Re: Factors Affecting the Length of the Rest Interval

[Guest guest]

>

> My question is can you have the best of both worlds by doing

contrasting

> exercise pairings (ie. Bench & Rows). If you do a set of bench,

rest 60

> seconds, set of rows, rest 60 s, set of bench, etc. Will you still

get

> the acute growth hormone response from the shorter rest periods by

> alternating exercises or does it have to be the same exercise

> stimulating the same fibers with a short rest period to get this

> response? If not, than you sacrifice the gh response for a strength

> training rest period that maximizes recruitment, correct?

Do read the following:

Varying Weight Training Intensity Increases Growth Hormone In Women

http://www.the-aps.org/press/journal/06/25.htm

Possible explanation for changes in muscle tone and metabolic

function found

BETHESDA, Md (Dec. 1, 2006) – Women 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, 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 study, " Chronic resistance training in women potentiates growth

hormone in vivo bioactivity: characterization of molecular mass

variants, " was carried out by Kraemer, Jeff S. Volek, Barry A.

Spiering and Carl M. Maresh of the University of Connecticut, Storrs;

Bradley C. Nindl, U.S Army Research Institute of Environmental

Medicine, Natick, Mass.; O. Marx, The University of

Pennsylvania, Philadelphia; Lincoln A. Gotshalk, University of Hawaii

at Hilo; Jill A. Bush, University of Houston, Texas; and Jill R.

Welsch, M. Mastro and Wesley C. Hymer, The Pennsylvania State

University, University Park, Penn. The The American Physiological

Society published the study.

Hormone comes in different forms

Growth hormone, produced in the pituitary, plays an important role in

bone and muscle development, particularly in women. Men, on the other

hand, rely to a greater extent on muscle-building testosterone. Since

women rely on growth hormone to increase muscle and bone strength,

the more growth hormone stimulated by a type of exercise, the better

its outcome. Growth hormone also plays a role in fighting tissue

breakdown, staving off stress fractures and improving metabolic

function.

The growth hormone molecule is composed of 191 amino acids, but

sometimes the molecules break apart to form smaller pieces. Other

times these smaller pieces join together into larger pieces,

including pieces that are larger than the original molecule. In

addition, growth hormone can attach to binding proteins. It has been

shown that there are more than 100 variants of the growth hormone

molecule.

This study looked at growth hormone variants using two different

tests that measured an immune response, known as immunoassays.

Immunoassays are the tests physiologists have traditionally used in

such studies. The researchers added a third test, the tibia line rat

growth assay, to detect the biological action of the hormones, a

novel approach to the study of growth hormones in exercise.

Type of growth hormone varies with exercise

The researchers divided the participants into two groups: an upper

body training group and a total body training group. The two groups

were then subdivided: Half used heavier weights with fewer

repetitions (up to eight) while the other half used lighter weights

with a greater number of repetitions (up to 12).

The researchers took blood samples before and after the initial

training (acute exercise) session that all participants did as the

start of the study. They also obtained blood samples before and after

the final training session 24 weeks later (chronic exercise). One of

the unique aspects of the study was that it continued over a

relatively long time.

The researchers made these findings:

· The presence of growth hormone varied with the training regimen.

· 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. "

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Carruthers

Wakefield, UK