Treading water for 10 minutes - how hard can it be?

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

RJP

Contributor
Scuba Instructor
Divemaster
Messages
13,460
Reaction score
5,929
Location
New Jersey
# of dives
1000 - 2499
Decided to split this post off as a new thread. It was originally intended to be a reply to another where there was discussion about how hard it is to tread water for 10min, whether some people are inately negatively buoyant, etc. My position in that thread was two-fold:

  1. It's nearly impossible for a human with air in their lungs to be negatively bouyant, certainly not SIGNIFICANTLY so
  2. Ultimately, anyone can float/tread for 10min with no problem at all
Based on this previous thread, I decided to conduct an "n=1" observational study while I was in the pool at my gym this morning. For background, I'm 6'2" and 170lbs. Not a "greek god" by any stretch of the imagination but as someone who bikes >5,000mi a year and swims 1.5-2.0mi three times a week I have a fairly low body fat percentage, so I'm not a "floater" at all.

After my morning swim of 3,000m (so I was good and tired) I swam out to the deep end and tried to float. Laying on my back with a normal, full breath my feet sank under me. As I settled in to a vertical position I was able to float with my head tilted back so that my chin, mouth, nose, and ears were out of the water. By controlling my breathing I was able to float this way for 10min without any sculling/kicking at all - arms crossed at my chest, legs crossed at my ankles. This was at 6am this morning. I could easily still be there floating motionless now if I wanted to be.

Next I tried to manage keeping my head above water in this same position with my lungs empty. I wanted to see how much effort was required to make up for not having the benefit of the buoyancy of the air in my lungs. From a motionless vertical position I exhaled completely and, as one would expect, I sank to the bottom. I came back to the surface and attempted to stay there with lungs mostly empty by managing my breathing the OPPOSITE as when I was floating motionless - inhaling/exhaling quickly and holding my breath OUT. As I was negatively buoyant at this point, it was going to be necessary to move my arms and/or legs to stay at the surface. However, I didn't need to do very much. I was able to keep my entire head above the surface with VERY little effort. I kept my ankles crossed and merely sculled my hands/arms slowly, every few seconds. I did this for 10min with no problem at all... could have done it for an hour or more.

So I found that a person with little body fat with full lungs needed ZERO effort to remain at the surface, and with empty lungs needed very little effort to do so. However, this next exercise was the interesting part...

For my final try, I attempted to keep my head above the surface by kicking my feet and sculling with my hands and arms. I didn't utilize my breathing to control my buoyancy, but simply breathed as needed to support the level of physical activity in which I was engaged. I didn't do this in "frantic mode" but did try to move with the same level of vigor with which we see the typical OW student conduct their tread. I was completly surprised at how very strenuous - and largely innefective - this approach was in keeping my head above water. And, it got worse as time went on. As I started to get fatigued my breathing became labored, my kicking and sculling became less effective, and I had to work harder at keeping my head above water and/or hold my breath briefly as my mouth/nose ocassionaly dipped under the surface. It was a vicious cycle. Completing the task was not impossible, but I was genuinely glad when the 10min was up. This approach was not only much harder than either of the other two, and not only far less effective at keeping my head abover water... it actually seemed to pull me UNDER the water as much as it kept me above the water.

So, it occurs to me that it's unfortunate that we ask students to do their tread at the BEGINNING of the course... long before we ever give them any information about how to control their buoyancy with their lungs or convey the importance/efficiency of economy of movement.

Does anyone actually demonstrate this "skill" prior to asking students to do it? I know I'm going to start doing so!

Ray
 
I am currently about 160 lbs and 16% body fat.

I was out at Lake George last week snorkeling. Wearing a 3mm shorty, 5mm neoprene booties, Cressi Frog fins, a mask, and a snorkel, I took a deep breath at the surface and stopped moving.

I sank straight down. Touched the bottom, with 3 feet of water over my head. It wasn't even slow.

Not everyone's physiology is the same as yours.

