relation between body fat and speed

relation between body fat and speed

Post by Paul Big-Ears Men » Sun, 30 Jan 1994 10:46:23


    >I am swimming for fitness and because I have discovered I just love it!  
    >I am overweight quite a bit, and my present body fat is about 35%.   I've
    >worked a lot on endurance and technique, but I wonder if anybody can tell
    >me if, as I reach my goal of about 25% body fat, I will swim faster?  In
    >other words, is there a relationship between proportion of body that is
    >fat and ability to swim fast, holding constant technique, etc.?  

Yup, the more fat you have, the better you float.  If you have the same
strength and technique at 25% as you do at 35%, in general, you'll find it more
"challenging" to keep up with your 35% performance.  Sorta contrary to the
idea of losing fat, isn't it?

Take it from someone has under 5% body fat. Otherwise known to to have all
the swimming characteristics of a brick!!!!

  Paul Menon,
  Dept of Computer Science,
  Royal Melbourne Institute of Technology,
  124 Latrobe Street,
  Melbourne 3001,
  Victoria, Australia.

ph:    +61 3 660 3209/2348
fax:   +61 3 662 1617

 
 
 

relation between body fat and speed

Post by Santa Traugo » Sat, 29 Jan 1994 21:50:55

I am swimming for fitness and because I have discovered I just love it!  I am
overweight quite a bit, and my present body fat is about 35%.   I've worked a
lot on endurance and technique, but I wonder if anybody can tell me if, as I
reach my goal of about 25% body fat, I will swim faster?  In other words, is
there a relationship between proportion of body that is fat and ability to
swim fast, holding constant technique, etc.?  

 
 
 

relation between body fat and speed

Post by St » Mon, 31 Jan 1994 03:51:13


Quote:
Big-Ears Menon) writes:
>Yup, the more fat you have, the better you float.  

 And the more weight you have to drag through the water.  You have to put
more kinetic energy into dragging yourself through the water (KE=1/2mv^2 for
all you physicists out there).   More body size and thus resistance as
well.  Fat, which takes up so much space for its weight, expecially
increases your surface area
 If you have less body fat than you usually do, then you're in good shape.  
The actual percentage of fat that means "in shape" varies from person to
person, but it's being in shape for you that correlates to swimming fast.  

Quote:
>Take it from someone has under 5% body fat. Otherwise known to to have all
>the swimming characteristics of a brick!!!!

I hope you have arms and legs to swim with, I don't think a brick does.  A
hydroplane doesn't exactly float unless it's standing still, but it's a hell
of a lot faster than other boats of comparable size (or bigger!) which
just float.  Take it from someone with the same body fat who does not swim
like a brick (certainly no Olympics in my future, but I'm not a complete
slacker).

Steve-O

--
If your ship hasn't come in, swim out to it!

 
 
 

relation between body fat and speed

Post by Rich Randol » Mon, 31 Jan 1994 00:54:40



Quote:

>    >I am swimming for fitness and because I have discovered I just love it!  
>    >I am overweight quite a bit, and my present body fat is about 35%.   I've
>    >worked a lot on endurance and technique, but I wonder if anybody can tell
>    >me if, as I reach my goal of about 25% body fat, I will swim faster?  In
>    >other words, is there a relationship between proportion of body that is
>    >fat and ability to swim fast, holding constant technique, etc.?  

>Yup, the more fat you have, the better you float.  If you have the same
>strength and technique at 25% as you do at 35%, in general, you'll find it more
>"challenging" to keep up with your 35% performance.  Sorta contrary to the
>idea of losing fat, isn't it?

    I don't know about that. Floating is *NOT* swimming! The forward motion
in swimming is the result of the resolution of a number of forces and buoyancy
is just one of them.

    Generally speaking if your percentage of body fat drops as a result of
hard training you will get stronger and sleeker and faster. Go for it!

 
 
 

relation between body fat and speed

Post by Ed Whit » Mon, 31 Jan 1994 07:16:42

Quote:

>  And the more weight you have to drag through the water.  You have
to put
> more kinetic energy into dragging yourself through the water
(KE=1/2mv^2 for
> all you physicists out there)....

