Hi, this is Dr. Dale Wagner, an Exercise Physiologist
in the Human Performance division of Exercise Science
at Utah State University.
We're here today to do a body composition measurement.
We're going to be using skin folds for this measurement.
Skin fold is a field method technique.
It's a small device, we can take it with us anywhere.
So that's one of the big advantages of skin fold.
It's a portable instrument.
Also, fairly low cost, relative to the other instruments
that we have.
A good set of skin full calipers might run about $250.
So relatively inexpensive, compared
to some of our laboratory methods which might be $40,000.
On the skin fold measurement, what we're really doing here
is we're measuring the subcutaneous fat, that's
the fat right underneath the skin.
And a double fold of skin.
So we're going to take a pinch, and in that pinch,
there's going to be a double layer of skin
and the underlying fat that's caught between that skin.
Based on that information, based on the subcutaneous fat
that we get, we're making an estimate or prediction
about total body fat.
There's a variety of sites to take.
I'm just going to show you one site, so that you get the idea.
So we're going to do a measurement on the tricep site.
So we're going to measure the right side of the body.
And so I'm going to take a measurement.
It's always good to have good anatomical locations here.
So let's go to the right arm, and we're
going to take a measurement on the tricep so the back
of the arm.
So my anatomical landmarks for the tricep
are midweight between the acromion
process on the shoulder, and the olecranon process on the elbow.
So I'm going to find the acromion
process despite feeling for the end of the bone.
And can you bend your arm at 90 degrees for me?
Makes it easy to find the olecranon process.
And so I'm going to go midway between there.
And so for her, that's right there.
I want to be on the back of her arm,
so I just take my tape measure around
to the back to make sure I'm in the right location.
And then I'm going to put a little mark
so that I know the spot that I want to measure.
From here, I'm going to put my fingers just about a centimeter
above that mark.
I'm going to take a fairly wide pinch,
I'm going to pinch and pull.
And as I pull, the muscle is going
to sink back down into the bone, and I'm just
going to be left with subcutaneous fat
and the double fold of skin.
Just relax your arm.
So I'm going to pinch and pull.
I'm left with my fold and I put the calipers right
below my fingers.
And I wait for about three seconds
before I read the dial on the caliper.
And that's it.
That's all there is to skin folds.
And then we would do a multiple set of sites.
There's a variety of equations, there's
a lot of different equations.
Some equations are what we call generalized equations.
Therefore, they're based on a large age range of people,
maybe 18 to 65 or so.
Then we have other equations that are very specific.
For example, we have a female athlete equation, which
we might use on this subject.
The important thing is to use the right equation
for your client.
There's a variety of skin fold sites.
Some common typical sites would be the triceps
like I just did here.
An abdomen, super iliac, thigh.
They're also very common skin fold sites.
Again the advantages here, it's a low cost field method,
small, portable.
The disadvantage is it requires a certain amount of technique,
a certain amount of skill, takes quite a bit of practice
in order to be able to become competent in using
the correct anatomical landmarks and pinching
with the right amount of force, in order
to get an accurate measurement.