Re: Hyperplasia (was Failure's findings)

[Guest guest]

> From: " Brad Schoenfeld " <highnrg123@...>

>

> Several studies have shown that bodybuilders have a greater number of

> fibers than control groups. Some have hypothesized that this may be

> related to hyperplasia (1). But since the studies didn't take fiber

> counts prior to the start of an exercise program, the results are

> rather nebulous as to whether training actually increased fiber

> number (resulted in hyperplasia) or is simply a function of genetics.

> is perhaps the leading research proponent of training-induced

> hyperplasia and has published on the subject (2).

>

> One study that I found did look at the fiber characteristics between

> powerlifters, bodybuilders and a control group (3). From what I can

> gather (I was only able to pull the abstract), the bodybuilders and

> powerlifters both had greater fiber number than the control group.

I do not have these papers that you reference. I am curious, did these

authors control for the angle of pennation of fibers? One of the problems

with taking a biopsy and counting fibers per area is that simple changes in

the angle of pennation of fibers can make hyperplasia appear to occur.

Bodybuilders have huge muscles, and this hypertrophy is going to be

accompanied by changes in the angle of pennation of fibers. Thus, a cross

section of muscle of a particular size will appear to have more fibers than

a control group. I also heard of a paper once that showed that bodybuilders

did not have larger fibers than controls. Again, though, you have the same

problem. A simple change in the angle of pennation of a fiber may make it

appear that hypertrophy has not occurred even though it has. It's like

taking a paper towel cardboard tube and looking at it down the center. If

you tilt the tube, the diameter of the opening will appear to get

smaller...if you increased the diameter of the opening it would appear that

there was no change compared to when you were looking at it down the center.

I am of the stance that hyperplasia does not occur in humans. One must

remember that, unlike some types of animals where hyperplasia has been

demonstrated to occur, human muscle fibers are not multi-innervated. Thus,

if a fiber divides, one of those fibers has no innervation. In animals

where hyperplasia has been shown, fibers are multi-innervated. Thus, if a

fiber splits, each fiber can be separately innervated.

Here is an interesting story. Gonyea, who Dr. studied under, is

famous for his animal hyperplasia research. However, the late Phil

Gollnick, one of the godfathers of exercise physiology who was at this

university and who my major professor studied under, criticized Gonyea for

his early animal hyperplasia studies for the lack of control of angle of

pennation. It's interesting how your teachers can influence you. I think

that Gonyea believes hyperplasia occurs in humans, and I know Dr.

does. However, Gollnick was adamant that it doesn't, and his graduate

student, my major professor Sally Blank, also contends that it doesn't. Of

course, now it's been passed down to me and I contend that it doesn't as

well.

Krieger

Graduate student, exercise science

Washington State University

" Our greatest glory is not in never failing, but in rising up every time we

fail. " - Ralph Waldo Emerson

[Guest guest]

> > From: " Brad Schoenfeld " <highnrg123@a...>

> >

> > Several studies have shown that bodybuilders have a greater

number of

> > fibers than control groups. Some have hypothesized that this may

be

> > related to hyperplasia (1). But since the studies didn't take

fiber

> > counts prior to the start of an exercise program, the results are

> > rather nebulous as to whether training actually increased fiber

> > number (resulted in hyperplasia) or is simply a function of

genetics.

> > is perhaps the leading research proponent of training-

induced

> > hyperplasia and has published on the subject (2).

> >

> > One study that I found did look at the fiber characteristics

between

> > powerlifters, bodybuilders and a control group (3). From what I

can

> > gather (I was only able to pull the abstract), the bodybuilders

and

> > powerlifters both had greater fiber number than the control group.

>

>

> I do not have these papers that you reference. I am curious, did

these

> authors control for the angle of pennation of fibers? One of the

problems

> with taking a biopsy and counting fibers per area is that simple

changes in

> the angle of pennation of fibers can make hyperplasia appear to

occur.

> Bodybuilders have huge muscles, and this hypertrophy is going to be

> accompanied by changes in the angle of pennation of fibers. Thus,

a cross

> section of muscle of a particular size will appear to have more

fibers than

> a control group. I also heard of a paper once that showed that

bodybuilders

> did not have larger fibers than controls. Again, though, you have

the same

> problem. A simple change in the angle of pennation of a fiber may

make it

> appear that hypertrophy has not occurred even though it has. It's

like

> taking a paper towel cardboard tube and looking at it down the

center. If

> you tilt the tube, the diameter of the opening will appear to get

> smaller...if you increased the diameter of the opening it would

appear that

> there was no change compared to when you were looking at it down

the center.

> I am of the stance that hyperplasia does not occur in humans. One

must

> remember that, unlike some types of animals where hyperplasia has

been

> demonstrated to occur, human muscle fibers are not multi-

innervated. Thus,

> if a fiber divides, one of those fibers has no innervation. In

animals

> where hyperplasia has been shown, fibers are multi-innervated.

Thus, if a

> fiber splits, each fiber can be separately innervated.

>

I only have the abstracts to these studies. I saved them from an

article that I wrote several years ago that dealt indirectly with the

topic. Unfortunately, the abstracts don't account for the

methodology used. But you make an excellent point. Kawakami

performed a study that showed bodybuilders had significantly greater

pennation angles than controls so this definitely can be a problem if

not accounted for.

I too am skeptical that hyperplasia does exist in humans (although it

is fairly conclusive that it does take place in animals). I wondered

the same thing as to how, if it does take place, the fiber would be

innervated. I can't imagine that neural hyperplasia would accompany

the phenomenon. I'd be interested if anyone has a hypothesis about

this?

Brad Schoenfeld, CSCS