GENDER
DIFFERENCES
IN
STRENGTH
AND
MUSCLE
CHARACTERISTICS
GENDER
DIFFERENCES
IN
STRENGTH
AND
~lliSCLE
FIBER
CHARACTERISTICS
By
ANDREA
ELIZABETH
JANE
MILLER,
B.A.
A
Thesis
Submitt.~d
to
the
School
of
Graduate
Studies
in
Partial
Fulfillment
of
the
Requirements
for
the
Degree
Master
of
Science
McMaster
University
(c)
Copyright
by
Andrea
Elizabeth
Jane
Miller,
December 1990
MASTER
OF
SCIENCE
(1990)
MCMASTER
UNIVERSITY
(Human
Biodynamics)
Hamilton,
Ontario
TITLE:
Gende~
Differences
in
Strength
and Muscle
Fiber
Chara1:teristics
AUTHOR:
Andre.i
Elizabeth
Jane
Miller,
(York
University)
B.A.
SUPERVISOR:
Profe.3sor
J.D.
MacDougall
NUMBER
OF
PAGES:
(xvi)
,145
ii
ABSTRACT
A
gender
difference
in
absolute
muscle
strength
is
well
documented.
The
e'xtent
to
which
quantitative
(fiber
area
and
number)
and
qualitative
(specific
tension)
differences
in
muscle
contribute
to
this
is
not
well
understood.
The
purpose
of
this
study
was
to
examine
a
variety
of
muscle
characteristics
in
the
biceps
brachii
and
vastus
lateralis
in
a
sample
of
males
(n-8)
and
females
(n=8)
with
a
wide
range
of
tJ~aining
histories.
Measurements
included
motor
unit
number,
size
and
activation,
and
voluntary
strength
of
the
elbow
flexors
and
knee
extensors.
Fiber
characteristics
were
determined
from
needle
biopsies
and
muscle
areas
by
computerized
tomographical
scanning.
Females
were
approximately
52%
and
66%
as
strong
as
the
males
in
the
upper
and
lower
body
respectively.
A
significant
(p
:::;
.05)
correlation
was
found
between
strength
and
muscle
cross-sectional
a~ea.
Females
had
45,
41,
30
and
25%
smaller
muscle
cross-sectional
areas
for
the
biceps
brachii,
total
elbow
flexors,
vastus
lateralis
and
total
knee
extensors
respectively
(p
~
.01).
No
significant
gend~r
difference
was
found
in
the
strength
to
cross-sectional
area
ratio
for
elbow
flexion
and
knee
extension.
Males
had
significantly
larger
type
I
fiber
areas
(4597
vs.
3483
2
2
urn
)
and
mean
fiber
areas
(6632
vs.
3963
urn
)
than
females
in
biceps
brachii
(p<.OS)
and
significantly
larger
type
II
fiber
areas
(7700
vs.
4040
wm2)
and
mean
fiber
areas
(7070
vs.
4290
urn2)
in
the
iii
vastus
lateralis
(p~.05).
The
difference
in
type
II
fiber
area
in
the
biceps
brachii
was
not
statistically
significant
despite
the
fact
that
these
fibers
were
almost
twice
as
large
in
the
males
as
in
2
the
females
(8207
vs.
4306
urn).
No
significant
gender
difference
was
found
in
biceps
fiber
number
(180,620
vs.l56,872)
or
muscle
area
to
fiber
area
ratio
in
the
vastus
lateralis
(451,468
vs.
465,007).
No
significant
gender
differences
were
found
in
any
of
the
motor
unit
characteristics.
The
results
indicate
that
the
primary
determinant
of
the
greater
muscle
strength
of
males
is
their
larger
mean
fiber
areas
which
results
in
greater
muscle
cross-sectional
areas.
iv
