Growth hormone, produced in the pituitary, plays an important role in bone and muscle development in women, while men rely more on testosterone, according to background information in the study.

Researchers at the University of Connecticut and elsewhere conducted the study, which is published in the December issue of the American Journal of Physiology-Endocrinology and Metabolism.

Growth hormone also plays a role in fighting tissue breakdown, improving metabolic function and staving off stress fractures.

In this study, researchers compared different weight-training regimens and different testing methods and concluded that the role of growth hormone in women's muscle development may be more complicated than previously believed.

"We found that growth hormone was responsive to moderate and heavy exercise regimens having 3 to 12 repetitions with varying weight loading," principal author William J. Kraemer, of the University of Connecticut, said in a prepared statement.

"Women need to have heavy loading cycle or workout in their resistance training routines, as it helps to build muscle and bone," he said.