Why Does Weight Training Work for Women
Varying weight training intensity increases growth hormone
who undertake a long-term weight training program produce
more biologically active growth hormone, a finding that
allows physiologists to understand why weight training
improves muscle tone and optimizes metabolic function.
A study published in the December issue of the American
Journal of Physiology-Endocrinology and Metabolism looked at
different forms of growth hormone, used different testing
methods, and varied weight training regimens. The research
found that the role of growth hormone in women's muscle
development may be more complicated than previously thought.
"We found that growth hormone was responsive to moderate and
heavy exercise regimens having 3-12 repetitions with varying
weight loading," said the study's principal author, William
J. Kraemer. "Women need to have heavy loading cycle or
workout in their resistance training routines, as it helps
to build muscle and bone."
The researchers made these findings:
The presence of growth hormone varied with the training
The presence of growth hormone varied with the test used
to detect it. This suggests that pituitary function and
the release of different sizes of growth hormone is
altered with weight training.
The body can adapt and produce more or less of certain
sizes of growth hormone with weight training. In this
study, the larger sized growth hormone variants appear
to increase with heavy resistance training.
"This study shows that not every form of growth hormone
responds in the same way, but is dependent upon the exercise
protocol," Kraemer explained. "This may forever change the
way we look at growth hormone in the circulation with
exercise and training."
This study was supported by a grant from the US Department
of Defense Women's Health Initiative.
Note: This story has been adapted from a news release issued
by American Physiological Society.