Actually Steve-O, it's stopping all the extra weight and restarting
it at each wall that takes a lot of energy.  The lighter you are,
the lower the change in momentum at each turn.  Take it from a not
light
enough miler...

Ed.

 
 
 

relation between body fat and speed

Post by Mark D Willia » Wed, 02 Feb 1994 12:01:12

Quote:




>>Yup, the more fat you have, the better you float.  If you have the same
>>strength and technique at 25% as you do at 35%, in general, you'll find it more
>>"challenging" to keep up with your 35% performance.  Sorta contrary to the
>>idea of losing fat, isn't it?

>HUH ?!?!  Are you saying that you will swim better at 35% body fat than 25%?
>I think you better try again.  While fat *may* provide better buoyancy (bouyancy
>also has to do with muscle/bone density and lung capacity), fat *does* provide
>drag!  Drag is what you _don't_ want in swimming.  The more drag you have, the
>harder you are going to have to work to get from end of the pool to the other.
>If you want an analogy, put a 150 hp engine in a 4000lb vehicle and run a 1/4
>mile.  Now put the same engine in a 2500lb vehicle and run a 1/4 mile.  Which
>do you think will be faster (provided aerodynamics, gearing, tires, etc) are
>the same?  

Strictly speaking, this analogy is misleading. True, the more drag you have,
the harder it is to get from one end of the pool to the other. However, you
are suggesting that given equal amounts of power output, for different
masses,  you are doing different amounts of work to go the same distance.
Work = (Force)*(Distance). Now, since this is horizontal work (i.e. our
force acting through a distance is a horizontal distance, not the vertical distance which would be relevant if we were considering object mass) the force
to consider is not the weight of the objects, but the force needed
to maintain a constant velocity against the internal friction of wheels,
bearings, etc. and the force needed to maintain a constant velocity against
aerodynamic drag. Now, according to fluid mechanics:

Drag Force = 1/2 * (fluid density) * (Velocity)^2 * (Drag Coefficient) * (X-sectional area)

Since you have stated that aerodynamics, gearing, tires, etc are all the same,
this would imply that the drag force for the two vehicles is the same, and
therefore the work done will be the same, regardless of their mass, if they
maintain constant velocity over the 1/4 mile, because, according to
the above equation, with same drag coefficient, and cross sectional area,
since the two vehicles are the same in all respects except for their mass,
they will have the same drag force to fight and therefore will do the
same amount of work (i.e. Drag Force * (1/4 Mile). )

However, if we look at the drag force equation, for the same velocity,
and fluid density (obviously we all swim in water), we will presumably
have a larger drag coefficient, and cross-sectional area if we have
more body fat--we are presumably rounder! :-) and therefore, the
drag force should be greater if we have more body fat, and we will do more
work. Same answer, different method! Phew....

Mark D. Williams

------------------------------
My opinions reflect those of no one but
myself. So there.

 
 
 

relation between body fat and speed

Post by Kevin Wagn » Wed, 02 Feb 1994 00:52:48



Quote:

>    >I am swimming for fitness and because I have discovered I just love it!  
>    >I am overweight quite a bit, and my present body fat is about 35%.   I've
>    >worked a lot on endurance and technique, but I wonder if anybody can tell
>    >me if, as I reach my goal of about 25% body fat, I will swim faster?  In
>    >other words, is there a relationship between proportion of body that is
>    >fat and ability to swim fast, holding constant technique, etc.?  

>Yup, the more fat you have, the better you float.  If you have the same
>strength and technique at 25% as you do at 35%, in general, you'll find it more
>"challenging" to keep up with your 35% performance.  Sorta contrary to the
>idea of losing fat, isn't it?

HUH ?!?!  Are you saying that you will swim better at 35% body fat than 25%?
I think you better try again.  While fat *may* provide better buoyancy (bouyancy
also has to do with muscle/bone density and lung capacity), fat *does* provide
drag!  Drag is what you _don't_ want in swimming.  The more drag you have, the
harder you are going to have to work to get from end of the pool to the other.
If you want an analogy, put a 150 hp engine in a 4000lb vehicle and run a 1/4
mile.  Now put the same engine in a 2500lb vehicle and run a 1/4 mile.  Which
do you think will be faster (provided aerodynamics, gearing, tires, etc) are
the same?  In addition, the bouyancy argument doesn't hold much water (no pun
intended) because you should be generating your own lift from your swimming
stroke.  Also, the less weight you have, the more energy that can be distributed
to the heart, lungs, and muscles that are doing the actual work.  NOT the fatty
tissue that is just laying there creating drag.