Also, with a full-body 5/4/3, a 5mm hood, 5mm gloves, 6lb backplate and *empty* (as in, 100 psi) double Catalina 80s, I sink like a stone with an empty wing.
 


  1. It's nearly impossible for a human with air in their lungs to be negatively bouyant, certainly not SIGNIFICANTLY so
  2. Ultimately, anyone can float/tread for 10min with no problem at all

Not if the person is uncomfortable in the water. The tests are not really for swimming or treading water. They do demonstrate a minimal level of comfort in the water.




---------- Post Merged at 01:54 PM ---------- Previous Post was at 01:53 PM ----------

I am currently about 160 lbs and 16% body fat.

I was out at Lake George last week snorkeling. Wearing a 3mm shorty, 5mm neoprene booties, Cressi Frog fins, a mask, and a snorkel, I took a deep breath at the surface and stopped moving.

I sank straight down. Touched the bottom, with 3 feet of water over my head. It wasn't even slow.

Not everyone's physiology is the same as yours.

Also, with a full-body 5/4/3, a 5mm hood, 5mm gloves, 6lb backplate and *empty* (as in, 100 psi) double Catalina 80s, I sink like a stone with an empty wing.

How was your body fat measured?
 
I am currently about 160 lbs and 16% body fat.

I was out at Lake George last week snorkeling. Wearing a 3mm shorty, 5mm neoprene booties, Cressi Frog fins, a mask, and a snorkel, I took a deep breath at the surface and stopped moving.

I sank straight down. Touched the bottom, with 3 feet of water over my head. It wasn't even slow.

Not everyone's physiology is the same as yours.

Also, with a full-body 5/4/3, a 5mm hood, 5mm gloves, 6lb backplate and *empty* (as in, 100 psi) double Catalina 80s, I sink like a stone with an empty wing.

Doesn't that mean your over weighted then? Why not switch to a lighter backplate?
 
Doesn't that mean your over weighted then? Why not switch to a lighter backplate?

I'm thinking about it. I have an Al plate somewhere that I might switch to. I probably shouldn't have said "like a stone," as I had to exhale a bit to start sinking at the surface with the tanks so empty.

Then again, I just got a 3mm hooded vest to replace the hood so I'll probably just stick with the SS plate. I can swim the whole thing up no problem at 60' and full tanks, so I'm not worried about it.
 
This is a basic part of the swim test I have done 100's (probably 1000's) of times with scouts. Even the skinny 11y/o scouts can float.

My view was it's not a test, is a simple lesson for the boys to relearn every year that if you don't panic, you can float until you someone rescues you or you swim your way out of the problem. You can tell people this all day long, but making them prove it to themselves is better and more likely to sink in (I know, bad pun).
 
I'm thinking about it. I have an Al plate somewhere that I might switch to. I probably shouldn't have said "like a stone," as I had to exhale a bit to start sinking at the surface with the tanks so empty.

Then again, I just got a 3mm hooded vest to replace the hood so I'll probably just stick with the SS plate. I can swim the whole thing up no problem at 60' and full tanks, so I'm not worried about it.

I dive a SS BP/W these days ( if you remember me from the old days... go figure... ) and it seems locked on for 5/3 3/2 suit with no extra weight. But when I ditch the suit and go skin I'm clearly overweighted. Still, I'm not sure I really want to have 2 (partial) rigs. I tend to just suit up and head for the thermocline ASAP.

Yes, I can swim it up also. But I just love how it feels when you don't have to put much air in the wing.
 
I can tread water for 10 minutes and am very comfortable in the water. No matter how relaxed I am, no matter how deep a breath I take, if I stop moving in fresh water, I go straight down. In salt, I can almost float, almost. There are all kinds of factors that effect this from bone density to muscle mass.
 
I'm a sinker. It annoys me, but it's reality. The only place i've been able to float is in the mediterranean sea, which has higher salt content. It annoys me that people can just float effortlessly - if I stop moving, I sink.
 
https://www.shearwater.com/products/perdix-ai/

Back
Top Bottom