I was playing in the water today. With a full breath and not moving the water level was at my eyeballs. Not below them either. At them. It did not take much exhaling to go totally under. A full exhale and I sunk like a stone. There is no way I can do any breathing without doing some work to stay a bit high.
I am about 25 pounds heavier than I was in high school and college and in my 20’s. And all the weight gain has NOT been due to working out. I am in way worse shape now and most of that gain is probably fat, not muscle.
I float incredibly, I cannot dive in fact. I had a swim instructer just shrug eventually and admit yes without weights I cannot submerge or go to the bottom. They didn’t believe it at first, and I’m not “fat” at all it is just that despite looking normal my body is mostly fat in a normal person shape.
I’m not sure what you mean. One poster has low body fat and sinks. The other has high body fat and floats extraordinarily well. What’s there to reconcile?
That’s enough of an explanation. Even expert swimmers can’t outswim a rip current if they don’t know that they’re supposed to swim parallel to the shore to get out of it. The hazards of rip currents (and how to mitigate those hazards) are well-publicized nowadays - it seems to pop up on the evening news with annoying frequency - and yet people still drown in them on a distressingly regular basis. It’s not surprising at all that an expert swimmer would succumb to a rip current in the 1960’s, when the hazard was far less well-publicized.
The human body is mostly water, so on the average the density of the human body is pretty close to water… but not exactly that of water. If your average body density is equal to the density of water, you’ll be neutrally buoyant. If less, you’re positively buoyant. If greater, negatively buoyant.
Since average body density is so close to that of water anyway, slight differences in physiology between individuals can have a dramatic effect on how buoyant they are. The same person can have his buoyancy change by changes in his body – I’m slightly more buoyant now than I was as a teen, less so than when I was 60+ lbs overweight.
If you’re an indifferent swimmer, your body’s innate buoyancy is going to control how you float. Very buoyant people struggle to submerge. Others struggle to stay afloat. But the visible difference between the two people may be slight, since it basically comes down to the ratio of bone/muscle/fat each has.
This may not match your experience. That is the problem everyone always has in these swimming threads – they can’t understand that what they have experienced is not universally applicable. You may be able to float effortlessly. Some people cannot.
I’m still not getting it. More dense means less fat. Those people who are denser (more muscular) do not float well. Those that are less dense (fatty) float easily.
The trick is floating with your head at the top though.
Some people never get a chance to go to a pool long enough to learn this stuff as kids. Even if they do, you have to learn it in water over your head. Many pools now don’t even have deep ends, so kids aren’t going to learn this as often.
Yep. And percentage body fat estimations used to be made using a formula called the Siri equation:
% BF = (495 / p) - 450.
with p being the average body density measured in grams per cm[sup]3[/sup]. The numbers I have heard is that lean muscle mass is 1.1 g/cm[sup]3[/sup] and 0.9 g/cm[sup]3[/sup], which would make that equation work out exactly right on those ends of the scale (i.e., insert 1.1 for p and get a BF% of 0%; insert 0.9 and get 100%.) There are other equations that are more fine-tuned. (The Mrozek equation, for instance, uses 457 and 414.2 as the numbers.)
At any rate, it’s the relationship here that’s important. As body fat percentage goes up, average density goes down.
True enough. And I withdraw my assertion that everyone floats.
I was thinking about this thread on Saturday when I was swimming. I tried floating on my stomach with my head above water. Couldn’t do it without at least a little treading motion in my hands. And this was in salt water, and I have one of those sexy, bouyant bodies.
Jamie, when I was lean enough to sink, by far the greatest amount of lean mass was in my legs. Think thighs like Eric Heiden in his prime. I had to buy jeans several inches large in the waste in order to get my legs into them.
On a lean human, most of the stuff that is less dense than water (so provides flotation) is in the torso. The lungs of course are full (or can be made full) of air, but the stomach and intestines usually contain enough gas bubbles to provide some boyancy, and brains and other organs are fatty enough to also be slightly boyant. Women, to one degree or another, have fatty-floaty bits on thier chests and hips. Men tend to have more fat on and in thier gut, and we all can carry a bit of fat even inside our bones (yellow marrow).
Anyway, my point is that the fact that your legs are atrophied may make you more boyant as a whole, because the lean muscle that isn’t there would have been heavier than water.
No, I wasn’t suggesting that fat was more dense than muscle, rather that the overall density of those who are “fat” is greater than that of those who are lean and muscular. Because they simply have more mass. So more ‘massive’ not more dense. My bad.