Unless you plan on swimming *** in the Artic Ocean, the extra body fat is
not going to do you any good.

Quote:

>Take it from someone has under 5% body fat. Otherwise known to to have all
>the swimming characteristics of a brick!!!!

Take it from me, 6% body fat *and* 16 years competitive experience.

Kevin Wagner
Engineer
Cadence Design Systems & Kansas Swimming, 1987-1991

 
 
 

relation between body fat and speed

Post by St » Wed, 02 Feb 1994 14:04:55

WOOWOOWOOWOOWOOWOOWOOWOOWOOOWOOOWOOWOOWOOWOO...

<Physics police pull up and step out of hovercraft>


arizona.edu (Mark D Williams) writes:

Quote:
>Strictly speaking, this analogy is misleading. True, the more drag you have,
>the harder it is to get from one end of the pool to the other. However, you
>are suggesting that given equal amounts of power output, for different
>masses,  you are doing different amounts of work to go the same distance.
>Work = (Force)*(Distance).

<the ***come out>

This is inadequate to even begin to describe the complex motion of swimming
and the work you do.  In ***stroke you accelerate and decelerate quite a
bit.  Efficiency of *** flow at differing fat levels is a consideration.
Even the mass of swinging arms and kicking legs comes into play.

Quote:
>Now, since this is horizontal work (i.e. our
>force acting through a distance is a horizontal distance, not the vertical
>distance which would be relevant if we were considering object mass)

<the rights are read..."You have the right to a calculator...anything you
scribble can and will be used against you on the quiz...">

What about up+down motion of ***stroke and fly?  The torsional motion of
freestyle and arm movement?

Quote:
>the force to consider is not the weight of the objects, but the force
>needed to maintain a constant velocity against the internal friction of
>wheels, bearings, etc. and the force needed to maintain a constant velocity
>against aerodynamic drag. Now, according to fluid mechanics:
>Drag Force = 1/2 * (fluid density) * (Velocity)^2 * (Drag Coefficient) * (X-
>sectional area)

<the prisoner is dragged away to the mad scientist's asylum to await trial>

This would be nice if (Velocity)^2 were a nice, constant term.  No one has
ever developed a very good mathematical model for such complex and variant
human locomotion, especially immersed in a fluid.  Don't try to simplify it
like this.  

Quote:
>Since you have stated that aerodynamics, gearing, tires, etc are all the
same,
>this would imply that the drag force for the two vehicles is the same, and
>therefore the work done will be the same, regardless of their mass, if they
>maintain constant velocity over the 1/4 mile, because, according to
>the above equation, with same drag coefficient, and cross sectional area,
>since the two vehicles are the same in all respects except for their mass,
>they will have the same drag force to fight and therefore will do the
>same amount of work (i.e. Drag Force * (1/4 Mile). )

<the death penalty is recommended>

Well, it's about cars but I'll go for it anyway.  It still takes less work
to move a lighter car 1/4 mile with the same drag coefficients and such
because of a non-constant velocity (you begin at the starting line and start
at the wall at V=0, to keep the analogy with swimming).  The difference in
what the engine can put out will be made up in a faster time between the
markers (less time for the engine to put a chunk of energy, thus a
smaller chunk).  The reason is that the lighter car will accelerate to its
maximum velocity faster than the heavy one.  There's a certain amount of
energy that has to go into the car itself in the form of kinetic energy
(1/2mV^2), and the rest goes into fighting drag.  Car races can be won
and lost in getting out of the pits and accelerating to maximum velocity
right after turns, if they're the same on the straightaways.  Kind of like
swimming, where you can beat an equal-speed swimmer on the strength of
starts and turns.

