-MonofinFor our own training I had made a few adjustments on the alignment and now things are getting somewhere. Also I had brought along some soap, to make the wearing of the monofin a lot better. Putting it on and getting your feet out of the pockets was so much easier now. Never the less I still think it’s a bit of a strange fin for me to work with. So for today I just wanted to see if the alignment tweak was working, and so far I’m liking it a lot.

Next up was some distance, where I agreed with Jorg just to take it slowly and do somewhere between 3-4 laps. First two laps were focussed and without a problem in technique, but yet again in the 50 – 75 I felt myself speeding up. After the turn into the 4th lap it almost felt like sprinting and the relax-ness was gone, so I surfaced and called it a day at around 95 meters. Very happy with it though, as small steps will get me forward!

Jorg tweaked his alignment a little further as well and did a few good test runs with the monofin. Although everything looked good on the outside, he told me he was not all that relaxed and a little bit too tense… But hey that’s what you get when you go out to the gym and workout your arms just before the freediving session ;). Good job training anyway! Respect, I know how it feels.

Next week I’ll make some adjustements to the aligning again and hopefully I’m able to get it right this time. Stay tuned for more on that topic.