L. R.
Brilla,
Western
Washington
University,
Bellingham,
WA
98225,
and
V.
Conte,
BALCO
Laboratories,
Burlingame,
CA
94010.
A
double-blind,
randomized
study
was
conducted
to
determine
the
effect
of
a
novel
zinc
and
magnesium
formulation
(ZMA)
on
anabolic
hormone
levels
and
strength
in
athletes.
Members
of
the
University
football
team
(n=27)
had
blood
collected
at
the
beginning
and
end
of
an
8
week
period
of
intensive
training.
Subjects
were
supplemented
with
ZMA
(n=12)
or
placebo
(n=15)
for
the
8
weeks.
The
ZMA
group
took
3
capsules
nightly
that
contained
a
total
of
30
mg
of
ZN
as
monomethionine/aspartate,
450
mg
of
Mg
as
aspartate
and
10.5
mg
of
vitamin
B-6.
The
plasma
Zn
and
Mg
levels
increased
in
the
ZMA
group
by
29.1%
(.804
to
1.038
mcg/ml)
and
6.2%
(19.43
to
20.63
mcg/ml),
respectively,
while
levels
decreased
in
the
placebo
group
by
4.4%
(.836
to
.799
mcg/ml)
and
9.2%
(19.68
to
18.04
mcg/ml),
respectively.
The
total
and
free
testosterone
levels
in
serum
increased
in
the
ZMA
group
by
32.4%
(567.9
to
752.7
ng/dl)
and
33.5%
(132.1
to
176.3
pg/mL),
respectively,
in
contrast
to
the
placebo
group
which
decreased
by
10.5%
(588.8
to
526.8
ng/dL)
and
10.2%
(141.0
to
126.6
pg/mL),
respectively.
The
serum,
IGF-1
levels
increased
in
the
ZMA
group
by
3.6%
(424.2
to
439.3
ng/mL)
and
decreased
in
the
placebo
group
by
21.5%
(437.3
to
343.3
g/mL).
All
comparisons
were
statistically
significant
(P<0.001).
Pre
and
post
isokenetic
strength
determinations
in
newton
meters
were
made
using
a
Biodex
dynamometer.
Subjects
(ZMA
n=10;
placebo
n=11)
were
measured
for
maximum
quadricep
strength
on
the
right
leg
at
180
degrees
per
sec
(strength)
and
300
degrees
per
second
(functional
power).
The
ZMA
strength
group
change
at
180
degrees
per
second
was
11.6%
(189.9
to
211.8)
compared
to
the
placebo
group
change
of
+44.6%
(204.2
to
209.1)
and
the
ZMA
group
change
at
300
degrees
per
sec.
was
+18.2%
(316.5
to
373.7),
in
contrast
to
the
+9.4%
(369.5
to
404.3)
for
the
placebo
group
(P<0.05).
These
findings
suggest
that
nightly
supplementation
with
ZMA
significantly
increases
Zn
and
Mg
levels,
anabolic
hormone
levels
as
well
as
strength
and
power
in
athletes.
Sports
Medicine,
Training
and
Rehabilitation
Journal,
November
1998
(in
press)
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