April 03, 2009

Muscle Mass Won't Grow in Women Over 80

FRIDAY, April 3 (HealthDay News) -- Weight training did not build muscle mass in octogenarian women but still helped them lift more weight than before, a small study conducted by Ball State University in Indiana finds.

The six women in their 80s worked out three times a week for three months on a machine designed to strengthen the thigh's quadriceps muscle. MRIs done before and after the program showed no increase in thigh muscle mass, and muscle biopsies showed no changes at the cellular level, even though the women could lift 26 percent more weight at the end of the program than at the start.

The researchers believe the increase in the amount of weight the women could lift came from the boost training gives to the nervous system as it activates and synchronizes muscles.

The researchers had similar results in a previous study with octogenarian men, although yet another study with 70-year-old women doing resistance training resulted in the participants increasing muscle mass by 5 percent.

"The message of the study is that exercise is good for octogenarians, just not as good as we thought it would be. We should do all we can to educate people to build up the muscle before 80," Ball State researcher Scott Trappe said in a news release issued by the American Physiological Society, which published the study in the Journal of Applied Physiology.

Good muscle strength helps older people avoid the potentially fatal trips and falls they are more prone to. Muscle atrophy can often occur in the elderly if they spend longer periods of time immobile due to illness or sedentary lifestyles.

Trappe's team noted that the muscle fibers of the octogenarian women, while fewer in number, were large and healthy looking, and contained much higher levels of the genes linked to muscle growth than young people. This may mean that, by age 80, a muscle has reached its operating capacity.

More information

The U.S. National Institute on Aging has more about falls and fractures.

-- Kevin McKeever
SOURCE: American Physiological Society, news release, March 31, 2009
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