Quote:
>However, if we look at the drag force equation, for the same velocity,
>and fluid density (obviously we all swim in water), we will presumably
>have a larger drag coefficient, and cross-sectional area if we have
>more body fat--we are presumably rounder! :-) and therefore, the
>drag force should be greater if we have more body fat, and we will do more
>work. Same answer, different method! Phew....

<sentence...20 years to life...>

I still agree that higher body fat (which just means you're out of shape)
means slower swimming.  The question of swimmers with a naturally high body
fat level being better swimmers seems answered by statistics, it's not
so.  In general, it's OK to say that it's harder to move a large
object through water.  It takes more energy to displace the water that the
object moves through.  The energy lost in actual drag on the body is poorly
understood when the body is going through such a complicated motion.  Even
the drag coefficient term can change in seconds if you break out in a sweat
on the blocks.  I think everyone without a few paralell crays should leave
the drag stuff alone (I certainly won't touch it).

Steve-O  (if you're a *physicist* and you think I screwed up, then correct
        me!)

--
If your ship hasn't come in, swim out to it!

 
 
 

relation between body fat and speed

Post by Mark D. Willia » Thu, 03 Feb 1994 01:13:52

Quote:

>WOOWOOWOOWOOWOOWOOWOOWOOWOOOWOOOWOOWOOWOOWOO...

><Physics police pull up and step out of hovercraft>


>arizona.edu (Mark D Williams) writes:
>>Strictly speaking, this analogy is misleading. True, the more drag you have,

><the ***come out>

>This is inadequate to even begin to describe the complex motion of swimming
>and the work you do.  In ***stroke you accelerate and decelerate quite a
>bit.  Efficiency of *** flow at differing fat levels is a consideration.
>Even the mass of swinging arms and kicking legs comes into play.

This is inadequate to describe the complex motion of swimming? Yes, of
course it is. But unless we want to run some computational models on
a Cray, the best we can do is make some (over)-simplifications, and
try to draw some conclusions from them. Strictly speaking, the car
analogy _was_ somewhat misleading.

And the car analogy is not somewhat inadequate to help describe the
complex motion of swimming?

Quote:
><the rights are read..."You have the right to a calculator...anything you
>scribble can and will be used against you on the quiz...">
>What about up+down motion of ***stroke and fly?  The torsional motion of
>freestyle and arm movement?

Again, an admitted over-simplification.

Quote:
><the prisoner is dragged away to the mad scientist's asylum to await trial>
>This would be nice if (Velocity)^2 were a nice, constant term.  No one has
>ever developed a very good mathematical model for such complex and variant
>human locomotion, especially immersed in a fluid.  Don't try to simplify it
>like this.  

You'll note that in my post I added the caveat of constant velocity
over the 1/4 mile. Yes, another over-simplification. Of course swimming
involves acceleration and deceleration.

OK, fine. Don't simplify it like this. Well, then I suppose anyone
that wants to make any assertions about this topic had better
start writing the grant proposals, because we expect full numerical
and theoretical rigor in this newsgroup.

Quote:
><the death penalty is recommended>
>The reason is that the lighter car will accelerate to its
>maximum velocity faster than the heavy one.  There's a certain amount of
>energy that has to go into the car itself in the form of kinetic energy
>(1/2mV^2), and the rest goes into fighting drag.  Car races can be won
>and lost in getting out of the pits and accelerating to maximum velocity
>right after turns, if they're the same on the straightaways.  Kind of like
>swimming, where you can beat an equal-speed swimmer on the strength of
>starts and turns.

Again, You'll note that in my posting, I said for _constant_ velocity over the
1/4 mile. You throw acceleration into the picture, and everything is
different. Yes, another _over_-simplification.

Quote:
><sentence...20 years to life...>
>I think everyone without a few paralell crays should leave
>the drag stuff alone (I certainly won't touch it).

Right on. No more postings on this topic, you hear?! (Unless of course,
you have those parallel crays fired up).

Quote:
>Steve-O  (if you're a *physicist* and you think I screwed up, then correct
>        me!)

How could I have been so presumptuous.

Mark D. Williams

-------------------------------
My opinions reflect those of
no one but myself. So there.